长白山北坡植物群落复杂性的海拔梯度变化

应用梯度格局法在长白山北坡海拔700m-2600m的坡面上每100 m海拔设置一样地,共计20块样地,通过对同一群落各样方间的相异性测定,对各海拔植物群落的复杂性进行了分析。结果表明,以主林层乔木种的二元数据计算的结果,除亚高山岳桦林外,其它各海拔群落的样方间均表现出较高的相异性,特别是低海拔的阔叶红松林平均相异系数达0.74,明显高于其它植被类型;暗针叶林各群落间差异不大,相对而言1400 m群落样方间的相异性略高于其它群落,表现出过渡性群落树种组成的复杂性;岳桦林树种组成简单,样[(\267\275\274\344\322\262\261\355\317\326\263\366\275\317\270\337\265\304\\317\340\313\306\320\324\241\243)-0.1(\322\324\271\340\304\276\326\326\265\304\266\376\324\252\312\375\276\335\\274\306\313\343\265\304\310\272)]落内的相异性,虽低海拔的阔叶红松林总体上高于其它群落,但差异趋势并不像乔木种那么明显。以各草本植物与所有植物种的二元数据计算的各海拔群落内样方间的相异性,表现出非常相近的趋势,群落内样方间草本植物及所有植物种均以阔叶红松林及高山冻原差异最大,暗针叶林基本稳定于比较相近的水平。图3表1参8。     

Changes in species composition and diversity in the restoration process of sub-alpine dark brown coniferous forests in western Sichuan Province, China

By adopting the concept of space as a substitute for time, we analyzed the dynamics of species composition and diversity of different restoration sequences (20, 30, 40, 50 years) in two secondary forest types in western Sichuan Province, distributed in a northerly or northwesterly direction. The analysis was based on the results of measurements of 50 plots located at elevations between 3100–3600 m. The forests originated from natural regeneration in combination with reforestation of spruce when the old-growth bamboo-dark brown coniferous forests and moss-dark brown coniferous old growth forests were harvested. Similar old-growth dark brown coniferous forests at ages ranging between 160 and 200 years were selected as the reference forests for comparisons. We recorded 167 species of vascular plants from 44 families and 117 genera. There was no significant difference in terms of the number of species among secondary forests. But the importance values of dominant species varied during the restoration processes. The dominant species in the secondary forests is Betula albo-sinensis, while Abies faxoniana is the dominant species in old-growth dark brown coniferous forests. Species richness increased significantly with restoration processes. It increased quickly in secondary forests during the period from 30 to 40 years, but decreased significantly in the old-growth dark brown coniferous forests. The species richness among growth forms decreased in the following order: herb layer > shrub layer > tree layer. The maximum value of the evenness index occurred in secondary forests at age 40 and remained relatively stable in the bamboo-birch forests, but the evenness index tended to decrease in moss-birch forests and slightly increased in the old-growth mossdark brown coniferous forests. There was a statistically significant difference in the eveness index between the tree and shrub layers as well as between the tree layer and the herb layer, but there was no significant difference between the shrub layer and the herb layer. The value of the Shannon index increased over restoration time. In bamboo-birch forests, the maximum value of the Shannon index was 3.80, recorded at age 50. In moss-birch forests, the maximal value was 3.65, reached in this forest at age 30. The value of the Shannon index of old-growth dark brown coniferous forests was recorded between younger secondary and older secondary forests. The value of the dominance index of communities varied. At the first stage of restoration, it increased, and at the end it was decreased. The dominance index of the tree layer had a similar trend as that of the community dominance index, but was more variable. The minimum value of the dominance index of the tree layer in the moss-birch forests reached 20 years earlier than that of the bamboo-birch forests. There was a significant difference among restoration sequences in the α diversity indices except for the dominance index. No significant differences between the two secondary forest types were detected. Over age, the value of the Bray-Curtis index between secondary forest and old-growth dark brown coniferous forest increased. __________ Translated from Scientia Silvae Sinicae, 2007, 43(5): 17–23 [译自: 林业科学]     

Leaf and twig litter decomposition of main species in different forests along the north slope of Changbai Mountain, northeast China

