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1
Vasconcelos, Heraldo L., and J. Malcolm Cherrett. "Leaf-cutting ants and early forest regeneration in central Amazonia: effects of herbivory on tree seedling establishment." Journal of Tropical Ecology 13, no. 3 (1997): 357–70. http://dx.doi.org/10.1017/s0266467400010567.
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ABSTRACTThe effects of herbivory by the leaf-cutting antAtta laevigataFr. Smith on the re-establishment of forest trees in an abandoned farm near Manaus, central Amazonia, were investigated. Experimental seedling transplants and observations on seedlings which emerged naturally in the study area showed that damage by leaf-cutting ants negatively affected tree seedling survival and growth. However, excluding leaf-cutting ants from experimental plots for 20 mo did not significantly increase tree seedling densities. The number of seedlings emerging varied considerably between plots and this obscured any effect the ants may have had on seedling survivorship. Taller seedlings, and seedlings attacked only once, suffered less mortality than smaller seedlings and seedlings attacked twice or more. In general, mortality was greater for those species preferred by the ants, indicating that selective herbivory by leaf-cutting ants affects tree species composition. The number of seedlings attacked byA. laevigataremained approximately constant throughout the period of this study in spite of the fact that the number available for attack increased. Thus, the chance of any individual seedling being attacked declined with time, suggesting that the effect ofAttaherbivory on tree establishment is stronger during the first few years of forest regeneration.
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Thompson, T. E., and L. J. Grauke. "Pecan Tree Growth and Precocity." Journal of the American Society for Horticultural Science 128, no. 1 (2003): 63–66. http://dx.doi.org/10.21273/jashs.128.1.0063.
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Precocity of pecan [Carya illinoinensis (Wangenh.) C. Koch] seedlings (year of first fruit production) was studied in relation to original seed measurements (nut weight, buoyancy, volume, and density) and in relation to growth index (GI) measurements of seedling trees for 4 years. A total of 2,071 pecan seedlings, representing nine controlled-cross families, were studied. Original seed measurements were not related to precocity of resultant seedling trees; but seed weight, buoyancy, and volume were significantly correlated with seedling growth rates. Nut density was negatively related to growth of seedlings. These relationships show the importance of original seed measurements and seed parentage in determining seedling growth, and have direct relevance in pecan nursery operations to increase general rootstock seedling vigor. Seedling growth rate was significantly correlated to precocity levels, with measurements taken in the later years of the study showing the highest correlations with precocity. This strong growth-precocity relationship may have negative genetic implications since a common breeding objective is to produce more precocious cultivars that maintain smaller tree size in mature orchards.
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Santos, Gildomar Alves dos, David Francis Robert Philip Burslem, Milton Serpa de Meira Jr, and Stanislau Parreira Cardozo. "Introduction of native tree species into degraded Cerrado vegetation." Interação 21, no. 2 (2021): 61–84. http://dx.doi.org/10.53660/inter-102-s127.
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Experimental restoration using tree seedlings is a common strategy for accelerating succession on degraded post-agricultural land formerly occupied by Cerrado vegetation. Seedling growth in degraded tropical lands is constrained by various factors. The goal of this study was to evaluate the seedling growth and survival of seven native tree species used to accelerate forest recovery in a gully area with stressful environmental conditions. The experimental design involved fenced and unfenced blocks, presence and absence of fertilization and use of an adhesive to prevent ant herbivory (four treatments with four replicates). Seedlings were planted in December 2006 and collection of data on seedling basal diameter, height, mortality and herbivory started on January 24th 2007 and continued every three months, until final data collection on January 31st 2009 (9 measurement dates). Overall seedling survival was 38 % and protecting seedlings did not influence growth, but seedlings grew faster in response to the addition of fertilizer containing N, P and K. The use of the adhesive Tanglefoot to exclude leaf cutter ants had no influence on growth. Fencing reduced seedling mortality, but combining fencing with Tanglefoot did not. Nutrient availability limits seedling growth and survival in the gully. Direct planting of seedlings of native trees may accelerate succession in degraded Cerrado lands subject to interventions that overcome constraints on seedling growth and survival.
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Woods, Michaela J., Meredith Cobb, Katie Hickle, and Ryan W. McEwan. "Assessing the Efficacy of Seedling Planting as a Forest Restoration Technique in Temperate Hardwood Forests Impacted by Invasive Species." Forests 10, no. 8 (2019): 699. http://dx.doi.org/10.3390/f10080699.
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The emerald ash borer (Agrilus planipennis Fairmaire; EAB) is an invasive insect that causes mortality of trees in the genus Fraxinus, creating canopy gaps that may facilitate invasion by exotic plants. Planting native tree seedlings under EAB-infested Fraxinus may accelerate succession and preclude invasive plant expansion; however, the effectiveness of this approach has not been experimentally tested. We assessed understory seedling planting of Quercus rubra, Carya laciniosa, and Juglans cinerea in EAB-infested forests, where the invasive shrub Lonicera maackii (Amur honeysuckle) was removed. We tested whether the use of plastic tree shelters (“tree tubes”) or planting season (fall versus spring) contributed to the success of the reforestation plan by measuring growth rates (cm/yr) and survivorship two and seven years after planting. After seven years, seedling survivorship was <25% for all species and planting techniques. Quercus rubra exhibited poor survivorship with one seedling surviving to the conclusion of the experiment. Juglans cinerea and C. laciniosa had higher survivability and growth rates than did Q. rubra after two and seven years. Effects of tree tubes were weak and temporary. After 2 years, Q. rubra seedling survivorship was higher in tree tubes; however, by the end of the experiment 29 of the 30 Q. rubra seedlings in tree tubes had died. Juglans cinerea seedlings grew faster when planted in the fall compared to the spring, but overall survivorship of these seedlings was unaffected by planting season. Neither the use of tree shelters nor the planting season contributed to the growth or survival of C. laciniosa seedlings. In summary, our results indicate that seedling planting of Carya and Juglans may be a useful way to increase biodiversity in regenerating forests; however, the resource-expensive processes of over-wintering seedlings and using tree shelters may not increase the success of reforestation efforts.
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Nichols, J. Doland, Victor K. Agyeman, Francis Balfour Agurgo, Michael R. Wagner, and Joseph R. Cobbinah. "Patterns of seedling survival in the tropical African tree Milicia excelsa." Journal of Tropical Ecology 15, no. 4 (1999): 451–61. http://dx.doi.org/10.1017/s0266467499000942.
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The spatial patterns of canopy tree and seedling life stages in the African Tropical Tree Milicia excelsa were examined to test the Janzen–Connell hypothesis (escape hypothesis). The Janzen–Connell hypothesis states that the mortality of seeds and seedlings is highest near the adult tree and declines with distance away from the adult tree of the same species. This hypothesis argues that this effect is partially responsible for maintaining the high tree species diversity of tropical forests. Solar radiation and fruit dispersal were investigated as possible explanations of observed patterns in seedling distribution. Milicia excelsa trees ≥30 cm DBH were found to be randomly dispersed and occurred at a density of ≤1 ha. Milicia excelsa seedlings were located in small clumps between parent trees and up to 150 m from parents at a mean density of 65 seedlings ha−1. Fruits were in abundance (>9000 on the ground) beneath female trees. Light levels at locations of natural seedlings ranged from 2–29% of full irradiance. Planted seedlings did not suffer greater mortality closer to adult conspecifics, and survived at light levels between 2–37% of full irradiance. Phytolyma spp., gall-forming psyllids which cause high mortality in Milicia seedlings in large openings and plantations, were not observed on any natural or planted seedlings, although galls were present in the crowns of dominant trees.
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Kunstler, Georges, Joël Chaduf, Etienne K. Klein, Thomas Curt, Monique Bouchaud, and Jacques Lepart. "Tree colonization of sub-Mediterranean grasslands: effects of dispersal limitation and shrub facilitation." Canadian Journal of Forest Research 37, no. 1 (2007): 103–15. http://dx.doi.org/10.1139/x06-225.
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Encroachment of trees into low-productivity grasslands is a serious threat to grassland biodiversity throughout Europe. Although the rate of encroachment of trees into grassland is variable and poorly understood, it is thought to result from variation in tree seedling recruitment, which is limited mainly by the availability of safe sites and the dispersal distances of propagules. In this study, we established spatially explicit models of seedling recruitment for two major sub-Mediterranean trees: Quercus pubescens Willd. and Fagus sylvatica L. We quantified the spatial distribution of Q. pubescens and F. sylvatica seedlings up to 20 years old at three grassland sites. We also quantified the spatial distribution and size of mature trees and of the two dominant species of shrubs, Buxus sempervirens L. and Juniperus communis L., at each of the three sites. Ninety-eight percent of the regeneration took place under shrub canopy. Quercus pubescens seedlings showed higher seedling production per unit of canopy area and longer mean effective dispersal distances than did F. sylvatica seedlings. Quercus pubescens seedlings also had a large advantage over F. sylvatica seedlings for establishment in open areas. Juniperus shrubs were better safe sites for the establishment of Q. pubescens and F. sylvatica seedlings than were Buxus shrubs. We calculated indices of seedling dispersal limitation and safe site availability for recruitment for four dates. In the dolomitic Causse grasslands examined in this study, the availability of safe sites for germination and survival was far more important than seedling dispersal limitation for recruitment of both tree species.
