Academic literature on the topic 'Seedling stands'
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Journal articles on the topic "Seedling stands"
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Groninger, J. W., J. R. Seiler, S. M. Zedaker, and P. C. Berrang. "Photosynthetic response of loblolly pine and sweetgum seedling stands to elevated carbon dioxide, water stress, and nitrogen level." Canadian Journal of Forest Research 26, no. 1 (1996): 95–102. http://dx.doi.org/10.1139/x26-010.
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Seedling stands of loblolly pine (Pinustaeda L.) and sweetgum (Liquidambarstyraciflua L.) were grown in monoculture or mixed stands for two growing cycles in controlled-environment chambers. Treatments consisted of ambient (408 ppm) and elevated (806 ppm) CO2, concentrations, water-stressed and well-watered conditions, and low (20 kg N/ha) and high (215 kg N/ha) nitrogen application rates. Photosynthesis rates were measured under ambient and elevated cuvette CO2 concentrations for both whole stands and individual seedlings from these stands. Significant interactions between CO2 and water suggested that elevated CO2 concentration compensated for low water availability in individually measured loblolly pine and in whole seedling stands regardless of stand type. Expressing photosynthesis on a soil area versus a leaf-mass basis influenced the photosynthetic rankings of the three stand types relative to one another. Net photosynthetic rates per unit leaf mass were 390 and 880% higher in individually measured seedlings than in whole monoculture stands for loblolly pine and sweetgum, respectively. Lower photosynthetic contributions from lower canopy leaves in whole seedling stands compared with the upper canopy leaves used in individual-seedling measurements were thought to be responsible for lower photosynthetic rates in seedling stands. These results suggest that photosynthetic response is influenced by canopy dynamics that are unaccounted for by individual-seedling measurements of photosynthesis. Differences in photosynthetic response between loblolly pine and sweetgum stands and individuals are thought to be largely due to species-specific differences in canopy light extinction characteristics.
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Tuskan, G. A., K. E. Francis, S. L. Russ, W. H. Romme, and M. G. Turner. "RAPD markers reveal diversity within and among clonal and seedling stands of aspen in Yellowstone National Park, U.S.A." Canadian Journal of Forest Research 26, no. 12 (1996): 2088–98. http://dx.doi.org/10.1139/x26-237.
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Fire in 1988 created a situation that allowed a rare aspen seedling recruitment event to occur within Yellowstone National Park. Through the use of (i) 194 randomly amplified polymorphic DNA (RAPD) markers from 14 select primers, (ii) measures of population diversity, and (iii) neighbor-joining analysis it was determined that the postfire aspen seedling population contains greater diversity within each of the four sampled stands than that found within all of the 10 sampled mature aspen stands that pre-existed the fire. Unlike previous studies, a large portion of the molecular variation in both the seedling and mature populations was partitioned among stands. Furthermore, variation was unexpectedly detected among ramets within each mature stand. The mature stands appear to be clonally derived, yet individual ramets within stands varied slightly and incrementally in their RAPD profile. These data suggest that somatic mutations may be occurring and accumulating in clonal aspen stands. A proposed scenario of stand establishment and development involving the accumulation of somatic mutations and elimination of genetically related seedlings arising from a rare founder event provides the theoretical basis for the observed differences among and within seedling and mature stands of aspen in Yellowstone National Park.
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Schultheis, Jonathan R., Daniel J. Cantliffe, Herbert H. Bryan, and Peter J. Stoffella. "Improvement of Plant Establishment in Bell Pepper with a Gel Mix Planting Medium." Journal of the American Society for Horticultural Science 113, no. 4 (1988): 546–52. http://dx.doi.org/10.21273/jashs.113.4.546.
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Abstract Germinated pepper (Capsicum annuum L.) seeds were combined with plug-mix, or plug-mix and Liquagel or Laponite 445 gel at various concentrations and volumes of solution to determine their effects on plant stands and seedling growth. Treatments with pregerminated seed led to earlier, more uniform seedling emergence and larger seedlings than those with non-pregerminated seeds. Final plant stands were similar for both treatments. Plant stands and seedling growth were greater and more uniform with Liqua-gel gel mix formulations than Laponite. Seeds in planting mixes with high concentrations of Laponite (2.0% by volume) and large volumes of gel solution (1.75 liter per liter of plug-mix) in dry and moist soils emerged slower and resulted in lower and less uniform stands than the plug-mix treatments. The optimum gel mix medium for plant establishment (rate and total emergence, stand uniformity, and early seedling growth) consisted of 1.0 liter of plug-mix per 1.25 liters of gel solution at a Liqua-gel concentration of 1.0%.
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Fried, Jeremy S., John C. Tappeiner II, and David E. Hibbs. "Bigleaf maple seedling establishment and early growth in Douglas-fir forests." Canadian Journal of Forest Research 18, no. 10 (1988): 1226–33. http://dx.doi.org/10.1139/x88-189.
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Survival, age and height distributions, and stocking of bigleaf maple (Acermacrophyllum Pursh) seedlings were studied in 1- to 250-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in western Oregon to identify the stages in stand development in which bigleaf maple is most likely to establish successfully from seed. Maple seedling emergence averaged 30–40% where seeds were planted and protected from rodents but was typically <2% for unprotected seeds. Seedling survival after 2 years was highly dependent on canopy density, measured by percent sky. Average 1st-year survival of seedlings originating from planted, protected seeds was highest in clearcuts (1–2 years old, 36% survival, 56% sky) and pole-size stands (41–80 years old, 30% survival, 17% sky) with sparse understories and canopies. It was lowest in young stands with dense canopies (20–40 years old, 4% survival, 8% sky) and old stands (81–250 years old, 14% survival, 13% sky) with dense understories. Naturally regenerated populations of bigleaf maple seedlings, which occurred in aggregations (0.005–0.04 ha in area), were most abundant (up to 10 000/ha) in pole-size Douglas-fir stands. Although seedling size distributions within stands had a strongly inverse J shaped form, size distributions within aggregations appeared more normal (bell-shaped). Seedling age rarely exceeded 15 years. Seedlings grew slowly in the understory, often reaching only 25 cm in height after 8–10 years, and were intensively browsed by deer. Naturally regenerated seedlings were virtually absent from clearcuts, probably because of dense competing vegetation and lack of seed caused by poor dispersal and seed predation. The "window" for the most successful establishment of bigleaf maple seedlings appears to begin after canopy thinning and end before forbs and shrubs invade.
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Kim, Choonsig, Terry L. Sharik, Martin F. Jurgensen, David S. Buckley, and Richard E. Dickson. "Effects of nitrogen availability on northern red oak seedling growth in oak and pine stands in northern Lower Michigan." Canadian Journal of Forest Research 26, no. 6 (1996): 1103–11. http://dx.doi.org/10.1139/x26-122.
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The nitrogen (N) status and dry weight increment of northern red oak (Quercusrubra L.) seedlings in relation to N availability were examined at various levels of canopy cover and understory removal treatments under field conditions in red oak and red pine (Pinusresinosa Ait.) stands. Net N mineralization rates over two growing seasons following canopy cover treatments were determined by the in situ buried bag technique. Canopy removal increased N mineralization in both oak and pine stands. Net N mineralization rates were ≈1.2–2.2 times higher in the clearcut and the other partial canopy cover treatments than in the uncut stands. Net N mineralization in the same canopy cover treatments was ≈2–3 times higher in red oak stands than in red pine stands. However, red oak seedlings from the same canopy cover treatments in both stand types had similar dry weight, N concentrations, N content, and N-use efficiency despite differences in soil N availability. The only exception was ≈2 times greater seedling dry weight and N content in the red oak clearcuts compared with the red pine clearcuts. The similarity in seedling performance within partial canopy removal or uncut stands may have been due to limiting factors other than N in the red oak stands. Red oak seedlings from litter removal treatments within the clearcuts had significantly higher N-use efficiency than those from the herb and shrub removal treatments. These results suggest that (i) canopy manipulation increases soil N availability; (ii) increases in dry weight and N uptake by red oak seedlings when forest canopies are completely removed are due, in part, to increased available soil N; (iii) red oak seedling response to soil N availability resulting from no or only partial canopy removal may be the same in different stand types (e.g., red oak vs. red pine) because factors other than N, such as light, are limiting.
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Valverde-Barrantes, OJ, JA Hogan, and OJ Rocha. "EFFECTS OF CANOPY OPENNESS ON SEEDLING SURVIVAL AND GROWTH AFTER SELECTIVE LOGGING IN A MONODOMINANT LOWLAND SWAMP FOREST IN COSTA RICA." JOURNAL OF TROPICAL FOREST SCIENCE 34, no. 1 (2022): 34–47. http://dx.doi.org/10.26525/jtfs2022.34.1.34.
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The mechanism proposed to explain tree monodominance in tropical forests is that the dominant species forms a dense canopy and produces shade-tolerant seedlings, which together favor selfreplacement. Under this hypothesis, seedlings of monodominant species should have limited ability to respond to drastic increases in understory light, like those resulting from logging. Therefore, monodominant species should lose their seedling dominance after logging-induced canopy opening. To test this hypothesis, the current study measured seedling survival and growth of the monodominant species, Prioria copaifera, and its main competitor, Pentaclethra macroloba, in two forest stands that differ in logging history and in an unlogged stand in southeastern Costa Rica. Although, growth rates and survival of previously established seedlings were similar for both species across the three stands, seedling survival and growth decreased as light increased, with the effect being more pronounced for Prioria than for Pentaclethra. The study also investigated the ability of Prioria to respond to changing light environments by transplanting seedlings into logging-induced canopy gaps. Contrary to prediction, Prioria seedlings survived and grew better in gap centers than in gap edges or under a closed canopy. This result contrasts with established seedlings that cannot acclimate to changes in light conditions. Therefore, we conclude that continued Prioria dominance in selectively logged forests depends more on seedling production after canopy disturbance than on the established seedling present before disturbances.
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Park, Byung Bae, Youngtak Ko, Jonathan O. Hernandez, Ser-Oddamba Byambadorj, and Si Ho Han. "Growth of Deciduous and Evergreen Species in Two Contrasting Temperate Forest Stands in Korea: An Intersite Experiment." Plants 11, no. 7 (2022): 841. http://dx.doi.org/10.3390/plants11070841.
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Poor seedling establishment and growth can be a result of the limitation of light and soil resources in the forest understory. Here, we investigate the interacting effects of stand and soil characteristics on the seedling growth of deciduous species (Fraxinus rhynchophylla and Zelkova serrata) and evergreen species (Pinus koraiensis) through a 3-year intersite experiment in two contrasting forest stands. Seedlings were grown in both oak and pine stands using two different soil types, i.e., gray-brown forest soil (GB) and red-yellow forest soil (RY). Soil physicochemical properties, light intensity, tree-seedling height, root-collar diameter (RCD), and biomass growth were analyzed between two stands and/or soil types. Light availability was generally more abundant in the pine stand (mean: 1074.08 lx or 20.25%) than the oak stand (mean: 424.33 lx or 9.20%) throughout the year. The height and RCD growth of fast-growing and deciduous F. rhynchophylla and Z. serrata were higher in the pine than in the oak stand, particularly in GB soil. The growth of the slow-growing and evergreen P. koraiensis was not affected by the forest stand, except for its higher root growth in the oak stand and RY soil. Therefore, abundant light availability can enhance the growth and seedling establishment of F. rhynchophylla and Z. serrata in the pine-stand understory. Contrarily, P. koraiensis may be planted in the understory regardless of light condition, but with a slower growth rate.
