Model Computations on Sequestration of Carbon in Managed Forests and Wood Products under Changing Climatic Conditions in Finland

The aim of this study was to assess the effects of forest management on carbon sequestration in forests and wood products by using a gap-type forest model interfaced with a wood product model. The assessment is based on total carbon sequestration, i.e. the amount of carbon left in vegetation, litter, soil organic matter and products when the flows of carbon back to the atmosphere have been subtracted. Thirty mixed-species stands, representing medium fertility sites in southern Finland, were included in each simulation for 300 years under current climatic conditions and predicted conditions of changing climate. The average total balance for the first 100 years was higher in the unmanaged system than in the managed system, but for the second and third 100-year periods the results were clearly opposite. Differences in the total balance between the treatments were larger during the first 100 years than over the whole 300-year period. Under conditions of changing climate, differences in carbon sequestration between management options were more pronounced than under current climatic conditions. Under current climatic conditions with the 100-year time frame, the ratio between the total annual balance and annual gross production was 0·208–0·289. Over the whole 300 years, however, efficiency was much lower, 0·088–0·121. Under changing climatic conditions, efficiency was also lower, 0·182–0·252 and 0·081–0·096, respectively. Different management alternatives clearly produced different amounts of timber for the production process; under conditions of changing climate, timber production was substantially enhanced. However, total carbon storages at the end of the simulation varied less than timber production. In the managed system, the flow back into the atmosphere was largest from litter, 41–51% of the total outflow, the flow from vegetation was 23–28%, from soil organic matter 22–25%, emissions from products 1–7%, and emissions from landfills 0–3%. If emissions due to the use of machinery in timber harvesting and transportation were included, they made up only 0·03–0·33% of the total outflow.     

Fragmented forest in tropical landscape--the case of the state of Selangor,Malaysia

This paper presents the pattern and changes of fragmented forest in relation with changes of total forest cover in the state of Selangor in three decades.In this study,inventoried forest cover maps of Selangor in 1971/1972,1981/1982 and 1991/1992 produced by the Forestry Department of Peninsular Malaysia were digitized to examine the changes in area and number of fragmented forest.Results showed that in 1971/1972,16 fragmented forests were identified in Selangor.All fragmented forests were identified as diptercoarp forest.A decade later the number of fragmented forests increased by approximately 44%(23).Of the 23 fragmented forests,two were peat swamp forests whereas the remaining were dipterocarp forests.In 1991/1992 the number of fragmented forests(12)was reduced by 47.8%.Two of the fragmented forests were Fragmentation of both dipterocrp and peat swamp forests occurred profoundly during the period between 1971/1972and 1981/1982,which consequently increased the number of fragmented forests compared with before the period of 1971/1972 where fragmentation happened only at dipterocarp forests.However,many fragmented forests vanished between the 1981/1982 and 1991/1992 periods.     

Termite assemblages in a West-African semi-deciduous forest and teak plantations

Responses of termite assemblages to the conversion of semi-deciduous forest into teak plantations were studied in the Lama Forest Reserve in Benin, West Africa. Four belt transect surveys were run in each of the two forest types, adopting a modified termite diversity assessment protocol. Termite assemblages were remarkably species-poor in both forest types, with only 19 species encountered altogether. The low species richness was due to the rarity of soil-feeders of the soil/humus interface and the absence of true soil-feeders in the compact vertisol soil. Species richness was significantly higher in semi-deciduous forest than in teak plantations, but termite encounters were significantly lower. Termite assemblage and feeding group structure differed significantly among forest types. Wood-feeders were recorded only in semi-deciduous forest. In contrast, fungus-growers were more species-rich and about four times more abundant in teak plantations, mainly due to one Ancistrotermes species. The humification score, which depicts the position of termite assemblages along a gradient of increasing humification of their food substrate, was significantly higher in teak plantations, due to the absence of wood-feeders and the preponderance of fungus-growers. Combined principal components and multiple regression analysis identified two significant predictors of termite assemblages, soil water content and leaf litter biomass. The abundance of fungus-growers in teak plantations seemed to be mainly related to the high leaf litter biomass. Indirect evidence also suggests that lower predation pressure by ants on termites in teak plantations may have contributed to the abundance of termites.     

上海江湾机场植物群落多样性研究

以市区内江湾机场失去管理后出现的自然植被为研究对象，通过群落学调查研究，分析了群落的种类组成以及结构特征，阐明了群落的恢复过程和潜力。结果表明，江湾机场的植被可划分为4个外貌类型，16个群落类型。自然植被表现为以草本群落为主、辅以少量木本植物群落为特征的分布格局。非地带性因素主导着植被发生和演替，很难达到上海以亚热带常绿阔叶林为主的地带性植被类型。     

云南森林生态破坏的经济损失分析

本文介绍了云南省森林资源状况因其遭到破坏而造成的危害，并分别用影 子工程法，替代市场法和土地价值法等基础方法对云南省森林破坏的泥沙流失损失，伴随土壤流失的氮素损失和林业产值补偿损失进行了分析。     

森林的平均价值、分布和边际价值

目前的价值核算体系忽略了森林的质量、分布、功能等至关重要的因素，因而不能真实的反映森林的价值针对当前价值核算的不足，讨论了森林的平均价值、分布以及边际价值，并指出了当前的生态建设应注意的问题。     

森林对非点源污染的调控研究

借助大量观测资料分析研究了不同森林类型、不同土地利用状况以及不同尺度下 ,森林对非点源污染的调控能力较强 ,坡面森林可使固体污染物减少 60 %以上 ,林地的营养元素损失减少 30～ 50 %。对于不同尺度下的流域 ,森林覆盖率高的流域水质参数指标大多低于森林覆盖率低的流域 ,尤其是 NH+ 4 ,从坡面小流域到大流域急剧下降。被采伐过的流域的水温上升 0 .2～ 0 .4℃ ,N损失量从 4kg/hm2· a上升到 1 42 kg/hm2· a。     

纳板河自然保护区参与性有效管理研究初探

纳板河自然保护区内农民落后的耕作方式，对土地的不合理利用以及政策和社会发展等因素对热带雨林带来巨大压力。对其实施有效管理，合理利用土地和野生生物资源，开征资源补偿素，完善管理体制和规章制度，可在帮助当地农民脱贫的同时，有效地保护热带雨林及其生境。     

论森林生态效益补偿的对象与原则

森林生态效益补偿在改善生态环境、促进经济与社会、人与社会和谐发展过程中有着重要的现实意义,中国在这方面的立法尚不完善,在着重论述了中国森林生态效益补偿的对象和基本原则时,提出了自己的观点和看法.