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CHAROENSUK, Anun, Mullica JAROENSUTASINEE, and Krisanadej JAROENSUTASINEE. "Seed Production and Seedling Establishment of Parah Trees in Khao Nan National Park, Thailand." Walailak Journal of Science and Technology (WJST) 15, no. 3 (2017): 213–23. http://dx.doi.org/10.48048/wjst.2018.3928.
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Parah (Elateriospermum tapos Blume) is a native species of southern Thailand, and is a dominant tree in Khao Nan National Park. There have been few studies of Parah seeds or of seedling establishment. Biotic and abiotic environmental factors interact with seeds and may affect the future of tree populations. This is the first study to determine the factors affecting seeds and seedlings of Parah trees in Khao Nan National Park, Thailand, during 2014 - 2016. We tested 3 factors: (1) parental tree diameter at breast height (DBH), (2) altitude, and (3) distance from the main road. We studied seeds collected from trees, seeds harvested by humans, seed predation, seeds left on the forest floor, and rotten seeds. We measured seed weight, seed size, seedling height, and seedling root collar diameter (RCD). Our results showed that the number of seeds and seedlings per tree, seed weight, seed size, seed harvesting, seed predation, seeds left on the forest floor, rotten seeds, and seedling height varied between the years of study. There was no difference in seeds harvested by humans from 2014 - 2016. The number of seeds per tree and seeds harvested by humans were positively associated with parental tree DBH in 2015 and 2016. The number of seeds left on the forest floor was positively associated with parental tree DBH, and distance from the main road, but was negatively associated with altitude, in 2015, and there was no association in 2016. The number of seeds predated by frugivores was positively associated with altitude in 2016. The number of seedlings per tree was positively associated with distance from the main road. Seedling height was positively associated with distance from the main road, and negatively associated with tree DBH in 2015 and altitude in both years. We found significant results which led to the conclusion that seed production and seeds harvested by humans were positively associated with parental tree size.
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de Steven, Diane. "Tropical tree seedling dynamics: recruitment patterns and their population consequences for three canopy species in Panama." Journal of Tropical Ecology 10, no. 3 (1994): 369–83. http://dx.doi.org/10.1017/s0266467400008038.
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ABSTRACTA study of seedling demography of three shade-tolerant canopy tree species (Quararibea asterolepis, Trichilia tuberculata, and Tetragastris panamensis) was initiated to integrate with long-term studies of tree fruit production and of tree population dynamics on Barro Colorado Island, Panama. Over a five-year period, all seedlings (height <50 cm) and small saplings (height ≥50 cm to dbh 1 cm) were measured and monitored in permanent tree-centred transects (N = 10–11 trees per species). Survival rates increased with plant size class and were similar among species. Maximum height growth rates increased with increasing plant size, but average growth rates did not; this disparity suggests the importance of release from understorey suppression for long-term recruitment success. Among the three species, Quararibea had the lowest standing seedling densities and almost no sapling recruitment, whereas Tetragastris had the highest densities of both seedlings and saplings; Trichilia seedling and sapling densities were intermediate. In all three species, a few trees produced very high seedling and sapling densities in comparison with the sample average. All three species exhibited a year of exceptionally high new seedling recruitment during the study period; these good years were not coincident among the species but instead reflected the species' phenological differences. Since seedling survival becomes relatively constant and high after the first few years of life (c. 80% y−1), such large new cohorts persist as a year-class effect in the seedling population and thus maintain seedling numbers over time. The interspecific differences in seedling and sapling dynamics were consistent with overall 10-year trends of a declining Quararibea population, a stable Trichilia population, and an increasing Tetragastris population.
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Ketter, Benjamin L., and Ricardo M. Holdo. "Strong competitive effects of African savanna C4 grasses on tree seedlings do not support rooting differentiation." Journal of Tropical Ecology 34, no. 1 (2018): 65–73. http://dx.doi.org/10.1017/s0266467418000020.
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Abstract:Rooting differentiation between established trees and grasses has been well documented in savannas, but it remains unclear to what extent tree-grass rooting differences affect competition between newly established seedlings and grasses. To examine this question, a greenhouse experiment was conducted at the University of Missouri, USA. Twenty 3-mo-old seedlings each of two African savanna tree species (Acacia nigrescens and Colophospermum mopane) were grown for 8 mo with two crossed factors: grass competition and irrigation depth. Strong negative effects of grass competition on final seedling biomass and leaf photosynthetic and stomatal conductance occurred in both tree species, but no effects of irrigation depth were detected. There was a clear tree species by grass competition interaction, suggesting interspecific variation in competitive response. The results emphasize the importance of below-ground competition with grasses for physiological and morphological responses of tree seedlings, while minimizing the importance of tree-grass rooting depth differences as a factor in modulating the competitive response of trees to grasses at the seedling stage.
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Chapman, Colin A., and Lauren J. Chapman. "Frugivory and the fate of dispersed and non-dispersed seeds of six African tree species." Journal of Tropical Ecology 12, no. 4 (1996): 491–504. http://dx.doi.org/10.1017/s026646740000972x.
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ABSTRACTThe relationship between seedling recruitment (under and away from parent trees) and the behaviour of seed dispersers and predators, was explored in a three-year study in Kibale National Park, Uganda. On the basis of 1261 hours of observation, the foraging activity of the diurnal frugivores which fed on fruit from six tree species was quantified. The fate of dispersed and non-dispersed seeds and seedlings was examined experimentally. The findings suggest that a trade-off exists between factors that promote seedling growth in areas with high seedling density and factors that promote dispersal by frugivores. For example, dispersal ofMimusops bagshaweiincreases both seed and seedling survival; seeds placed away from adult conspecifics had a 8% lower probability of disappearing than seeds placed under adults and seedlings away from adults had a 30% greater probability of surviving than seedlings grown under adults. In contrast, forUvariopsis congensis, dispersed seeds had a 56% greater probability of disappearing than seeds directly under a parent tree, while the survival of dispersed and non-dispersed seedlings was similar. Non-dispersed seed and seedling disappearance were correlated with the percentage of the fruit crop removed from focal trees, suggesting that the ability to survive under an adult maybe related to other aspects of the tree's life history.
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Bellingham, P. J., and S. J. Richardson. "Tree seedling growth and survival over 6 years across different microsites in a temperate rain forest." Canadian Journal of Forest Research 36, no. 4 (2006): 910–18. http://dx.doi.org/10.1139/x05-308.
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We investigated whether canopy tree seedlings have different growth and mortality rates on different microsites in montane rain forests of the western South Island, New Zealand. Seedling relative height growth rates of three species, Podocarpus hallii, Quintinia acutifolia, and Weinmannia racemosa, were very low (mean = 0.037 cm·cm–1·year–1). Seedling growth rates were higher on logs than on the ground at high light levels, but the probability of seedling death on logs was also greater at high light levels. Seedling foliar N and P concentrations were generally not different between logs and the ground. Growth rates and foliar N concentrations of Quintinia and Weinmannia were greater for seedlings on tree fern trunks than for seedlings on the ground. Mortality rates did not differ between seedlings on tree fern trunks and seedlings on the ground. Seedling densities of Quintinia and Weinmannia were greater on logs and tree ferns than on the ground. Podocarpus densities were not different between logs and the ground, and this species did not occur on tree ferns. Quintinia and Weinmannia benefit from establishment on elevated microsites but this is not clearly the case for Podocarpus. Tree regeneration niches for such slow-growing species can only be determined through long-term studies.
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Blazier, Michael A., and Michael Dunn. "Stock Type, Subsoiling, and Density Impact Productivity and Land Value of a Droughty Site." Southern Journal of Applied Forestry 32, no. 4 (2008): 154–62. http://dx.doi.org/10.1093/sjaf/32.4.154.
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Abstract Management practices that overcome low seedling survival and poor tree growth of well-drained, droughty sites can improve their productivity and profitability. This study was established to explore tree and stand growth trends, potential forest product yields, and land expectation values of loblolly pine on a droughty site in response to (1) seedling stock type, (2) subsoiling, and (3) stand density regime. In winter 1993, container (CONT) and bareroot (BARE) seedlings were planted with or without subsoiling at 746 trees per hectare (TPH). BARE seedlings were planted without subsoiling at 1,493 TPH to provide a comparison between low-density treatment combinations and a conventional (CONV) management regime for this site type. Tree growth was monitored periodically through age 13 years. Yield trajectories were estimated by predicting forest product yields with FASTLOB using age 13 years stand characteristics, and land expectation value was determined from revenue predictions and costs associated with each treatment. Low-density regimes that included CONT seedlings or subsoiling before BARE seedling planting improved tree growth through midrotation and had yield estimates comparable with that of a CONV regime. However, land expectation values associated with subsoiling were lower than those of low-density CONT and CONV regimes because of its cost and negligible benefits for seedling survival.
