共查询到20条相似文献，搜索用时 15 毫秒
1.
The influence of woody and herbaceous plant competition, either alone or in combination, on microclimate and growth of planted eastern white pine (Pinus strobus L.) seedlings was examined over four consecutive growing seasons in a central Ontario clearcut. Treatments that manipulated the comparative abundance of these two plant functional groups significantly affected light availability, soil moisture, and air and soil temperature regimes. These microclimate alterations, coupled with the relative competitiveness of herbaceous and woody vegetation, corresponded to temporal changes in vegetation cover and dominance. The more rapid colonization and growth of the herbaceous plant community, dominated by bracken fern (Pteridium aquilinum) and ericaceous shrubs (Kalmia sp., Vaccinium sp.), resulted in this form of vegetation being a comparatively important early competitor for soil moisture. As the woody plant community, dominated by naturally regenerated trembling aspen (Populus tremuloides Michx.), grew in height and leaf area, it became a comparatively strong competitor for both light and soil moisture. For all vegetation treatments combined, white pine seedling growth responses were strongly correlated with total cover of competing vegetation and its relative influence on above- and belowground microclimatic variables. Higher total cover of competing vegetation was generally associated with lower light and soil moisture availability and cooler soil temperatures. Multiple regression analyses indicated that pine seedling relative height growth increased with soil moisture content and growing season soil heat sum, while seedling relative diameter and relative volume growth increased with light availability. 相似文献
2.
Effects of three aspen (Populus tremuloides Michx.) canopy removal treatments and root trenching on understory microenvironment and moisture were tested at Parkland
and Boreal sites in Alberta, Canada. Aspen canopies moderated air temperature by reducing maximums and increasing minimums,
and increased the frost-free period in the understory by reducing radiative frosts. When daily differences were found among
canopy treatments, maximum absolute humidity was greater with complete canopy removal. Maximum daily relative humidity was
greater in openings at night than with either full or partial canopy cover. Predictably, increasing aspen cover reduced PAR
reaching the understory. Soil moisture response was highly variable, changing with site, aspen density and precipitation patterns,
but there were only marginal differences due to root trenching. In the Parkland site, soil moisture conservation from aspen
canopy and leaf litter effects were masked by tree uptake in most periods, but a net increase in soil water (+5.2%) was observed
during drought. Soil and microclimatic conditions in thinned aspen stands suggest potentially favourable production benefits
from developing and adopting agroforestry systems in these northern ecosystems. 相似文献
3.
Natural regeneration is an important process to reverse the loss of forests. Understanding the process of natural regeneration is crucial for achieving sustainable forest management. In this study, we examined the effects of seed and pollen dispersal in naturally regenerated populations of Castanopsis fargesii. Genetic variation in six populations along two successional series (three successional stages in each series: early, pre-climax, and climax) was assayed using RAPD (random amplified polymorphic DNA) markers. High genetic variability was observed as measured with Shannon's information index. A majority of genetic variation was distributed within populations (Φst = 0.1271) and significant isolation by distance existed among populations. A contrasting pattern of genetic variation along these two series was observed, representing different scenarios of natural regeneration processes. The ratio of the number of migrants between the mature populations to the number of migrants from the mature to immature populations was estimated as 1.146 ± 0.099 to 1.981 ± 0.164, implying that comparable seed and pollen dispersal might exist at a fine spatial scale (∼2 km2). The results suggest the critical role of seed dispersal in shaping genetic composition and diversity in the second-growth forests. Barriers to seed dispersal from a variety of genetic sources could result in low genetic diversity in naturally regenerated populations. Management that facilitates the connectivity of newly regenerated stands with mature forests could be effective for natural regeneration given the predominant role of short-distance dispersal of seeds in this species. 相似文献
4.
