To see the other types of publications on this topic, follow the link: Spruce seedling.
Journal articles on the topic 'Spruce seedling'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Spruce seedling.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
O'Neill, G. A., C. P. Chanway, P. E. Axelrood, R. A. Radley, and F. B. Holl. "An assessment of spruce growth response specificity after inoculation with coexistent rhizosphere bacteria." Canadian Journal of Botany 70, no. 12 (1992): 2347–53. http://dx.doi.org/10.1139/b92-294.
Full textAbstract:
The influence of inoculation with rhizosphere bacteria on hybrid spruce (Picea glauca × engelmannii) seedling growth was investigated by isolating bacteria from the rhizosphere of naturally regenerating spruce seedlings collected from two ecologically distinct zones of British Columbia. Forty bacterial strains from spruce were screened in a seedling growth experiment, and several strains were shown to stimulate spruce seedling growth. The three most effective spruce growth promoting strains from each ecological zone were then tested in a seedling growth response specificity experiment in which seed, soil, and bacteria from both spruce ecosystems were examined in all possible treatment combinations, including pasteurized soil. Spruce seedling growth was primarily affected by seed and soil source (Salmon Arm > Mackenzie for both factors), and by soil pasteurization (pasteurized > unpasteurized). Significant growth effects due to bacterial treatment in the specificity experiment occurred only in pasteurized soil, but seedling biomass accumulation was stimulated by up to 59% in response to inoculation. There was no evidence of growth response specificity that was related to plant – bacteria adaptation within spruce ecotypes; two of the Mackenzie bacterial strains significantly inhibited growth of Mackenzie seedlings in Mackenzie soil, but two strains stimulated the growth of Salmon Arm seedlings, one in each soil type. Two Salmon Arm strains significantly stimulated growth of Mackenzie seedlings on Salmon Arm soil, and two strains stimulated the growth of Salmon Arm seedlings, one in each soil type. Seedling biomass was greater when treatments of spruce seed, soil, and rhizosphere bacteria that originated from the same geographic site were pooled and compared with treatments in which at least one factor originated from the other site. However, this effect was explained by the significant seed × soil interaction in the absence of bacteria; mean seedling biomass was greatest when spruce seed and soil treatments with the same geographic origin were pooled and compared with unrelated seed – soil combinations. Seedlings from pooled treatments were also significantly larger when bacteria and soil had a common geographic origin, but only when tested in pasteurized soil. Our results indicate that spruce growth promoting rhizosphere bacteria can be isolated from naturally regenerating spruce seedlings, but growth response variability was observed between trials. Seedling growth promotion by bacterial strains was not related to the use of spruce ecotypes, soil, and (or) rhizosphere bacteria with a common geographic origin. Key words: spruce seedlings, growth, inoculation, rhizosphere bacteria.
2
Attree, S. M., S. Budimir, and L. C. Fowke. "Somatic embryogenesis and plantlet regeneration from cultured shoots and cotyledons of seedlings from stored seeds of black and white sprees (Picea Mariana and Picea glauca)." Canadian Journal of Botany 68, no. 1 (1990): 30–34. http://dx.doi.org/10.1139/b90-005.
Full textAbstract:
Embryogenic callus was induced from cultured explants of 12- to 30-day seedlings germinated from 10- and 4-year stored seeds of black and white spruce, respectively. Plantlets were regenerated from a 12-day black spruce seedling derived embryogenic callus. This is the oldest conifer seedling material shown to give rise to embryogenic callus, and the first demonstration in spruce that seedling-derived embryogenic calli are competent of plantlet regeneration. The effect of a cytokinin pretreatment on embryogenic callus induction from 12-day black spruce seedling shoot explants was investigated. Although an induction frequency of 18% occurred after 2 weeks preculture of shoot explants on medium containing 4.5 μM benzyladenine, the cytokinin pretreatment was not significantly superior to controls given no pretreatment (12%). Age of explant influenced embryogenic induction frequencies from black and white spruce. Explants from 21-day black spruce seedlings produced embryogenic calli at a frequency of 5%. In comparison, shoot explants from 12- and 30-day white spruce seedlings given no benzyladenine pretreatment displayed induction frequencies of 38 and 18%, respectively.
3
Chanway, C. P., and F. B. Holl. "First year field performance of spruce seedlings inoculated with plant growth promoting rhizobacteria." Canadian Journal of Microbiology 39, no. 11 (1993): 1084–88. http://dx.doi.org/10.1139/m93-164.
Full textAbstract:
The influence of plant growth promoting rhizobacteria on field performance of hybrid spruce (Picea glauca × engelmannii) was investigated by inoculating seedlings with rhizobacteria capable of stimulating seedling growth in a controlled environment. Two spruce ecotypes (from Mackenzie and Salmon Arm, British Columbia) and two bacterial strains previously isolated from naturally regenerating seedlings of each spruce ecotype were evaluated. Planting trials were conducted in the ecosystem from which each spruce ecotype and associated bacterial strain were originally collected, and at two alternative sites. Hydrogenophaga pseudoflava, which was isolated from Mackenzie spruce seedlings, caused increases in seedling biomass or branch number of up to 49%, but was most effective as a root growth promoter of the Salmon Arm spruce ecotype. Pseudomonas putida, which originated from Salmon Arm spruce seedlings, increased seedling biomass or branch number in two trials, but had inhibitory effects in three others. There was no indication that growth promotion was related to a common ecotypic origin of seedlings and rhizobacteria, or that bacteria were more effective in the ecosystem from which they were originally isolated. However, Salmon Arm spruce growth promotion by H. pseudoflava was greatest at the poorest quality planting site.Key words: field trials, inoculation, PGPR, spruce.
4
Jalkanen, Anneli. "Growth and Morphology of Black Spruce, Jack Pine, and White Spruce Container Seedlings in Northern Ontario." Northern Journal of Applied Forestry 12, no. 2 (1995): 69–74. http://dx.doi.org/10.1093/njaf/12.2.69.
Full textAbstract:
Abstract The development of morphological attributes of containerized seedlings during the growing season was studied in eight crops from three nurseries in Northern Ontario, including four black spruce crops, three jack pine crops, and one white spruce crop. The variability was proportionally largest in root and shoot dry mass, followed by height and diameter. During seedling growth, proportionally the variability of size did not seem to increase. In absolute scale, however, differences between individual seedlings increased more than differences between seedling trays, possibly due to competition between individuals. Height and shoot growth were greater in the beginning of the growing season, and diameter and root growth were greater toward the end. In comparison to standards, the balance between morphological attributes (height/diameter, shoot/root) was usually acceptable, and usually independent of seedling size. The easiest way of monitoring crop development is to take seedling samples at regular intervals and to construct a growth progression curve for seedling height, if diameter growth reaches acceptable level. Care should be taken that the height of seedlings does not increase too much at the expense of diameter and root development in the larger crops. To monitor this, height-diameter ratios and shoot-root ratios might be measured a couple of times during the growing season to take corrective action if necessary. North. J. Appl. For. 12(2):69-74.
5
Fogal, W. H., G. Jobin, H. O. Schooley, S. J. Coleman, and M. S. Wolynetz. "Stem incorporation of gibberellins to promote sexual development of white spruce, Norway spruce, and jack pine." Canadian Journal of Forest Research 26, no. 2 (1996): 186–95. http://dx.doi.org/10.1139/x26-022.
Full textAbstract:
Stem incorporation of gibberellins (GA4/7 60:40) by injecting a liquid formulation or implanting a solid formulation was evaluated for promoting sexual reproductive development and for effects on vegetative development and foliage chlorosis in seedling and grafted white spruce, Piceaglauca (Moench) Voss; seedling Norway spruce, Piceaabies (L.) Karst.; and jack pine, Pinusbanksiana Lamb., seed trees. Spruces were treated with a single application of 0.76 or 1.53 mg GA4/7 per square centimetre of stem cross-sectional area at breast height during the late stage of shoot elongation (June 9 for white spruce and June 19 and 20 for Norway spruce). Jack pine was treated with a single early (July 5) or late (August 15) application of 1.53 mg GA4/7/cm2 or a split early–late application of 0.76 mg GA4/7/cm2. Results were evaluated in the subsequent season (i) by counting seed and pollen strobili, developing vegetative shoots, latent vegetative buds, and dead buds and (ii) by assessing foliage chlorosis and mortality. The numbers of seed strobili were increased by injections of GA4/7 at low and high application rates on seedling white spruce and Norway spruce and by the high application rate on grafted white spruce; implants were effective on seedling white and Norway spruce at the high application rate. In jack pine, the number of seed strobili was not increased by GA4/7. The numbers of pollen strobili were not significantly increased by GA4/7 treatments to white spruce or Norway spruce but were increased on jack pine by a single early injection at the high rate and split injections at the low rate. The number of developing vegetative shoots was reduced by GA4/7 injections at both rates on white spruce grafted trees and Norway spruce; the implants reduced them only on the grafted white spruce given the low rate. For the spruces, treatments with GA4/7 did not influence bud mortality. Foliage chlorosis and mortality, evident on jack pine but not on white or Norway spruce trees, was more severe with injections than with implants.