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Boudreau, S., and M. J. Lawes. "Density- and distance-dependent seedling survival in a ballistically dispersed subtropical tree species Philenoptera sutherlandii." Journal of Tropical Ecology 24, no. 1 (2008): 1–8. http://dx.doi.org/10.1017/s026646740700466x.
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Abstract:We examine the density- and distance-dependent seedling survival of Philenoptera sutherlandii, a common pod-bearing and dehiscent legume (Fabaceae) in Ongoye Forest, South Africa. Short-range ballistic dispersal causes seed to fall beneath the parent tree, where density- or distance-dependent mortality effects are expected to be concentrated. One hundred and eighty marked seedlings were monitored in a 0.5-ha plot containing 30 adults. Our survival data do not support the escape hypothesis. Predation levels declined with increasing seedling density (positive density-dependent survival), but seedling survival after 15 mo was not distance-dependent. Nevertheless, a unimodal (hump-shaped) recruitment curve, typically associated with decreasing seedling density and increasing seedling survival with distance, was observed. In the context of ballistic dispersal, this recruitment curve may indicate a hump-shaped dispersal kernel with predator satiation at high seedling densities near a parent tree. This recruitment curve likely arises because generalized insect seedling predators while attracted to the adult trees also tend to forage farther away. Short dispersal distances, in turn generate the high densities needed to satiate seed and seedling predators. Predator satiation results in long-term survival rates in P. sutherlandii similar to more widely dispersed and less common tree species.
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Mao, Peili, Guangxuan Han, Guangmei Wang, Junbao Yu, and Hongbo Shao. "Effects of Age and Stand Density of Mother Trees on EarlyPinus thunbergiiSeedling Establishment in the Coastal Zone, China." Scientific World Journal 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/468036.
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Effects of age and stand density of mother tree on seed germination, seedling biomass allocation, and seedling growth ofPinus thunbergiiwere studied. The results showed that age of mother tree did not have significant influences on seed germination, but it was significant on seedling biomass allocation and growth. Seedlings from the minimum and maximum age of mother tree had higher leaf mass ratio and lower root mass ratio than from the middle age of mother tree. Moreover, they also had higher relative height growth rate and slenderness, which were related to their biomass allocation. Stand density of mother tree mainly demonstrated significant effects on seed germination and seedling growth. Seed from higher stand density of mother tree did not decrease germination rate, but had higher mean germination time, indicating that it delayed germination process. Seedlings of higher stand density of mother tree showed higher relative height growth rate and slenderness. These traits of offspring from higher stand density of mother tree were similar to its mother, indicating significant environmental maternal effects. So, mother tree identity of maternal age and environments had important effects on natural regeneration of the coastalP. thunbergiiforest.
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Arai, Nobumasa, and Tomohiko Kamitani. "Seed rain and seedling establishment of the dioecious tree Neolitsea sericea (Lauraceae): effects of tree sex and density on invasion into a conifer plantation in central Japan." Canadian Journal of Botany 83, no. 9 (2005): 1144–50. http://dx.doi.org/10.1139/b05-089.
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We studied the effects of differences in parent sex and density on seed rain and seedling and (or) sapling recruitment in a dioecious tree species (Neolitsea sericea (Bl.) Koidz.) with bird-dispersed seeds. We established four microhabitats: male or female trees inside or outside a single patch. The density of bird-disseminated seeds was significantly higher beneath females and inside the patch than beneath males and single trees outside the patch; this led to higher density of emerged seedlings inside the patch. The survival rate of germinated seedlings was also higher inside the patch than below single trees. In contrast, the survival rate of saplings was highest beneath males outside the patch, although very few seeds are dispersed beneath single males. Seedling and sapling recruitment beneath females and inside the patch will be accelerated owing to higher density of dispersed seeds, high seedling survival, and greater sapling density. In contrast, recruitment beneath males will be very slow. However, microhabitats beneath males are probably more suitable for seedling and sapling recruitment than microhabitats beneath females, since the survival rate of saplings was higher beneath males. Parental sex-biased seed rain and seedling and (or) sapling recruitment in dioecious plants may explain the regeneration pattern at a local scale.
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Kirika, Jasper Mbae, Katrin Böhning-Gaese, Bonny Dumbo, and Nina Farwig. "Reduced abundance of late-successional trees but not of seedlings in heavily compared with lightly logged sites of three East African tropical forests." Journal of Tropical Ecology 26, no. 5 (2010): 533–46. http://dx.doi.org/10.1017/s0266467410000283.
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Abstract:Logged forests form an increasingly large proportion of tropical landscapes but disproportionately few studies have studied the impact of forest disturbance, e.g. lightly vs. heavily logged, on tree and seedling communities simultaneously. We sampled all trees (on 1 ha) and all recently germinated seedlings (on 90 m2) in three lightly and three heavily logged sites in each of the following three East African tropical forests: Budongo Forest and Mabira Forest in Uganda and Kakamega Forest in Kenya. We analysed species richness, diversity, abundance and community composition of late- and early-successional trees and seedlings. We recorded no difference in species richness or diversity of late-successional or early-successional trees between lightly and heavily logged sites. However, the abundance of late-successional species was lower in heavily than lightly logged sites. Moreover, there was no difference in species richness or diversity of trees among the three forests. Yet, abundances of late-successional trees were higher in Budongo Forest than in Mabira Forest and Kakamega Forest. Species richness, diversity and abundance of seedlings did not differ between lightly and heavily logged sites. Only the abundance of seedlings of late-successional species differed among the forests with more individuals in Budongo Forest than in Mabira Forest. This was corroborated by non-metric multidimensional scaling (NMDS) showing clear differences in composition of tree and seedling communities among the three forests. Thus, both, the tree and seedling communities differed significantly among the three forests but not between lightly and heavily logged sites.
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BAKKE, IVONETE ALVES, JOSÉ EVANALDO RANGEL DA SILVA, OLAF ANDREAS BAKKE, and ANTONIO LUCINEUDO DE OLIVEIRA FREIRE. "SEED DISPERSAL, SEEDBANK, SEEDLING SURVIVAL, AND INITIAL GROWTH OF THREE CAATINGA TREES." Revista Caatinga 33, no. 4 (2020): 1007–16. http://dx.doi.org/10.1590/1983-21252020v33n416rc.
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ABSTRACT Myracrodruon urundeuva, Handroanthus impetiginosus and Amburana cearensis are Caatinga tree species that produce valuable timber, but little is known about their ecology. The objective of this study was to evaluate the seed distribution of these species on the forest floor before and after seed dispersal; and seedling emergence, survival, and growth during the rainy season after dispersal of seeds. There were no remaining viable seeds of these species in the seedbank before seed dispersal. The average numbers of seeds after seed dispersal were 188 seed m-2 in a 30 m radius around M. urundeuva, 9 seed m-2 in a 10 m radius around H. impetiginosus, and 5 seed m-2 in a 20 m radius around A. cearensis. The distance of seed dispersal reached 30, 20, and 10 m for M. urundeuva, H. impetiginosus, and A. cearensis trees, respectively, due to differences in tree height, seed weight, forest density, and wind intensity. Seedling emergence was observed during 4 (M. urundeuva) and 9 (H. impetiginosus and A. cearensis) weeks. High mortality predominated at the beginning and end of the rainy season for M. urundeuva and A. cearensis, respectively, while practically all H. impetiginosus seedlings survived. M. urundeuva showed the highest mortality but had higher number of established seedlings than the other species. Seedling survival peaked around 5 m from the tree base. Seedling recruitment and natural regeneration of these trees are assured in the Caatinga site evaluated.
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Norden, Natalia, and Pablo R. Stevenson. "Influence of frugivore activity on the species abundance of seedlings and saplings in a lowland tropical forest in Colombia." Journal of Tropical Ecology 31, no. 4 (2015): 291–303. http://dx.doi.org/10.1017/s0266467415000164.
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Abstract:Although seed dispersal plays a critical role for plant regeneration, the long-term benefits of frugivores for recruitment success have been poorly explored. We evaluated the relative importance of tree species abundance and of frugivore-related factors for successful plant recruitment on 18 tree species in a lowland Colombian rain forest. We combined census data from four 1-ha plots of trees (>10 cm dbh), saplings (1–5 cm dbh) and seedlings (<1.7 m) with a dataset describing tree–frugivore interactions. Seedling abundance was higher for large-seeded species dispersed by the spider monkey, while sapling abundance was higher for large-seeded species dispersed by birds. The identity of the dispersal agent and its interaction with seed size explained 20–30% of the total variance in seedling and sapling abundance across scales. Seed size consistently influenced the species abundance of seedlings and saplings across scales, but in opposite ways. These developmental changes suggest that what is beneficial to seedlings is not necessarily beneficial to saplings. Species identity explained 10–50% of the total variance in seedling and sapling abundance among and within 1-ha plots. Overall, our findings suggest that recruitment success is context-dependent as the relative importance of the different variables addressed may shift along spatial and temporal scales.