Katrin Rosenvald Ivika Ostonen Veiko Uri Mats Varik Leho Tedersoo Krista Lõhmus 《European Journal of Forest Research》2013,132(2):219-230
The influence of forest ageing on fine-root morphology and relations between fine-root and leaf characteristics is poorly studied. The aim of this study was to analyse age-driven changes in ectomycorrhizal roots (EcM roots) and leaf morphology in a chronosequence of silver birch (Betula pendula Roth.), which would provide a better understanding of adaptation responses and acclimation capacity of tree roots and leaves. The chronosequence included six age classes (3, 6, 14, 32, 45, and 60 years.). All stands had regenerated naturally and grew in a highly productive Oxalis forest site type in Estonia. Most changes in the morphology of EcM roots and leaves of silver birch occur faster at a young age. The functional parameters—mean specific area of EcM root (SRA) and leaf specific area (SLA) as well as leaf N—decreased with age. EcM root SRA and specific root length (SRL) decreased with stand age as a result of increased mean diameter and tissue density. In age classes of 6, 14, and 32 years, the total number of dominating EcM taxa was 34, and the distribution of four different dominating EcM exploration types (contact-, short-, medium-, long-distance) was similar. We conclude that high values of SRA, SLA, and leaf N measured in young silver birch stands indicate high activity of physiological processes necessary for fast-growing young trees. A decrease of SLA and SRA and N in the chronosequence of fertile stands of silver birch is most probably caused by down-regulation of growth, affecting simultaneously leaves and fine roots. 相似文献
5.
Key message
Forty years after clear-cutting mixed old-growth forest (broadleaf/Korean pine) in the Changbai Mountain area (Northeast China), a mixed forest with natural broadleaf regeneration and larch plantation displayed larger microbial biomass and activity in the soil than either a naturally regenerated birch forest or a monospecific spruce plantation.Context
Clear-cutting with limited restoration effort was until the end of the twentieth century the norm for managing primary forests in Northeast China. Forest restoration plays an important role in the recovery of soil quality after clear-cutting, but the effects of different regeneration procedures on forest soil quality remain poorly known in Northeast China.Aims
We assessed the effects of three regeneration procedures, i.e., (i) naturally regenerated birch forest, (ii) spruce plantation, and (iii) naturally regenerated broadleaf species interspersed with planted larch on soil quality and microbial activity in the Changbai Mountain area. An old-growth mixed broadleaf/Korean pine forest was used as a reference.Methods
Physical and chemical properties and microbial biomass were recorded in the soil. Basal respiration and carbon mineralization were measured with a closed-jar alkali-absorption method.Results
Microbial biomass was smaller in the birch forest and spruce plantation than in the old-growth and the mixed broadleaf/larch forests. Moreover, microbial biomass, microbial quotient, and potentially mineralizable carbon were larger in the mixed broadleaf/larch than in the birch forest, while no difference was found between spruce plantation and birch forest for microbial biomass and microbial quotient. Basal respiration and metabolic quotient were larger in the birch forest as compared to the three other forest types, indicating a larger energy need for maintenance of the microbial community and lower microbial activity in the naturally regenerated birch forest.Conclusion
Mixed broadleaf/larch forest displayed a larger microbial biomass and higher substrate use efficiency of the soil microbial community than either naturally regenerated birch forest or spruce plantation. The combined natural and artificial regeneration procedure (mixed broadleaf-larch forest) seems better suited to restore soil quality after clear-cutting in the Changbai Mountain.6.
桉树的抗旱性研究进展 总被引：9，自引：0，他引：9
在干旱和半干旱地区,为了成功地栽培桉树,许多学者从不同角度对桉树种群的抗旱性机理和它们对不同干旱环境的反应进行了研究和探讨。结果认为,桉树种群的遗传基因能适应于干旱的环境。生长在水分短缺条件下的植株,是通过各种途径保持组织水含量在细胞免受伤害的临界值以上而达到其适应。一般来说,具有旱生植物特征的桉树种群对干旱的适应能力较强,它们能够生存在较干旱的环境条件下,但不可能从湿润的气候环境中取得生长优势。 相似文献
7.
To evaluate the influence of excessive N deposition on the water consumption of a Japanese plantation forest, 1-year-old seedlings of major plantation trees, Cryptomeria japonica (Japanese cedar) and Chamaecyparis obtusa (Hinoki cypress), were treated with combinations of two N levels (Moderate N and High N) and two soil water conditions (Dry and Moist) for 4 months. The High N treatment received five times as much N as in the Moderate N treatment; the total amount of N added in the High N treatment was roughly 25 times the annual N deposition in precipitation. An increase in soil N availability increased the needle transpiration rate, needle biomass, and needle N content of C. japonica under the Moist treatment, whereas those of C. obtusa were not significantly affected by soil N treatment at either soil water level. Needle N content in C. japonica was positively related to needle photosynthetic rate and transpiration rate. Our results suggested that excessive N deposition has the potential to enhance water consumption in C. japonica stands on moist soils. However, the effects of increased N deposition would be insignificant for C. japonica grown on dry sites. Unlike in C. japonica, water consumption in C. obtusa would be unlikely to respond to excess N deposition, regardless of the soil moisture level. Moreover, the significant reduction in the fine root to needle ratio observed with excessive N application in C. japonica under both Dry and Moist treatments suggests that excessive N deposition is likely to cancel out the tree's morphological adaptation to drought. 相似文献
8.