From 2001 to 2003, the litter decomposition dynamics of dominant tree species were conducted using a litterbag burying method in the broadleaf-Korean pine forest, spruce-fir forest and Ermans birch forest, which represents three altitudinal belts in Changbai Mountain, northeast China. The spatial and temporal dynamics of litter decomposition and the effects of litter properties were examined. Furthermore, the decomposition trend of different species was simulated by the Olson model, and results showed that annual mass loss rates increased over time, but was not significantly correlated. Leaf decomposition rates increased after decomposing for 638 days (1.75 years), and the order of dry weight remaining rates of leaf litter for different species is: Asian white birch (Betula platyphylla) (24.56%) < Amur linden (Tilia amurensis) (24.81%) < Korean pine (Pinus koraiensis) (38.48%) < spruce (Picea jezoensis var. microsperma) (41.15%) < Ermans birch (Betula ermanii) (41.53%) < fir (Abies nephrolepis) (42.62%). The dry weight remaining rates of twig litter was smaller than that of leaf litter, and followed the order of Amur linden (44.98%) < fir (64.62%) < Korean pine (72.07%) < spruce (73.51%) < Asian white birch (77.37%) < Ermans birch (80.35%). The simulation results by the Olson model showed that, in leaf, the 95%-decomposition rates ranged from 4.5 to 8.0 years, and annual decomposition rate (k) followed the order of Amur linden (0.686) > Asian white birch (0.624) > Korean pine (0.441) > spruce (0.406) > fir (0.397) > Ermans birch (0.385); in twig, it ranged from 7.8 to 29.3 years, and k follows the order: Amur linden (0.391) > fir (0.204) > Korean pine (0.176) > spruce (0.157) > Asian white birch (0.148) > Ermans birch (0.102). In general, the differences of decomposition rate are evident between leaf and twig litter and among species, and were higher in broad-leaved species compared with coniferous species at the same elevation, and decreased with the ascending of elevation. __________ Translated from Acta Ecologica Sinica, 2006, 26(4): 1,037–1,046 [译自: 生态学报]     

红松、刺楸人工针阔混交林物种多样性研究

通过对红松、刺楸人工混交林,红松纯林物种多样性的研究,结果表明,红松、刺楸混交林物种丰富度最大,植物种类最多,红松纯林仅为混交林的43%,总数量为混交林的32%,红松、刺楸混交林乔木层多样性指数为1.430 5,均匀度指数为0.687 9,优势度指数为0.290 6,丰富度指数为1.413 7,而红松纯林多样性指数、均匀度指数均为0,优势度指数为1,丰富度指数为0.371 2。在灌木层中,混交林与纯林各项指标区别不大,只有丰富度指数为混交林(纯林。在草本层中,混交林各项指数基本都大于纯林,只有均匀度指数红松纯林(混交林。     

华中神农架箭竹(Fargesia spathacea)群落之海拔多样性

通过对华中神农架海拔1500米至2600米之间11个箭竹样方的研究，阐述了箭竹群落物种丰富度，物种多样性，物种均匀性，生活型谱及群落类型的海拔变化。从最低样方(1680米)到最高样地(2570米)，微管束植物从30种降为7种，服从线性模型：Y=55.99-1.83X(R2=0.84，P<0.001)；物种多样性从3.18降为1.78，服从线性模型：Y=4.67-0.10X (R2=0.72，P=0.001；物种均匀度在0.83至0.99之间变化，但与海拔并不相关。在生活型谱中，一年生植物，地下芽植物和大高位芽树木的百分比随海拔升高而升高；灌木和中高位芽树木随海拔升高而降低；多年生草本和半灌木与海拔关系不大。箭竹群落可分为5种类型：常绿阔叶林下，落叶阔叶林下，温性针叶林下，寒温性针叶林与混交林下，纯箭竹林。     

Comparison of fractal characteristics of species richness patterns among different plant taxonomic groups along an altitudinal gradient

This study was done using the non brown fractal model to quantify and compare the variations in the species richness of trees, shrubs, herbs and all plants along an altitudinal gradient and to characterize the dominating ecological processes that determine the variations. Two transects were sampled far away from any anthropogenic disturbances along the shady slopes of the Dongling mountains in Beijing, China. Both transects were continuous and 2 m wide, and every individual tree and shrub was recorded in each of them. Discrete quadrats of 1 m × 1 m were located along the transects A and B for estimation of the herb species richness along the altitudinal gradients. The level interval between the quadrats was 10 m and 25 m respectively. In this study, transects A and B were combined into one transect AB, and 40 m was selected as the optimal quadrat length along the altitudinal gradients for measuring the plant species richness patterns. Species richness in each quadrat was calculated using a program written in Matlab 6.0. Direct gradient analysis was used to describe the overall trends in the species richness of trees, shrubs, herbs and other plants with change in altitude, while the non-brown fractal model was used to detect more accurately their variations at various scales along the gradient. The model assumed that each class of ecological processes affecting the distribution of a variable could be represented by an independent spatial random function. Generally, ecological phenomena are determined not by a single ecological process but by multiple ones. These processes act on ecological patterns within their own spatial scales. In the non-brown fractal model, the spatial random functions are nested within a larger range of spatial scales. The relative contribution of the spatial random functions to the spatial variation of a variable is indicated by a weighting parameter that has to be greater than or equal to zero. In this paper, we reached the following results and conclusions. Firstly, the direct gradient method describes the general trends of trees, shrubs, herbs and all plants along the altitudinal gradient but is unable to provide further details on the altitudinal variations in the species richness. The non-brown fractal model brought out the altitudinal variations in the species richness of trees, shrubs and herbs at various scales and related them to the ecological processes. The sharp changes in the double-log variograms suggest that the non-brown fractal model is suitable for characterizing the altitudinal patterns in the species richness of trees, shrubs and herbs at various scales but is not appropriate for explaining the variations in the plant species richness, since no significant changes were found in the double-log variograms in this case. Secondly, for the trees, the double-log variogram was divided into two scale ranges (0–245 m and 245–570 m), with a fractal dimension of 1.83 and 1.10, respectively, implying that changes in the tree species richness were random at small scales (0–245 m) and almost linear at large scales (245–570 m) along the altitudinal gradients. This suggests that altitudinal variations in the tree species richness are dominated by short-range processes at small scales and by long-range processes at large scales. Thirdly, for shrubs and herbs, the double-log variograms exhibited three ranges (0–101 m, 125–298 m and 325–570 m), and the fractal dimensions were 1.78 and 1.97, 1.56 and 1.43, and 1.08 and 1.25, respectively. The results indicate that, as in the case of trees, species richness of shrubs and herbs are distributed randomly at small scales and change in a linear manner at large scales although variations in the herb species richness is less heterogeneous than shrub species richness at large scales. These results also indicate that species richness of shrubs and herbs change approximately like brown movement at middle scales. The results also suggest that altitudinal variations in the specie richness of shrubs and herbs are dominated by three ecological processes, short-range ecological processes at small scales, long-range ecological processes at large scales, and brown fractal processes at middle scales. Interestingly, comparisons of the variations in the species richness of shrubs and herbs reveal that shrubs and herbs present the same scale range in spatial variation in species richness but display different trends in species richness along the altitudinal gradient, i.e. the shrub species richness decreased with increasing elevation whereas the herb species richness peaked at the mid-high elevation. These patterns suggest that although the scales at which the main processes affect patterns in species richness are the same, the processes are completely different, or the processes are similar but the responses of the shrubs and herbs to the ecological processes are different. Finally, the plant species richness did not show any obvious pattern along the altitude gradient and maintained a constant fractal dimension across all scales, this is perhaps because the processes defining the patterns of plant species richness had similar weights and acted over closely related scales. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(6): 901–909 [译自: 植物生态学报]     

Understory woody vegetation in manmade Mediterranean pine forests: variation in community structure along a rainfall gradient

Natural regeneration that occurs in the understory of Mediterranean pine monocultures provides the basis for the transition of these simply structured systems toward a more complex and sustainable state. However, the course and consequences of this process, and its relationships with environmental and silvicultural variables, are still inadequately understood. We investigated the relationship between rainfall amount and understory woody vegetation (UWV) structure in mature (40–50 year) Pinus halepensis plantations in the Mediterranean zone of Israel, where rainfall ranges from 280 mm/year in the south to 900 mm/year in the north. We measured abundance, diversity and species composition on south- and north-facing slopes, in forest sites distributed along the rainfall gradient. UWV abundance, as measured by cover percentage and height, increased with rainfall amount along the entire gradient (2–113% and 0.1–3.4 m, respectively), more rapidly on north-facing slopes. Species composition varied along the rainfall gradient, with ranges of species occurrences corresponding to those in unforested habitats. The relationship between rainfall and UWV species richness was positive throughout most of the rainfall gradient, possibly with a shift in pattern at the highest rainfall levels. UWV richness increased sharply with increasing abundance, up to a certain point with no further increase in richness as abundance increased further. We concluded that UWV structure in the studied forest environment and climatic range is strongly determined by rainfall and suggested that the design and management of Mediterranean forests should focus more on optimizing water availability for the various components.     

Fossil history and modern distribution of the genus Abies (Pinaceae)

The plants of the genus Abies are dominant and key species in the dark coniferous forest in the Northern Hemisphere. There are 52 species, one subspecies and 12 varieties in the genus Abies in the world. The history and modern distribution of Abies were discussed. The genus has three modern distribution centers: South Europe, North America and East Asia. These areas are also rich in fossil records. The vertical distribution regions of Abies are from sea level to an elevation of 4,700 m, concentrated in 1,000–2,000 m (15 species). In China, the genus distributes in 20 provinces, especially abundant in the Hengduan Mountains. Meanwhile, endemic and relic phenomena are obvious in this genus. There are seven relic species with both limited individuals and limited distributed regions. Based on the fossil records and the latest phylogenetic data, the following hypothesis was proposed: Abies originated from the middle and high altitudes of the Northern Hemisphere in the middle Cretaceous and it was dispersed southward in the Eocene due to global climate cooling down. The distribution of Abies was deeply influenced by geological events such as the uplift of Himalaya, the Alps, the Rocky Mountains, the occurrence of the Asian Monsoon as well as the Quaternary glaciers. Finally, the current distribution pattern appeared in the Quaternary. The genus Abies has a fossil history and modern distribution pattern similar to that of Cathaya and Pseudolarix. __________ Translated from Acta Botanica Yunnanica, 2006, 28(5): 439–452 [译自: 云南植物研究]     

长白山二道白河森林流域河岸带阔叶红松林最小面积与a多样性(英文)

河岸带是森林小流域单元的重要组成部分之一。由于河水的影响和边缘效应等因素的综合作用,河岸带植物群落与远离河岸带的森林群落在组成、结构和分布格局等方面存在较大差异,其群落最小面积也不同。本文对长白山原始阔叶红松林河岸带植物群落最小面积和物种丰富度进行了探讨。结果表明河岸带植物群落的最小面积均小于森林内部植物群落的最小面积。对于长白山原始阔叶红松林群落而言,在河岸带,包括群落的60%、80%、90%植物种类时的平均最小面积分别为80m2、180m2和320m2左右;;对应于远离河岸带的森林内部,包括群落的60%、80%、90%植物种类时的平均最小面积分别为260m2、380m2和480m2左右。河岸带植物群落的物种丰富度、均匀度和Shannon-Wiener指数普遍高于森林内部植物群落,但优势度则相反。表4参20。     

Plant and bird diversity in rubber agroforests in the lowlands of Sumatra,Indonesia

Plant and bird diversity in the Indonesian jungle rubber agroforestry system was compared to that in primary forest and rubber plantations by integrating new and existing data from a lowland rain forest area in Sumatra. Jungle rubber gardens are low-input rubber (Hevea brasiliensis) agroforests that structurally resemble secondary forest and in which wild species are tolerated by the farmer. As primary forests have almost completely disappeared from the lowlands of the Sumatra peneplain, our aim was to assess the contribution of jungle rubber as a land use type to the conservation of plant and bird species, especially those that are associated with the forest interior of primary and old secondary forest. Species-accumulation curves were compiled for terrestrial and epiphytic pteridophytes, trees and birds, and for subsets of ‘forest species’ of terrestrial pteridophytes and birds. Comparing jungle rubber and primary forest, groups differed in relative species richness patterns. Species richness in jungle rubber was slightly higher (terrestrial pteridophytes), similar (birds) or lower (epiphytic pteridophytes, trees, vascular plants as a whole) than in primary forest. For subsets of ‘forest species’ of terrestrial pteridophytes and birds, species richness in jungle rubber was lower than in primary forest. For all groups, species richness in jungle rubber was generally higher than in rubber plantations. Although species conservation in jungle rubber is limited by management practices and by a slash-and-burn cycle for replanting of about 40 years, this forest-like land use does support species diversity in an impoverished landscape increasingly dominated by monoculture plantations.     

Interspecific relationships in the forest community dominated by Pinus kwangtungensis, an endangered species endemic to China

Interspecific relationships in a natural forest dominated by Pinus kwangtungensis, a rare and endangered pine species endemic to China, were studied based on inventory data from 7,200 m² plots in Nanling National Nature Reserve. With the aim to quantitatively analyze the relationships of P. kwangtungensis to other species in the forest community and to their habitat, the continuous transect sampling method was employed by placing a horizontal transect (10 m × 120 m) at a 100 m altitudinal interval from 1,100 m to 1,600 m a.s.l., which represents the altitudinal range of P. kwangtungensis in Nanling National Nature Reserve. Each transect was further divided into 12 contiguous quadrats (10 m × 10 m) for plant censuses. Both canonical correspondence analysis (CCA) and cluster analysis were used to detect the interspecific relationships. The results showed the following: 1) occurrence frequency of P. kwangtungensis in Nanling was ranked Class A in terms of Raunkiaer’s law of frequency. P. kwangtungensis dominated in the canopy more than in the subcanopy and understory; 2) both Spearman rank correlation (SRC) coefficients and Pearson correlation coefficients indicated that the number of positive covariation couplets was significantly higher than the negative covariation couplets in the forest community, although SRC appeared to be more sensitive than Pearson correlation analysis. Except for the negative covariation with Litsea elongata, P. kwangtungensis exhibited no significant correlation with other dominant species; 3) altitude, slope, slope aspect, slope shape, thickness of humus layer, and thickness of litter all had significant correlations with the three axes in CCA plot, and the environmental factors in the first two axes defined the ecological conditions of the community. The grouping of the 105 canopy tree species was made according to the characteristics of the species along the first axis. Altitude was the most effective factor influencing the distribution of P. kwangtungensis; 4) variability in spatial distribution among the 105 canopy tree species could be attributed to variations to site environmental factors. The results from CCA and cluster analysis indicated that environmental factors influenced the distribution and ecological characteristics of the plant species in the forest community dominated by P. kwangtungensis. __________ Translated from Acta Ecologica Sinica, 2006, 26(4): 1,063–1,072 [译自: 生态学报]     

Structure and species composition of novel forests dominated by an introduced species in northcentral Puerto Rico

The African tulip tree, Spathodea campanulata Beauv., is an introduced species forming novel forest types in Puerto Rico. These forests develop naturally after deforestation, agricultural use and land abandonment, and there are many questions as to their ecological characteristics. We sampled structure and species composition of large, small, and juvenile trees (≥10, ≥2.5 to <10, and <2.5 cm diameter at breast height, respectively) in nine secondary forests dominated by S. campanulata on alluvial, karst, and volcanic substrates in northcentral Puerto Rico. No differences were found in S. campanulata forest structure between substrates. Of a total of 79 species found, 17 were introduced. Forests on karst and alluvium had the highest and lowest global species richness, respectively. Species richness increased from large to small to juvenile trees in most sites, but more so on karst. The percentage of introduced species was inversely related to species richness of tree size classes on all substrate types. The dominance of S. campanulata in the large tree size class was highest and lowest in alluvial and volcanic sites, respectively, and decreased from large to small to juvenile trees on all substrate types. Species richness of S. campanulata forests is lower than that of native forests on equivalent substrates. Although land use history affects composition, the juvenile tree species established in S. campanulata forests seems to correspond to the geological substrate were sites are found. This study shows S. campanulata restores forest structure and native tree species on abandoned agriculture and grazing lands in Puerto Rico. Management of these novel forests should consider them as resources were natural processes have the potential of making them more diverse.     

Individual growing conditions that affect diameter increment of tree saplings after selection harvesting in a mixed forest in northern Japan

We analyzed temporal patterns in diameter growth of saplings following selection harvesting in an uneven-aged mixed stand dominated by Abies sachalinensis, Acer mono, Quercus crispula, and Betula ermanii in Hokkaido, northern Japan. We examined interspecific differences in growth responses to local growing conditions including harvesting intensity, crowding, stem size, and past duration of the small growth period. Consistent with expectations based on shade tolerance of the species, the age at which the individual reached a diameter at breast height (DBH) of 12.5 cm was highest for A. sachalinensis and lowest for B. ermanii. The interspecific growth differences between saplings that had or had not experienced local harvesting increased gradually for A. sachalinensis and B. ermanii, but peaked at around 4–6 years after harvesting for Q. crispula. Generalized linear mixed model analysis clearly suggested that individual growth conditions required to enhance diameter growth of saplings differed considerably among species. For Q. crispula and B. ermanii, local harvesting intensity was most strongly and positively associated with diameter growth rate, whereas for A. sachalinensis and A. mono, stem size had the strongest negative effect. Abies sachalinensis saplings responded more to surrounding harvesting when they were relatively small, whereas A. mono showed a weak opposite response. The duration of the small growth period before harvesting had negative effect for A. sachalinensis, but not for the other species. Our study indicated that the influence of selection harvesting on growth of shade-tolerant species depends upon pre- and post-harvest growing conditions.     

Long-term effects on tree regeneration of soil scarification with microtopography manipulation in mixed forests of central Hokkaido,northern Japan

Natural regeneration of canopy tree species is generally poor under a selective cutting regime practised in mixed conifer–hardwood stands on Hokkaido, northern Japan, and is prevented by dense bamboo layers in the understory. To promote tree regeneration, we scarified soil in ten sites, with elevations ranging from 420 to 760 m, in 1979, with a rake-equipped bulldozer to produce three different artificial microtopographies (concave, flat, and convex). Twenty-six years after scarification, six canopy tree species (Acer mono, Abies sachalinensis, Betula ermanii, B. maximowicziana, Kalopanax pictus, and Picea jezoensis) had become well established. Abies sachalinensis and B. ermanii regenerated at all sites. Picea jezoensis was well established in high-elevation sites, whereas other hardwood tree species (A. mono, B. maximowicziana, and K. pictus) were well established at low-elevation sites. The Betula species dominated upper layers of regenerated trees, and two conifer species (A. sachalinensis and P. jezoensis) occupied lower layers. Regenerated densities of four (of six) major tree species were positively correlated with standing timber volume of mother trees, whereas those of shade-intolerant species (two Betula species and K. pictus) were negatively correlated with standing timber volume of all canopy trees. Small-seeded species (P. jezoensis and the two Betula species) had higher regeneration densities on convex sites than on other microtopographies. Adequate seed supply, convex substratum for small-seeded species, and control of light conditions for shade-intolerant species should be taken into account when planning regeneration of desirable tree species in central Hokkaido.     

Individual-scale responses of five dominant tree species to single-tree selection harvesting in a mixed forest in Hokkaido, northern Japan

We investigated the individual-scale responses of five dominant species (Abies sachalinensis, Acer mono, Tilia japonica, Quercus crispula, and Betula ermanii) to single-tree selection harvesting in a conifer–broadleaved mixed forest in Hokkaido, northern Japan. Using data from stems with a diameter at breast height of ≥12.5 cm, collected during 20 years of monitoring a 6.7-ha stand, we analyzed the effects of harvesting in the neighborhood on tree recruitment and the growth (diameter class transition) and mortality of the residual trees. The effects of harvesting varied considerably among tree sizes and species. Harvesting improved the recruitment of A. mono and B. ermanii, and moderated the negative effect of the initial basal area of the surrounding canopy trees on the recruitment of Q. crispula. Conversely, harvesting limited the recruitment of A. sachalinensis by offsetting the positive effect of the initial basal area of the surrounding canopy trees. The growth of A. sachalinensis and Q. crispula decreased with the initial basal area of the surrounding canopy trees. Harvesting in the neighborhood resulted in an improvement in the growth of the trees of these species only in the smaller size classes. With increasing local harvesting intensity, the mortality of smaller A. sachalinensis trees decreased, whereas the mortality of larger trees increased. These results suggest that differences in the local harvesting intensity, spatial patterns of harvesting, and initial stand structures influence the stand-scale dynamics in response to partial harvesting in the mixed forests of this region.     

Differences in bird species diversities between a natural mixed forest and a coniferous plantation

Bird species diversity and bird species richness were surveyed in a natural mixed forest (mature forest) and in a coniferous plantation (30–40 years old) monthly from 1990 to 1994. These forests were 20 km apart and had similar weather conditions and soil types. There were larch and cedar plantations, and hardwoods along streams in the coniferous plantation. In the natural mixed forest, 55 bird species were found, whereas 40 species were recorded in the coniferous plantation. The species diversity of bird communities was significantly higher in the natural mixed forest than in the coniferous plantation mixed with hardwood trees. This result indicates that the coniferous plantation mixed with hardwood trees, presumed to be a more simplified environment, is likely to be less inhabitable for many bird species than the natural mixed forest, suggesting a relationship between the diversity of the forest environment and the diversity of the bird community. A higher number of bird species was recorded in the small coniferous forest mixed with hardwood trees compared with those in the coniferous plantation. The mixing of broad-leaved trees in a coniferous plantation was suggested to be effective in increasing number of bird species. These tendencies were recorded all through the year during our study. In snow-covering periods, both the diversity and the bird species richness fell in all study sites every year. Snow cover would have greater effect on bird species diversity in the coniferous plantation than in other forest types probably due to diet shortages caused by the snow cover over the forest floor.     

Water-holding characteristics of litter in different forests at the Lianxiahe watershed

We surveyed the forest litter amount at the Lianxiahe watershed in the Three Gorges Reservoir Area and analyzed some hydrological characteristics such as the maximum water-holding capacity and water absorption rate of litter in six types of forests, i.e. the Cupressus funebris forest, the coniferous mixed forest, the coniferous and broad-leaved mixed forest, the broad-leaved forest, the Pinus massoniana forest, the bush forest. Results showed that the litter amount follows the order of the coniferous and broad-leaved mixed forest > the pure C. funebris forest, the P. massoniana forest > the coniferous mixed forest > the broad-leaved forest > the bush forest. The maximal water holding capacity of the undecomposed litter is in the order of the C. funebris forest > the coniferous mixed forest > the bush forest > the coniferous and broad-leaved mixed forest > the broad-leaved forest > the P. massoniana forest. The maximal water-holding capacity of the half-decomposed litter is the P. massoniana forest > the coniferous and broad-leaved mixed forest > the C. funebris forest > the coniferous mixed forest > the broad-leaved forest > the bush forest. In this watershed, the water holding capacity of the litter in the C. funebris forest is the highest, followed by the coniferous mixed forest, coniferous and broad-leaved mixed forest, P. massoniana forest, broad-leaved forest and bush forest. When the soil is covered only by litter, both the maximal rainfall amount and intensity in different forest stands are different if there is no water infiltration and runoff from the ground surface. __________ Translated from Journal of Huazhong Agricultural University, 2005, 27(2): 207–212 [译自: 华中农业大学学报, 2005, 24(2): 207–212]     

Growing stock variation in different teak （Tectona grandis） forest stands of Mizoram,India

The growing stock assessment of three different teak forest stands （Tuirial： 500 m asl, Sairang： 200 m asl and Phunchawng： 550 m asl） was done in 2006 in Mizoram, India. Five diameter classes were arbitrarily established for knowing the volume attribute data and population structure, viz. a （10-20 cm）, b （20-30 cm）, c （30-40 cm）, d （40-50 cm）, and e （50-60 cm）. Results revealed that the density of the individuals among the studied stands varied from 280 stems/ha to 620 stems/ha. The average diameter of all the individuals ranged between 27.48 cm and 35.43 cm. Similarly, the average height was oscillated between 17.87 m and 22.24 m. The total basal area was recorded between 24.28 m2.ha-1 and 45.80 m2.ha＂l. The maximum and minimum values of total growing stock under all the diameter classes were 669.01 m3.ha-1 and 284.7 m3.ha-1, respectively. The representation of population structure of different stands explained that the perpetuation of this species was ensured for a quite long time.     

桂西南不同树种人工林评价研究

对桂西南多个树种、多种经营模式人工林的生长量、林下土壤及植被的调查研究和经济效益分析表明:米老排、红椎、西南桦等速生阔叶树种的生长量优于针叶树种,其中,胸径、树高年平均生长量以米老排为最高,分别达1.67 cm、1.29 m,分别比马尾松增长60.6%、61.2%,比杉木增长70.4%、57.3%;林分的年平均蓄积生长量则以西南桦为最高,达20.44 m3·hm-2·a-1,比杉木高了近2倍.阔叶林的经济效益明显优于针叶林,混交林的效益优于针叶纯林,树种之间效益比较达显著或极显著差异,其中以西南桦的效益最好,年平均产值达21 459.7元·hm-2,比杉木高10倍多.对土壤理化性质的研究表明:荒地造林后,土壤的密度、保水性、通透性得到改良;土壤有机质含量提高,富铝化作用增强,而其它的土壤养分,不同树种之间差异较大,但从总体看,阔叶林在改良土壤理化性质方面优于针叶纯林.