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Johnson and Yeakley. "Microsites and Climate Zones: Seedling Regeneration in the Alpine Treeline Ecotone Worldwide." Forests 10, no. 10 (2019): 864. http://dx.doi.org/10.3390/f10100864.
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Microsites, local features having the potential to alter the environment for seedling regeneration, may help to define likely trends in high-elevation forest regeneration pattern. Although multiple microsites may exist in any alpine treeline ecotone (ATE) on any continent, some microsites appear to enhance density of seedling regeneration better than others. Known seedling regeneration stresses in the ATE include low temperature, low substrate moisture, high radiation, drought, wind, and both high and low snowfall amount. Relationships among various microsite types, annual temperature, annual precipitation, and tree genera groups were assessed by synthesizing 52 studies from 26 countries spanning six continents. By categorization of four main microsite types (convex, concave, object, and wood) by mean annual precipitation and temperature, four major climatic zone associations were distinguished: cold & dry, cold & wet, warm & dry, warm & wet. Successful tree recruitment varied among microsite types and by climatic zones. In general, elevated convex sites and/or decayed wood facilitated earlier snow melt for seedlings located in cold & wet climates with abundant snowfall, depressions or concave sites enhanced summer moisture and protected seedlings from wind chill exposure for seedlings growing in cold & dry locations, and objects protected seedlings from excessive radiation and wind in warm & dry high locations. Our study results suggest that climate change will most benefit seedling regeneration in cold & wet locations and will most limit seedling regeneration in warm & dry locations given likely increases in fire and drought. Study results suggest that high-elevation mountain forests with water-limited growing seasons are likely to experience recruitment declines or, at best, no new recruitment advantage as climate warms. Climate envelope models, generally focusing on adult trees rather than seedling requirements, often assume that a warming climate will move tree species upward. Study results suggest that climate models may benefit from more physically-based considerations of microsites, climate, and current seedling regeneration limitations.
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Seiwa, Kenji, and Kihachiro Kikuzawa. "Phenology of tree seedlings in relation to seed size." Canadian Journal of Botany 69, no. 3 (1991): 532–38. http://dx.doi.org/10.1139/b91-072.
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Vertical growth patterns and leaf dynamics of seedlings of 31 deciduous broad-leaved tree species with different seed sizes were examined under either open or shaded conditions. Seed size positively affected initial seedling height and leaf longevity, and negatively affected duration of leaf emergence and leaf-turnover rate. Large-seeded species completed shoot elongation and almost all of their annual leaf production in a short period, irrespective of shading. Small-seeded species attained maximum heights similar to those of large-seeded species under open conditions by having a longer duration of leaf emergence, higher resource allocation to leaf production, and rapid leaf turnover. However, leaf-production and leaf-turnover rates were reduced by shading for small-seeded species, a trait that resulted in lower final seedling heights for small- versus large-seeded species. In small-seeded species, maximum seedling growth was attained only under open conditions through changes in the phenology of leaf dynamics. In contrast, growth of large-seeded species was independent of the effect of light limitation. The importance of seed size in determining seedling establishment success depends on the relationships between seasonal change of environmental light conditions and characteristics of seedling phenology, which are related to seed size. Key words: seed size, tree seedlings, leaf dynamics, phenology, establishment strategies.
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Kingery, J. L., and R. T. Graham. "The Effect of Cattle Grazing on Ponderosa Pine Regeneration." Forestry Chronicle 67, no. 3 (1991): 245–48. http://dx.doi.org/10.5558/tfc67245-3.
Full textAbstract:
During the summer and fall of 1982, a study was established on the Nez Percé National Forest in central Idaho to assess the effects of cattle grazing on the performance of a new ponderosa pine (Pinus ponderosa Laws.) plantation. Three study sites were located in a Douglas-fir/ninebark (Pseudotsuga menziesii/Physocarpus malvaceus) habitat type. Results after six years showed that livestock use can influence tree seedling establishment. Mortality and damage to tree seedlings from cattle resulted primarily from trampling rather than from browsing. Five and one-half percent of the seedlings were damaged by cattle, of which 3.6% died. Browsing by deer and elk caused the most growth loss. Overall damage was greatest from non-animal causes. Seedling quality at the time of planting, handling of the seedling, and droughty conditions during the first two years of the study contributed to this type of damage. Overall performance of the tree seedlings were relatively poor. Total mortality to tree seedlings resulting from all sources of damage was 43.6% for the grazed treatment and 25.3% for the non-grazed treatment.
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LePage, Philip T., Charles D. Canham, K. Dave Coates, and Paula Bartemucci. "Seed abundance versus substrate limitation of seedling recruitment in northern temperate forests of British Columbia." Canadian Journal of Forest Research 30, no. 3 (2000): 415–27. http://dx.doi.org/10.1139/x99-223.
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We examine the influence of (i) the spatial distribution and abundance of parent trees (as seed sources) and (ii) the abundance and favourability of seedbed substrates, on seedling recruitment for the major tree species in northwestern interior cedar-hemlock forests of British Columbia, under four levels of canopy openness (full canopy, partial canopy, large gap, and clearcut). Substrate distribution varied with canopy openness, and substrate favourability was a function of both canopy openness and seedling species. Lack of suitable substrates was the predominant factor limiting seedling density under full canopies. Partial canopy and gap sites provided a broad range of favourable substrates in close proximity to parent trees, resulting in the highest observed seedling densities. There was much higher effective dispersion of seedlings away from parent trees in gaps than in the partially cut stands. Seedling dispersion to clearcut sites was poor with seedlings being tightly restricted to a narrow band along the forest edge. Thus, seedling recruitment in these forests was a reflection of the interaction between the abundance of seed and substrate favourability, and the relative importance of these factors varied significantly with canopy structure.
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Eissenstat, David M., Javier F. Espeleta, and Eric L. Whaley. "Responses of the Fine Roots of Citrus to Dry Surface Soil." HortScience 31, no. 4 (1996): 577a—577. http://dx.doi.org/10.21273/hortsci.31.4.577a.
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Despite the frequent occurrence of hot, dry surface soil, little is known about the fate of roots in this soil layer during and following periods of surface drought. Phosphorus uptake kinetics were examined in surface roots of citrus seedlings exposed to different periods of drought. Exposure to dry soil for up to 43 days had no effect on phosphate uptake of excised roots measured at solution concentrations of 50, 750, and 1500 μm phosphate. Effects of surface drought on fine root behavior of seedlings and bearing trees were examined in the field using a split-pot arrangement. At the end of 5 weeks of drought, only about 1% of the roots in the top pot of either the seedling or tree had died. By 8 to 9 weeks of drought, about 26% of the fine laterals of the adult citrus had died, but only 6% had died in the seedling. After 15 weeks of drought, 33% of the mature tree fine roots had died but only 8% had died in the seedling. Root-soil respiration per gram root at this time was at least twice as high in the seedling as in the mature tree. Fine roots of citrus are remarkably tolerant to dry surface soils of about 5 weeks duration, both in terms of root survival and resumption of physiological activity after rewetting.
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Grauke, L. J., and J. W. Pratt. "Pecan Bud Growth and Freeze Damage are Influenced by Rootstock." Journal of the American Society for Horticultural Science 117, no. 3 (1992): 404–6. http://dx.doi.org/10.21273/jashs.117.3.404.
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Seven open-pollinated pecan [Carya illinoinensis (Wangenh.) K. Koch] stocks were grown in a nursery in blocks. Bud growth of ungrafted seedlings was influenced by rootstock, with growth being more advanced on `Curtis', `Elliott', `Apache', and `Sioux' seedlings than on `Moore', `Riverside', and `Burkett'. Bud growth of grafted trees was influenced by scion, with growth of `Candy' being most advanced, while `Cape Fear' trees were more advanced than `Stuart'. Growth of `Candy' grafted trees was affected by rootstock, with growth being more advanced on `Elliott' and `Curtis' seedling rootstock as compared to `Apache', Sioux', `Riverside', and `Burkett' seedling rootstock. Tree damage caused by a May freeze was directly related to bud growth and was influenced by scion and rootstock.
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Taylor, Alan H., Zisheng Qin, and Jie Liu. "Tree regeneration in an Abiesfaxoniana forest after bamboo dieback, Wang Lang Natural Reserve, China." Canadian Journal of Forest Research 25, no. 12 (1995): 2034–39. http://dx.doi.org/10.1139/x95-220.
Full textAbstract:
Bamboos in the understory of Abiesfaxoniana Render & Wilson forests in China impede tree regeneration when they are mature. However, bamboos die back every few decades and may synchronize tree seedling establishment on the forest floor. Tree seedling regeneration patterns were studied beneath 20 canopy gaps and adjacent closed forest in an old-growth A. faxoniana forest where understory bamboos died back in 1976. Most seedlings of A. faxoniana, Acercaudatum Wallich, and Betulautilis D. Don in gaps established 2 years after dieback of the bamboo Fargesiadenudata Yi. Acercaudatum seedlings in gaps were taller than those of B. utilis or A. faxoniana, and B. utilis seedlings were fourfold more abundant in gaps than the other species. All species (except A. caudatum) had greater seedling densities in gaps, but there were no density differences among species beneath closed forest. Bamboo cover and maximum culm height were greater under gaps than forest, and it takes bamboo seedlings about 18 years to grow to full height. Bamboo seems to reduce the success of an advanced regeneration strategy and promotes synchronized seedling establishment in gaps after it dies back.