6
Fukasawa, Yu, Yoko Ando, Satoshi N. Suzuki, Mineaki Aizawa, and Daisuke Sakuma. "Climate influences the effect of fungal decay type on regeneration of Picea jezoensis var. hondoensis seedlings on decaying logs." Canadian Journal of Forest Research 50, no. 1 (2020): 73–79. http://dx.doi.org/10.1139/cjfr-2019-0147.
Full textAbstract:
Hondo spruce (Picea jezoensis var. hondoensis (Mayr) Rehder)) is separately distributed among several mountainous regions in central Japan as remnant populations of the last glacial period. To identify factors that affect Hondo spruce seedling regeneration on decaying logs, we investigated the relationships between climatic conditions, log properties, including decay type by fungi, and Hondo spruce seedling density on logs using data from seven subalpine Hondo spruce forests in central Japan. The results showed that the presence of soft rot was associated with higher seedling density, and the effect of brown rot in sapwood and white rot in heartwood on the predicted number of spruce seedlings on logs switched from positive to negative with increasing temperature and precipitation. Because soft rot occurs under humid conditions, the use of forest management techniques that increase the number of logs with soft rot in sapwood (e.g., by keeping the forest floor moist) are recommended for the sustainable regeneration of Hondo spruce. However, the relationships between wood decay type and seedling regeneration can also be affected by climate condition and thus are more complex than previously thought.
7
Wolken, Jane M., Simon M. Landhäusser, Victor J. Lieffers, and Uldis Silins. "Seedling growth and water use of boreal conifers across different temperatures and near-flooded soil conditions." Canadian Journal of Forest Research 41, no. 12 (2011): 2292–300. http://dx.doi.org/10.1139/x11-136.
Full textAbstract:
To test the hypothesis that seedling growth and water use increase with soil temperature and improved soil aeration and vary with species, we evaluated the above- and below-ground growth and water use of seedlings of four northern boreal conifer species: black spruce ( Picea mariana (Mill.) B.S.P.), white spruce ( Picea glauca (Moench) Voss), tamarack ( Larix laricina (Du Roi) K. Koch), and lodgepole pine (Pinus contorta Dougl. ex Loud.) grown under different temperature and near-flooded soil conditions. Seedlings were grown in specialized pots that maintained the water table level at either 15 cm (high water table treatment: very wet) or 30 cm (low water table treatment: moderately wet) below the soil surface, and whole-seedling transpiration was assessed. Soil temperature (5, 10, or 20 °C) was controlled with a water bath surrounding the pots. Although some species were sensitive to the high water table treatment, soil temperature was the driver of seedling growth and water use. We ranked the ability of the seedlings of the species to tolerate the cold soil conditions examined as black spruce > lodgepole pine > tamarack > white spruce. The ranking of the ability to tolerate near-flooded conditions was tamarack and lodgepole pine > black spruce > white spruce.
8
Man, Rongzhou, and Victor J. Lieffers. "Effects of shelterwood and site preparation on microclimate and establishment of white spruce seedlings in a boreal mixedwood forest." Forestry Chronicle 75, no. 5 (1999): 837–44. http://dx.doi.org/10.5558/tfc75837-5.
Full textAbstract:
Microclimate and seedling response of planted white spruce were investigated under four canopy densities (control – a 120-year old uncut aspen/white spruce stand, low and high residual densities of shelterwood canopy, and clearcut) and three site preparation treatments in the Lower Foothills of central Alberta. The partial canopy of the shelterwoods had a less extreme environment than the clearcut: higher humidity and soil temperature, lower maximum air temperature and occurrence and severity of night frost, and a light regime that was nearly optimum for height growth of juvenile white spruce. Planted white spruce seedlings had earlier bud break, lower seedling mortality and terminal bud mortality, higher rates of photosynthesis and stomatal conductance, and greater height and diameter increments under shelterwoods than those in either clearcut or control. Site preparation increased soil temperature, decreased seedling mortality and improved growth, especially diameter growth. This study demonstrates how shelterwoods and site preparation can improve the establishment of white spruce. The findings of this study can be applied to the situations where white spruce establishes in the understory. Key words: shelterwood, site preparation, white spruce, seedling response, microclimatic conditions.
9
Simpson, David G., and Alan Vyse. "Planting stock performance: Site and RGP effects." Forestry Chronicle 71, no. 6 (1995): 739–42. http://dx.doi.org/10.5558/tfc71739-6.
Full textAbstract:
Douglas-fir [Pseudotsuga menziesii var glauca (Beissn.) Franco], interior spruce [Picea glauca Moench (Voss), Picea engelmannii (Parry) and their naturally occurring hybrids] and lodge-pole pine (Pinus contorta Dougl.) seedlings were planted on several forest sites in south central British Columbia. At planting, root growth potential (number of newly elongated roots longer than 10 mm per seedling) was determined. Trees were assessed for survival and height for at least five years. Survival of Douglas-fir and growth of all three species was affected by planting site, probably reflecting moisture and growing season temperature differences among sites. High (> 70%) survival, but not total height or mean annual relative growth rate was associated with root growth potential levels greater than 10 new roots per seedling in interior spruce and lodgepole pine. Survival and growth of Douglas-fir were not related to root growth potential. Fertilization of interior spruce seedlings at planting decreased survival 18% over seven growing seasons, and did not affect growth of surviving seedlings. Key words: reforestation, root growth potential, seedling quality, Douglas-fir, interior spruce, lodgepole pine, field performance
10
Morris, D. M., G. B. MacDonald, and K. M. McClain. "Evaluation of morphological attributes as response variables to perennial competition for 4-year-old black spruce and jack pine seedlings." Canadian Journal of Forest Research 20, no. 11 (1990): 1696–703. http://dx.doi.org/10.1139/x90-226.
Full textAbstract:
The sensitivity of seedling morphological attributes to changing competition levels was evaluated on 4-year-old black spruce (Piceamariana (Mill.) B.S.P.) and jack pine (Pinusbanksiana Lamb.) seedlings to determine the most appropriate response variables to be used in the assessment of early plantation performance. A total of 720 seedlings (360 per species) were sampled between 1987 and 1989, covering a range of stock types, soil textures, and competition levels. A competition index, derived from hemispherical photographs, provided an estimate of incident radiation received by each sampled seedling. Seedling stem volume at time of planting was used as a covariate in the regression analyses. Stratification by plantation was done to account for variations in site quality. The results from this study demonstrated that total height or current height increment were not reliable for quantifying individual seedling response to inter specific competition for 4-year-old black spruce or jack pine plantations. Overall, the most consistent response variable was total seedling dry weight. Coefficients of determination ranged from 0.116 to 0.534 for black spruce and from 0.601 to 0.810 for jack pine across the range of sites and stock types. If it is inappropriate to determine total seedling dry weight, root collar diameter would be the best substitute. Correlation coefficients between these two variables were 0.897 for black spruce and 0.912 for jack pine.
11
Sutherland, D. Craig, and Robert J. Day. "Container Volume Affects Survival and Growth of White Spruce, Black Spruce, and Jack Pine Seedlings: A Literature Review." Northern Journal of Applied Forestry 5, no. 3 (1988): 185–89. http://dx.doi.org/10.1093/njaf/5.3.185.
Full textAbstract:
Abstract This paper is the first general review of the affects of container volume on the survival and growth of containerized white spruce, black spruce, and jack pine seedlings. The review shows that the literature on this topic is fragmentary and inconsistent. Seedling growth in the greenhouse production phase has been more completely quantified than subsequent establishment and growth after out-planting in the field. In the greenhouse production phase, seedling growth increased from 72 to 360% when the container volume was tripled in size. After outplanting in the field, seedling growth trends were more variable. Seedling height growth increased from 34 to 84% when container volume was tripled in size. Seedling survival was more difficult to assess because of limited data. Only white spruce showed a 10% increase in survival with an increase in container volume. The indications from this literature review suggest that nursery managers and practicing foresters should become more aware of the limitations imposed on seedling survival and growth due to container volume. To maintain optional survival and growth for white spruce, black spruce and jack pine, the container volume should range from 90 to 120 cm3. North. J. Appl. For. 5:185-189, Sept. 1988.
12
Wallstedt, Anna, Andrew Coughlan, Alison D. Munson, Marie-Charlotte Nilsson, and Hank A. Margolis. "Mechanisms of interaction between Kalmia angustifolia cover and Picea mariana seedlings." Canadian Journal of Forest Research 32, no. 11 (2002): 2022–31. http://dx.doi.org/10.1139/x02-124.
Full textAbstract:
Sites dominated by Kalmia angustifolia L. are often associated with slow decomposition of organic matter, decreased nitrogen (N) mineralization rates, and low black spruce (Picea mariana (Mill.) BSP) productivity. The objective of this study was to separate the effects of belowground competition by Kalmia from the effects of water-soluble soil phenols on black spruce seedlings growing under different levels of Kalmia cover. A factorial greenhouse bioassay was established in which black spruce seedlings were grown for 6 months in intact blocks of soil with three different levels of Kalmia cover. The soil was treated with charcoal to reduce the amounts of water-soluble phenols, and (or) tubes were inserted to exclude Kalmia roots. At low Kalmia cover, reducing the level of belowground competition increased seedling biomass by 134%. However, reducing belowground competition did not increase seedling biomass at the two higher levels of Kalmia cover. It is possible that seedling biomass remained low because of an increased immobilization of N in the organic layer. Furthermore, the proportion of ectomycorrhiza morphotypes differed among seedlings growing under different levels of Kalmia cover. The effect of water-soluble phenols on seedling growth remains uncertain, since we observed a confounding effect of the charcoal treatment on soil microbial biomass and seedling response.