Ning Du Renqing Wang Jian Liu Xiuru Zhang Xiangfeng Tan Wei Wang Hua Chen Weihua Guo 《Agroforestry Systems》2013,87(2):403-416
Light and soil moisture availability are two important abiotic factors influencing plant growth in an agroforestry system. Different soil moisture and light treatments were applied to examine the combined impact of drought and shade on the morphological plasticity of Vitex negundo var. heterophylla (Chinese chastetree) and Ziziphus jujuba var. spinosa (Spine jujube). We found that the interaction of light and soil moisture was orthogonal in the two species. V. negundo captured irradiance efficiently with relatively long petiole and petiolule, while Z. jujuba maintained higher branches to absorb light than V. negundo. Compared to the seedlings under full sunlight, the palmately compound leaves of V. negundo under low light showed larger specific leaf area (SLA), lower ratio of leaflet length to width and higher leaf mass ratio (leaf biomass to total biomass); in contrast, the simple leaves of Z. jujuba under low light showed larger SLA and ratio of leaf length to petiole length. In both species, drought reduced the branch number, mean internode length of stem, and increased root mass ratio (root biomass to total biomass), but leaf morphology showed little variation to the decreased soil moisture. Between the two species, V. negundo is more shade-tolerant, while Z. jujuba is more drought-tolerant. In an alley cropping system, the spacing can be smaller in the V. negundo-crop system than the Z. jujuba-crop system when soil moisture is adequate. However, the V. negundo-crop system should be managed with more caution under the soil moisture limited conditions. 相似文献
9.
以104份欧洲黑杨不同基因型(无性系)为材料,通过生长量和生理指标的测定,研究土壤施氮和不施氮条件下其氮素利用效率的差异。结果表明:不同供氮水平下,不同基因型欧洲黑杨生长差异显著。根据2个供氮水平的苗木年平均材积生长量将欧洲黑杨群体划分为4个类型:双高效型、高氮高效型、低氮高效型和双低效型,并结合氮反应指数在双高效型与高氮高效型中分别筛选出8个氮素利用效率高、生长表现优良的基因型,具较高的育种价值。比较分析欧洲黑杨不同基因型氮素利用效率相关指标,发现双高效型的净光合速率、硝酸还原酶和谷氨酰胺合成酶活性、根系干质量、体积、比表面积均高于高氮高效型,初步揭示了不同类型欧洲黑杨氮利用效率存在差异的机理。 相似文献
10.
Aspen (Populus tremuloides Michx.) is a foundational tree species of the North American boreal forest. After disturbance, clonal aspen stands quickly achieve canopy closure by sending up numerous clonal shoots (root suckers) from their lateral root system. Controlled aboveground disturbance will commonly induce prolific root suckering and thereby increase stem density in clonal aspen stands, but it is unclear if increases in stem density will be observed in planted seedling-origin aspen stands. The objectives of this study were to determine (1) overall root suckering response of planted aspen to aboveground disturbance; (2) if different cut heights of the stem or infliction of root damage impact the number of root suckers produced. We found that planted aspen regenerated readily after disturbance, averaging five root suckers per cut tree. However, individual response was highly variable, ranging from zero to 29 root suckers per root system. Of the cut trees, 75% produced at least one root sucker and 60% produced at least one stump sprout. Cutting trees close to the soil surface produced more root suckers than leaving a 25 cm stump. While root system size (mass and length) was well correlated with aboveground measures of planted aspen, root suckering was not related to root system size. As a result of increased forest reclamation efforts in the boreal forest region the planting of aspen has become a more common practice, necessitating a better understanding of the regeneration dynamics and root suckering potential of these planted and seedling-origin aspen forests. 相似文献
11.
Aspen (Populus tremula) is capable of reproducing both sexually and asexually from root suckers, the latter being more common. Seedlings are rare
even though potential seed production is enormous. The aim of this study was to find out how different moisture conditions
affect emergence and survival of aspen seedlings on burned soil. We set up a sowing experiment on mineral soil and on humus.
The sowing was done at 240 microsites (θ7 cm) in 15 blocks (1×1 m). Treatments were sowing time, watering and sowing shelter.
A total of 1463 seedlings emerged on mineral soil and 26 on humus. Watering, covering, their interaction, block and sowing
time had significant effects on the number of seedlings. The largest numbers of seedlings were recorded at microsites that
were watered and covered. The survival of seedlings was 20% during the growing season and 45% over winter. We conclude that
seedbed conditions and moisture are the most essential factors for sexual reproduction of aspen. Short-term weather conditions
have an important effect on seedling emergence and are likely to greatly affect field studies. 相似文献
12.
Effects of reforestation by native tree species on species assemblages of carabid beetles were studied between 40-year-old regenerating plantations and 100-year naturally regenerated forests in Southwestern China. Two old naturally regenerated forest types (ca.100 years old) were chosen: hemlock-spruce forests (Tsuga chinensis and Picea brachytyla) and birch forests (Betula albo-sinensis). Three young regenerating forest types (ca. 40 years old), including spruce plantations (P. brachytyla), larch plantations (Larix kaempferi and Larix mastersian), and natural broad-leaved forests, were established after the logging of the old naturally regenerated forests. Using pitfall traps, we compared the distribution of carabid beetles in the five forest types. Three replicated plots for each forest type were chosen, and each plot was investigated with four trap sites twice each month during the growing season (May to October) in 2004. Our results showed that species richness and abundance were significantly higher in the young regenerating forests than in the old naturally regenerated forests. Analysis of complementarity in carabid species lists across the forest ages and types showed that the old naturally regenerated birch forests had the lowest similarity with the young regenerating larch plantations, and the highest similarity was shown between the two young regenerating plantations. Although PCoA ordination grouped the carabid assemblages according to forest type and forest age, the overall similarity among all forest types was high. Moreover, quantitative character species analysis did not detect significant species associated with forest types and ages. Based on the specificity and fidelity, most carabid species were abundant in all habitats, and only a few species were restricted in one or two forest types. Multiple linear regression between the species richness, abundance and Shannon diversity of carabids and of five environmental variables showed that the cover of canopy and herbaceous layer, and the depth of leaf litter had significant effects in determining richness, abundance and diversity of carabid beetles. Thus, the young regenerating forests at the mature stage could provide an appropriate habitat for most forest species of carabids survived in adjacent old naturally regenerated forests and might replace the role in part of the old-growth forests in sustaining the diversity of carabid assemblages. But some species are still restricted in old naturally regenerated forests, so in order to protect the diversity of carabid assemblages, it is necessary to sustain the intact old naturally regenerated forests when reforesting with some native tree species following natural succession. 相似文献
13.
[目的]克隆马尾松谷胱甘肽过氧化物酶基因,并对其进行功能研究。[方法]采用RACE技术克隆基因c DNA序列,实时荧光定量PCR检测基因在马尾松干旱胁迫下的表达模式,花序浸泡法转化拟南芥,并对转基因与野生型拟南芥的生长表型和根系生长进行分析。利用荧光显微镜技术对转基因拟南芥不定根进行GFP荧光检测。[结果]克隆到1个871 bp的GPX基因全长c DNA序列,命名为Pm GPX6。Pm GPX6包括513 bp的完整开放阅读框,编码170个氨基酸残基。Pm GPX6蛋白与油松Pt GPX蛋白同源性达95%。Pm GPX6在马尾松根中高表达,茎、叶中表达量低。在干旱胁迫下,Pm GPX6在根、茎、叶中的表达量均在第15天达到最大,随后出现下降趋势。过表达Pm GPX6与野生型拟南芥植株在正常水分条件下表型与根长差异不大,但在干旱胁迫下,转基因植株根系更长。转基因拟南芥根在蓝色光激发下能发出强烈的绿色荧光,表明Pm GPX6基因能高效表达。[结论]推测Pm GPX6可能参与马尾松干旱胁迫应答。 相似文献
14.
Aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench.) Voss) were planted 0.5 m apart in intimate mixtures in 5 × 4 m plots, with two moisture regimes—irrigation versus control—and five species compositions—pure aspen (Aw100), mixed aspen and spruce (Aw83Sw17, Aw50Sw50, Aw17Sw83), and pure spruce (Sw100), replicated six times. Fifth-year assessments indicated that irrigation increased individual tree growth (height, RCD, crown width), plot leaf area index (LAI), and wood biomass. Increased aspen composition reduced the availability of soil moisture and consequently the growth of individual trees. With increased aspen composition more growth was allocated to stem in aspen and to foliage in white spruce. Comparatively, aspen responded more to irrigation and thus their growth is more dependent on precipitation than that of spruce. Among the three growth variables assessed, height responded more to irrigation in both species. Equal mixtures and aspen-dominated mixtures in control plots had higher productivity in terms of total wood biomass in both absolute and relative terms. The implications of these findings are discussed in relation to managing aspen and white spruce mixedwood forests under increasing drought expected as a result of climate change. 相似文献
15.