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Weisberg, Peter J., and William L. Baker. "Spatial variation in tree regeneration in the forest-tundra ecotone, Rocky Mountain National Park, Colorado." Canadian Journal of Forest Research 25, no. 8 (1995): 1326–39. http://dx.doi.org/10.1139/x95-145.
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Ecotone vegetation may be especially sensitive to climate change. In particular, the invasion of subalpine meadows by tree seedlings has been well documented. However, there has been no systematic analysis of tree regeneration across the environmental heterogeneity of the alpine forest–tundra ecotone (FTE). Also, the position of the FTE may be relictual from more favorable climates of the past and therefore unresponsive to changing climate. To assess the environmental controls on FTE tree regeneration, to determine whether the ecotone might be relictual, and to determine whether tree invasion of nonforested FTE areas is occurring, we measured tree regeneration in various environments within the FTE of Rocky Mountain National Park, Colorado. Generally, seedling establishment appears to be controlled by patterns of soil moisture. Little seedling establishment was observed in krummholz openings, except for high seedling densities in willow wetlands. Tree seedling invasion of tundra is rare. Therefore, the upper limits of the FTE in Rocky Mountain National Park may be relictual from more favorable climates of the past. Abundant seedling establishment in patch forest openings suggests that patch forest may be poised to change to closed forest.
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ADEYEMI, Christiana O., Kehinde S. OLORUNMAIYE, Elizabeth O. ORHUAMEN, and Kike O. OGUNSOLA. "Germination and Seedling Development of Seeds from Different Parkia biglobosa (Jacq) G. Don Trees." Notulae Scientia Biologicae 5, no. 1 (2013): 120–26. http://dx.doi.org/10.15835/nsb518341.
Full textAbstract:
The effect of daylight, continuous illumination and acid scarification on the seed germination and seedling vegetative growth (epicotyl and hypocotyl lengths, and number of secondary roots) of different Parkia biglobosawere investigated in the Plant Physiology Laboratory University of Ilorin, Ilorin Kwara State Nigeria. Seeds from two out of the twenty six Parkia tree samples (trees B and T) germinated within 24 hours of planting in the daylight germination study while seeds from another tree (Q) did not germinate until the third week after planting (3WAP). Some seeds have higher germination percentage both in the daylight (preliminary germination study) and in the continuous light (illuminated study). The treatment with concentrated Sulphric acid (conc. H2SO4)was effective in breaking the seed dormancy as seeds from eight (8) trees produced one hundred percent (100%) germination. At p= 0.05 the length of epicotyl and hypocoty1 lengths were significantly different as seedling vegetative growth were long in the seedlings from the daylight experiment than the continuous light experiment. The vegetative growths of the seedlings from the scarified seed were longer at 15min of scarification in all except in trees F and Z. It was observed that the time of scarification affect the both seed germination and seedling development.
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Runde, Douglas E., Dale L. Nolte, Wendy M. Arjo, and William C. Pitt. "Efficacy of Individual Barriers to Prevent Damage to Douglas-Fir Seedlings by Captive Mountain Beavers." Western Journal of Applied Forestry 23, no. 2 (2008): 99–105. http://dx.doi.org/10.1093/wjaf/23.2.99.
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Abstract We tested the ability of individual tree seedling protectors to deter mountain beavers from damaging Douglas-fir seedlings. Using captive mountain beavers in field pens, we tested 20 products representative of a wide range of barriers suitable for protecting individual tree seedlings from rodent damage. Eleven products protected 95% or more of seedlings from damage. Tree shelters and fabric shelters provided the most protection; 98 and 95% of seedlings were undamaged, respectively. Rigid mesh protector tubes protected 81% of seedlings, and protection netting protected 55% of seedlings. Purchase prices varied widely; protection netting was least expensive, followed by rigid mesh tubes, fabric shelters, and tree shelters. Seedling growth was greatest within fabric shelters and plastic tree shelters. Materials used to construct 15 of the 20 tree protectors were tested using captive mountain beavers in small sheltered pens. Here, samples of barrier materials were used to block access to a favored food. The four materials that excluded all test animals in all trials were from unvented tree shelters with solid seamless walls. Seven materials failed to exclude any animals in the sheltered-pen trials.
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Qie, Lan, Alexander D. Elsy, Ashley Stumvoll, et al. "Impending Regeneration Failure of the IUCN Vulnerable Borneo Ironwood (Eusideroxylon zwageri)." Tropical Conservation Science 12 (January 2019): 194008291882335. http://dx.doi.org/10.1177/1940082918823353.
Full textAbstract:
The regeneration of many climax species in tropical forest critically depends on adequate seed dispersal and seedling establishment. Here, we report the decreased abundance and increased spatial aggregation of younger trees of the Borneo ironwood ( Eusideroxylon zwageri) in a protected forest in Sabah Malaysia. We observed a high level of seedling herbivory with strong density dependence, likely exacerbated by local aggregation and contributing to the progressively shrinking size distribution. We also note the largely undocumented selective herbivory by sambar deer on E. zwageri seedlings. This study highlights the combined impact of altered megafauna community on a tree population through interlinked ecological processes and the need for targeted conservation intervention for this iconic tropical tree species.
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Jones, Robert H., Ralph D. Nyland, and Dudley J. Raynal. "Response of American Beech Regeneration to Selection Cutting of Northern Hardwoods in New York." Northern Journal of Applied Forestry 6, no. 1 (1989): 34–36. http://dx.doi.org/10.1093/njaf/6.1.34.
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Abstract Root sprout and seedling regeneration of American beech was sampled in two maple-dominated northern hardwood stands 13-14 years after single-tree selection cutting. The largest stems had been advance regeneration, and seedlings comprised a substantial and well-distributed portion of these. Among stems established after the cut, root sprouts outnumbered seedlings. Total beech regeneration abundance was correlated with basal area of overstory beech. For long-term beech control, it may be useful to reduce beech seedling populations before selection cutting, and to cut large diameter beech trees. North. J. Appl. For. 6:34-36, March 1989.
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Delissio, Lisa J., Richard B. Primack, Pamela Hall, and H. S. Lee. "A decade of canopy-tree seedling survival and growth in two Bornean rain forests: persistence and recovery from suppression." Journal of Tropical Ecology 18, no. 5 (2002): 645–58. http://dx.doi.org/10.1017/s0266467402002420.
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The population dynamics of 8500 shade-tolerant tree seedlings of 13 tree species were followed for 10 years at rain forests in Lambir Hills National Park and Bako National Park, Malaysian Borneo. Since these dipterocarp forests have lower rates of canopy gap formation than do rain forests elsewhere, tree seedling biology was predicted to differ. Approximately 50% of seedlings present in 1986 were still alive in 1996. Seven out of thirteen had seedling populations composed predominantly of individuals that were at least 10 years old. These seedlings can undergo alternating periods of relatively rapid and slow growth. Many seedlings that grew rapidly in the first census interval survived through a period of suppression in the second census interval, and conversely many seedlings with a history of suppression had exceptionally high growth in the final census interval. Seedlings of South-East Asian forest tree species are long-lived and appear to be adapted to long periods of suppression in the understorey.
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Silva, Richardson Barbosa Gomes da, Mônica Moreno Gabira, Débora Zanoni do Prado, Gláucia Uesugi, Danilo Simões, and Magali Ribeiro da Silva. "Influence of Mean Leaf Angles and Irrigation Volumes on Water Capture, Leaching, and Growth of Tropical Tree Seedlings." Forests 11, no. 11 (2020): 1198. http://dx.doi.org/10.3390/f11111198.
Full textAbstract:
Research Highlights: The mean leaf angle and crown projection area can be used as criteria for grouping tree seedling species in different irrigation zones in tree nurseries with overhead microsprinkler systems, preventing water and fertilizer waste, and increasing growth. Background and Objectives: There are important gaps in current functional knowledge about how plant architecture, especially the mean leaf angles of tree seedlings, affect water and nutrient solution capture in overhead microsprinkler systems. These gaps contribute to water and fertilizer waste in tree nurseries. This research aimed to ascertain how mean leaf angles affect irrigation water capture, leaching, and the growth of tree seedlings given different volumes of irrigation. Materials and Methods: Nine species of tree seedlings with different mean leaf angles were submitted to four irrigation volumes (8, 10, 12, and 14 mm) applied daily by overhead microsprinklers in a split-plot design completely randomized. The variables leaching fraction, height, stem diameter, shoot, root, and total dry mass, Dickson quality index, crown projection area, root system quality, and leachate electrical conductivity were evaluated. Results: For species with mean leaf angles of −54, 31, 38, 42, 55, 57, and 58°, the 8 mm irrigation volume was sufficient to produce greater growth and less leaching. For species with angles of −56 and −14°, the 14 mm irrigation volume was required to produce greater growth. Conclusions: The tree seedling species with positive mean leaf angles facilitate irrigation water and nutrient solution capture, allowing the application of lower irrigation volume. On the other hand, some tree seedling species with negative mean leaf angles hinder irrigation water and nutrient solution capture, requiring the application of higher irrigation volume. When the tree seedling species have a negative mean leaf angle, but the crown projection area is small, the difficulty of water and nutrient solution reaches directly the substrate is attenuated.
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Link, Arthur F., Trey Turnblacer, Cierra K. Snyder, Sarah E. Daugherty, and Ryan M. Utz. "Low Recruitment of Native Trees in a Deciduous Forest Associated with Japanese Barberry (Berberis thunbergii) Invasion." Invasive Plant Science and Management 11, no. 1 (2018): 20–26. http://dx.doi.org/10.1017/inp.2018.1.
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AbstractInvasive plants may dramatically impact forest ecosystems by establishing dense populations and suppressing the recruitment of native tree species. One invasive shrub currently spreading throughout eastern deciduous forests of North America, Japanese barberry (Berberis thunbergii DC), may be limiting tree recruitment in stands where it invades. Once established, B. thunbergii becomes densely populated within forest understories and suppresses native plants by competing for limited resources, altering soil conditions, and changing the understory microclimate. To quantify native seedling inhibition caused by B. thunbergii invasion, we conducted an observational study on seedling abundance within forest plots that were either invaded or not invaded by B. thunbergii and used survey data to generate Bayesian models of native seedling densities along gradients of increasing B. thunbergii stem counts and aboveground plant dry mass. Model outputs predicted that B. thunbergii–invaded plots had 82% lower seedling densities compared with uninvaded plots. Native tree seedling densities were very low even in areas with moderate B. thunbergii density, suggesting that reduced tree seedling densities are observed even at low densities of invasion. Our findings indicate that forests invaded with B. thunbergii harbor substantially lower densities of native tree seedlings, with potentially significant long-term consequences for forest ecological integrity, biodiversity, and ecosystem services.
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McGuire, John P., Robert J. Mitchell, E. Barry Moser, Stephen D. Pecot, Dean H. Gjerstad, and Craig W. Hedman. "Gaps in a gappy forest: plant resources, longleaf pine regeneration, and understory response to tree removal in longleaf pine savannas." Canadian Journal of Forest Research 31, no. 5 (2001): 765–78. http://dx.doi.org/10.1139/x01-003.
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Resource availability and planted longleaf pine (Pinus palustris Mill.) seedling and understory vegetation response within and among three sizes of experimentally created canopy gaps (0.11, 0.41, 1.63 ha) in a mature longleaf pine savanna were investigated for 2 years. Longleaf pine seedlings and understory vegetation showed increased growth in gaps created by tree removal. Longleaf pine seedling growth within gaps was maximized approximately 18 m from the uncut savanna. Increased longleaf pine seedling survival under the uncut savanna canopy observed after the first year suggests that the overstory may facilitate establishment of longleaf pine seedlings rather than reduce survival through competition. Despite the relative openness of the uncut longleaf pine forest, light quantity was increased by tree removal. Light was also the resource most strongly correlated with seedling and understory vegetation growth. Although net N mineralization was correlated to seedling response, the amount of variation explained was low relative to light. Belowground (root) gaps were not strong, in part because of non-pine understory roots increasing in biomass following tree removal. These results suggest that regeneration of longleaf pine may be maximized within gap sizes as small as approximately 0.10 ha, due largely to increases in light availability.
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Khan, Afsheen. "Seedling diversity and spatial distribution of some conifers and associated tree species in highly disturbed Western Himalayan regions in Pakistan." Journal of Forest Science 67, No. 4 (2021): 175–84. http://dx.doi.org/10.17221/138/2020-jfs.
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This article encompasses the impacts of disturbance, regeneration potential of conifers and the dynamics of tree species seedlings along the spatial scale in Murree forest. The seedling status preferably of conifers along with associated broadleaved dominant tree species is determined by a quantitative evaluation of diversity functions. An empirical approach is applied to predicting the future of seedlings under stress as well as the current hypothetical appearance of seedlings in the forest. The need of analysing diversity of this forest is due to highly disturbed conditions there, and this paper is designed to know the recent trends of species diversity in the area. Species diversity and species abundance at a seedling level are estimated by using standard formulas of diversity measurements. Thirty stands are used for the evaluation of seedling abundance in highly disturbed conditions with the examination of diversity in the area. Seedling density is too low in the forest whereas diversity is also in poor condition. Seedlings from four conifers with three broadleaved species in different stands indicated the low density of future trees. The mean density·ha<sup>–1</sup> of pine seedlings is consecutively low in Pinus wallichiana (16 ± 2), Pinus roxburghii (11 ± 3), Cedrus deodara (9 ± 3), Abies pindrow (8 ± 3). The correlation coefficient is as low as 0.76, 0.66 and 0.61 in Pinus roxburghii, Cedrus deodara and Abies pindrow, respectively, while Pinus wallichiana showed a significant correlation, i.e. P &gt; 0.5. Hence, this study claims that the survival of the forest is threatened as seedling density and diversity are too low. This forest needs serious attention towards preventing and conserving pines and other associated species seedlings for the existence of this forest in future.
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McGuire, Krista L. "Recruitment dynamics and ectomycorrhizal colonization of Dicymbe corymbosa, a monodominant tree in the Guiana Shield." Journal of Tropical Ecology 23, no. 3 (2007): 297–307. http://dx.doi.org/10.1017/s0266467406003968.
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The dynamics of early life-history stages are important for understanding regional diversity patterns in tropical trees. In this study, patterns of seed removal, seedling survival and ectomycorrhizal (ECM) colonization in monodominant and mixed tropical rain forests in Guyana were investigated during a masting event of an ECM monodominant tree, Dicymbe corymbosa. Two seed densities (1 m−2 and 6 m−2) were tested in two forest types (monodominant versus mixed) with 10 plots per treatment (40 plots total). Germination success, seed and seedling survival after 1 y were measured for the monodominant tree, and four non-dominant canopy tree species found in both forest types (Eschweilera sagotiana, Licania laxiflora, Chrysophyllum sanguinolentum and Carapa guianensis). A significant effect of forest type was detected for seed removal and seedling survival. In the mixed forest, seed removal was higher for all species, with 27% average removal compared with 7% average seed removal in the monodominant forest. Germination success was significantly lower for all but one species in the mixed forest, with average germination of 41% compared with 78% germination in the monodominant forest. Seed and seedling survival of the monodominant tree was greatest within the monodominant forest with 93% of seeds germinating and 85% of seedlings surviving after 1 y compared with 65% germination and 15% seedling survival in the mixed forest. Per cent ectomycorrhizal colonization of Dicymbe corymbosa was near 100% in the monodominant forest, but significantly lower (14%) in the mixed forest. These results suggest that seedling survival patterns, rather than seed survival, are more important for recruitment success in this system and that ectomycorrhizal inoculum may limit establishment of Dicymbe corymbosa in the mixed forest.
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Burton, Philip J., Jesy Simons, Steve Brittingham, Daniel B. Thompson, Darin W. Brooks, and Lawrence R. Walker. "Regeneration dynamics of Great Basin bristlecone pine in southern Nevada." Canadian Journal of Forest Research 50, no. 6 (2020): 589–94. http://dx.doi.org/10.1139/cjfr-2019-0404.
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Great Basin bristlecone pine (Pinus longaeva D.K. Bailey) is an important and long-lived tree species found at high elevations in the interior southwest of the United States, but little is known about its regeneration requirements and response to disturbance. We conducted extensive surveys of seedling regeneration and environmental attributes of regeneration sites in undisturbed forest dominated by this species in the Spring Mountains of southern Nevada. Additional surveys tallied new seedling densities and site attributes 4 years after a wildfire in the same area. Seedlings, saplings, and juvenile trees were less abundant than adult trees in the unburned forest, and soils had lower bulk density and greater depth, moisture, and soil organic matter under adult trees than in open areas. Seedling distributions in both unburned and burned forest showed a negative relationship to a heat load index governed by aspect. The density of new seedlings after the fire was negatively related to distance from unburned forest edges. Seedlings were found in clusters and were associated with adult trees (live or dead) in both unburned and burned stands. Seedling emergence from animal-dispersed caches was more frequent in burned habitats than in unburned habitats. These natural regeneration dynamics provide potential guidance for restoration efforts in this ecosystem.
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Polanía, Brayan S., Ana M. Aldana, Marius Bottin, et al. "Effect of Seasonal Rains and Floods on Seedling Recruitment and Compositional Similarity in Two Lowland Tropical Forests." Forests 11, no. 12 (2020): 1297. http://dx.doi.org/10.3390/f11121297.