13
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.
Full textAbstract:
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 – 89% of bareroot spruce, least – 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.  
14
Roden, Michael J., and Phillip E. Reynolds. "Hexazinone site preparation improves black spruce seedling survival and growth." Forestry Chronicle 71, no. 4 (1995): 426–33. http://dx.doi.org/10.5558/tfc71426-4.
Full textAbstract:
Granular (PRONONE 10G and 5G) and liquid (VELPAR L) hexazinone (1 to 4 kg ai ha−1) were applied to a northern New Brunswick clearcut (loams, silt loams, and clay loams) to reduce raspberry [Rubus idaeus L. var. strigosus (Michx.) Maxim] competition. Treatment, using skidder-mounted herbicide application equipment, was completed in May and September 1986, with planting of 2+2, bareroot, black spruce seedlings [Picea mariana (Mill.) B.S.P.] in June 1986 and in June 1987. Seedling survival and growth were measured yearly for five growing seasons after planting. By August 1991, raspberry cover for three treatments remained less than that for controls. Survival of seedlings planted approximately one month after spring treatment was less than controls, but seedling height and stem diameter were greater than that of control seedlings for most treatments. Survival and growth of seedlings planted approximately one year after spring treatment or nine months after fall treatment were greater than that of control seedlings for most treatments. Fifth-year height and stem diameter of seedlings planted nine months after fall treatment were negatively correlated with raspberry height (r2 = 0.729, height and 0.745, diameter), decreasing as raspberry height increased. Over the five-year observation period, hexazinone formulation did not affect raspberry control, but did affect seedling survival and growth. Spring treatment with PRONONE 10G (2 kg ai ha−1), with planting delayed by one year, provided the best treatment to achieve both optimal seedling survival and growth during plantation establishment. Key words: liquid hexazinone, granular hexazinone, site preparation, black spruce, growth parameters, seedling survival, raspberry competition
15
Roden, Michael J., and Phillip E. Reynolds. "Site preparation with sulfonylurea herbicides improves black spruce seedling growth." Forestry Chronicle 72, no. 1 (1996): 80–85. http://dx.doi.org/10.5558/tfc72080-1.
Full textAbstract:
Metsulfuron (ALLY or ESCORT), 36 and 72 g ai ha−1, and sulfometuron (OUST), 150 to 450 g ai ha−1, were applied to a northern New Brunswick clearcut (silty clay loams and silty clays) to reduce raspberry [Rubus idaeus L. var. strigosus (Michx.) Maxim.] competition. Treatment, using skidder-mounted herbicide application equipment, occurred in May and August 1986, with planting of 2+2, bareroot, black spruce seedlings [Picea mariana (Mill.) B.S.P.] in June 1986 and in June 1987. Seedling survival and growth were measured yearly for five growing seasons after planting. By August 1991, raspberry height was less in many treatments than in controls. Survival of seedlings planted one month after spring treatment was less than controls, and no significant height or stem diameter increases were observed. Growth and survival of seedlings planted approximately one year after spring treatment were greater than that of control seedlings. Fifth-year stem diameter of these seedlings, planted after site preparation with sulfometuron, was negatively correlated (r2 = 0.715) with raspberry height, decreasing as raspberry height increased. Survival of seedlings planted after some summer treatments was also less than controls, and no significant growth increases were noted for seedlings planted after site preparation with sulfometuron. Summer treatment with metsulfuron was more efficacious and resulted in greater seedling growth than spring treatment; however, greater seedling survival occurred after spring treatment. We conclude that spring treatment with sulfometuron (300 g ai ha−1), with planting delayed by one year, provided the optimal treatment to achieve maximal seedling survival and growth during plantation establishment. Black spruce seedlings appear to benefit (i.e. enhanced survival or growth) from site preparation with these herbicides only when planting is delayed by several months following their use. Key words: metsulfuron, sulfometuron, site preparation, black spruce, growth parameters, seedling survival, raspberry competitition
16
Shishido, Masahiro, and Christopher P. Chanway. "Spruce growth response specificity after treatment with plant growth-promoting Pseudomonads." Canadian Journal of Botany 77, no. 1 (1999): 22–31. http://dx.doi.org/10.1139/b98-197.
Full textAbstract:
Naturally regenerating hybrid spruce seedlings (Picea glauca (Moench) Voss beta Picea engelmannii Parry) were collected from sites near Mackenzie, Salmon Arm, and Williams Lake, British Columbia, Canada. Bacteria were isolated from roots and screened in greenhouse trials for their ability to enhance spruce growth. Three strains belonging to the genus Pseudomonas were selected for study based on their disparate geographic origins and their capacity to consistently stimulate spruce seedling growth in screening trials. Factorial experiments were performed in the greenhouse to evaluate the effectiveness of these Pseudomonas strains with different spruce ecotypes. Factors tested were spruce seed sources, Pseudomonas isolates, and forest floor soils originating from different sites. Three levels of each factor were studied: one spruce seedlot, one Pseudomonas isolate, and one forest floor type each originated from a site at Mackenzie, Salmon Arm, and Williams Lake, British Columbia. Fourteen weeks after treatments were established, spruce biomass accumulation was greatest when spruce ecotypes were inoculated with bacteria originating from the same geographical area as spruce seed. However, Pseudomonas strains originating from sites other than the seed collection area also stimulated seedling growth significantly, rendering the difference in growth promotion between bacterial treatments small and insignificant. In addition, spruce growth promotion was not enhanced when seed was treated with combinations of Pseudomonas strains and forest floor soils originating from the same forest ecosystem. We conclude that specificity between spruce ecotypes and plant growth-promoting rhizobacteria strains can be detected under carefully controlled conditions, thereby supporting the hypothesis that growth-promoting bacteria may adapt to their plant hosts. However, the growth advantage accruing to seedlings treated with bacteria originating from the same ecosystem is small and suggests that it is not necessary to match Pseudomonas strains with spruce ecotypes and soil types for effective seedling growth promotion.Key words: Pseudomonas, spruce, specificity, growth promotion.
17
Côté, Mathieu, Jean Ferron, and Réjean Gagnon. "Invertebrate predation of postdispersal seeds and juvenile seedlings of black spruce (Picea mariana) in the boreal forest of eastern Canada." Canadian Journal of Forest Research 35, no. 3 (2005): 674–81. http://dx.doi.org/10.1139/x05-001.
Full textAbstract:
We used an extensive vertebrate exclosure experiment to evaluate black spruce (Picea mariana (Mill.) B.S.P.) postdispersal seed and seedling predation by invertebrates in three boreal habitats of Eastern Canada: recent burn, sprucemoss, and lichen woodland. Between 9% and 19% of seeds were eaten by invertebrates. Seed predation was higher in recent burns than in sprucemoss and lichen woodlands. Abundance and diversity of potential invertebrate seed consumers sampled in pitfall traps also varied among habitat types. Among the invertebrate seed consumers sampled, Myrmica spp. (Hymenoptera: Formicidae) and Pterostichus adstrictus (Eschscholtz, 1823) (Coleoptera: Carabidae) were the most numerous; Formica spp. (Hymenoptera: Formicidae) and Pterostichus punctatissimus (Randall, 1838) (Coleoptera: Carabidae) were also present. Between 2% and 12% of juvenile black spruce seedlings were eaten by invertebrates. The most important seedling consumers were slugs (molluscs). Invertebrate predation of seeds and seedlings was highest (19% and 12%) in recent burns, indicating that invertebrate predation may significantly influence black spruce regeneration in these sites.
18
Lavoie, Janie, Miguel Montoro Girona, and Hubert Morin. "Vulnerability of Conifer Regeneration to Spruce Budworm Outbreaks in the Eastern Canadian Boreal Forest." Forests 10, no. 10 (2019): 850. http://dx.doi.org/10.3390/f10100850.
Full textAbstract:
Spruce budworm (Choristoneura fumiferana) is the main defoliator of conifer trees in North American boreal forests, affecting extensive areas and causing marked losses of timber supplies. In 2017, spruce budworm affected more than 7 million ha of Eastern Canadian forest. Defoliation was particularly severe for black spruce (Picea mariana (Mill.) B.S.P.), one of the most important commercial trees in Canada. During the last decades, intensive forest exploitation practices have created vast stands of young balsam fir (Abies balsamea (L.) Mill.) and black spruce. Most research focused on the impacts of spruce budworm has been on mature stands; its effects on regeneration, however, have been neglected. This study evaluates the impacts of spruce budworm on the defoliation of conifer seedlings (black spruce and balsam fir) in clearcuts. We measured the cumulative and annual defoliation of seedlings within six clearcut black spruce stands in Quebec (Canada) that had experienced severe levels of defoliation due to spruce budworm. For all sampled seedlings, we recorded tree species, height class, and distance to the residual forest. Seedling height and species strongly influenced defoliation level. Small seedlings were less affected by spruce budworm activity. As well, cumulative defoliation for balsam fir was double that of black spruce (21% and 9%, respectively). Distance to residual stands had no significant effect on seedling defoliation. As insect outbreaks in boreal forests are expected to become more severe and frequent in the near future, our results are important for adapting forest management strategies to insect outbreaks in a context of climate change.