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Bank, S. K., P. Rao, R. S. Tripathi, and H. N. Pandey. "Dynamics of tree seedling populations in a humid subtropical forest of northeast India as related to disturbance." Canadian Journal of Forest Research 26, no. 4 (1996): 584–89. http://dx.doi.org/10.1139/x26-067.
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Recruitment and survival of four important broad-leaved tree species, viz Quercusdealbata L., Quercusgriffithii Hk., Rhododendronarboreum Sm., and Schimakhasiana Dyer., were studied over 2 years in the undisturbed, mildly disturbed and highly disturbed forest stands of a subtropical humid forest of Meghalaya, northeast India. Recruitment of S. khasiana seedlings was maximum in the highly disturbed stand, while Q. dealbata seedlings were abundant in the undisturbed and mildly disturbed stands. Seedlings of Q. dealbata, Q. griffithii, and R. arboreum were equally successful in all the stands, while S. khasiana seedlings showed better survival in the highly disturbed stand than in the mildly disturbed and undisturbed stands. Six microenvironmental factors, viz photosynthetically active radiation, relative humidity, air temperature, soil temperature, soil moisture, and thickness of litter on the forest floor, were correlated with the age-specific mortality rate of seedlings. In Q. dealbata, Q. griffithii, and S. khasiana, mortality rate was significantly affected by microenvironmental factors, while in R. arboreum mortality was not correlated with any of the microenvironmental factors. On the basis of seedling recruitment and survival pattern, it was concluded that Q. dealbata, Q. griffithii, and R. arboreum were successful in both disturbed and undisturbed forest stands, while S. khasiana seedlings showed better survival and establishment in the disturbed stands.
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Kneeshaw, Daniel D., and Yves Bergeron. "Ecological factors affecting the abondance of advance regeneration in Quebec's southwestern boreal forest." Canadian Journal of Forest Research 26, no. 5 (1996): 888–98. http://dx.doi.org/10.1139/x26-097.
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Boreal forest disturbance regimes have changed during the past century, in turn changing regeneration and stand dynamics of these forests. This is occurring at the same time that the forest industry is emphasizing operations that take advantage of pre-established natural regeneration. This study has therefore investigated the effect of various ecological factors on the abundance of Abiesbalsamea (L.) Mill., Piceaglauca (Moench) Voss, Piceamariana (Mill.) BSP, Thujaoccidentalis L., Betulapapyrifera Marsh., and Populustremuloides Michx. natural regeneration in some boreal stands in the Abitibi region of Quebec. Abiotic ecological site classification variables were found to be poorly correlated with seedling densities for most species. Parent trees, as a seed source, and stand type, for its influence on the quality of the seedbed, were strongly correlated with abundant conifer regeneration. As expected, time since fire was positively correlated with seedling abundance for late successional species, whereas it was not related to the abundance of early successional species. Post-fire disturbances, such as those due to spruce budworm (Choristoneurafumiferana (Clem.)) outbreaks, accounted for the variations in seedling densities observed with respect to stand age. The presence of budworm-caused gaps was positively correlated with regeneration abundance, whereas shrub competition, which was greatest in large gaps, was negatively correlated with advance regeneration density. Forest management based on abundance of pre-established regeneration should focus mainly on mixed stands because seedling density is very low in hardwood stands and because of the strong competition found in large gaps of resinous forests. The low number of seedlings observed, especially in coniferous stands, may limit the effectiveness of operations that take advantage of advance regeneration. The large variability observed among site and stand types limits their operational use in predicting seedling densities.
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Zhou, Minyi, Terry L. Sharik, Martin F. Jurgensen, Dana L. Richter, Margaret R. Gale, and Thomas D. Drummer. "Regeneration of Northern Red Oak in Relation to Ectomycorrhizae in Oak and Pine Stands after Overstory and Understory Manipulations." Northern Journal of Applied Forestry 15, no. 4 (1998): 182–90. http://dx.doi.org/10.1093/njaf/15.4.182.
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Abstract Growth of northern red oak (Quercus rubra L.) seedlings in relation to colonization by indigenous ectomycorrhizal (ECM) fungi was studied in oak and pine stands in northern Lower Michigan that were subjected to overstory and understory manipulations. Two stand types (oak and pine), three blocks of each stand type, four canopy cover treatments (clearcut, 25% cover (50% cover in the first year), 75% cover and uncut), and two understory treatments (shrub removal and untreated control) were involved in the experiment. Northern red oak acorns from a common seed source were sown in May 1991 to simulate natural regeneration. Seedling growth and its relation to percent ECM were evaluated for the first two growing seasons. A significantly larger root-collar diameter of northern red oak seedlings was found in pine stands than in oak stands for the first growing season (P < 0.001). However, this difference could not be explained by overall ECM colonization. Seedling growth and ECM colonization were not affected by the shrub removal treatment during the first two growing seasons. In contrast, northern red oak seedling size and weight were strongly influenced by the overstory treatment, with lower levels of canopy cover resulting in larger seedlings. Seedlings had the greatest percent ECM in the partial cover treatment (25-50%) and the lowest percent ECM in the clearcut. After accounting for the effects of canopy cover, the relationship between total biomass of northern red oak seedlings and percent ECM was positively correlated (P = 0.001) during the first growing season and negatively correlated (P = 0.038) during the second growing season. A positive relationship between root/shoot ratio and percent ECM also existed in the first year (P = 0.003) in both oak and pine stands, but only in the oak stands in the second year (P = 0.039). These results indicate that ECM promoted more root development than shoot development, particularly underpartial canopy cover (25%-50%) treatments, where the greatest percent ECM and largest root/shoot ratio were found. Moreover, our results suggest that these partial canopy cover treatments provide a favorable balance between ECM abundance and northern red oak seedling development in both oak and pine stands on intermediate quality sites, and may lead to northern red oak regeneration success on such sites. North. J. Appl. For. 15(4):182-190.
Dissertations / Theses on the topic "Seedling stands"
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Holgén, Per. "Seedling performance, shelter tree increment and recreation values in boreal shelterwood stands /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 1999. http://epsilon.slu.se/avh/1999/91-576-5854-4.pdf.
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Groninger, John William. "Stand dynamics and gas exchange in loblolly pine and hardwood seedling stands : impact of elevated carbon dioxide, water stress and nutrient status /." Diss., This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-08272007-163923/.
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Doust, Susan Jillian. "Seed and seedling ecology in the early stages of rainforest restoration /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18410.pdf.
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Bapela, Mahwahwatse Johanna. "Variation of active constituents in Euclea natalensis based on seedling stages, seasons, and fertilizers." Pretoria : [s.n.], 2007. http://upetd.up.ac.za/thesis/available/etd-06262008-095522/.
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Bapela, Mahwahwatse Johanna. "Variation of active constituents in Euclea natalensis based on seedling stages, seasons, and fertilizers." Diss., University of Pretoria, 2008. http://hdl.handle.net/2263/25856.
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Euclea natalensis A.DC. belongs to the Ebenaceae family, and is extensively distributed along the eastern coast of southern Africa. Many Euclea species are widely gathered by indigenous people because of their medicinal properties. Roots of these plant species are frequently used to treat respiratory complications such as chest pains, bronchitis, pleurisy and asthma. Ground root powder is topically applied in cases of leprosy and is used by some ethnic groups to treat toothache and headache. The bioactivity encountered is attributable to naphthoquinones, which are common phenolic compounds in the Ebenaceae family. Naphthoquinones isolated from E. natalensis (shinanolone, 7-methyljuglone, diospyrin, isodiospyrin and neodiospyrin) have exhibited a broad spectrum of antimicrobial activity. The demand for these products will escalate due the amount of plant material required to further research. We need to explore techniques that can maximize their productivity. The present study was conducted on E. natalensis, in an attempt to establish if there exists any correlation between the accumulation of naphthoquinones and stages of seedling growth, seasonal fluctuations and application of fertilizers. A possible correlation between seedling growth stages and the accumulation of naphthoquinones (shinanolone, 7-methyljuglone and diospyrin) was investigated in seeds and seedlings of Euclea natalensis. In this study, the seeds represented the first stage, whereas the second seedling stage was defined as the stage when the radicles were about 6 cm long. The lengths of the seedlings at the third, fourth and fifth seedling stages were 9 cm, 12 cm and 16 cm respectively. Plant materials collected from the five seedling stages were separately extracted using chloroform and the naphthoquinones were then quantified by means of High Performance Liquid Chromatography (HPLC). Mobile phase of MeCN: H2O: AcOH (62.5: 32.5: 5) was used as an eluent in an isocratic mode and at a flow rate of 0.8 ml/min. Standard curves of each of the four compounds were obtained by making a series of dilutions in the concentration range of 22.5 µg/ml to 2.25 µg/ml. Ten microlitres of each dilution was injected three times into the HPLC, and the run time for each injection was 20 minutes. Calibration curves were then generated and used for the quantification of each compound. Shinanolone, which was the only naphthoquinone detectible in seeds, accumulated at variable rates (P<0.01) and no trend could be established between its synthesis and seedling growth. The content of shinanolone ranged from 87.5 mg/kg dry weight (dw) in seeds to a high mean value of 1047 mg/kg (dw) during the fourth seedling stage. A significant correlation (P<0.01) was found between the mean concentrations of 7-methyljuglone and seedling growth. 7-Methyljuglone was quantified at a high mean level of 5003 mg/kg during the third seedling stage and was not detected in the seed samples. A positive correlation (P<0.01) was established between the concentration of diospyrin and seedling stages. Diospyrin was detected at an elevated mean concentration of 6182 mg/kg during the fifth seedling stage, which was higher than the other quantified naphthoquinones. Seasonal variation of naphthoquinones (shinanolone, 7-methyljuglone, diospyrin, isodiospyrin and neodiospyrin) was investigated from eleven plants of E. natalensis subsp. natalensis growing in natural populations, over a period of four seasons. The roots were harvested, dried, extracted and analysed as in the previous study. The mean levels of shinanolone and 7-methyljuglone were found to be uniform in all the seasons and no statistically significant variation could be found between seasonal changes and their mean concentrations. Accumulation of isodiospyrin and neodiospyrin varied significantly with seasonal changes (P<0.05). These two bioactive naphthoquinones were detected only in summer and autumn respectively, and not in winter. A statistically significant variation (P<0.05) was established between the levels of diospyrin and seasonal fluctuations. Diospyrin was detected at a mean concentration of 3190 mg/kg (dw) during spring, which was higher than the other naphthoquinones quantified in all four seasons. The effect of NPK fertilizers on growth performance and accumulation of naphthoquinones (shinanolone, 7-methyljuglone, diospyrin, isodiospyrin and neodiospyrin) in seedlings of E. natalensis grown in shade and under field conditions was investigated. Each group was subdivided into four subgroups, which were then subjected to four respective treatments of water-soluble foliar feed (2:1:2 (44) NPK) at three different concentrations. Treatments tested were as follows: Treatment 1 at 40 g/l, Treatment 2 and Treatment 3 at 20 g/l and 10 g/l respectively. The control group received only supplemental water. The first harvest was conducted after 6 months of application of fertilizers and the second one was done after 12 months of treatment. Roots and shoots were harvested and analysed separately. The naphthoquinones were quantified as previously described. The bioactivity of root extracts from seedlings was tested against Mycobacterium smegmatis and extracts with lower MIC were further tested on M. tuberculosis. Growth parameters differed between the two groups, with seedlings from the shadehouse showing more plant vigour than the field grown plants. No significant interaction could be established between the measured growth factors and treatment. A significant interaction (P<0.001) was found between Treatment 2 and shadehouse seedlings. Treatment 2 enhanced vegetative performance with the mean values of fresh weight of shoots and roots being twice as much as their respective control mean values. A significantly positive correlation was established between the concentration of shinanolone (P<0.01), isodiospyrin (P<0.05) and neodiospyrin (P<0.05) with fertilization from field-grown seedlings. Application of NPK fertilizers significantly (P<0.05) increased the accumulation of neodiospyrin in seedlings subjected to shadehouse conditions. The most potent naphthoquinone, 7-methyljuglone, was found to be abundant in all the extracts and was quantified at a high mean concentration of 10200 mg/kg from shadehouse seedlings. Root extracts of E. natalensis seedlings grown under field conditions were generally more active against the bacterial strain of M. smegmatis as compared to extracts acquired from roots of seedlings maintained under a shadehouse setting. A lowest minimum inhibitory concentration (MIC) of 0.78mg/ml against M. smegmatis was observed from the second harvest of field-cultivated seedlings of the control and Treatment 1 subgroups. The MIC values for shadehouse seedlings ranged from 1.6 to 6.3 mg/ml. Minimum bactericidal concentration (MBC) values from all the extracts tested were relatively higher than their respective MIC’s. Root extracts of E. natalensis were more active against M. tuberculosis and their MIC values were lower than the tested concentrations. Extracts acquired from field-grown seedlings were more active against M. smegmatis with a lowest MIC value of 0.78 mg/ml. Extracts from the control group and Treatment 1, which had less application of fertilizers were more active against strains of M. tuberculosis with MIC value of 10 µg/ml. This shows the selectivity of E. natalensis against the mycobacterial strain of M. tuberculosis. Based on the findings, synthesis and accumulation of naphthoquinones in E. natalensis is highly variable within individuals of the species investigated. Naphthoquinones accumulate in relatively higher amounts in roots of E. natalensis than in the aboveground structures, which validate their harvest by indigenous people. The concentration of shinanolone varied slightly and its production increased with seedling growth. The synthesis of 7-methyljuglone is independent of fertilisation as its accumulation was enhanced in seedlings subjected to control treatment. Neodiospyrin and isodiospyrin were always present in every sample obtained from the seedlings but they were not detectible in every profile of samples from mature plants. Diospyrin is the only naphthoquinone that was detected in every sample analysed and also quantified in high concentrations from mature plants harvested in spring. The study showed that depending on the requirement of a particular naphthoquinone for research, one could target the seasons and seedling stages recommended from this study. This study also showed that field-cultivated seedlings produced more potent naphthoquinones than the ones subjected to controlled environments.<br>Dissertation (MSc (Plant Science))--University of Pretoria, 2008.<br>Plant Production and Soil Science<br>unrestricted
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Socolowski, Fabio. "Ecologia germinativa, relações alométricas e o efeito da massa das sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae) sobre a emergência e desenvolvimento das plântulas /." Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/100667.