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Research Highlights: Seasonally flooded and terra firme forests are characteristic ecosystems of the Colombian Orinoco Basin and of great importance in the maintenance of regional biodiversity and ecosystem function. These forests have a unimodal precipitation regime that can cause a temporal effect on the seedling regeneration niche. This could partly explain the high diversity and coexistence of plant species in these forests, as well as the similarity in composition of seedlings and trees. Background and Objectives: Seedlings are a key factor in the assembly of plant communities. We evaluated the effect of flooding and rains on the dissimilarity and compositional affinity between trees and seedlings of seasonally flooded and terra firme forests. Materials and Methods: the tree community of these forests in San Martín (Meta, Colombia) was characterized and compared with their respective seedling communities before (June) and after (December) rain and flooding (during the rainy season). We evaluated plant species diversity and abundance (Shannon diversity and Pielou eveness index), as well as the compositional dissimilarities of each tree community with their corresponding seedling community sampled at the beginning and end of rains and flooding (Bray–Curtis dissimilarity). We also compared sampling site composition using a NMDS analysis. Results: We found that the terra firme forest had higher diversity compared to the flooded forest. Seedling density in the seasonally flooded forest decreased significantly after the flood but not in the terra firme forest at the end of the rainy season. The compositional dissimilarity between trees and seedlings in the seasonally inundated forest also decreased after the flood. However, this pattern was not evident in the terra firme forest. Conclusions: These results indicate that seasonal flooding generates a strong ecological filter that affects the realized niche of plants in these forests. Our results can contribute valuable information for the effective development of assisted restoration and conservation programs.
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Lantagne, Douglas O., Carl W. Ramm, and Donald I. Dickmann. "Tree Shelters Increase Heights of Planted Oaks in a Michigan Clearcut." Northern Journal of Applied Forestry 7, no. 1 (1990): 24–26. http://dx.doi.org/10.1093/njaf/7.1.24.
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Abstract A shelterwood cut, applied in 1954, failed to adequately regenerate oaks on an upland site in southern Michigan. At age 22, the stand, dominated by dogwood, red maple, black cherry, and other low-quality species, was clearcut and planted to 2-0 northern red oak seedlings. Four treatments included: control (clearcut harvest only), woody brush control, plastic tree seedling shelters, and woody brush control plus tree seedling shelters. The northern red oak seedlings planted in tree shelters were 42% taller than unsheltered seedlings after 2 growing seasons. Over 64% of sheltered seedlings were 3 ft high or taller, compared to only 22% of the unsheltered seedlings, after 2 growing seasons. Woody brush control appeared to have no effect on the 2-year height of planted red oak. North. J. Appl. For. 7(1):24-26, March 1990.
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Saúco, Víctor Galán, María José Grajal Martín, Domingo Fernández Galván, Águeda Coello Torres, José Juárez, and Luis Navarro. "Occurrence of Spontaneous Tetraploid Nucellar Mango Plants." HortScience 36, no. 4 (2001): 755–57. http://dx.doi.org/10.21273/hortsci.36.4.755.
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A putative polyploid seedling tree appeared among the polyembryonic mango (Mangifera indica L.) `Gomera-1', widely used as a rootstock in the Canary Islands. Initially detected because of its wider and more coriaceous leaves, further studies showed that fruit from this seedling are considerably larger than normal, although all other fruit characteristics (including polyembryony) were similar to those of standard `Gomera-1' (G-1) fruit. The progeny of this plant has, to date, proved to be morphologically identical to the mother plant. Studies of seedlings from normal G-1 trees growing in the same orchard showed that 10% of the plants had morphological characteristics similar to those of the putative polyploid seedling. Flow cytometry and chromosome count analyses confirmed that G-1 is diploid, whereas the putative polyploid is a stable tetraploid. The study also showed that the morphologically abnormal seedlings from diploid parent trees were spontaneous tetraploids.
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Kreyling, Juergen, Andreas Schmiedinger, Ellen Macdonald, and Carl Beiekuhnlein. "Potentials of Natural Tree Regeneration after Clearcutting in Subalpine Forests." Western Journal of Applied Forestry 23, no. 1 (2008): 46–52. http://dx.doi.org/10.1093/wjaf/23.1.46.
Full textAbstract:
Abstract Regeneration of interior mountain forests still is not adequately understood, although these forests are subject to intensified use over the last decades. We examined factors influencing the success of natural tree regeneration after harvesting in the Engelmann spruce–subalpine fir zone of the Monashee Mountains, British Columbia, Canada. Distance from the forest edge was an important factor for regeneration; at distances exceeding 70 m from the forest edge only 50% of plots showed sufficient natural regeneration to meet stocking targets compared with 90% of plots closer to forest edges. Seedling density and growth were superior in the more protected southern portions of clearcuts. Seedling growth was less in plots containing high cover of downed woody debris. There was no relationship between understory plant diversity or composition and tree seedling regeneration. However, cover of fireweed (Epilobium angustifolium) had a significant negative relationship with density but not growth of tree seedlings, particularly for lodgepole pine (Pinus contorta var. latifolia). Cover of fireweed decline substantially within the first 10 years after clearcutting. We conclude that natural regeneration of trees has potential to help achieve stocking targets and also to maintain natural diversity of tree species if spatial constraints, especially thresholds in clearcut size, are considered.
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Lu, Pengxin, Wayne Bell, Paul Charrette, and Megan Thompson. "Performance of jack pine (Pinus banksiana) rooted cuttings from proliferated dwarf shoots versus seedlings 8 years after planting." Canadian Journal of Forest Research 42, no. 7 (2012): 1404–9. http://dx.doi.org/10.1139/x2012-079.
Full textAbstract:
Growth and tree form characteristics of jack pine (Pinus banksiana Lamb.) rooted cuttings propagated from proliferated dwarf shoots (PDS) were compared with seedlings in two field trials 8 years after establishment. Results indicated that jack pine rooted cuttings from PDS can grow as well as seedlings and maintain acceptable tree form. Rooted cuttings of progeny from the 22 top-ranking open-pollinated families in a seedling seed orchard of jack pine were 4.2% taller and 10% larger in diameter at breast height than commercial seedlings tested on the same sites, which indicates that rooted cuttings have potential in realizing genetic gains in jack pine tree improvement programs. Rooted cuttings increased the proportion of trees with normal branching characteristics and reduced the percentage of trees with excessive heavy branches in the Sault St. Marie trial, which had larger tree sizes. However, longer term monitoring (20 to 25 years) is needed to determine stability of jack pine rooted cuttings planted on sandy soil where wind throw may become a problem as tree size increases.
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Domic, Alejandra I., José M. Capriles, and Gerardo R. Camilo. "Evaluating the fitness effects of seed size and maternal tree size on Polylepis tomentella (Rosaceae) seed germination and seedling performance." Journal of Tropical Ecology 36, no. 3 (2020): 115–22. http://dx.doi.org/10.1017/s0266467420000061.
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AbstractIn vascular plants, larger seeds are generally associated with higher germination potential, healthier seedlings and overall higher rates of survivorship. How this relationship holds or what other physiological tradeoffs evolved in plants adapted to high-altitude environments, such as the tropical and subtropical highland Polylepis tree, remain unclear. In this study, we evaluated the relationship between seed mass and seedling performance by testing the reserve effect, the metabolic effect, and the seedling-size effect hypotheses in Polylepis tomentella Weddell (Rosaceae). Since the relationship between fitness and seed size can often depend on maternal plant size, we additionally investigated the association between germination success, seedling performance (survival, relative growth rate (RGR) and height), and size of bearing-seed trees under controlled greenhouse conditions. Our results showed that heavier seeds are more likely to germinate, but we did not find evidence that could support the reserve effect, metabolic effect or seedling-size effect. As seedlings from larger and medium seeds exhibited comparatively similar RGR, survival percentages and final size, maternal plant size was positively associated with improved seed quality and seedling performance. These results demonstrate that seed mass and maternal size during early seedling establishment are critical for Polylepis persistence, demography and conservation.
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Marro, Nicolás, Florencia Soteras, Noelia Cofré, et al. "NEOTROPICAL TREE PRODUCTION: INSIGHTS INTO GERMINATION, GROWTH AND OUTPLANTING FOR Maytenus boaria." CERNE 23, no. 3 (2017): 377–85. http://dx.doi.org/10.1590/01047760201723032344.
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ABSTRACT Knowledge about tree production practices is essential to support forest restoration projects, but is still lacking for many tree species. Maytenus boaria is a neotropical tree distributed across the temperate and subtropical South American mountains. In central Argentina, it is mainly restricted to the most preserved forest remnants. Attempts to plant this species have had little success due to difficulties in seedling production and low seedling survival. We set up four trials aiming to identify the constraints of seedling production and outplanting. Under greenhouse conditions, we evaluated (i) pre-germination treatments and (ii) seedling response to inoculation with arbuscular mycorrhizal fungi (AMF). In the field, we planted M. boaria saplings as well as saplings of the most abundant tree in our study site and recorded (iii) survival and height for 10 years. Finally, (iv) we quantified natural recruitment in an attempt to determine M. boaria regeneration niche. Germination varied from 13.1 to 29.2% among treatments. Depulped seeds stratified at 5 ºC showed the highest germination (29.2%). Shoot phosphorus concentration in AMF-treated seedlings was significantly higher (45%) than in non-inoculated seedlings. Survival of M. boaria saplings was similar to that of the most abundant tree in our study site, but their lower height suggested limited growth. We recorded low abundance of M. boaria seedlings in the field; therefore, we were unable to identify the characteristics of its regeneration niche. Reforestation activities should include seed depulping and stratification at 5 ºC to improve germination. The capacity of AMF to enhance nutrition should be evaluated under field conditions.