19
Roberts, Dane R., Peter Toivonen, and Stephanie M. McInnis. "Discrete proteins associated with overwintering of interior spruce and Douglas-fir seedlings." Canadian Journal of Botany 69, no. 3 (1991): 437–41. http://dx.doi.org/10.1139/b91-060.
Full textAbstract:
Seasonal protein changes were followed in seedlings of interior spruce (a mixture of Picea glauca and P. englemannii) and Douglas-fir (Pseudostuga menziesii) by sodium dodecylsulfate – polyacrylimide gel electrophoresis. A 30-kDa protein in seedlings of Douglas-fir and a 30- and 27-kDa protein in interior spruce that were not detected in the late summer accumulated in seedling tissues during the fall. These proteins remained present throughout the winter but declined rapidly in seedlings during the initial flush of spring growth. There was an increase in the total protein content of interior spruce seedling tissues during the fall; however, the accumulation of the 30- and 27-kDa protein was tissue specific, since it increased in the apical bud, shoot, and root tissue but not in the leaves. By late fall these proteins represented approximately 15% of the total seedling protein. Measurements of variable chlorophyll fluorescence indicated that the accumulation of these overwintering proteins was associated with the seasonal decline in photosynthetic capacity. These results suggest that conifer seedlings may utilize these proteins as a storage reserve during overwintering. Key words: conifers, electrophoresis, overwintering, proteins, seasonal, seedlings.
20
Comeau, Philip G., Thomas F. Braumandl, and Chang-Yi Xie. "Effects of overtopping vegetation on light availability and growth of Engelmann spruce (Piceaengelmannii) seedlings." Canadian Journal of Forest Research 23, no. 10 (1993): 2044–48. http://dx.doi.org/10.1139/x93-255.
Full textAbstract:
To examine the effects of overtopping vegetation on solar irradiance reaching Engelmann spruce (Piceaengelmannii Parry) seedlings and on crop seedling performance, neighborhood studies were established at six sites in mixed shrub–herb and fireweed communities of the Interior Cedar–Hemlock zone of southern British Columbia. These communities were dominated by mixtures of fireweed (Epilobiumangustifolium L.), thimbleberry (Rubusparviflorus Nutt.), red raspberry (Rubusidaeus L.), and (or) bracken fern (Pteridiumaquilinum (L.) Kuhn). Three hundred and eighty-eight planted Engelmann spruce seedlings, between 1 and 5 years of age, served as plot centers for measurements in 1990 and 1991. Vegetation had been clipped around 109 of these seedlings in 1988, 1989, and 1990. Seedling diameter and height were measured in the autumn of 1990 and 1991. Vegetation cover, vegetation height, and the fraction of full sunlight reaching the top branches of each spruce seedling were measured in midsummer of 1991. A simple competition index (CI), based on visually estimated percent cover, height of each species present within 1.26 m of the crop seedling, and crop-seedling height, can be used to estimate the fraction of full sunlight reaching crop seedlings. Measurements of transmittance through vegetation canopies are correlated with this competition index and could be useful as a separate, objective assessment of competition levels. Seedling growth was related to both seedling-needle biomass (at the beginning of the year) and either CI or the amount of light reaching crop seedlings during midsummer. Growth increased as needle biomass or irradiance reaching the seedling increased and decreased as CI increased. Since CI can be calculated from simple field measurements and since seedling growth is related to CI, this index has potential utility in evaluating the need for operational release treatments. Transmittance measurement provides an equally useful, and potentially more objective approach to evaluating the need for release treatment. Results from this study suggest that cumulative effects of competition result at least in part from effects on growth of seedling leaf mass.
21
Shishido, Masahiro, and Christopher P. Chanway. "Colonization and growth promotion of outplanted spruce seedlings pre-inoculated with plant growth-promoting rhizobacteria in the greenhouse." Canadian Journal of Forest Research 30, no. 6 (2000): 845–54. http://dx.doi.org/10.1139/x00-010.
Full textAbstract:
Seeds of two hybrid spruce (Picea glauca (Moench) Voss × Picea engelmannii Parry ex Engelm.) ecotypes were inoculated with one of six plant growth-promoting rhizobacteria (PGPR) strains previously shown to be able to stimulate spruce growth in controlled environments. The resulting seedlings were grown in the greenhouse for 17 weeks before outplanting at four reforestation sites. Inoculation with five of the six strains caused significant seedling growth promotion in the greenhouse, which necessitated analysis of relative growth rates (RGR) to evaluate seedling performance in the field. Four months after outplanting, most strains enhanced spruce shoot or root RGRs in the field, but seedling growth responses were strain specific. For example, Pseudomonas strain Ss2-RN significantly increased both shoot and root RGRs by 10-234% at all sites, but increases of 28-70% were most common. In contrast, Bacillus strain S20-R was ineffective at all outplanting sites. In addition, seedlings inoculated with four of the six strains had significantly less shoot injury than control seedlings at all sites. Evaluation of root colonization by PGPR indicated that bacterial population declines were not related to spruce growth response variability in the field. Our results indicate that once plant growth promotion is induced in the greenhouse, seedling RGR can increase by more than 100% during the first growing season in the field. However RGR increases of 21-47% were more common and may be more representative of the magnitude of biomass increases that can result from PGPR inoculation.
22
Reynolds, Phillip E., and Michael J. Roden. "Short-term Performance of two hexazinone formulations: Efficacy, seedling survival and growth." Forestry Chronicle 71, no. 2 (1995): 228–32. http://dx.doi.org/10.5558/tfc71228-2.
Full textAbstract:
Liquid (VELPAR L) and dry-flowable (VELPAR ULW) hexazinone (2 kg ai ha−1) were aerially applied to a northern New Brunswick clearcut to reduce raspberry [Rubus idaeus L. var. strigosus (Michx.) Maxim] competition. Treatments were applied in June 1987; planting with containerized (multipot) black spruce [Picea mariana (Mill.) B.S.P.] was conducted 2 and 14 months after treatment in August 1987 and 1988. Seedling survival and growth were measured yearly through August 1991. Hexazinone formulation did not affect raspberry control, seedling survival, or growth. Five growing seasons after treatment, raspberry cover was generally less in treated plots than in controls. Seedling survival did not differ among treatments for seedlings planted at either time interval after hexazinone treatment. Seedlings planted 14 months after hexazinone treatment grew poorly compared with those planted 2 months after herbicide treatment. Stem volume of seedlings planted 2 months after hexazinone treatment exceeded that of control seedlings in the first growing season after planting and remained greater than that of control seedlings through 1991. Stem volume increases over controls were restricted to the second growing season after planting for seedlings planted 14 months after hexazinone treatment. Fourth-year stem volume of seedlings planted 2 months after hexazinone treatment was correlated with raspberry cover (r2 = 0.34). As raspberry cover increased, black spruce growth decreased. Key words: liquid hexazinone, dry-flowable hexazinone, site preparation, black spruce, multipot stock, seedling survival, stem volume, raspberry cover
23
Lajzerowicz, Cleo C., Michael B. Walters, Marek Krasowski, and Hugues B. Massicotte. "Light and temperature differentially colimit subalpine fir and Engelmann spruce seedling growth in partial-cut subalpine forests." Canadian Journal of Forest Research 34, no. 1 (2004): 249–60. http://dx.doi.org/10.1139/x03-198.
Full textAbstract:
We compared the relative impacts of light, soil N, and soil temperature on Engelmann spruce (Picea engelman nii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) seedling growth by quantifying (i) microsite environment-growth relationships for N-fertilized and unfertilized planted seedlings in shelterwood, patch cut, and clearcut harvest treatments and (ii) growth, photosynthesis, and biomass allocation for greenhouse-grown seedlings at 5, 10, and 15 °C soil temperatures. Fertilization did not affect seedling growth. Furthermore, soil N availability did not vary among harvest treatments. In contrast, clearcut compared with shelterwood seedlings had greater mass (fivefold), light availability (twofold), and soil temperatures (1.6 °C). Across harvest treatments, spruce and fir mass increased linearly to 100% open-sky light (R2 = 0.51 and 0.57, respectively), and temperature and light combined explained more variation in mass than light alone (adjusted R2 = 0.58 for both species). Spruce growth was more sensitive to temperature than fir in both field and greenhouse experiments. Diminished growth at low soil temperature was associated with lower photosynthesis and not lower leaf fraction. Thus, soil temperature and light colimit seedling growth in subalpine forests, but responses were species-specific and consistent with microenvironment differences in spruce and fir regeneration niches.
