江西省世行贷款‘项目林收获量预测

根据世行贷款项目林中1－7年的平均高及优势木平均高等有关资料，结合利用江西编制的有关地位指数表、蓄积量生长过程表及江西省贫困地区林业发展项目可行性报告等材料，对江西省世行贷款项目林的蓄积收获量进行预测。预测结果显示，项目林可获取的材材积为22743736m^3。其中间伐商品材材积为760199m^3，主伐商品材材积为21983537m^3。     

徐淮平原农田防护林主要造林树种生长特性

对徐淮平原农田防护林杨树生长特性的研究结果表明：①同一林带不同林木个体随着年龄的增长，树高、胸径和冠幅的绝对差异逐渐增大而相对差异逐渐减小。②林带建立２￣３ａ后，林木进入速生期。③树高、胸径和材积生长符合Ｌｏｇｉｓｔｉｃ方程。④林网中不同杨树无性系生长速度从快到慢依次是：ＮＬ－１１６杨，ＮＬ－１２１杨，Ｗ－４６杨，ＮＬ－２０３杨，Ｉ－６９杨和Ｉ－２１４杨，基干林带中ＮＬ－１０５杨和ＮＬ－１０６杨生     

雷州林业局桉树混交造林模式评价

对10种桉树与相思混交模式林分的生长量、生物量、经济效益、土壤性质等方面的研究表明:桉树与相思混交能够提高混交林中桉树的胸径和材积生长量,但在造林密度相同的条件下,混交林分无论从产量还是从经济效益上都不如桉树纯林高,营造混交林能够很好地维持地力,提高林地土壤养分含量。     

川西亚高山三个森林群落的凋落物动态

Litter production, components and dynamics were investigated and forest floor litter was quantified throughout a whole year in three subalpine forests, dominated by tree species of spruce （SF）, fir （FF） and birch （BF）, in Western Sichuan, China, in order to understand the key factors that influenced litter production and dynamics. Litterfall in the three forests consisted mainly of leaves, woody litter, reproductive organs and moss. Contribution of leaf litter to the total litterfall was significantly （P 〈 0.05） greater than that of woody litter, reproductive organs or moss. Regardless of the stands, litterfall exhibited a marked monthly variation with the maximum litterfall peaks occurring in October, with smaller peaks occurring in February for SF and FF, and May for BF. The analysis indicated that tree species, stand density, leaf area index （LAI）, stand basal area and stand age were the key factors determining litter production. Meanwhile tree species and phenology controlled the litter dynamics, with wind and snow modifying the litter components and dynamics.     

Microhabitats of Collembola (Insecta: Entognatha) in beech and spruce forests and their influence on biodiversity

Collembolan communities were studied in 41 microhabitats in beech and spruce forests of south ( ofín and umava) and central (Jevany) Bohemia. The communities of Collembola were analysed using TWINSPAN and CANOCO programs. The aim of this study was to establish differences between patch (microhatitat) communities and the main forest community in spruce and beech forests, the differences between both types of forests and among different regions of Bohemia. Further questions were: is there a difference in microhabitat communities during secondary forest succession? do some species live exclusively in one or few microhabitats? and does microhabitat diversity influence the biodiversity in forest soils? Material comprising  25 590 specimens of Collembola belonging to 142 species was analysed. Highly significant differences were determined between microhabitat communities in beech and spruce forests, as well as among forests in different regions of Bohemia. Significant differences were also found among microhabitats in forests of different ages. Also, some microhabitat communities of Collembola, e.g. moss on boulders, were significantly different from their main forest community. Certain collembolan species existed exclusively in one or two microhabitats. Patches therefore influenced substantially biodiversity in these forest soils.     

Rapid deforestation and fragmentation of Chilean Temperate Forests

The temperate forests of Chile are classified a biological “hotspot” as a result of their high species diversity and high endemism. However, they are being rapidly destroyed, with significant negative impacts on biodiversity. Three land-cover maps were derived from satellite imagery acquired over 25 years (1975, 1990 and 2000), and were used to assess the patterns of deforestation and forest fragmentation in the coastal range of south-central Chile. Between 1975 and 2000, there was a reduction in natural forest area of 67% in the study area, which is equivalent to an annual forest loss rate of 4.5% per year using a compound-interest-rate formula. Forest fragmentation was associated with a decrease in forest patch size, which was associated with a rapid increase in the density of small patches (<100 ha), and a decrease in area of interior forest and in connectivity among patches. Since the 1970s, native forest loss was largely caused by an expansion of commercial plantations, which was associated with substantial changes in the spatial configuration of the native forests. By 2000, most native forest fragments were surrounded by highly connected exotic-species plantations. The assessment of forest loss and fragmentation provides a basis for future research on the impacts of forest fragmentation on the different component of biodiversity. Conservation strategies and land use planning of the study area should consider the spatial configuration pattern of native forest fragments and how this pattern changes over time and space at landscape level.     