利用LI-COR-8100土壤CO2通量自动测量系统测定了湖北赤壁幕布山区采伐毛竹林土壤表面CO2通量及5 cm深度的土壤温度、湿度,研究了采伐对毛竹林土壤呼吸的影响,并用壕沟法区分各组分呼吸。结果表明:采伐显著增加了毛竹林的土壤温度,但对土壤湿度无显著影响;采伐能增加土壤呼吸、凋落物呼吸与矿质呼吸,但降低了根系呼吸;土壤总呼吸及组分呼吸与土壤温度呈指数相关(R2=32.63%84.50%),与土壤湿度呈线性相关(R2=40.60%93.50%),运用土壤温度、湿度复合模型能提高预测土壤呼吸的准确性(R2=41.40%96.20%)。采伐毛竹林土壤呼吸的增加主要因为采伐后土壤温度升高所致。 相似文献
16.
[目的]研究干旱处理中油茶叶片内源激素、果实生长的变化规律以及地表覆盖、土壤翻耕2种措施对缓解干旱胁迫的效果。[方法]以6年生长林4#油茶为试验材料,设置自然状况、干旱胁迫、地表覆盖及土壤翻耕4个处理,采用酶联免疫吸附分析法(ELISA)测定油茶叶片内源激素,并分析果实的生长状况。[结果]研究表明:(1)干旱胁迫开始两周后,即当土壤含水率低于24.0%~26.8%,油茶叶片内源激素开始启动对干旱的响应机制。(2)干旱胁迫使油茶叶片IAA含量下降,ABA含量上升,GA含量先上升后下降,ZR含量下降并维持在较低水平,ZR/IAA值下降;地表覆盖及土壤翻耕可以有效缓解干旱对叶片IAA、GA、ZR含量的影响,而对叶片ABA含量、ZR/IAA的影响不显著;油茶通过内源激素含量的变化来应对干旱胁迫的影响。(3)干旱胁迫使油茶果实横径减小,果实纵径出现负增长,而地表覆盖及土壤翻耕相对于干旱胁迫使得果实横径生长量分别增加了73.20%、75.58%,可以有效缓解干旱胁迫对油茶果实纵径生长的影响。[结论]生产上通过地表覆盖及土壤翻耕可以有效缓解干旱对油茶果实生长的影响,地表覆盖技术措施可进一步推广应用。 相似文献
17.
Steffen Taeger Barbara Fussi Monika Konnert Annette Menzel 《European Journal of Forest Research》2013,132(3):481-496
Seedlings of ten provenances of Scots pine (Pinus sylvestris L.) from the southwestern to the central part of the species distribution range were investigated in a greenhouse experiment under dry conditions compared to a well-watered control. We conducted an isozyme study and recorded phenology as well as growth traits during the first year of growth. Genetic variability and genetic diversity increased from the westernmost provenances to those central to the distribution. Provenances from the Apennines and Spain revealed the strongest genetic differentiation compared to all others, whereas populations from Germany, Poland and Bulgaria were found to belong to the same gene pool. Seedling development and bud set were faster in northern populations. Shoot length was highest for Polish and German provenances within both regimes, populations from France and Spain had the longest roots. Reduced soil moisture slowed later development stages and delayed bud set for all provenances by about 5 days. Shoot growth decreased considerably under the dry regime for all provenances. German provenances were the most sensitive to drought, whereas Spanish provenances showed adaptation to drought conditions indicated by the lowest reduction in shoot growth relative to optimum conditions. The results of this pilot study show that under more pronounced drought conditions with repeated drought events, the so far established superiority of northeastern provenances compared to southwestern ones could diminish in the future. 相似文献
18.