24
Veselá, Petra, Martina Vašutová, Karolína Hofmannová, Magda Edwards-Jonášová, and Pavel Cudlín. "Ectomycorrhizal Community on Norway Spruce Seedlings Following Bark Beetle Infestation." Forests 10, no. 9 (2019): 740. http://dx.doi.org/10.3390/f10090740.
Full textAbstract:
Ectomycorrhizal (ECM) fungi importantly influence seedling growth, nutrition, and survival and create an extensive mycelial network interconnecting tree species and enabling resource redistribution. Due to their symbiotic relationship with trees, they are impacted by forest disturbances, which are of increasing relevance due to climate change. The effect of disturbance on seedling colonization and their morphology is still largely unknown. Seedling growth parameters and the ECM fungal assemblage on the roots of Norway spruce (Picea abies (L.) H. Karst.) seedlings were assessed in mature spruce forests attacked and destroyed by bark beetle and in a mature non-attacked forest as a reference. We did not detect significant differences in number of ECM species on seedling roots among forest types, but ECM species composition changed; Tylospora fibrillosa (Burt) Donk, Meliniomyces variabilis Hambl. & Sigler, and Phialocephala fortinii C.J.K. Wang & H.E. Wilcox were characteristic species in the forest destroyed by bark beetle, whereas Lactarius, Cortinarius, and Russula were in the mature forest. Forest type further significantly influenced the height, root length, and root collar thickness of seedlings and the proportion of exploration types of mycorrhizae.
25
Bachand, George D., John D. Castello, Michail Schaedle, Stephen V. Stehman, and William H. Livingston. "Effects of tomato mosaic Tobamovirus infection on red spruce seedlings." Canadian Journal of Forest Research 26, no. 6 (1996): 973–81. http://dx.doi.org/10.1139/x26-107.
Full textAbstract:
Height, weight, root volume, shoot length, needle length and weight, and total chlorophyll content were measured for both control and tomato mosaic Tobamovirus (ToMV)-inoculated red spruce (Picearubens Sarg.) seedlings in each of five, 3-month growth periods. Mean bud-break rating was determined for each seedling in growth period 5. In January 1995 the freezing tolerance of control and ToMV-infected seedlings was determined. Approximately 85% of the inoculated seedlings became infected with ToMV, as determined by enzyme-linked immunosorbent assay of young root tissue. Reduction in seedling height, weight, root volume, bud break, and mean shoot length of infected seedlings was observed when compared with control seedlings. The rate of increase over time in height, weight, and root volume was lower (54, 57, and 52%, respectively) in infected seedlings compared with control seedlings. Additionally, needles of infected seedlings were less susceptible to freezing damage than those of control seedlings. However, virus infection had no effect on the freezing tolerance of roots.
26
Henneb, Mohammed, Nelson Thiffault, and Osvaldo Valeria. "Regional Climate, Edaphic Conditions and Establishment Substrates Interact to Influence Initial Growth of Black Spruce and Jack Pine Planted in the Boreal Forest." Forests 11, no. 2 (2020): 139. http://dx.doi.org/10.3390/f11020139.
Full textAbstract:
In eastern Canada, spruces (Picea spp.) and pines (Pinus spp.) are among the main commercial species being logged for their lumber or wood fiber. Annually, about 175 million seedlings are planted in areas totaling ~100,000 ha. Appropriate microsite selection is essential during reforestation operations, given that it can improve the chances of survival and initial growth of the seedlings. In fir (Abies spp.) and spruce forests of eastern Canada, the optimal characteristics of establishment microsites have yet to be identified; these would be determined by different physical and climatic variables operating at several scales. Our study determined the influence of climatic (regional-scale), edaphic (stand-scale), local (microsite-scale) and planting conditions on the establishment substrate and initial growth of black spruce (Picea mariana Britton, Sterns and Poggenb.) and jack pine (Pinus banksiana Lamb.). Substrate characterization and growth monitoring (three growing seasons) for the two species were conducted on 29 planted cutblocks that were distributed over an east–west climatic gradient (precipitation and temperature) in the balsam fir and black spruce–feather moss forests of Quebec (Canada). Linear mixed models and multivariate analyses (PCAs) determined the effects of climatic, edaphic and micro-environmental variables and their interactions on the establishment substrate and seedling initial growth. The predictive models explained, respectively, 61% and 75% of the growth variability of black spruce and jack pine. Successful establishment of black spruce and jack pine depended upon regional conditions of precipitations and temperature, as well as on their interactions with stand-scale edaphic variables (surface deposit, drainage and slope) and local variables (micro-environmental) at the microsite-scale (establishment substrate types and substrate temperature). Mineral, organo-mineral and organic establishment substrates exerted mixed effects on seedling growth according to regional precipitation and temperature conditions, as well as their interactions with edaphic and local variables at the stand and microsite-scales, respectively.
27
Nosko, Peter, and Kenneth A. Kershaw. "The influence of pH on the toxicity of a low concentration of aluminum to white spruce seedlings." Canadian Journal of Botany 70, no. 7 (1992): 1488–92. http://dx.doi.org/10.1139/b92-186.
Full textAbstract:
Week-old white spruce seedlings were grown for 7 days at pH 4.5, 3.9, 3.65, or 3.5 using a continuous flow system to deliver experimental solutions. At each pH, seedlings received either no aluminum or 10 μM Al, a concentration 2 – 3 orders of magnitude lower than the reported minimum Al concentrations required to induce toxicity symptoms in seedlings of a variety of tree species. In – Al treatments, root elongation was reduced at pH 3.9 and root dry weight was reduced at pH 3.5, compared with seedlings grown at pH 4.5. Exposure to 10 μM Al caused further reduction of root growth, the magnitude of which increased as pH decreased. This suggests that seedling root growth was affected by the increased proportion of the total Al existing as phytotoxic Al3+ at lower pH values or by an interaction of Al3+ and H+. Neither pH nor Al affected shoot growth. Both acidity and Al could limit natural regeneration of white spruce by preventing seedling establishment. Key words: aluminum toxicity, soil acidity, forest decline, white spruce, Picea glauca, forest regeneration.
28
Lajzerowicz, C. C., A. Vyse, M. Jull, and T. Newsome. "Performance of planted Engelmann spruce and subalpine fir seedlings in British Columbia's southern mountains." Forestry Chronicle 82, no. 1 (2006): 84–94. http://dx.doi.org/10.5558/tfc82084-1.
Full textAbstract:
We compared survival and growth of planted seedlings of Engelmann spruce and subalpine fir across a range of harvest opening sizes (> 10 ha, 1 ha, 0.2 ha, 0.1 ha, 0.03 ha and individual tree selection) from three silvicultural systems trials in high-elevation spruce – subalpine fir forests in south-central British Columbia. Climatic patterns and growing season air and soil temperatures were similar across sites. Seedling survival decreased with opening size. Local site climates, influenced by aspect and moisture and air drainage, were more influential than elevation. Seedling growth was best in large openings and similar in opening sizes from 1 ha to 0.1 ha. Smaller openings created by group selection and individual tree selection methods were not favourable for successful planting at elevations close to timberline. The two species had similar absolute and relative growth rates but spruce responded more strongly to better growing environments. Key words: planted seedlings, Engelmann spruce, Picea engelmannii Parry ex Engelm., subalpine fir, Abies lasiocarpa (Hook.) Nutt., opening size, elevation effects, silvicultural systems, British Columbia, mountain forests
29
Holmström, Emma, Helena Gålnander, and Magnus Petersson. "Within-Site Variation in Seedling Survival in Norway Spruce Plantations." Forests 10, no. 2 (2019): 181. http://dx.doi.org/10.3390/f10020181.
Full textAbstract:
Seedling survival was evaluated from inventories of a large set of Norway spruce plantations in privately owned forests in southern Sweden. The inventories were conducted at the time of planting and a subset was re-inventoried three years later. This enabled comparison of regeneration success after soil scarification and planting. The acquired data enabled evaluation of annual and climatic variation of seedling mortality since inventories were made on newly established clearcuts distributed spatially throughout three regions in southern Sweden and repeated in five consecutive years. Within-site variation was also captured via the use of a large number of sample plots on each clearcut. To do so, thirty sample plots were established within weeks of planting on 150 clearcuts. Small- and large-scale site and management variables were recorded as well as the numbers of suitable planting spots and planted seedlings. Three years later, 60 of the initially surveyed clearcuts were revisited and the numbers of both planted and naturally regenerated seedlings counted. On average, 2000 seedlings ha−1 were planted and 1500 seedlings ha−1 had survived after three years. However, there was high variation, and in 42% of the revisited sample plots no mortality was recorded. Important variables for seedling survival identified by linear regression analysis included the number of suitable planting spots, soil moisture conditions and annual variation in available soil water.
30
Hallsby, Goran. "Field performance of outplanted Norway spruce: effects of organic matter amendments and site preparation." Canadian Journal of Forest Research 25, no. 8 (1995): 1356–67. http://dx.doi.org/10.1139/x95-148.