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Orientador: Massanori Takaki<br>Banca: João Domingos Rodrigues<br>Banca: Silvio Moure Cícero<br>Banca: José Marcos Barbosa<br>Banca: Márcia Balistiero Figliolia<br>Resumo: Este estudo teve como objetivo avaliar a relação entre a massa e características morfométricas de frutos e sementes de Tecoma stans, bem como relacionar a massa das sementes a suas características morfológicas, utilizando paquímetro e imagens de raios X, e fisiológicas, através da germinação, emergência e desenvolvimento inicial de suas plântulas, sob duas condições de luminosidade . a pleno sol e sombra. Além disso, também foram avaliados os efeitos de diferentes condições de temperatura e luz constantes, em laboratório, e em ambiente natural no sol e na sombra na germinação e emergência das plântulas. A massa dos frutos apresentou relações lineares significativas e positivas com suas características morfológicas e de produção de sementes. As relações entre a massa das sementes e suas características morfológicas foram positivas e significativas, porém na forma de uma função potência, sendo esta relação mais evidente com a largura do embrião. A massa das sementes também esteve relacionada a determinadas anomalias do desenvolvimento embrionário, observadas nas imagens de raios X. A germinação, a emergência e o desenvolvimento inicial das plântulas foram significativamente afetados pela massa das sementes, porém somente durante os três primeiros meses de desenvolvimento no ambiente de sol. A temperatura apresentou efeito na germinação e suas sementes germinaram tanto na luz quanto no escuro, contudo a emergência e sobrevivência das plântulas no ambiente de sol foi superior em relação ao observado na sombra.<br>Abstract: This study had the objective to evaluate the relationship between the mass and the morphometric characteristics of Tecoma stans fruits and seeds, as well as to relate the seed mass with its morphometric characteristics, utilizing caliper and X-ray images, and physiological characteristics, thought germination, emergency and seedlings initial development, under two conditions of light - at the sun and shade. More than, also were evaluated the effects of different conditions of constant temperature and light, under laboratory, and natural environment under sun and shade in the germination and emergency of the seedlings. The fruit mass presented positive, significative linear relationship with his morphological characteristics and with its seed production characteristics. The relationship between seed mass and its morphological characteristics were positive and significative, nevertheless with the model (shape) of power function, being the relationship more clear with the embryo width. The seed mass also was related to determinate anomalies of the embryo development that could be observed in the X-ray images. The germination, the seedling emergence and the initial seedling development were significative affected by seed mass, but only in the firth three months of development at the sun environment. The temperature affected Tecoma stans seed germination in both light and darkness environment, however the seedlings emergency and survival was greater at the sun environment than shade.<br>Doutor
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Dugo, Tesfaye Letta <1976>. "Association mapping of stem rust resistance in durum wheat at the seedling and adult plant stages." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5935/1/Dugo_Tesfaye_tesi.pdf.
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In wheat, stem rust is known to rapidly evolve new virulence to resistance genes. While more than 50 stem rust resistance (Sr) loci have been identified in wheat, only a few remain effective, particularly against the highly virulent race Ug99 (TTKSK race) and a mixture of durum-specific races. An association mapping (AM) study based on 183 durum wheat accessions was utilized to identify resistance loci for stem rust response in Ethiopia over four seasons and artificial inoculation with Ug99 (TTKSK race) and a mixture of durum-specific races under field conditions as well as in greenhouse test at seedling stage under controlled conditions for resistance to four highly virulent stem rust races: TRTTF, TTTTF, (TTKSK (Ug99) and JRCQC. The panel was profiled with 1,253 SSR and DArT markers. Twelve QTL-tagging markers were significant (P < 0.05) across three to four seasons. The role of Sr13, Sr9, Sr14, Sr17, and Sr28 was confirmed. Thirteen significant markers were in regions with no Sr genes/QTLs.
The results under controlled conditions showed that 15, 20, 19 and 19 chromosome regions harbored markers that showed significant effects for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. These genomic regions showed marker R2 values ranging from 1.13 to 8.34, 1.92 to 17.64, 1.75 to 23.12 and 1.51 to 15.33% for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. The study demonstrates that stem rust resistance in durum wheat is governed in part by shared loci and in part by race-specific ones. The QTLs identified in this study through AM will be useful in the marker-assisted development of durum wheat cultivars with durable stem rust resistance.
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Dugo, Tesfaye Letta <1976>. "Association mapping of stem rust resistance in durum wheat at the seedling and adult plant stages." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5935/.
Full textAbstract:
In wheat, stem rust is known to rapidly evolve new virulence to resistance genes. While more than 50 stem rust resistance (Sr) loci have been identified in wheat, only a few remain effective, particularly against the highly virulent race Ug99 (TTKSK race) and a mixture of durum-specific races. An association mapping (AM) study based on 183 durum wheat accessions was utilized to identify resistance loci for stem rust response in Ethiopia over four seasons and artificial inoculation with Ug99 (TTKSK race) and a mixture of durum-specific races under field conditions as well as in greenhouse test at seedling stage under controlled conditions for resistance to four highly virulent stem rust races: TRTTF, TTTTF, (TTKSK (Ug99) and JRCQC. The panel was profiled with 1,253 SSR and DArT markers. Twelve QTL-tagging markers were significant (P < 0.05) across three to four seasons. The role of Sr13, Sr9, Sr14, Sr17, and Sr28 was confirmed. Thirteen significant markers were in regions with no Sr genes/QTLs.
The results under controlled conditions showed that 15, 20, 19 and 19 chromosome regions harbored markers that showed significant effects for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. These genomic regions showed marker R2 values ranging from 1.13 to 8.34, 1.92 to 17.64, 1.75 to 23.12 and 1.51 to 15.33% for races TRTTF, TTTTF, TTKSK and JRCQC, respectively. The study demonstrates that stem rust resistance in durum wheat is governed in part by shared loci and in part by race-specific ones. The QTLs identified in this study through AM will be useful in the marker-assisted development of durum wheat cultivars with durable stem rust resistance.
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Socolowski, Fabio [UNESP]. "Ecologia germinativa, relações alométricas e o efeito da massa das sementes de Tecoma stans L. Juss. ex Kunth (Bignoniaceae) sobre a emergência e desenvolvimento das plântulas." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/100667.
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socolowski_f_dr_rcla.pdf: 774673 bytes, checksum: 524e3b5dcb3693c8da59453eb583ea90 (MD5)<br>Este estudo teve como objetivo avaliar a relação entre a massa e características morfométricas de frutos e sementes de Tecoma stans, bem como relacionar a massa das sementes a suas características morfológicas, utilizando paquímetro e imagens de raios X, e fisiológicas, através da germinação, emergência e desenvolvimento inicial de suas plântulas, sob duas condições de luminosidade . a pleno sol e sombra. Além disso, também foram avaliados os efeitos de diferentes condições de temperatura e luz constantes, em laboratório, e em ambiente natural no sol e na sombra na germinação e emergência das plântulas. A massa dos frutos apresentou relações lineares significativas e positivas com suas características morfológicas e de produção de sementes. As relações entre a massa das sementes e suas características morfológicas foram positivas e significativas, porém na forma de uma função potência, sendo esta relação mais evidente com a largura do embrião. A massa das sementes também esteve relacionada a determinadas anomalias do desenvolvimento embrionário, observadas nas imagens de raios X. A germinação, a emergência e o desenvolvimento inicial das plântulas foram significativamente afetados pela massa das sementes, porém somente durante os três primeiros meses de desenvolvimento no ambiente de sol. A temperatura apresentou efeito na germinação e suas sementes germinaram tanto na luz quanto no escuro, contudo a emergência e sobrevivência das plântulas no ambiente de sol foi superior em relação ao observado na sombra.<br>This study had the objective to evaluate the relationship between the mass and the morphometric characteristics of Tecoma stans fruits and seeds, as well as to relate the seed mass with its morphometric characteristics, utilizing caliper and X-ray images, and physiological characteristics, thought germination, emergency and seedlings initial development, under two conditions of light - at the sun and shade. More than, also were evaluated the effects of different conditions of constant temperature and light, under laboratory, and natural environment under sun and shade in the germination and emergency of the seedlings. The fruit mass presented positive, significative linear relationship with his morphological characteristics and with its seed production characteristics. The relationship between seed mass and its morphological characteristics were positive and significative, nevertheless with the model (shape) of power function, being the relationship more clear with the embryo width. The seed mass also was related to determinate anomalies of the embryo development that could be observed in the X-ray images. The germination, the seedling emergence and the initial seedling development were significative affected by seed mass, but only in the firth three months of development at the sun environment. The temperature affected Tecoma stans seed germination in both light and darkness environment, however the seedlings emergency and survival was greater at the sun environment than shade.
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Zhang, Xuemei. "Ecology and Management of Pythium species in Float Greenhouse Tobacco Transplant Production." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/101779.