The effect of land use type on the dynamics and annual rate of net nitrogen mineralization (NNM) in a naturally generated silver birch stand and in a grassland, both on abandoned agricultural land, was assessed in situ in the upper 0–20 cm soil layer using the method of buried polyethylene bags. Annual NNM rate in the birch stand (156 kg N ha−1 year−1) was higher than in the grassland (102 kg N ha−1 year−1); in both cases NNM covered a major part of the plants annual nitrogen demand. The rate of NNM in the upper 0–10 cm soil layer in the birch stand (99 kg N ha−1 year−1) exceeded the respective rate of NNM in the grassland (51 kg N ha−1 year−1) roughly two times. In the grassland the rates of NNM in the 0–10 and 10–20 cm layers were equal; in the birch stand NNM in the 0–10 cm layer was 1.7 times higher than in deeper 10–20 cm layer. The intensity of daily NNM in the upper 0–10 cm soil layer in the birch stand was the highest in June and in the grassland in May, 776 and 528 mg kg−1 N day−1, respectively. In our study no significant correlation was found between NNM and the environmental factors monthly mean soil temperature, soil moisture content and pH. 相似文献
19.
Tomasz Gradowski Victor J. Lieffers Simon M. Landhäusser Derek Sidders Jan Volney John R. Spence 《Forest Ecology and Management》2010
Aspen and balsam poplar regeneration from root suckers were assessed in boreal mixedwood forests nine years after logging in a variable retention experiment (EMEND Project—Ecosystem Management Emulating Natural Disturbance) located north of Peace River, Alberta, Canada. Five levels of retention of mature trees (2%, 10%, 20%, 50% or 75% of the original basal area) were applied in stands dominated by aspen, white spruce or mixtures of the two species. Basal area of aspen (or that of aspen plus balsam poplar combined) prior to logging strongly influenced sucker density of aspen (or aspen + balsam poplar combined) and in some cases their growth. Nine years after harvest there was a decline in sucker density and volume ha−1 with increasing retention levels of aspen (or both poplars combined); sucker density declined by 50% when only 20% of the original basal area was left in the stand. Retaining mature spruce trees in the stand had little influence on the number of suckers but did affect their total volume ha−1. Thus, we suggest that by knowing stand aspen and balsam poplar density prior to logging and varying levels of retention of aspen and balsam poplar or conifers at harvest, the density of Populus regeneration can be predicted by managers, thereby allowing them to create a range of mixedwood conditions. 相似文献
20.
《Forest Ecology and Management》2004,193(3):355-370
The availability of coarse woody debris (CWD) and distribution of dead trees into categories of mortality (dead standing, broken and uprooted) were investigated in north-temperate forests of central Europe (Lithuania). The studied area comprised 188.7 ha and included 18 different stands 40–130 years of age with a variety of tree species (spruce (Picea abies (L.) Karst.), pine (Pinus sylvestris L.), alder (Alnus glutinosa (L.) Gaertn.), birch (Betula pendula Roth and B. pubescens Ehrh.), aspen (Populus tremula L.), oak (Quercus robur L.), forest types (caricus-sphagnum, vaccinium-myrtillus, oxalis, myrtillus-oxalis, caricus-calamagrostis) and edaphic conditions (peaty, sandy, loamy soils of different moisture). The stands were excluded from wood harvesting for at least 30 years. A total of 11 365 dead trees (over 10 cm in DBH) or 6160.7 m3 of dead wood was found (60.2 trees/ha and 32.6 m3/ha). The volume of CWD per hectare was larger in older stands (rS=0.78, P<0.01). Tree mortality during the last 2 years consisted of 482 trees and 381 m3, or 1.28 trees/ha×year and 1.01 m3/ha×year. In 25–33% of cases it was wind-related. Uprooted and broken trees were of larger DBH than dead standing. The distribution into the categories of mortality was strongly dependent on tree species (chi-square test, d.f.=10,P=0). Dead standing dominated in CWD of pine and alder. Broken trees comprised almost a half in CWD of aspen, and about one-third in birch, alder and oak. Uprooting most often occurred in spruce, aspen and birch. Edaphic conditions and stand age had a pronounced impact on distribution into mortality categories for spruce (chi-square test, d.f.=20, P<0.00001) and pine (d.f.=8, P≤0.0003). On peat soil, only a minority of trees of both pine and spruce was uprooted, and standing dead prevailed. In CWD of spruce and pine, the proportions of both dead standing and broken decreased and that of uprooted trees increased on mineral soils of higher moisture and bulk density in older stands. By contrast, uprooting in birch and alder occurred less often on more wet sites, where the proportions of standing snags were higher. A total of 41 species of wood-decomposing polypores were found in the study area. Among those, 10 (24%) were of conservation value. 相似文献