Full textAbstract:
Norway spruce (Piceaabies (L.) Karst.) seedling survival and growth response to site preparation methods involving different utilization of humus (forest floor material from the F- and H-layers) and chipped slash were studied on a recently clear-felled spruce site in northern Sweden. Five mounding treatments (pure mineral soil, mineral mound covered by or mixed with either of the two types of organic matter) and two unscarified treatments (with or without a chipped slash mulch) were applied in a randomized block design. Half of the blocks were planted in the year of clear-felling (1990) and the remaining blocks in 1991. Containerized (1/0) seedlings mechanically protected against Hylobiusabietis L. were used. For both planting occasions, seedling survival after 3 years exceeded 90% in most treatments and the occurrence of injuries was significantly (p < 0.05) affected by soil treatments only in the 1990 plantation. In general, the largest seedlings (height, dry weight, needle weight, needle length, leading shoot terminal bud diameter) developed in mounds containing humus, and mounds containing chipped slash produced the smallest seedlings. Mixing chipped slash with mineral soil appeared to suppress seedling growth. The results also indicate that planting delay should be avoided to permit Norway spruce seedlings to benefit fully from the growth-stimulating potential of humus. Successful planting without site preparation might depend on the avoidance of planting delay.
31
Imo, Moses, and Victor R. Timmer. "Vector competition analysis of black spruce seedling responses to nutrient loading and vegetation control." Canadian Journal of Forest Research 29, no. 4 (1999): 474–86. http://dx.doi.org/10.1139/x99-020.
Full textAbstract:
Impacts of methods to overcome competing vegetation (fertilization, herbicide application, and shading) on conventional and nutrient-loaded black spruce (Picea mariana (Mill.) BSP) seedlings were examined on six forest site types in northeastern Ontario using vector competition analysis. Four sites (Alnus; hardwood; mixedwood, herb rich; and mixedwood, herb poor) were selected to represent high competition, and two sites (feathermoss and Vaccinium) to represent low-competition forest sites. Although similar in biomass before planting, loaded seedlings had greater N, P, and K content than nonloaded seedlings. After planting, loaded seedlings outperformed growth of nonloaded seedlings under all vegetation-control treatments on all sites. Herbicide application eliminated noncrop vegetation but resulted in significantly higher seedling biomass only on the high-competition Alnus site. Field fertilization stimulated weed growth resulting in seedling suppression on the high-competition sites, while nutrient loading countered weed competition on most sites. Interpretation of these results by vector competition analysis revealed that, without fertilization, competition for nutrients was the primary factor limiting seedling growth, while competition for light and (or) moisture was greater after fertilizer addition on weed-prone sites. Similar interpretation revealed no seedling-weed interactions in the less competitive sites.
32
Wang, G. Geoff, and Kevin J. Kemball. "Effects of fire severity on early survival and growth of planted jack pine, black spruce and white spruce." Forestry Chronicle 86, no. 2 (2010): 193–99. http://dx.doi.org/10.5558/tfc86193-2.
Full textAbstract:
Two boreal mixedwood stands burned by the 1999 Black River wildfire in southeastern Manitoba, Canada were selected to study the effect of fire severity on early survival and growth of planted jack pine (Pinus banksiana), black spruce (Picea mariana) and white spruce (Picea glauca) seedlings. In each stand, three fire severity classes (scorched, lightly burned, and severely burned) were identified based on the degree of forest floor consumption. Fire severity was not a significant factor on mortality. No mortality difference was found among species, except for year 5 when jack pine had significantly higher mortality than both black spruce and white spruce. Jack pine and black spruce had their highest mortality in year 4, while white spruce had its highest mortality in year 1. Under natural competition, seedling growth increased with increasing fire severity. When competition was removed, fire severity did not affect seedling growth. Regardless of fire severity and competition, jack pine had better diameter and height growth than black spruce, which, in turn, grew slightly taller than white spruce. Planted seedlings faced less intense vegetation competition on severely burned plots compared to scorched or lightly burned plots. Regardless of fire severity and species, competition increased with time since planting. Our study results indicate that planting immediately after a wildfire is a viable option to establish conifer components on burned boreal mixedwood stands. Key words: fire severity, plantation, regeneration, Pinus banksiana, Picea mariana, Picea glauca
33
Moss, Melissa, and Luise Hermanutz. "Postfire seedling recruitment at the southern limit of lichen woodland." Canadian Journal of Forest Research 39, no. 12 (2009): 2299–306. http://dx.doi.org/10.1139/x09-150.
Full textAbstract:
Although fire is the primary mechanism driving regeneration in open black spruce ( Picea mariana (Mill.) BSP) lichen woodland, there are limited data concerning the sources of seedling mortality across the range of burn severity. We monitored planted seedlings in areas of high and low burn severity in Terra Nova National Park (Newfoundland, Canada) to determine sources and patterns of mortality of black spruce seedlings among burn treatments following a recent burn (2002). The importance of herbivory by small mammals as a source of seedling mortality was evaluated using small cages that excluded voles and non-native snowshoe hare. Overall seedling mortality was high (79%) in all areas; mortality was similar in areas of low (73%) and high (76%) burn severity, and highest in edge areas adjacent to closed-canopy forest (90%). Drought, rather than herbivory, was the most common cause of mortality during the first two seasons following germination. Seedling mortality at the southern edge of the lichen woodland was comparable to that found in other studies, but sources differed, emphasizing the spatially variable nature of mortality. Based on the level of seedling recruitment, our results suggest lichen woodland will return at this site.
34
Jacobi, Volker, and John D. Castello. "Infection of red spruce, black spruce, and balsam fir seedlings with tomato mosaic virus." Canadian Journal of Forest Research 22, no. 7 (1992): 919–24. http://dx.doi.org/10.1139/x92-122.
Full textAbstract:
Red spruce (Picearubens Sarg.), black spruce (Piceamariana (Mill.) B.S.P.), and balsam fir (Abiesbalsamea (L.) Mill.) seedlings were root inoculated with tomato mosaic virus, potted, and maintained in a cold frame. The virus was detected by enzyme-linked immunosorbent assay in root extracts of several inoculated seedlings of each species 6–12 months postinoculation, and in root extracts of approximately 35–40% of both inoculated and noninoculated seedlings of each species 12–18 months postinoculation. Virus spread apparently occurred from the roots of infected to noninfected seedlings within the cold frame. The presence of virus in root extracts was confirmed by immunoelectron microscopy. The virus was not detected in the needles of any seedling at any time by either enzyme-linked immunosorbent assay or immunoelectron microscopy. A transitory needle chlorosis was observed in approximately 14% of the inoculated black spruce and 30% of the inoculated red spruce seedlings, but tomato mosaic virus was not detected in all plants with symptoms.
35
Youngblood, Andrew P. "Effect of shelterwood removal methods on established regeneration in an Alaska white spruce stand." Canadian Journal of Forest Research 20, no. 9 (1990): 1378–81. http://dx.doi.org/10.1139/x90-182.
Full textAbstract:
Seedling damage during overstory removal was compared among different yarding methods; almost three times more mortality was associated with rubber-tired ground skidding than with skyline cable yarding. Seedlings ranging in height from 0.4 to 1.0 m generally received less damage or had lower mortality rates from cable yarding than did shorter or taller seedlings. Snowpack disturbance and percentage of seedling mortality were positively correlated. Results suggested that with attention to seedling height growth and yarding method, the shelterwood regeneration system is a viable option for white spruce (Piceaglauca (Moench) Voss) stand regeneration in interior Alaska.
36
Templeton, C. W. G., K. D. Odlum, and S. J. Colombo. "How to identify bud initiation and count needle primordia in first-year spruce seedlings." Forestry Chronicle 69, no. 4 (1993): 431–37. http://dx.doi.org/10.5558/tfc69431-4.
Full textAbstract:
Bud initiation and subsequent bud development are key steps in the nursery production of first-year temperate spruce seedlings for reforestation. An understanding of the bud initiation and development processes and monitoring methods are of vital importance to both tree seedling nursery workers and foresters. A review of bud morphology and the bud development process is given for spruce seedlings. The equipment required and techniques used in the determination of bud initiation, and estimation of the number of needle primordia are presented. When properly applied, the examination of spruce buds forms a cornerstone for successful nursery management using extended greenhouse culture. Key words: bud initiation, bud morphology, bud dissection, black spruce, Picea mariana, needle primordia, nursery management
37
Jobidon, Robert, J. Robert Thibault, and J. André Fortin. "Effect of straw residues on black spruce seedling growth and mineral nutrition, under greenhouse conditions." Canadian Journal of Forest Research 19, no. 10 (1989): 1291–93. http://dx.doi.org/10.1139/x89-197.
Full textAbstract:
The potential allelopathic (phytotoxic or beneficial) effect of barley, oat, and wheat straw mulches was evaluated on growth, mineral nutrition, and mycorrhizal status of black spruce seedlings, under greenhouse conditions. The various straws did not affect spruce seedling height growth over a 2-month growth period. The newly formed fine roots of treated and control seedlings were mycorrhizal. Oat and wheat straw significantly enhanced foliar phosphorus content, as compared with the control. All treatments significantly depressed foliar manganese content, indicating that the straws could exert a detrimental effect on manganese uptake. Therefore, it is suggested that monitoring the status of manganese in planted spruce seedlings when using allelopathic cover straw mulches be used as a method for preventing the establishment of weed species.