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Pythium diseases are common in the greenhouse production of tobacco transplants and can cause up to 70% seedling loss in hydroponic (float-bed) greenhouses. However, the symptoms and consequences of Pythium diseases are often variable among these greenhouses. A tobacco transplant greenhouse survey was conducted in 2017 in order to investigate the sources of this variability, especially the composition and distribution of Pythium communities within greenhouses. The survey revealed twelve Pythium species. Approximately 80% of the surveyed greenhouses harbored Pythium in at least one of four sites within the greenhouse, including the center walkway, weeds, but especially bay water and tobacco seedlings. Pythium dissotocum, followed by P. myriotylum, were the most common species. Pythium myriotylum, P. coloratum, and P. dissotocum were aggressive pathogens that suppressed seed germination and caused root rot, stunting, foliar chlorosis, and death of tobacco seedlings. Pythium aristosporum, P. porphyrae, P. torulosum, P. inflatum, P. irregulare, P. catenulatum, and a different isolate of P. dissotocum, were weak pathogens, causing root symptoms without affecting the upper part of tobacco seedlings. Pythium adhaerens, P. attrantheridium, and P. pectinolyticum did not affect tobacco seeds or seedlings. The consequences of Pythium infection were more likely to be severe when they occurred during seed germination than at seedling emergence, or after plant stem elongation when seedling roots had started to grow into underlying nutrient solutions, depending on the species of Pythium. High and low variation was observed among isolates of P. dissotocum and P. myriotylum, respectively. Pythium myriotylum co-existed with multiple other Pythium or oomycete species in the same environments within tobacco greenhouses, and significant in vitro and/or in vivo interactions between P. myriotylum and some naturally co-existing species were revealed. Pythium porphyrae may have the potential to protect tobacco seeds and seedlings from P. myriotylum infection. Greenhouse Pythium control trials identified ethaboxam, mefenoxam, and copper ionization as potentially promising alternatives to etridiazole for Pythium disease management in tobacco transplant production. The outcomes of this project provide useful new information to better understand the composition, distribution, and diversity of Pythium communities in tobacco transplant greenhouses and to improve Pythium disease management for tobacco transplant production.<br>Doctor of Philosophy<br>Pythium diseases are common in tobacco transplant production and can cause up to 70% seedling losses in hydroponic (float-bed) tobacco transplant greenhouses. However, little is known about the composition and distribution of Pythium communities in tobacco transplant greenhouses. This project began with a tobacco transplant greenhouse survey, in which 12 Pythium species were recovered from center walkways, weeds, greenhouse bay water, and tobacco seedlings. Pythium dissotocum and P. myriotylum were the two types (species) of Pythium most commonly found in the survey. Pythium myriotylum, P. coloratum, and P. dissotocum were aggressive pathogens that suppressed seed germination and caused root rot, stunting, foliar chlorosis, and death of tobacco seedlings. Pythium aristosporum, P. porphyrae, P. torulosum, P. inflatum, P. irregulare, P. catenulatum, and an isolate of P. dissotocum, were weak pathogens causing root symptoms without affecting the upper part of tobacco seedlings. Pythium adhaerens, P. attrantheridium, and P. pectinolyticum did not affect tobacco seeds or seedlings. The symptoms caused by infection by Pythium species differed among host (tobacco) growth stages, except for the most aggressive species, P. myriotylum. High levels of variation were observed among isolates of P. dissotocum, in terms of vegetative growth rate (on V8 agar media) and aggressiveness on tobacco seed and seedlings. Pythium myriotylum was found to co-exist with multiple other Pythium or oomycete species (neighbor isolates) in the same environments within tobacco greenhouses. Significant interactions between P. myriotylum and some neighbor isolates were revealed, and these interactions significantly affect the consequences of P. myriotylum infection of tobacco seeds. Greenhouse Pythium control trials identified two chemical water treatments (ethaboxam and mefenoxam), and a non-chemical water treatment (copper ionization) as potentially promising alternatives to the current standard Pythium control (etridiazole) for Pythium disease management in tobacco transplant production. The outcomes of this project provide useful new information to both better understand the composition, distribution, and diversity of Pythium communities in tobacco transplant greenhouses and to improve Pythium disease management for tobacco transplant production.
Books on the topic "Seedling stands"
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Levy, Louise. The density and distribution of Sitka spruce and western hemlock seedling banks in partially harvested stands in Southeast Alaska. U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station, 2010.
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Deal, Robert L. (Robert Leslie), Tappeiner, J. C. (John C.), and Pacific Northwest Research Station (Portland, Or.), eds. The density and distribution of Sitka spruce and western hemlock seedling banks in partially harvested stands in Southeast Alaska. U.S. Dept. of Agriculture, Forest Service, Pacific Northwest Research Station, 2010.
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Gerald, Heath, and United States. Forest Service. Southern Research Station, eds. Underplanting shortleaf pine seedlings beneath a residual hardwood stand in the Ouachita Mountains: Results after seven growing seasons. U.S. Dept. of Agriculture, Forest Service, Southern Research Station, 2001.
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Koch, John M. The use of fire and soil scarification as a means of establishing jarrah (Eucalyptus marginata) seedlings under an existing eucalyptus stand in rehabilitated bauxite mines. s.n, 1992.
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Petersen, Terry D. Dynamics of size structures: Simulation and experiments in seedling stands of Pseudotsuga menziesii and Fraxinus mandshurica. 1989.
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Huffman, David W. Regeneration of salal: Seedling establishment and the effects of overstory stand density on clonal morphology and expansion. 1992.
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Szewczyk, Janusz. Rola zaburzeń w kształtowaniu struktury i dynamiki naturalnych lasów bukowo-jodłowo-świerkowych w Karpatach Zachodnich. Publishing House of the University of Agriculture in Krakow, 2018. http://dx.doi.org/10.15576/978-83-66602-35-9.
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The aim of the study was to determine the influence of different disturbances (both natural and anthropogenic) on species composition and stand structure of old-growth mixed mountain forests in the Western Carpathians. These stands are usually dominated by beech, fir and spruce, mixed in different proportions. The tree main species represent different growth strategies, and they compete against each other. The longevity of trees makes the factors influencing the stand structure difficult to identify, even during longitudinal studies conducted on permanent research plots. That is why dendroecological techniques, based upon the annual variability of tree rings, are commonly used to analyze the disturbance histories of old-growth stands. Dendroecological methods make it possible to reconstruct the stand history over several centuries in the past by analyzing the frequency, intensity, duration and spatial scale of disturbances causing the death of trees. Combining the dendroecological techniques with the detailed measurements of stand structure, snag volume, CWD volume, and the analyses of regeneration species composition and structure allows us to identify the factors responsible for the changes in dynamics of mixed mountain forests. Various disturbance agents affect some species selectively, while some disturbances promote the establishment of tree seedlings of specific species by modifying environmental conditions. Describing the disturbance regime requires a broad scope of data on stand structure, on dead wood and tree regeneration, while various factors affecting all the stages of tree growth should be taken into consideration. On the basis of the already published data from permanent sample plots, combined with the available disturbance history analyses from the Western Carpathians, three research hypotheses were formulated. 1. The species composition of mixed mountain forests has been changing for at least several decades. These directional changes are the consequence of simultaneous conifer species decline and expansion of beech. 2. The observed changes in species composition of mixed mountain forests are the effect of indirect anthropogenic influences, significantly changing tree growth conditions also in the forests that are usually considered natural or near-natural. Cumulative impact of these indirect influences leads to the decrease of fir share in the tree layer (spruce decline has also been observed recently),and it limits the representation of this species among seedlings and saplings. The final effect is the decrease of fir and spruce share in the forest stands. 3. Small disturbances, killing single trees or small groups of trees, and infrequent disturbances of medium size and intensity dominate the disturbance regime in mixed mountain forests. The present structure of beech-fir-spruce forests is shaped both by complex disturbance regime and indirect anthropogenic influences. The data were gathered in permanent sample plots in strictly protected areas of Babia Góra, Gorce, and Tatra National Parks, situated in the Western Carpathians. All plots were located in the old-growth forest stands representing Carpathian beech forest community. The results of the measurements of trees, snags, coarse woody debris (CWD) and tree regeneration were used for detailed description of changes in the species composition and structure of tree stands. Tree ring widths derived from increment cores were used to reconstruct the historical changes in tree growth trends of all main tree species, as well as the stand disturbance history within the past two to three hundred years. The analyses revealed complex disturbance history in all of the three forest stands. Intermediate disturbances of variable intensity occurred, frequently separated by the periods of low tree mortality lasting from several decades up to over one hundred years. The intervals between the disturbances were significantly shorter than the expected length of forest developmental cycle, in commonly used theories describing the dynamics of old-growth stands. During intermediate disturbances up to several dozen percent of canopy trees were killed. There were no signs of stand-replacing disturbances, killing all or nearly all of canopy trees. The periods of intense tree mortality were followed by subsequent periods of increased sapling recruitment. Variability in disturbance intensity is one of the mechanisms promoting the coexistence of beech and conifer species in mixed forests. The recruitment of conifer saplings depended on the presence of larger gaps, resulting from intermediate disturbances, while beech was more successful in the periods of low mortality. However, in the last few decades, beech seems to benefit from the period of intense fir mortality. This change results from the influence of long-term anthropogenic disturbances, affecting natural mechanisms that maintain the coexistence of different tree species and change natural disturbance regimes. Indirect anthropogenic influence on tree growth was clearly visible in the gradual decrease of fir increments in the twentieth century, resulting from the high level of air pollution in Europe. Synchronous decreases of fir tree rings’ widths were observed in all three of the sample plots, but the final outcomes depended on the fir age. In most cases, the damage to the foliage limited the competitive abilities of fir, but it did not cause a widespread increase in tree mortality, except for the oldest firs in the BGNP (Babia Góra National Park) plot. BGNP is located in the proximity of industrial agglomeration of Upper Silesia, and it could be exposed to higher level of air pollution than the other two plots. High level of fir regeneration browsing due to the deer overabundance and insufficient number of predators is the second clear indication of the indirect anthropogenic influence on mixed mountain forests. Game impact on fir regeneration is the most pronounced in Babia Góra forests, where fir was almost completely eliminated from the saplings. Deer browsing seems to be the main factor responsible for limiting the number of fir saplings and young fir trees, while the representation of fir among seedlings is high. The experiments conducted in fenced plots located in the mixed forests in BGNP proved that fir and sycamore were the most preferred by deer species among seedlings and saplings. In GNP (Gorce National Park) and TNP (Tatra National Park), the changes in species composition of tree regeneration are similar, but single firs or even small groups of firs are present among saplings. It seems that all of the analysed mixed beech-fir-spruce forests undergo directional changes, causing a systematic decrease in fir representation, and the expansion of beech. This tendency results from the indirect anthropogenic impact, past and present. Fir regeneration decline, alongside with the high level of spruce trees’ mortality in recent years, may lead to a significant decrease in conifers representation in the near future, and to the expansion of beech forests at the cost of mixed ones.
Book chapters on the topic "Seedling stands"
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Lula, Mikolaj, Kjersti Holt Hanssen, Martin Goude, et al. "Regeneration." In Managing Forest Ecosystems. Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-70484-0_3.
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Abstract In the context of continuous cover forestry (CCF), natural regeneration is the preferred form of regeneration, but it is a long-lasting and complex process. Shelter density has a large effect on the regeneration process and results. The selection system, particularly suited for shade-tolerant species like Norway spruce, relies on continuous regeneration and ingrowth into larger size classes. Regeneration and ingrowth rates vary significantly among stands, influenced by site and historical factors, with no clear relationship to current stand conditions. In the group system, edge trees influence regeneration by providing seeds, checking weed growth, and exerting competition. Regeneration in gaps is generally satisfactory for both Norway spruce and Scots pine. However, seedlings usually grow slower, especially close to the gap edges. The shelterwood system promotes regeneration through a successive, uniform opening of the canopy. Shelter trees provide seeds, and reduce seedling damage and competition from ground vegetation. On the other hand, the remaining overstorey shelter trees reduce seedling growth. Conversion to the selection system initiates regeneration in young stands, aiming for slow and steady regeneration. Given the rapid growth and crown closure in young stands, frequent manipulation of shelter density is essential during conversion, for example by opening small gaps.