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Woods, Kerry D. "Living long by staying small: stem layering as an adaptive life-history trait in shade-tolerant tree seedlings." Canadian Journal of Forest Research 38, no. 3 (2008): 480–87. http://dx.doi.org/10.1139/x07-136.
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Suppressed seedling banks are important in replacement dynamics in late-successional forests. However, demographic properties of seedling populations are poorly known, and there has been little attention to traits that might affect fitness in suppressed seedlings. Acer saccharum Marsh., a shade-tolerant dominant in eastern North American forests, frequently develops adventitious roots along prostrate portions of stems (“layering”). Measurements of Acer seedlings in old-growth forests in Michigan indicate that layered seedlings proportionally reduce structural allocations to older layered stem tissues, retain leaf area / height ratios of younger unlayered seedlings, and tend to survive longer. In tree seedlings, allometric consequences of normal stem growth lead to declining ratios of photosynthetic to nonphotosynthetic biomass, which potentially reduces shade tolerance and limiting age. The layering habit may defer this penalty by changing the allometry of growth. Resulting increases in life expectancy should increase chance of access to increased light and of reaching the canopy. Thus, because flowering is generally restricted to canopy trees, the tendency to layer may increase fitness. Properties of individuals in suppressed seedling banks may be selectively and ecologically important, shaping life histories and population dynamics.
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BARALOTO, CHRISTOPHER, PIERRE-MICHEL FORGET, and DEBORAH E. GOLDBERG. "Seed mass, seedling size and neotropical tree seedling establishment." Journal of Ecology 93, no. 6 (2005): 1156–66. http://dx.doi.org/10.1111/j.1365-2745.2005.01041.x.
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Johnson, Daniel J., Richard Condit, Stephen P. Hubbell, and Liza S. Comita. "Abiotic niche partitioning and negative density dependence drive tree seedling survival in a tropical forest." Proceedings of the Royal Society B: Biological Sciences 284, no. 1869 (2017): 20172210. http://dx.doi.org/10.1098/rspb.2017.2210.
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In tropical tree communities, processes occurring during early life stages play a critical role in shaping forest composition and diversity through differences in species' performance. Predicting the future of tropical forests depends on a solid understanding of the drivers of seedling survival. At the same time, factors determining spatial and temporal patterns of seedling survival can play a large role in permitting species coexistence in diverse communities. Using long-term data on the survival of more than 45 000 seedlings of 238 species in a Neotropical forest, we assessed the relative importance of key abiotic and biotic neighbourhood variables thought to influence individual seedling survival and tested whether species vary significantly in their responses to these variables, consistent with niche differences. At the community level, seedling survival was significantly correlated with plant size, topographic habitat, neighbourhood densities of conspecific seedlings, conspecific and heterospecific trees and annual variation in water availability, in descending order of effect size. Additionally, we found significant variation among species in their sensitivity to light and water availability, as well as in their survival within different topographic habitats, indicating the potential for niche differentiation among species that could allow for species coexistence.
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Buermeyer, Karl R., and Constance A. Harrington. "Fate of Overstory Trees and Patterns of Regeneration 12 Years After Clearcutting with Reserve Trees in Southwest Washington." Western Journal of Applied Forestry 17, no. 2 (2002): 78–85. http://dx.doi.org/10.1093/wjaf/17.2.78.
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Abstract Changes in management objectives for some forestlands in the Pacific Northwest have spurred interest in the creation of multistoried stands and the use of natural regeneration systems, but data on such systems are lacking. We assessed the status of the overstory trees and the regeneration 12 yr after a clearcut harvest with reserve trees in an even-aged, 145-yr-old Douglas-fir stand on a moderately productive site (site class 3) in southwest Washington. The 15 ha harvest unit was superimposed over two areas differentially thinned 15 and 34 yr before clearcutting. The clearcut harvest retained 18 trees/ha with a mean diameter of 63 cm. The reserved overstory trees had a 93% survival rate after 12 yr; most dead trees had been windthrown. Diameter growth for the reserved trees averaged 3.3 cm and was greatest during the most recent 3 yr period, which also had the highest growing-season precipitation. In a 1 ha mapped area, there were 5,854 seedlings/ha, and more than 99% of the regeneration was Douglas-fir. Most seedlings were less than 2 m tall. Seedling density was somewhat clumped (value of 2.1 for Pielou's index of nonrandomness), but 79% of randomly located 4.04 m2 (mil-acre) plots and 98% of 5 × 5 m grid cells had at least one conifer seedling. There was no obvious pattern of regeneration based on direction from the reserved trees, but both seedling density and seedling size within the drip lines of reserved tree crowns were less than in the rest of the area. The number of seedlings was similar on the two halves of the plot corresponding to the original thinning blocks, but seedling size and age differed. In the half of the study plot that had been twice lightly thinned, only 14% of the seedlings were >0.5 m tall; however, 41% of the seedlings were >0.5 m in the block that had been thinned more heavily. There was no difference between the thinning blocks in the ages of seedlings ≤0.5 m tall (mean age of 5 yr). This example of clearcutting with reserve trees resulted in reasonable survival of the overstory trees and adequate stocking but slow growth rates in the naturally regenerated Douglas-fir. Heavier thinning before harvest was associated with more advance regeneration, more shrub cover, and less windthrow of the reserved trees than in the more lightly thinned block. If an abundance of tree species other than Douglas-fir was desired on this site, interplanting would be required. West. J. Appl. For.17(2):78–85.
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Repáč, I., A. Tučeková, I. Sarvašová, and J. Vencurik. "Survival and growth of outplanted seedlingsof selected tree species on the High Tatra Mts. windthrow area after the first growing season." Journal of Forest Science 57, No. 8 (2011): 349–58. http://dx.doi.org/10.17221/130/2010-jfs.
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Bareroot and containerized seedlings (seedling type) of Norway spruce, Scots pine, European larch, European beech, and sycamore maple were outplanted in autumn 2008 and in spring 2009. Roots of a half of the seedlings were dipped into the commercial fungal product Ectovit prior to spring outplanting. Fifty seedlings were planted for each tree species and seedling type in each of 3 treatments (Autumn, Spring, Spring+Ectovit) and 3 replications (4,500 seedlings in total). Eighty-one per cent of containerized and 75% of bareroot seedlings (most &ndash; 89% of bareroot spruce, least &ndash; 59% of bareroot pine seedlings) survived after the first growing season. Planting time and Ectovit did not have a marked effect on survival, with the exception of the lower survival of containerized beech and spruce in autumn than in spring. The most extensive damage caused by game and mechanical weed control was found out in both broadleaves; most of the dry leading shoots occurred in beech. Besides beech, higher annual height increment of seedlings was observed in autumn than in spring planting time. Effect of Ectovit on seedling growth was not obvious. &nbsp;
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Castro, Jorge, and Alexandro Leverkus. "Effect of Herbaceous Layer Interference on the Post-Fire Regeneration of a Serotinous Pine (Pinus pinaster Aiton) across Two Seedling Ages." Forests 10, no. 1 (2019): 74. http://dx.doi.org/10.3390/f10010074.
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Herbaceous vegetation is a major source of interference with the regeneration of woody species. This is particularly the case after forest fires, as a dense herbaceous layer usually regenerates naturally. Although the competitive effect of the herbaceous vegetation upon tree seedlings has been widely studied, there are still gaps in knowledge for management related to the effect of tree seedling age and size on the outcome of the interaction. In this study, we seek to determine the response of maritime pine (Pinus pinaster Aiton) seedlings to herbaceous competition at two different seedling ages. For that, two treatments of herbaceous competition were implemented, namely unweeded (no action around pine seedlings) and weeded (herbaceous cover removed around pine seedlings). Treatments were conducted twice (2 and 4 years after the fire), and we monitored seedling survival and growth at the end of each growing season. The treatments were implemented across three adjacent landscape units that differed in the management of burned wood and that are representative of common post-fire scenarios: no intervention, salvage logging, and an intermediate degree of intervention. Weeding increased seedling survival from 44.7% to 67.8% when seedlings were 2 years old, but had no effect for four-year-old seedlings, which showed 99% survival. Seedling growth also increased in the weeding treatment, but only slightly. Moreover, growth (and survival for two-year-old seedlings) was strongly correlated with initial seedling size, particularly in the case of two-year-old seedlings. Initial pine seedling height was strongly and positively correlated with the height of the herbaceous layer, supporting the existence of microsite features that promote plant growth above competitive effects. The results support that management actions conducive to foster post-fire pine forest restoration in this Mediterranean ecosystem should reduce herbaceous competition at early stages after fire (second or third year) and focus on larger seedlings.