38
Morris, Dave M., Rob W. Mackereth, Dan R. Duckert, and Michael K. Hoepting. "The influence of soil rutting severity on regeneration potential and seedling performance for black spruce-dominated peatlands." Canadian Journal of Soil Science 89, no. 1 (2009): 57–66. http://dx.doi.org/10.4141/cjss07030.
Full textAbstract:
Excessive rutting continues to be recorded in post-harvest compliance inspections in black spruce peatlands across Ontario. These qualitative, visual assessments, however, cannot provide the necessary data to determine a site disturbance threshold that is linked to poor regeneration and seedling growth. In an attempt to provide this quantitative link, harvested black spruce [Picea mariana (Mill.) B.S.P.] peatland sites were surveyed and divided into severely rutted (non-compliant), moderately rutted, and non-rutted (compliant) blocks. In 1995, 2001, and 2006, each block was assessed for areal extent of rutting, number of plantable spots, moisture status, planting medium, competition level, stand density, species composition, and black spruce seedling survival and growth. Black spruce seedling survival in the severely-rutted block was significantly lower when compared with either the moderately rutted or the non-rutted blocks. A derived seedling survival model identified moisture class as having the largest influence on the probability of seedling survival. In terms of seedling growth, however, it was the non-rutted blocks that had the poorest performance. Based on a canonical discriminant analysis (CDA), competition factors, particularly ericaceous shrub cover, were the most important microsite factors influencing black spruce seedling growth. Overall, the moderately rutted block generated conditions that resulted in high conifer recruitment and good seedling survival and growth. Although the inference space of the study is small, the results suggest that black spruce peatland sites may benefit from a moderate level of site disturbance caused during harvest operations. Key words: Rutting severity, black spruce peatlands, survival, growth, microsite assessment
39
Thiffault, Nelson, Brian D. Titus, and Alison D. Munson. "Black spruce seedlings in a KalmiaVaccinium association: microsite manipulation to explore interactions in the field." Canadian Journal of Forest Research 34, no. 8 (2004): 1657–68. http://dx.doi.org/10.1139/x04-046.
Full textAbstract:
We established a field trial on an ericaceous-dominated clearcut in Quebec to determine the effect of Kalmia angustifolia L., Vaccinium angustifolium (Ait.), and V. myrtilloides (Michx.) on the growth and physiology of black spruce (Picea mariana (Mill.) BSP) seedlings and on soil characteristics over the first two growing seasons. Plots undergoing one of three treatments (shrub removal, humus removal, or undisturbed control) were planted with black spruce seedlings that were either unfertilized or spot fertilized at time of planting. In some of the undisturbed control plots, we also used 15NH415NO3 to compare uptake of broadcast N fertilizer by vegetation. The ericaceous shrubs had a significant negative impact on seedling growth. Growth reductions were not related to water stress, soil temperature, or soil moisture. Extractable NH4-N and P concentrations in mineral soil tended to decrease in the presence of ericaceous shrubs, but effects were not significant. Seedling foliar N concentration was also reduced in the presence of ericaceous shrubs. Of the total amount of 15N fertilizer found in vegetation, 64% was immobilized in Vaccinium spp., 31% in Kalmia, and 5% in black spruce, but spruce took up more 15N per unit of root biomass than the ericaceous shrubs. Kalmia had consistently higher predawn xylem water potentials than black spruce.
40
Rivard, Paul G., Paul M. Woodard, and Richard L. Rothwell. "The effect of water table depth on white spruce (Piceaglauca) seedling growth in association with the marsh reed grass (Calamagrostiscanadensis) on wet mineral soil." Canadian Journal of Forest Research 20, no. 10 (1990): 1553–58. http://dx.doi.org/10.1139/x90-207.
Full textAbstract:
The effect of water table depth (10, 20, and 40 cm) in association with marsh reed grass (CalamagrostisCanadensis (Michx.) Beauv.) on white spruce (Piceaglauca (Moench) Voss) 2 + 0 seedling survival and growth was tested over a 5-month period. All spruce seedlings grown alone survived, whereas, 16.7% of the trees died when grown with reed grass. The root weight and total weight of spruce seedlings and marsh reed grass were significantly affected by the water table depth. The weight of both components increased as the water table decreased. Over 80% of the roots by weight for both species were found in the upper 10 cm of the soil profile regardless of water table depth. The presence of marsh reed grass significantly affected the growth of spruce seedlings. The nutrient concentration of the white spruce foliage was significantly affected by water table depths and the presence of grass.
41
Reynolds, Phillip E., Donald A. Buckley, James A. Simpson, et al. "Alternative conifer release treatments affect leaf area index of competing vegetation and available light for seedling growth." Forestry Chronicle 73, no. 1 (1997): 83–89. http://dx.doi.org/10.5558/tfc73083-1.
Full textAbstract:
Leaf area index (LAI) of competing vegetation and photosynthetically-active radiation (PAR) for spruce seedling growth were measured during the first growing season after alternative conifer release treatments [brush saw, Silvana Selective, Release® (a.i., triclopyr) herbicide, Vision® (a.i., glyphosate) herbicide], and control (no treatment) were applied. Bareroot white [Picea glauca (Moench) Voss] and black [Picea mariana (Mill.) B.S.P.] spruce were planted between 1987 and 1991, and averaged 82 cm height in 1993 compared with 2.6 m for major competitors. Treatments were applied in 1993, the primary competitor being trembling aspen (Populus tremuloides Michx.). After the first growing season following treatments, LAI at seedling base differed (P = 0.002) among treatments, ranging from 2.04 (Vision®) to 3.88 (control) m2 m−2. The Vision® treatment had significantly lower LAI than the brush saw, Silvana Selective, and Release® treatments (means = 2.76,2.76, and 2.74 m2 m−2 respectively), and the control treatment had significantly greater LAI than all other treatments. LAI correlated well (r = 0.81) with measured competition levels, increasing as competition levels increased. Mean tip angle (MTA) did not differ among treatments, but was higher for the Vision® treatment, presumably because of lower deciduous tree and shrub cover. Available light (PAR) decreased as LAI increased r = −0.90). In 1994, few released seedlings were overtopped by competing vegetation, and available PAR at leader height was generally 100%. For control seedlings, available PAR at leader height varied among blocks, ranging from 20 to 50%. PAR at seedling base differed among treatments, was lowest (13%) for controls, highest (36%) for the Vision®, and intermediate (~ 26%) for all other treatments. Available PAR on a whole seedling basis (i.e. avg. of leader and base) ranged from 25% for control seedlings to 68% for seedlings released with Vision®. Key words: Fallingsnow Ecosystem Project, white spruce, black spruce, trembling aspen, Vision® (glyphosate), Release® (triclopyr), leaf area index (LAI), mean tip angle (MTA), competition indices, photosynthetically-active radiation (PAR), vegetation management, plant succession
42
Хуршкайнен (Khurshkaynen), Татьяна (Tat'yana) Владимировна (Vladimirovna), Елена (Elena) Михайловна (Mikhaylovna) Андреева (Andreyeva), Светлана (Svetlana) Карленовна (Karlenovna) Стеценко (Stetsenko), Геннадий (Gennadiy) Григорьевич (Grigor'evich) Терехов (Terekhov), and Александр (Aleksandr) Васильевич (Vasil'evich) Кучин (Kuchin). "INFLUENCE OF BIOPREPARATION VERVA AND VERVA-SPRUCE ON THE SCOTS PINE SEEDLINGS GROWTH." chemistry of plant raw material, no. 1 (March 6, 2019): 295–300. http://dx.doi.org/10.14258/jcprm.2019014248.
Full textAbstract:
The results of studying the influence of natural plant growth regulators Verva and Verva-spruce from coniferous wood greenery on the growth and development of Pinus sylvestris L. pine seedlings under the conditions of a forest nursery are presented. A comparative analysis of morphometric indices and accumulation of phytomass in the first two years of growth of pine seedlings grown from seeds treated with coniferous biopreparations of various concentration (experience) and without processing (control) is lead.
 Presowing treatment of seeds with Verva and Verva-spruce preparations at concentrations of 0.1 and 0.25 mL/kg by soaking within 6 hours has led to prolonged effect on growth rates of pine seedlings. Experimental seedlings had higher increments of the aerial part compared to the control: the height of the seedling tree of the first year was 40–84% higher, the second year – 29–47%; the diameter increased by 40–43% in one-year seedlings, and by 2–40% in biennial ones. High values of biometric parameters in two-year seedlings in the experimental versions correspond to the requirements for planting material of coniferous plants. The use of preparations Verva and Verva-spruce for seed presowing treatment will shorten the period of seedling cultivation and the cost of planting material.
43
Duchesne, Sonia, and Luc Sirois. "Phase initiale de régénération après feu des populations conifériennes subarctiques." Canadian Journal of Forest Research 25, no. 2 (1995): 307–18. http://dx.doi.org/10.1139/x95-035.