Acidification of primeval forests in the Ukraine Carpathians: Vegetation and soil changes over six decades

Changes to vegetation and soil were assessed in primeval forests of the Eastern Carpathians after a period of 59-68 years. We hypothesized that forest ecosystems were acidified through the long-distance transport of air pollutants. A total of 141 relevés and 20 soil profiles that had been studied in 1938 in spruce- and beech-dominated forests along an altitudinal gradient ranging from 1085-1575 m a.s.l. were re-surveyed from 1997 to 2006. Relevés were analyzed using multidimensional statistics and plant community characteristics (Shannon-Wiener’s index, equitability, fidelity, Ellenberg indication values - EIV); soil reaction and sorption complex properties were analyzed in soils.A total of 159 vascular plant taxa were recorded in 1938, of which 35 were not found during the repeat survey. During the later survey, 137 taxa were found, of which 13 were new findings. The upper mineral (A) as well as cambic or spodic (B) horizons were considerably acidified in both forest types. Both active and exchange soil reaction decreased by 0.1-0.3 units on average, exchangeable acidity significantly increased and the sum of base cations decreased in both soil horizons and forest types. Base saturation decreased by more than half of original values, with a maximum decrease of 68% found in the B-horizon of spruce forests. Whereas the herb layer developed along with soils in beech-dominated forests, EIV values for soil reaction increased in spruce-dominated forests, probably due to the movement of broadleaf woody species to higher elevations or due to the higher resistance of herb species to soil acidification. Significant changes to EIVs also occurred in the beech- and/or spruce-dominated forests for the factors of nitrogen, light moisture and temperature.There was an expansion of the lower tree and shrub layers, primarily Fagus sylvatica, Picea abies and Sorbus aucuparia in intermediate and higher elevations, which can be explained by reduced cattle grazing. Also, the dissipation of Juniperus communis and marked decline of Abiesalba are interpreted as being related to gradual changes in landscape management along with the effect of acid deposition. Since 1938, all stands have shown a significant increase in nitrophilous taxa such as Rubusidaeus, Athyrium distentifolium, Urtica dioica, Calamagrostis arundinacea, Stellaria nemorum. Significant decreases in the number of species, Shannon-Wiener’s index and equitability were only observed in spruce-dominated forests. Neophyte taxa were not detected in either the 1930s or the 1997-2006 period.     

中国热带地区次生林经营现状和技术

文章分析了中国热带地区次生林经营相关资料,在对广东、海南、广西和云南重点热带次生林林区或典型经营区进行实地调查的基础上,分析和总结了中国热带次生林经营管理政策、经营现状和经营技术。中国的热带次生林经营在中华人民共和国成立后不久的1951年开始提出,但在20世纪50至80年代中期,主要以利用为目的,经营方式以封山育林为主。到了80年代后期,经济相对发达的地区如广东开始从木材生产为主向生态营林方向转化的大规模经营活动,自然保护区建设规模加大。1998年发生严重的洪涝之后,中央政府加强了以林业为主题的生态环境建设,热带次生林开始得到有效的保护,这一阶段的经营特点是生态建设,经营方式以政府主导的生态公益林、天然林保护等工程建设为主。经营技术除封山育林外,强调了退耕还林、提高物种的多样性和地带性乡土树种的开发利用。但是,中国的热带次生林经营始终未能走出木材利用或是生态防护的两个极端,缺乏既提高生态效益又提高经济效益、能满足生态和林区居民生存经济需求的可持续经营技术和实践。     

毛竹林内混交擦树效果好

毛竹林内混交擦树,相互之间能起到很好的促进作用,既有利于加快毛竹成材,又可改善立地条件,提高了生产力。     

Regeneration dynamics and sylvigenesis in the moist deciduous forests of southwest India

Sustained management of natural forest depends on their ability to regenerate. The pace at which older trees are replaced by younger ones is important in this respect. This study was conducted to assess the demographic details of natural regeneration dynamics of south Indian moist deciduous forests. The status of natural regeneration has been assessed in eight localities of varying levels of disturbance in Thrissur Forest Division of Kerala State of southwest India. Enumeration of trees and their regeneration were analyzed at three levels of organization; whole-stand, stratum, and species.The trees of the forest were grouped into upper, middle and lower vertical strata. Species richness was highest in the middle stratum. Upper stratum species were commercially important. The mean basal area for the Forest Division was 12.83 m²/ha. and average number of trees per hectare (>=20 cm dbh) was 150. Regeneration of the upper stratum species was higher at about 10% gap in the canopy.The growing stock of established seedlings and saplings (height > 100 cm and dbh <=10cm) was very low compared to unestablished seedlings (height <=100 cm). Owing to very low survival probability in the sapling stage (dbh >=1 cm to <=10 cm), a low numbers of poles (dbh >=10 cm to <=20 cm) in the upper stratum was observed. Presence of fire, grazing, browsing and over expoitation by humans are the major constraints of natural regeneration recognized in these forests.