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Saif, Abdulwahid, Aref Al-Shamiri, and Abdulnour Shaher. "Development of new bread wheat resistant mutants for Ug99 rust disease (Puccinia graminis f. sp. tritici)." In Mutation breeding, genetic diversity and crop adaptation to climate change. CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0032.
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Abstract M<sub>3</sub> derived mutants from two bread wheat varieties, namely, 'Giza 186' and 'Saha 93', were screened for resistance to the rust Ug99 at two locations in Njoro (Kenya) and in Tihama (Yemen). At Tihama, two mutants of 'Giza 186' (G-M2-2010-1-28 and G-M2-2010-41-52) and four mutants of 'Saha 93' (S-M2-2010-16-12, S-M2-2010-21-13, S-M2-2010-22-14 and S-M2-2010-27-15) were seen to be resistant at both seedling and adult stages while their parents were resistant at seedling stage and susceptible at adult stage. In Kenya, the resistance score of the mutants was slightly different from those obtained at Tihama. The mutants G-M2-2010-1-28 and G-M2-2010-41-52 were stable in their level of resistance recorded at Tihama, but only two mutants of 'Saha 93' (S-M2-2010-16-12 and S-M2-2010-27-15) were resistant at both growth stages. S-M2-2010-22-14 and S-M2-2010-21-13 were resistant at the seedling stage while susceptible at adult stage. Further selection on these mutants for yield potential, agronomic performance and yellow rust disease resistance, as well as on selected mutants of both 'Giza 186' and 'Saha 93', at M5-M6 stages identified superior mutant lines compared with the two parents 'Saha 93' and 'Giza 186'. These included the line Erra-010-GM2w-41-52-40, which ranked first in yield (3768 kg/ha), followed by the lines Erra-010-SwM2-16-12-19, Erra-010-GM2w-1-28-18 and Erra-010-SwM2-22-14-6. Moreover, it can be concluded that Erra-010-GM2w-41-52-40 and Erra-010-SwM2-16-12-19 are highly recommended for their resistance to stem and yellow rust diseases as well as for yield potential and preference by farmers. Therefore, efforts are in progress to increase their seeds for dissemination over a wide range of farmers and wheat areas where rust diseases are an epidemic, and for registration of the lines as improved mutant varieties.
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Geras'kin, Stanislav, Roman Churyukin, Polina Volkova, and Sofiya Bitarishvili. "Using ionizing radiation for improving the development and yield of agricultural crops." In Mutation breeding, genetic diversity and crop adaptation to climate change. CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0043.
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Abstract The response of barley seedlings was studied after gamma irradiation of seeds with doses in the range of 2-50 Gy. It was shown that stimulation of plant growth occurred in the dose range of 16-20 Gy. The influences of the dose rate, the quality of seeds and their moisture on the manifestation of radiation effects were investigated. We studied, under controlled conditions, the activities of metabolic and antioxidant enzymes and observed an increase in their activity in the range of doses that cause stimulation of seedling growth. We showed that changes in the balance among different classes of phytohormones were probably involved in the acceleration of plant growth after irradiation of seeds using stimulating doses. Gamma irradiation of barley seeds significantly influenced the development of plants during the growing season. After irradiation with stimulating doses, we observed a reduction in the duration of the initial stages of ontogenesis; the phase of full ripeness occurred 5-7 days earlier than in the controls. The manifestation of the effect of irradiation depended on the conditions in which the plants developed. During the growing season of 2014, which was a dry year, plants originating from the irradiated seeds showed an increase in the number of productive stems, which led to an increase in yield by 34-38%; during the optimal 2015 season, an increase in the number of grains per spike caused an increase in yield by 8-29%. Therefore, our field study has shown that at least some hormetic effects can occur in the field. Irradiation of seeds can increase field germination, stimulate the growth and development of plants and increase their resistance to unfavourable environmental conditions. A more complete understanding of the underlying mechanisms of hormesis is needed to exploit its potential benefits in crop production.
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Sarsu, Fatma. "Screening Protocols for Heat Tolerance in Rice at the Seedling and Reproductive Stages." In Pre-Field Screening Protocols for Heat-Tolerant Mutants in Rice. Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-77338-4_2.
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Díaz Vélez, M. Celeste, Ana E. Ferreras, and Valeria Paiaro. "Seed dispersal interactions promoting plant invasions." In Plant invasions: the role of biotic interactions. CABI, 2020. http://dx.doi.org/10.1079/9781789242171.0090.
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Abstract Animal dispersers are essential for many non-native plants since they facilitate seed movement and might promote seed germination and seedling establishment, thereby increasing their chances of invasion. This chapter reviews the published literature on seed dispersal of non-native plant species by native and/or non-native animals. The following questions are addressed: (i) Are interactions between non-native plants and their animal dispersers evenly studied worldwide? (ii) Which are the distinctive traits (i.e. geographical origin, life form, dispersal strategy and propagule traits) of non-native plants that are dispersed by animals? (iii) Which are the most studied groups of dispersers of non-native plants around the world? (iv) Does the literature provide evidence for the Invasional Meltdown Hypothesis (non-native plant-non-native disperser facilitation)? (v) What is the role of animal dispersers at different stages of the non-native plant regeneration process? Our dataset of 204 articles indicates that geographical distribution of the studies was highly heterogeneous among continents, with the highest number coming from North America and the lowest from Asia and Central America. Most of the non-native plants involved in dispersal studies were woody species from Asia with fleshy fruits dispersed by endozoochory. More than the half of the animal dispersal agents noted were birds, followed by mammals, ants and reptiles. The dominance of bird-dispersal interactions over other animal groups was consistent across geographical regions. Although most of the studies involved only native dispersers, interactions among non-native species were detected, providing support for the existence of invasional meltdown processes. Of the total number of reviewed articles reporting seed removal, 74% evaluated seed dispersal, but only a few studies included seed germination (35.3%), seedling establishment (5.4%) or seed predation (23.5%). Finally, we discuss some research biases and directions for future studies in the area.
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Siahaan, Febrina Artauli. "Differences in Leaf Functional Traits of Canarium vulgare Leenh. Between Two Growth Stages: Mature vs. Seedling." In Advances in Biological Sciences Research. Atlantis Press International BV, 2023. http://dx.doi.org/10.2991/978-94-6463-166-1_48.
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Kärkkäinen, Katri, Sonja T. Kujala, Rosario Garcia-Gil, et al. "Genetic Effects." In Managing Forest Ecosystems. Springer Nature Switzerland, 2024. https://doi.org/10.1007/978-3-031-70484-0_7.
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Abstract Genetic effects of continuous cover forestry (CCF) are not well known. We need more research, especially on the genetics of spruce-dominated CCF sites. Levels of relatedness are of interest, as are estimates of safe limits for the intensity and duration of CCF practices that secure genetic potential for good growth and quality. With even-aged forestry, genetically improved regeneration material can be used to mitigate climate change-related risks through breeding and deployment recommendations. In CCF, currently based on natural regeneration, we assume that enough seedlings establish, and that sites contain enough genetic variation to enable natural selection and evolutionary processes. Based on research in other regions, the number of reproducing trees must be kept large to avoid excessive levels of relatedness and inbreeding and to maintain sufficient levels of genetic diversity. In some well-documented long-term experiments in other regions, intensive high-grading has led to slower growth rates, which could partly be due to genetic degradation of the stand. If contemporary recommendations for selection cutting are followed, negative genetic effects should be unlikely.
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Nautiyal, P. C., K. Sivasubramaniam, and Malavika Dadlani. "Seed Dormancy and Regulation of Germination." In Seed Science and Technology. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-5888-5_3.
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AbstractSeed germination and dormancy are vital components of seed quality; hence, understanding these processes is essential for a sound seed production system. The two processes are closely interrelated and regulated, both by genetic as well as environmental factors. While dormancy provides an inherent mechanism aimed at the survival of the plant species to withstand adverse external conditions by restricting the mature seed from germinating, the ability of the dehydrated seed to remain viable and produce a vigorous seedling upon hydration under favourable conditions is the key to the survival and perpetuation of the plant species. In addition, quality seed is expected to result in timely and uniform germination under favourable field conditions after sowing to establish a healthy crop stand. Therefore, in seed technology, dormancy is not considered a desirable trait in the seed lots used for sowing. Thus, to achieve the highest germination percentage, understanding the factors controlling these two interlinked and contrasting processes is vital. In seed testing and seed trade, knowledge of seed germination and dormancy is needed for a reliable assessment of seed quality and its planting value, and to make right decisions. Though much is yet to be understood, the present status of knowledge on these aspects has made significant advances, especially in genetic control, molecular mechanism, and physiological and environmental factors influencing germination and dormancy. The information compiled in this chapter may help the seed technologists in developing new methods for breaking dormancy and testing germination,
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González-Alday, J., C. Martínez-Ruiz, and F. Bravo. "Evaluating different harvest intensities over understory plant diversity and pine seedlings, in a Pinus pinaster Ait. natural stand of Spain." In Forest Ecology. Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-90-481-2795-5_16.
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Siregar, I. Z., and H. H. Hattemer. "Gene flow and mating system in a seedling seed orchard and a natural stand of Pinus merkusii Jungh. et de Vriese in Indonesia." In Genetic Response of Forest Systems to Changing Environmental Conditions. Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-015-9839-2_23.
Full textConference papers on the topic "Seedling stands"
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DUMINS, Karlis, Toms STALS, and Dagnija LAZDINA. "FOREST REGENERATION QUALITY ASSESSMENT BY ASTA SYSTEM." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.178.
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In Latvia one third of the total forest area is regenerated by planting tree seedlings and therefore it is important to choose the appropriate soil preparation method and the right type of regeneration material for each forest type. Usually the success of afforestation is evaluated by how high is the average seedling survival rate and growth parameters like height, annual increment, diameter at breast height while the location of the seedling is disregarded. This may be of great importance since in such stands the environmental conditions typically are not entirely homogenous. Micro topography differences impact seedling growth, because it modifies water regime, temperature, micronutrient availability, sun radiation and other factors. Therefore, aim of this work is to improve monitoring methods and determine the most efficient soil preparation and seedling preparation combination to improve the quality of forest regeneration. That could be done using ASTA documentation system originally developed to show seedling and mound location and density in planting area during mechanic planting. But it also allows to link the precise location of the seedling and growing conditions with its growing rate and survival and therefore it is easier to exclude seedlings that are affected by other factors than those that you are interested in, so you can gain more representative results. This also could be used in forest management. When using ASTA system it is also possible to display how different tree disease are distributed in the stand, if they have spread eventually or localized only in some parts of the stand, also it can be used for browsing and other tree damage monitoring in the stand. In conclusion: in harsh environmental conditions on unprepared forest soil and soil prepared in furrows made by disc trench larger seedlings show better survival rate. Survival of seedlings is significantly impacted by micro topography, whereas mounded micro sites equalize local environmental conditions that reduce impact of micro topography.
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Miezite, Olga, Baiba Jansone, Dace Brizga, and Linards Sisenis. "PROTECTION OF PINUS SYLVESTRIS L. STANDS FROM CURCULIONIDAE DAMAGE." In 22nd International Multidisciplinary Scientific GeoConference 2022. STEF92 Technology, 2022. http://dx.doi.org/10.5593/sgem2022v/3.2/s14.47.
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One of the long-term goals of the certification systems (FSC (Forest Stewardship Council) and PEFC (Program for the Endorsement of Forest Certification)) of sustainably managed forests that provide both social, environmental, and economic benefits is to completely phase out the use of chemical pesticides to protect planting material. It is in the interest of both nurseries and forest owners to find successful alternative, environmentally friendly solutions to safeguard pine saplings against Curculionidae. The studied two-year-old pine stands are located in the Hylocomiosa forest type with a total area of 4.27 ha. In 2016 clear-cutting was carried out, and in the spring of 2018, containerized seedlings were planted in areas with partial soil scarification in three repetitions in each area. Six plots with three variants in each of the repetitions were prepared. The work aims to evaluate the effectiveness of the use of P.sylvestris protection against damage Curculionidae while comparing untreated (control) lots with the ones treated with the systemic insecticide Actara or wax based on the number of damages and growth of seedlings. The intensity of tree damage and the incidence of damage over two years, depending on the type of seedling treatment, was assessed, and the average tree heights were measured and compared. With an increase in the incidence of weevil damage, the intensity of damage is also observed. At the same time, a significant (p>0.05) difference in lesions between the types of treatment of seedlings has not been established. Within two years, the death of trees due to weevil damage is insignificant - 2 % of all seedlings treated with the systemic insecticide Actara, 5 % of seedlings treated with wax Kvaae, and 6 % of untreated seedlings or control. The treatment of seedlings significantly affected their growth in the first and second years after planting (p less than 0.05). The use of wax Kvaae resulted in higher costs and similar protection effectiveness as the use of chemical means.
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Pats, E. N. "CRITERIA OF SEEDLING COLONIZATION IN SIBERIAN STONE PINE FORESTS IN TOMSK OBLAST." In Prirodopol'zovanie i ohrana prirody: Ohrana pamjatnikov prirody, biologicheskogo i landshaftnogo raznoobrazija Tomskogo Priob'ja i drugih regionov Rossii. Izdatel'stvo Tomskogo gosudarstvennogo universiteta, 2020. http://dx.doi.org/10.17223/978-5-94621-954-9-2020-12.
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The current state of reforestation of Siberian stone pine stands in the near-village Siberian stone pine forests in Tomsk Oblast is given by criteria of dark coniferous seedling colonization. Structure of the natural regeneration is very diverse and quite specific.
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MIEZĪTE, Olga, Jeļena RŪBA, Lāsma FREIMANE, Imants LIEPA, and Edgars DUBROVSKIS. "THE HEALTH STATUS AND NATURAL REGENERATION OF PINUS SYLVESTRIS L. AFTER THE SURFACE FIRE IN VACCINIOSA FOREST TYPE IN LATVIA." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.100.
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From abiotic factors the most effecting influence on forest ecosystems has fire. Two years after surface fire in the pine stands growing in Vacciniosa forest type. Two PL (hereinafter PL) were installed in medium-aged (49 years old, 2.3 ha) and two PLs - in maturing (96 years old, 2.5 ha) stands. In each PL (20x20 m), the numbering of the trees was carried out and their placement was fixed, as well as the diameter, height and height of the green crown were measured. The sanitary condition of each tree was evaluated. For registration of one-year and two-year seedlings in each sample plot 25 sampling units (1 m2) were used. The similar sampling units were used for evaluation of ground cover (5 in each PL diagonally arranged), the obtained samples were weighed. The purpose of the study was to analyze the health status and natural regeneration of P.sylvestris after the surface fire. The ground vegetation was completely burned out in the medium-aged stand, but in the maturing stand both ground vegetation and organic layer - mosaically. The average burning height of trees in the medium-aged forest stand was 0.6±0.64 m, in the maturing stand - at 2.3±0.34 m. The natural regeneration was not detected in the first year after surface fire in the medium-aged forest (only 58800 one-year seedlings were recorded at the second year after fire), while in the maturing stand it was at this time (46600 one-year and 14200 two-year seedlings). Insect damage and cracked bark was not detected.
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Li, Xiaoying, and Bo Zhang. "Improving Edamame Seedling Establishment by Determining the Optimal Temperature." In 2022 AOCS Annual Meeting & Expo. American Oil Chemists' Society (AOCS), 2022. http://dx.doi.org/10.21748/ybzg7716.
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Demand in the United States for edamame has increased over the past two decades. Edamame has become the second largest soyfood consumed in the US (25,000-30,000 tons annually). While domestic edamame production is slowly increasing, at least 70% of edamame consumed in the US is imported. Poor crop establishment is a major problem limiting edamame production. Seedling emergence ranges from 50-85%, which is lower than that of grain-type soybean ( >85%). Seedling stand can be improved by growing under the optimal temperature. Up to now, edamame is planted still based on grain-type soybean recommendations. The objective of this study was to determine the minimum, optimum, and maximum emergence temperatures of edamame. It will provide a scientific basis for deciding the best planting time of edamame, ultimately improving its seedling stand in the field. In this study, two edamame cultivars (VT Sweet and UA Kirksey) were tested for their seedling emergence percentage and emergence rate (i.e., emergence speed) at 5, 7, 10, 13, 16, 19, 21, 23, 25, 27, 29, 32, 35, 38, 41, 45 °C (soil temperature) using the LabFieldTM Simulation Table. Two grain-type soybean cultivars (MFS-48P1 and USF5618v) were checks. The results showed that the optimal temperature range for edamame seedling emergence is 25-32 °C, which is lower than that of grain-type soybean (29-36 °C). Soybean did not emerge at around 4 °C, however, edamame seeds may have a higher tolerance to low temperature compared with grain-type soybean. The maximum temperature varied little among soybean types, with an average of 41.08 °C. In addition, edamame needs more thermal time to emerge. The results indicate that edamame has a different emergence response to temperature compared with grain-type soybean. Edamame should be planted earlier than grain-type soybean and later planting may reduce edamame seedling emergence.
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Michelen Strofer, Carlos, Maha Haji, and Kapil Khanal. "Differentiable Programming to Enable Modern Optimization and Data-Driven Methods for Marine Renewable Energy." In DOE Seedling Symposium - Virtual, District of Columbia, United States of America - August - 2023. US DOE, 2023. http://dx.doi.org/10.2172/2430414.
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Marii, Liliana, Larisa Andronic, Marionela Sahanovschih, and Angela Ionascu-Urechii. "The effects of high temperature at different ontogenetic stages on some phenotypic indices in tomato plants." In Conferința științifică națională cu participare internațională "Integrare prin cercetare și inovare", dedicată Zilei Internaționale a Științei pentru Pace și Dezvoltare. Moldova State University, 2025. https://doi.org/10.59295/spd2024n.17.
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The study aims to investigate the tomato plants response to heat stress applied at the germination and seedling stages, evaluating certain phenotypic parameters in order to highlight possible particularities associated with adaptability to unfavorable environmental conditions. The research included three tomato genotypes with determined stress reactions that were designed into four variants: optimal-optimal, optimal-stress, stress-optimal, and stress-stress. The application of high temperatures at the germination stage significantly affects the subsequent development of tomato plants, resulting in a decrease in the average values of morphological traits compared to optimal conditions variants. The effects of heat stress vary depending on the genotype and the analyzed trait, with certain variants exhibiting specific vulnerabilities. Variance analysis shows that the temperature conditions and the stress application scheme significantly contribute to the variability of morphological traits, with stress at the germination stage having a dominant impact on architectural traits of plants, while genotype becomes the major influencing factor at the seedling stage. The results emphasize the importance of plant adaptability to thermal stress at different developmental stages.
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Maslyukov, E. A., V. A. Kravchenko, A. P. Kluev, A. N. Batyan, and A. O. Kunitskaya. "THE INFLUENCE OF THE COMBINED LASER AND GAMMA RADIATION ON THE INITIAL STAGES OF PLANT GROWTH." In SAKHAROV READINGS 2021: ENVIRONMENTAL PROBLEMS OF THE XXI CENTURY. International Sakharov Environmental Institute, 2021. http://dx.doi.org/10.46646/sakh-2021-1-294-297.
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The effect of the growth of winter wheat by 13.7 mm (9.33%), grown from pre-soaked seeds and irradiated with a dose of 2.7 J of combined laser radiation, was established. A similar radiation dose of 2.7 J of air-dry seeds caused an increase in the length of seedlings from 17.1 mm (11.03%) in the first experiment to 38.1 mm (39.42%) in the second experiment. It was shown that irradiation (MED-80, 160 and 300 mR / h) of 20-day-old seedlings of Phleum pratense, at doses of 0.07; 0.14; 0.28 Gy causes an increase in the pigment content 1 hour after irradiation in experimental plants.
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Popova, A. A., V. V. Molchanov, and E. A. Rad’kova. "OAK STANDS COMPREHENSIVE ANALYSIS IN VORONEZH, BASED ON DATA ON GROUND COVER, MORPHOMETRIC PARAMETERS OF LEAFS, ACORNS, SEEDLINGS CYTOGENETIC PARAMETERS." In All-Russian Scientific Conference, dedicated to the 90th anniversary of the Voronezh State Forestry University named after G.F. Morozov. Знание-М, 2020. http://dx.doi.org/10.38006/907345-73-7.2020.100.103.
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Представлены результаты комплексного мониторинга дубовых насаждений г. Воронежа, входящих в состав зеленого пояса. Был проведен анализ морфологических показателей листьев, желудей, напочвенного покрова, а так же цитогенетический анализ проростков желудей. Самое высокое биоразнообразие напочвенного покрова характерно для территорий: Маклок, Задонье, Биосферный заповедник. По морфометрическим параметрам наиболее крупные желуди характерны для популяций дубов, произрастающих в Шилово и Воронежском Биосферном заповеднике. Среди проанализированных факторов наиболее чувствительны к воздействию биотехносферы цитогенетические параметры патологий митоза в апикальных почечных и корневых меристемах, поражение листьев мучнистой росой, кривые распределения морфологических параметров листьев, желудей. Параметры биоразнообразия напочвенного покрова дубрав варьирует, но могут использоваться в качестве дополнительных параметров мониторинга
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Medvedev, D. "TECHNOLOGY FOR GROWING PLANTING MATERIAL IN FOREST NURSES." In Adaptation of forestry to climate change: nature-oriented solutions and digitalization. Forestry – 2024. FSBE Institution of Higher Education Voronezh State University of Forestry and Technologies named after G.F. Morozov, 2025. https://doi.org/10.58168/ffys2024_35-37.
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The article displays the main stages of growing trees in forest nurseries. The features of the production of seedlings and saplings are considered, and the most important criteria for obtaining healthy plant offspring are indicated. A conclusion is drawn about current areas of research in the field of mechanization of plant care.
Reports on the topic "Seedling stands"
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Levy, Louise S. Y., Robert L. Deal, and John C. Tappeiner. The density and distribution of Sitka spruce and western hemlock seedling banks in partially harvested stands in southeast Alaska. U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, 2010. http://dx.doi.org/10.2737/pnw-rp-585.
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Ward, Kimiora. Sierra Nevada Network white pine monitoring: 2022 annual report. National Park Service, 2023. http://dx.doi.org/10.36967/2301003.
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Five-needle white pines (Family Pinaceae, Genus Pinus, Subgenus Strobus), and in particular whitebark pine (Pinus albicaulis), limber pine (P. flexilis), and foxtail pine (P. balfouriana) are foundation species in upper subalpine and treeline forests of several National Park Service Pacific West Region parks, including Sequoia and Kings Canyon National Parks (SEKI) and Yosemite National Park (YOSE). The Sierra Nevada Network Inventory & Monitoring Program, in collaboration with the Klamath Network, Upper Columbia Basin Network, and Mojave Desert Network have implemented a joint long-term monitoring protocol to assess the current status and future trends in high elevation white pine communities. Key demographic parameters within white pine forest communities will be estimated by monitoring individual trees within permanent plots through time. This report documents the results of the 2022 field season, which was the ninth year of monitoring in SEKI and YOSE. The 2021 goal was to complete the first full measure of the third of three rotating panels (Panel 3) for each species-park population: YOSE-whitebark pine, SEKI-whitebark pine, and SEKI-foxtail pine. Each panel consists of 12 permanent 50 x 50 m (2,500 m2) plots that were randomly selected for each of the three populations. The full sampling array thus includes a total of 36 whitebark pine plots in YOSE, 36 whitebark pine plots in SEKI, and 36 foxtail pine plots in SEKI. Data from plot surveys will be used to characterize white pine forest community dynamics in SEKI and YOSE, including changes in tree species composition, forest structure, forest health, and demographics. Partial measures of Panel 3 were completed in 2017 (11 plots) in Yosemite whitebark pine, in 2017 (9 plots) in SEKI whitebark pine, and in 2014 (7 plots) and 2017-2018 (8, 1 plots) in foxtail pine. In 2022, the first full measure of all Panel 3 plots (and 2nd or 3rd remeasure of most plots) was successfully completed, and installation was completed on four of these plots in SEKI whitebark pine and two in foxtail pine. In total, the crew visited 36 sites during the 2022 field season, all from Panel 3. Within the 36 completed Panel 1 plots, a total of 6,398 trees were measured. Species composition, forest structure, and factors affecting tree health and reproduction including incidence and severity of white pine blister rust (Cronartium ribicola) infection, mountain pine beetle (Dendroctonus ponderosae) infestation, dwarf mistletoe (Arceuthobium spp.) infection, canopy kill, and female cone production were recorded. During the 2022 field season crews continued to count the total number of mature cones per tree for whitebark and foxtail pine, use crown condition codes to assess crown health, and tag individual seedlings to be tracked through time. All three of these procedures started in 2017 and are to be evaluated by each of the three participating networks over several years, to determine whether they should become permanent changes to the monitoring protocol. In YOSE, all 12 Panel 3 whitebark pine plots were measured. A total of 2,720 trees were sampled, which included 977 live whitebark pine trees and 1,605 other live conifers. An additional 135 trees (including 26 whitebark) were recorded as dead. The average number of live whitebark pine trees per plot was 81 (SD = 94). White pine blister rust (WPBR) aecia were observed on five whitebark pine in one plot in YOSE in 2022, and no trees in any plot had inactive cankers showing three or more indicators of WPBR. WPBR had previously been documented in this plot, so the number of plots where rust has ever been observed in Yosemite remains unchanged at six. However, an infection documented in plot 42 in 2021 was not observed again when the plot was resampled in 2022, so it is possible this number should be five. Mountain pine beetle activity was observed on one live whitebark pine and three live and one dead lodgepole pine in YOSE in 2022. Despite documentation of many stands impacted by beetle attack in the field crew notes, the quantified rate of MPB attack was lower than in 2021. Twenty-one percent of live whitebark pine trees produced female cones. Cone-bearing trees averaged 7 (SD = 10) cones/tree. Whitebark pine seedling density averaged 80 (SD = 152) seedlings per hectare. The largest number of whitebark pine seedlings found in a plot was 51 and five of the twelve plots contained whitebark seedlings. All 12 Panel 3 SEKI whitebark pine plots were measured in 2022, and installation was completed on four of these, so this Panel is now fully installed. Within these plots, 2,179 live whitebark pine, 10 live foxtail pine, and 297 other live conifers were sampled (including 5 live western white pine). The average number of live whitebark pine trees per plot was 181 (SD = 125). Although the crew observed white pine blister rust in seven SEKI whitebark Panel 3 plots, no active cankers (aecia) were observed, and no trees displayed 3 of 5 indicators, so no infections were quantified. Mountain pine beetle activity was observed in 18 live and 23 dead whitebark pine and 1 live and one dead lodgepole pine within three plots in SEKI. Dwarf mistletoe was not encountered. Seven percent of live whitebark pine trees produced female cones. Cone-bearing trees averaged 3.7 (SD = 3.6) cones/tree. Whitebark seedling regeneration averaged 700 (SD = 752) seedlings per hectare. The largest number of whitebark seedlings found in a plot was 19, and two of the 12 plots did not contain any whitebark seedlings. In the foxtail pine Panel 3, all 12 plots were measured in 2022, and installation was completed on two of these, so installation of the panel is now complete. Within these plots we measured 309 live foxtail pine, 302 live whitebark pine, and 380 other live conifers, including four live western white pine. An additional 112 dead or recently dead trees and 22 unidentified snags were also measured, 19 of which were foxtail pine. The average number of foxtail pine trees per plot was 26 (SD = 26). No signs of blister rust infection or mistletoe were observed on foxtail pine. Mountain pine beetle activity was observed on one dead foxtail pine, one live whitebark pine, and seven live and one dead lodgepole pines within four plots. Sixty-two percent of the foxtail pine trees produced female cones. Cone-bearing trees averaged 33 (SD = 53) cones/tree. Seven foxtail pine seedlings were recorded within five plots, resulting in an estimated 72 (SD = 98) seedlings per hectare. Eight whitebark pine seedlings and three lodgepole pine seedlings were also found within three additional plots.
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Zimmerman, Ephraim, and Staphanie Perles. Vegetation monitoring in relation to white-tailed deer browsing in First State National Historical Park: 2021 summary report. National Park Service, 2023. http://dx.doi.org/10.36967/2299655.
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Baseline information on canopy regeneration and plant community composition is needed in order to better understand white-tailed deer browsing impacts at First State National Historical Park (FRST). In 2021, the Pennsylvania Natural Heritage Program (PNHP) established 20 permanent vegetation monitoring plots following methods developed by the NPS Eastern Rivers and Mountains Network (ERMN) to assess and monitor trends in vegetation (Perles et al. 2014b; Perles et al. 2017). These protocols provided an efficient method of assessing the current status of native and non-native vegetation and deer browsing impact. This report documents the methodology used to quantify the vegetative composition of natural areas at FRST and provides a summary of the data collected in the first year of monitoring. This first year’s activities (2021) included the initial baseline vegetation assessment and summary of results from the baseline data analysis. A variety of metrics used to assess the impact of deer browsing on the vegetation were calculated and are presented. A second survey is proposed for 2024. PNHP used the NPS ERMN database and analysis methods (Perles et al. 2014b) to summarize the condition in year 1 (2021). In year 4 (2024), PNHP will investigate changes in the condition of browse-sensitive understory plants and tree seedlings. Plots occurred in a variety of settings, ranging from younger successional communities to more mature forest stands. Seventy-five percent (75%) of the plots occurred in Mature or Late Successional forests. Disturbances and stressors, such as deer browsing can strongly influence future forest structure as open woodlands mature. A large population of white-tailed deer may severely impact succession from the open woodlands towards closed canopy forest. In closed canopy, later successional forests, a large deer population may inhibit canopy tree recruitment leading to regeneration failure. Given that FRST managers desire to maintain the landscape as forest, it is important to maintain an adequate number of seedlings and saplings of tree species to ensure the persistence of canopy of native tree species as Mature and Late Successional Forests continue to age. The 20 permanent sampling plots occurred within 5 plant communities described by Ebert (2016) and were classified using agglomerative hierarchical clustering (HAC analysis) and indicator species analysis. The most common plant communities within the group of sampling plots were the Mixed oak – beech forest and Mesic mixed tulip – oak-hickory-beech forest. The remaining plots were found in successional Tuliptree woodland, Successional woodland, and Thicket types. All plots were assigned to these types described in Ebert (2016) and crosswalked to the National Vegetation Classification (USNVC). A total of 128 plant species were recorded from the 20 plots at FRST. Eighteen (18) species were found in over ½ of the plots surveyed, of which eight (8) were non-native. In all, 29 plants occurring in the plots (23% of total species richness) were considered introduced (non-native). Non-native plant cover ranged from 0–98% as measured in the monitoring plot quadrats. Indicators of deer browsing varied by plant community type at FRST. In general, the drier Mixed oak – beech forests showed substantially greater impact of deer browsing and fewer seedlings of canopy species in the understory. FRST monitoring protocols focus on a few plant species considered as preferred food for white-tailed deer. Sustained browsing may be affecting long-term viability of these species within the parks. Based on the status of these regeneration metrics in FRST, we suggest that the forest in FRST are in imminent regeneration failure. We define imminent failure as parks that are experiencing severe regeneration failure and are at risk of forest loss due to very low seedling and sapling abundance, as well as species mismatches between canopy and regeneration layers. Given the poor regeneration of canopy species across all community types at FRST, managers should seek opportunities to conduct adaptive management in the park’s forests, especially mixed oak – beech forest, to experiment with and monitor the effects of fire, browse exclosures, and canopy thinning to encourage native canopy tree regeneration.
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Israel, Alvaro, and John Merrill. Production of Seed Stocks for Sustainable Tank Cultivation of the Red Edible Seaweed Porphyra. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7696527.bard.
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Porphyra species (commonly known as ‘nori’ or ‘purple laver’) are edible red seaweeds rich in proteins, vitamins and other highly valued biogenic compounds. For years Porphyra has been cultured using seeded nets extended in the open sea, and its biomass consumed primarily in the Far East. While demands for international markets have increased steadily at an average of 20% per year, supplies are on the verge and not expected to meet future demands. Alternatively, land-based cultivation of seaweed has become attractive in the mariculture industry since (1) important growth parameters can be controlled, (2) is environmentally friendly and (3) perfectly matches with integrated aquaculture leading to sustainable, high quality products. During the last few years a tank cultivation technology for Porphyra has been developed at the Israeli institution. This technology is based on indoor production of asexual spores and their subsequent growth to 1-2 mm seedlings. The seedlings are then transferred to outdoor tanks and ponds when seawater temperatures drop to 20 °C, or below, and days become shorter during winter time. However, the current technology efficiently serves only about 100 m2 of ponds during one growth season. In order to produce seedlings in sufficient amounts, it is critical to address both technical and biological aspects of seedling production, securing optimal up-scale to commercial-size cultivation farms. We hypothesize that massive production of spores is related to thalli origin, thalli age and sporulation triggers, and that seedling survival and their subsequent growth potential is determined by the seawater quality and overall indoor growth conditions imposed. A series of bio-reactors were constructed and tested in which spore release and spore growth were separately studied. The main assessment criteria for optimal viability of the seedlings will be by determining their electron transport rate using PAM fluorometry and by subsequent growth and biomass yields in outdoor ponds. Altogether the project showed (1), controlled sporulation is possible in big outdoor/growth chamber settings provided initial stock material (small frozen seedlings) is at hand, (2), contamination problems can be almost completely avoided if stock material is properly handled (clean as possible and partially dehydrated prior to freezing), (3), spore release can significantly be enhance using high nutrient levels during thawing for P. yezoensis and P. haitanensis, but not for P. rosengurttii, (4), PAM fluorometry is an efficient tool to estimate growth capacity in both seedlings and juvenile thalli. The BARD funding also served to explore other aspects of Porphyra biology and cultivation. For example, the taxonomical status of Porphyra strains used in this study was defined (see appendix), and the potential use of this seaweed in bioremediation was well substantiated. In addition, BARD funding supported a number of opportunities and activities in the Israeli lab, direct or indirectly related to the initial objectives of the project such as: additional molecular work in other seaweeds, description of at least 2 new species for the Israeli Mediterranean, and continuous support for the writing of a book on Global Change and applied aspects of seaweeds. The technology for Porphyra cultivation in land-based ponds is readily available. This study corroborated previous know-how of Porphyra growth in tanks and ponds, and yet offers important improvements regarding seedling production and their handling for successful cultivation. This study supported various other activities opening additional important issues in the biology/cultivation/use of Porphyra and other seaweeds.
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Ward, Kimiora. Sierra Nevada Network high elevation white pine monitoring: 2021 annual report. National Park Service, 2024. http://dx.doi.org/10.36967/2302327.
Full textAbstract:
Five-needle white pines (Family Pinaceae, Genus Pinus, Subgenus Strobus), and in particular whitebark pine (Pinus albicaulis), limber pine (P. flexilis), and foxtail pine (P. balfouriana) are foundation species in upper subalpine and treeline forests of several National Park Service Pacific West Region parks, including Sequoia and Kings Canyon National Parks (SEKI) and Yosemite National Park (YOSE). The Sierra Nevada Network Inventory & Monitoring Program, in collaboration with the Klamath Network, Upper Columbia Basin Network, and Mojave Desert Network have implemented a joint long-term monitoring protocol to assess the current status and future trends in high elevation white pine communities. Key demographic parameters within white pine forest communities will be estimated by monitoring individual trees within permanent plots through time. This report documents the results of the 2021 field season, which was the eighth year of monitoring in Sequoia and Kings Canyon National Parks (SEKI) and Yosemite National Park (YOSE). The 2021 goal was to complete the third full re-measure of the second of three rotating panels (Panel 2) for each species-park population: YOSE-whitebark pine, SEKI-whitebark pine, and SEKI-foxtail pine. Each panel consists of 12 permanent 50 x 50 m (2,500 m2) plots that were randomly selected for each of the three populations. The full sampling array thus includes a total of 36 whitebark pine plots in YOSE, 36 whitebark pine plots in SEKI, and 36 foxtail pine plots in SEKI. Data from plot surveys will be used to characterize white pine forest community dynamics in SEKI and YOSE, including changes in tree species composition, forest structure, forest health, and demographics. The first full measure of all Panel 2 plots was completed over two years in 2013-2014, then a full remeasure of both parks? whitebark pine Panel 2 was conducted in 2016, with 10 of 12 SEKI-foxtail plots sampled that year. A third remeasure of all Panel 2 plots was not possible in 2021 because a smaller crew size was necessary during the COVID-19 pandemic. In total, the crew visited 37 sites, and sampled 31, during the 2021 field season. One plot in the YOSE whitebark pine frame was uninstalled before reading and one plot in the SEKI whitebark pine frame was uninstalled after reading, both for safety concerns. Four plots were not visited due to lack of capacity with the reduced crew size: one in each of the YOSE and SEKI whitebark frames, and three in the SEKI foxtail frame. A plot from Panel 3 in each of the parks? whitebark frames was measured, for a total of 11 plots measured in each whitebark pine frame. Nine plots were measured in the SEKI foxtail pine frame. Within the 31 plots completed, a total of 5,728 trees was measured. Species composition, forest structure, and factors affecting tree health and reproduction, including incidence and severity of white pine blister rust (Cronartium ribicola) infection, mountain pine beetle (Dendroctonus ponderosae) infestation, dwarf mistletoe (Arceuthobium spp.) infection, canopy kill, female cone production and regeneration were recorded. During the 2021 field season, crews continued to count the total number of mature cones per tree for whitebark and foxtail pine, use crown condition codes to assess crown health, and tag individual seedlings to be tracked through time. All three of these procedures started in 2017 and are to be evaluated by each of the three participating networks over several years, to determine whether they should become permanent changes to the monitoring protocol. In YOSE, 11 whitebark pine plots were re-measured, from Panels 2 and 3. A total of 2,810 trees were sampled, which included 586 live whitebark pine trees and 2,097 other live conifers. An additional 127 trees (including 17 whitebark pine) were recorded as dead. The forest crew noted little sign of white pine blister rust (WPBR) in Yosemite in 2021, and just a single inactive canker was observed on one whitebark pine in Panel 3, Plot 42, near Dana Meadows. This infection was new to plot 42, and it expands the total number of plots where white pine blister rust has been documented in Yosemite to six. The crew also noted little mountain pine beetle activity, documenting beetle galleries on 15 lodgepole pines in three Panel 2 plots. Dwarf mistletoe was not observed. The average number of live whitebark pine trees per plot was 53 (SD = 56). This was a low cone crop year for whitebark pine, with two percent of live whitebark pine trees producing female cones. Cone bearing trees averaged 2 (SD = 1) cones per tree. Whitebark pine seedling density averaged 90 (SD = 157) seedlings per hectare. The largest number of whitebark pine seedlings found in a plot was four, and three of the eleven plots contained whitebark seedlings. In SEKI, 10 of 12 Panel 2, and one Panel 3, whitebark pine plots were re-measured. Within these plots, 1,246 live whitebark pine, 30 live foxtail pine, and 861 other live conifers were sampled. WPBR was infrequently documented in the SEKI whitebark frame as well, with indicators of infection in Plot 31 near Window Creek and Plot 44 near Upper State Lake. These were the first infections documented in these plots, bringing the number of plots where WPBR has been documented in the SEKI whitebark panel to nine. Although WPBR was documented in Plot 27 near Charlotte Dome in 2016, it was not documented this year because putative cankers showing three signs of infection in 2016 showed only two or fewer signs in 2021. Mountain pine beetle activity was observed in one live lodgepole pine and two recently dead whitebark pine, within three plots in the SEKI whitebark sample frame. An exception to the low levels of mountain pine beetle activity was outside Plot 31 in the Window Creek area, where the forest crew noted many recently dead whitebark pine with signs of beetle activity. Dwarf mistletoe was not encountered. The average number of live whitebark pine trees per plot was 113 (SD = 86). Less than one percent of live whitebark pine trees produced female cones, each producing on average 2 (SD = 1) cones. Whitebark seedling regeneration averaged 303 (SD = 319) seedlings per hectare. The largest number of whitebark seedlings found in a plot was eight, and eight of the 11 plots contained whitebark seedlings. Nine of the 12 SEKI foxtail Panel 3 plots were remeasured. Within these plots, 413 live foxtail pine, 67 live whitebark pine, and 402 other live conifers were sampled. Ninety-two dead or recently dead trees were also documented, 65 of which were foxtail pine. No signs of blister rust infection, mistletoe, or mountain pine beetle were observed in the foxtail plots sampled. The average number of foxtail pine trees per plot was 46 (SD = 33). Fifty-four percent of the foxtail pine trees produced female cones, averaging 14 (SD =15) cones/tree. Only one foxtail pine seedling was recorded within the 9 foxtail pine plots, resulting in an estimated 14 (SD = 41) seedlings per hectare. Eight whitebark pine seedlings were also found within two plots.
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Czapowskyj, Miroslaw M., Robert V. Rourke, Walter J. Grant, and Walter J. Grant. Growth and nutrient status of black spruce seedlings as affected by water table depth. U.S. Department of Agriculture, Forest Service, Northeastern Forest Experimental Station, 1986. http://dx.doi.org/10.2737/ne-rp-591.
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Czapowskyj, Miroslaw M., Robert V. Rourke, Walter J. Grant, and Walter J. Grant. Growth and nutrient status of black spruce seedlings as affected by water table depth. U.S. Department of Agriculture, Forest Service, Northeastern Forest Experimental Station, 1986. http://dx.doi.org/10.2737/ne-rp-591.
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Guldin, James M., and Gerald Heath. Underplanting Shortleaf Pine Seedlings Beneath a Residual Hardwood Stand in the Ouachita Mountains: Results after Seven Growing Seasons. U.S. Department of Agriculture, Forest Service, Southern Research Station, 2001. http://dx.doi.org/10.2737/srs-rn-9.
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Guldin, James M., and Gerald Heath. Underplanting Shortleaf Pine Seedlings Beneath a Residual Hardwood Stand in the Ouachita Mountains: Results after Seven Growing Seasons. U.S. Department of Agriculture, Forest Service, Southern Research Station, 2001. http://dx.doi.org/10.2737/srs-rn-9.
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Boyle, Maxwell, and Elizabeth Rico. Terrestrial vegetation monitoring at Fort Pulaski National Monument: 2019 data summary. National Park Service, 2021. http://dx.doi.org/10.36967/nrds-2288716.
Full textAbstract:
The Southeast Coast Network (SECN) conducts long-term terrestrial vegetation monitoring as part of the nationwide Inventory and Monitoring Program of the National Park Service (NPS). The vegetation community vital sign is one of the primary-tier resources identified by SECN park managers, and monitoring is currently conducted at 15 network parks (DeVivo et al. 2008). Monitoring plants and their associated communities over time allows for targeted understanding of ecosystems within the SECN geography, which provides managers information about the degree of change within their parks’ natural vegetation. 2019 marks the first year of conducting this monitoring effort on four SECN parks, including Fort Pulaski National Monument (FOPU). Twelve vegetation plots were established at Fort Pulaski National Monument in August. Data collected in each plot included species richness across multiple spatial scales, species-specific cover and constancy, species-specific woody stem seedling/sapling counts and adult tree (greater than 10 centimeters [3.9 inches {in}]) diameter at breast height (DBH), overall tree health, landform, soil, observed disturbance, and woody biomass (i.e., fuel load) estimates. This report summarizes the baseline (year 1) terrestrial vegetation data collected at Fort Pulaski National Monument in 2019. Data were stratified across two dominant broadly defined habitats within the park (Maritime Tidal Wetlands and Maritime Upland Forests and Shrublands). Noteworthy findings include: Sixty-six vascular plant taxa were observed across 12 vegetation plots, including six taxa not previously known from the park. Plots were located on both Cockspur and McQueen’s Island. The most frequently encountered species in each broadly defined habitat included: Maritime Tidal Wetlands: smooth cordgrass (Spartina alterniflora), perennial saltmarsh aster(Symphyotrichum enuifolium), and groundsel tree (Baccharis halimifolia) Maritime Upland Forests and Shrublands: yaupon (Ilex vomitoria), southern/eastern red cedar (Juniperus silicicola + virginiana), and cabbage palmetto (Sabal palmetto). Four non-native species identified as invasive by the Georgia Exotic Pest Plant Council (GA-EPPC 2018) were found during this monitoring effort. These species (and their overall frequency of occurrence within all plots) included: Japanese honeysuckle (Lonicera japonica; 17%), bahiagrass (Paspalum notatum; 8%), Vasey’s grass (Paspalum urvillei; 8%), and European common reed (Phragmites australis; 8%). Two rare plants tracked by the Georgia Department of Natural Resources (GADNR 2013) were found during this monitoring effort. These include Florida wild privet (Forestiera segregata) and Bosc’s bluet (Oldenlandia boscii). Southern/eastern red cedar and cabbage palmetto were the most dominant species within the tree stratum of the maritime Upland Forest and Shrubland habitat type. Species that dominated the sapling and seedling strata of this type included yaupon, cabbage palmetto, groundsel tree, and Carolina laurel cherry (Prunus caroliniana). The health status of sugarberry (Celtis laevigata)—a typical canopy species in maritime forests of the South Atlantic Coastal Plain--observed on park plots appeared to be in decline, with most stems experiencing elevated levels of dieback and low vigor. Over the past decade, this species has been experiencing unexplained high rates of dieback and mortality throughout its range in the Southeastern United States; current research is focusing on what may be causing these alarming die-off patterns. Duff and litter made up the majority of downed woody biomass (fuel loads) across FOPU vegetation plots.