Full textAbstract:
The objective of this study was to investigate the first stage of post-fire regeneration of black spruce and jack pine in a black spruce woodland and a jack pine forest burned over in 1989 in the Radisson's region, in northern Quebec. Emphasis was given to determine the optimal microsites for black spruce and jack pine regeneration. Our results show that the burned over jack pine forest offers better substrates for seedling germination than the burned over black spruce one. A total of 139 seedlings were observed in the jack pine forest, whereas only 42 were recorded in the black spruce forest. In the jack pine forest, burned over humus was the preferred substrate for germination. Soil moisture content correlated with seed germination of both species. Soil temperatures at −5 cm and the soil surface influenced survival of black spruce seedlings in the jack pine forest
44
Côté, Mathieu, Jean Ferron, and Réjean Gagnon. "Impact of seed and seedling predation by small rodents on early regeneration establishment of black spruce." Canadian Journal of Forest Research 33, no. 12 (2003): 2362–71. http://dx.doi.org/10.1139/x03-167.
Full textAbstract:
Black spruce (Picea mariana (Mill.) BSP) postdispersal seed and juvenile seedling predation by small rodents (Peromyscus maniculatus (Wagner), Clethrionomys gapperi (Vigor), and Phenacomys intermedius (Merriam)) was assessed in three boreal habitats over a 2-year period using an extensive exclosurecontrol experiment. Small rodent relative abundance was measured during six periods using snap trapping. We found that seed and juvenile seedling predation by small rodents varied according to habitat type and over time. Indeed, seed predation was higher in sprucemoss forests than in other habitats, notably during the winter of 2002. During this period, seedling predation was higher in recent burns. This period of higher seed and juvenile seedling predation corresponded to an increase in small rodent abundance in our study area. We suggest that seeds and juvenile seedlings can become important food sources for small rodents during winter when fresh and succulent vegetation is rare, as shown by results of seed predation. The impact of small rodents on the early regeneration of black spruce in the eastern Canadian boreal forest is thus an important factor to consider to better understand the forest regeneration process in this particular biome. Rodents can have a major effect on regeneration following a burn and can also contribute to poor seedling establishment from natural seed rain under mature cover.
45
Johnsen, Kurt H. "Growth and ecophysiological responses of black spruce seedlings to elevated CO2 under varied water and nutrient additions." Canadian Journal of Forest Research 23, no. 6 (1993): 1033–42. http://dx.doi.org/10.1139/x93-132.
Full textAbstract:
Two controlled-environment studies examined growth and ecophysiological responses of black spruce (Piceamariana (Mill.) B.S.P.) seedlings to elevated CO2 under varied water and nutrient additions. Growth analyses were conducted followed by measurements of gas exchange, xylem pressure potential and foliar N concentrations. Growth under elevated CO2 (700 ppm) increased final seedling dry weights by 20–48% compared with seedling growth under ambient CO2 (350 ppm). Percent increases in seedling dry weight were greater under drought versus well-watered conditions and higher versus lower nutrient additions. Seedlings grown under elevated CO2 displayed higher water use efficiency than seedlings grown under ambient CO2. This was apparent based upon instantaneous gas exchange as well as xylem potential pressure measurements. Elevated CO2-induced stimulation of relative growth rate was greatest shortly after seedling emergence and decreased with increased seedling size. Acclimation of net photosynthesis was observed and was reversible. Analyses using allometric principles indicate net photosynthetic acclimation resulted from: (i) growth-induced nutrient dilution; (ii) a decrease in foliar N levels not owing to dilution; and (iii) a decrease in net photosynthetic activity.
46
Youngblood, Andrew P., and John C. Zasada. "White spruce artificial regeneration options on river floodplains in interior Alaska." Canadian Journal of Forest Research 21, no. 4 (1991): 423–33. http://dx.doi.org/10.1139/x91-057.
Full textAbstract:
Reforestation options for artificial regeneration of white spruce (Piceaglauca (Moench) Voss) were tested on three floodplain sites near Fairbanks, Alaska. Survival of containerized seedlings after outplanting was above 96%, regardless of harvest cutting method or mechanical site preparation, and declined little between the third and fifth growing seasons. Establishment and survival after direct seeding on seed spots was more variable and differed by harvest cutting method, by type of site preparation, and by the use of plastic seed shelters for seedling protection. Maximum terminal leader growth, seedling total height, and basal diameter were found on planted seedlings in clear-cut units on the better site. In clear-cut units prepared by blading on one site, basal diameter of seedlings five seasons after outplanting was almost 50% more than on similar surfaces in shelterwood units. Planted seedlings on unscarified surfaces and in small scalped patches generally had similar basal diameters. Results suggested that similar interior Alaska floodplain forests of white spruce can be successfully regenerated by using the clear-cutting harvest method and planting nursery-reared seedlings without mechanical site preparation.
47
Bigras, Francine. "Frost Tolerance of Black Spruce Seedlings (Picea Mariana) during Budbreak." HortScience 30, no. 4 (1995): 849C—849. http://dx.doi.org/10.21273/hortsci.30.4.849c.
Full textAbstract:
Spring frosts frequently cause significant damage to conifer seedlings during bud flushing and shoot elongation in forestry nurseries. To ensure adequate protection, levels of frost sensitivity must be known during these stages of development. Eight-month-old, containerized, black spruce seedlings were submitted to freezing temperatures of 0, –4, –6, –8, and –10C for 1, 2, 3, 4, 5, and 6 h at the following stages: 1) nonswollen buds; 2) swollen buds; 3) bud scales bursting, needle tips emerging; and 4) shoot elongation, 1 to 5 cm. After the treatments, seedlings were grown for 90 days in a greenhouse. Seedling survival then was estimated; dead seedlings discarded; and damage to buds, needles, and roots and shoot increment and diameter were measured on the remaining seedlings. Results show that frost sensitivity increases with the developing bud and shoot. A decrease in seedling and bud survival was noted with an increase in time of exposure (stages 2, 3, 4); otherwise, time exposure has no effect. Damage to needles and roots increases and diameter decreases with decreasing temperatures at all stages. Shoot increment was influenced by decreasing temperatures at stages 2 and 3 only.
48
Wang, G. Geoff, and Kevin J. Kemball. "Balsam fir and white spruce seedling recruitment in response to understory release, seedbed type, and litter exclusion in trembling aspen stands." Canadian Journal of Forest Research 35, no. 3 (2005): 667–73. http://dx.doi.org/10.1139/x04-212.
Full textAbstract:
Experimental seeding of balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) was implemented in three mature trembling aspen (Populus tremuloides Michx.) stands in southeastern Manitoba to test (i) the effect of vegetation (light) competition and seedbed type (undisturbed forest floor, exposed mineral soil, and rotten logs) on seedling recruitment over the first 2 years and (ii) the effect of broadleaf litter exclusion on seedling mortality during the first winter. The study indicated that, with adequate seed supply, seedbed type was the most important factor limiting seedling recruitment, especially the recruitment of white spruce, in trembling aspen stands. Seedling recruitment on the best and the worst seedbeds differed by 1.8 times for balsam fir but by 19 times for white spruce. Significant differences in soil moisture and temperature were found between seedbed types. Broadleaf litter exclusion also facilitated the recruitment of balsam fir and white spruce, but only on undisturbed forest floor. Vegetation (light) competition, however, did not limit seedling recruitment. On the contrary, the presence of understory vegetation benefited seedling recruitment on rotten logs. Compared with white spruce, balsam fir is better adapted to regenerate in trembling aspen stands. Balsam fir was about 4, 12, and 36 times better than white spruce when regenerating on exposed mineral soil, rotten log, and undisturbed forest floor, respectively.
49
Jacobs, Douglass F. "Reforestation of a Salvage-Logged High-Elevation Clearcut: Engelmann Spruce Seedling Response to Tree Shelters after 11 Growing Seasons." Western Journal of Applied Forestry 26, no. 2 (2011): 53–56. http://dx.doi.org/10.1093/wjaf/26.2.53.
Full textAbstract:
Abstract High-elevation clearcut sites in the southern Rocky Mountains are difficult to reforest successfully and many sites remain poorly stocked decades after harvest. This article presents results after 11 growing seasons of a project designed to examine use of tree shelters to provide initial shade for planted Engelmann spruce (Picea englemannii Parry ex Engelm.) seedlings. Seedlings were planted in 1996 on a 48-ha site at an elevation of approximately 3,273 m in southwestern Colorado, with different shelter colors providing various shading levels. A control, consisting of shading using debris within the site, was also included. Results after 2 years were presented previously. To examine seedling response to tree shelter removal after seedling establishment, half of shelters were removed in 2000 and seedlings were reassessed in 2007. Control seedlings had lower survival (35%) than any other treatment (ranging from 59 to 78%). Shelter removal in the lightest two shelter color treatments did not reduce survival, suggesting that seedlings can grow in full sun after 4 years of shading. The best overall seedling development (i.e., survival, absolute height, and root collar diameter) occurred in the lightest shelter color with shelters removed. Tree shelters offer a viable means to restore high-elevation spruce-fir sites where past reforestation has proven difficult.
50
Fleming, R. L., and D. S. Mossa. "Direct seeding of black spruce in northwestern Ontario: Seedbed relationships." Forestry Chronicle 70, no. 2 (1994): 151–58. http://dx.doi.org/10.5558/tfc70151-2.
Full textAbstract:
A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination