透光分层疏透度测定及其在次生林结构研究中的应用

次生林是中国森林的主体,对其进行合理的经营无疑对中国天然林资源保护及国家生态安全建设具有重大意义．次生林的结构(尤其是垂直结构)是该林种合理经营的重要因素．本文在以往研究的基础上,引入了分层疏透度的概念,并以透光分层疏透度表征林分的垂直结构;详细介绍了应用全天照片测定透光分层疏透度的方法与步骤．分析了透光分层疏透度在次生林结构研究和次生林的经营理论与技术研究中的应用前景．     

东北次生林生态系统保护与恢复技术探讨

东北森林在国家生态文明建设、生态环境保护、社会经济发展等方面发挥着重要的作用。本文在分析东北林区森林资源现状的基础上,指出东北次生林生态系统目前存在的问题,指明东北次生林生态系统的发展方向;结合未来三十年全国森林经营规划与国家天然林保护工程等,提出东北次生林生态系统保护、恢复与利用技术及对策,探讨了"后天保时代"(天然林保护工程结束以后)的次生林经营与保护,为东北林区的可持续发展指明了方向。     

森林干扰生态研究

陆地上80％的生态系统都已受到了来自人类和自然的各种干扰,森林生态系统也不例外．在各种干扰作用下,尤其是人类不合理的干扰导致世界范围内的森林退化／衰退已成为一个十分严峻的事实,因此,以维持、恢复森林生态系统固有的多种功能为基础,实现高效、稳定、可持续就成为经营森林生态系统的总目标．随着干扰的加剧,近年来生态学界更加关注的是“受干扰”生态系统的研究．干扰对森林生态系统主要生态过程的影响以及森林生态系统对干扰的响应等问题,已成为森林生态研究领域的国际前沿与热点．因此,系统地研究干扰条件下森林生态系统的生态过程,并在此基础上确立干扰森林的经营理论与技术,对中国天然林资源保护等林业工程实施及国家生态安全建设具有重要的科学和现实意义．本文在广泛收集国内外有关森林干扰研究结果的基础上,总结了森林干扰的基本概念,分析了干扰与森林经营的关系,探讨了森林干扰研究领域所涉及的内容和关注的基础问题,提出了森林干扰生态研究的主要内容与方向,对今后干扰森林生态研究和中国天然林保护等林业工程建设具有参考价值．     

中国天然林保护、生态恢复与可持续经营的理论与技术

全面总结了近年来中国在天然林保护与生态恢复的理论与技术实践方面所取得的研究进展。高度凝练出了天然林动态干扰与保育技术、典型退化天然林的生态恢复技术和天然林景观恢复与空间经营技术等三方面的创新成果,形成了天然林保护与生态恢复的理论与技术创新体系,对今后天然林保护、生态恢复与可持续经营进行了展望。     

长白山区阔叶红松林经营历史与研究历程

长白山区位于中国东北东部的山地森林区,地带性植被是阔叶红松林,是我国珍贵木材生产和东北森林带的重要载体,孕育着丰富的物种资源.短短120年来,长白山区广袤的原始森林几乎消失殆尽,被次生林、过伐林和人工林等替代.建国以来,东北的阔叶红松林经营理论与技术在红松更新规律、皆伐与择伐的争论中,在人们对阔叶红松林结构和功能认识不断深入的过程中逐渐完善.但目前红松更新问题依然存在,森林经营依然十分粗放.本文梳理了过去70年来阔叶红松林的经营历史及研究历程,分析当前森林资源类型和经营制度的形成过程,以期为该区天然林可持续经营和质量的精准提升等提供借鉴.     

中国北方天然林保护学术研讨会在沈阳召开

由国家林业局天然林保护工程管理中心、中国林学会、中国科学院沈阳应用生态研究所共同举办的中国北方天然林保护学术研讨会,于１９９９年４月１５—１７日在沈阳召开．与会代表８０余人分别来自东北四大森工集团、中国科学院及林业科研院所和高等院校、林业生产第一线以...     

米槠次生林和天然林细根养分及化学计量特征

探讨人为干扰对森林养分利用和生物地球化学循环特征的影响,对亚热带米槠(Castanopsis carlesii)次生林和天然林细根化学计量特征及其随土壤深度(0～80cm)的变化趋势进行了研究。结果表明,混合线性模型表明林分和土层深度对细根化学计量特征影响的主效应显著,但是交互作用不显著;米槠次生林细根N和P含量均显著低于天然林,而细根C浓度、C:N、C:P显著高于天然林,天然林1～2mm细根C浓度显著低于次生林;天然林和次生林细根N、P含量均随土层深度增加而呈显著下降趋势,C:N、C:P、N:P均随土层深度增加而呈显著上升趋势,且两林分下降趋势无显著差异;天然林和次生林细根N、P含量及N:P分别与土壤全N、全P含量和N:P存在线性关系,而细根N、P含量和N:P随土层深度变化均与直径显著相关,与细根比根长(SRL)无关。天然林经过人为干扰后,细根化学计量特征随土层深度变化规律虽未发生改变,但细根N和P浓度显著降低。     

人工林对海南鹦哥岭鸟类多样性的影响

为了解在天然林中所种植的人工林对鹦哥岭鸟类多样性的影响,于2005年10月～2006年4月,分别采用样带法和雾网法,对海南鹦哥岭的原生林、次生林、人工林及其林缘的鸟类多样性进行了比较研究.野外记录到鸟类102种,其中栗腹矶鸫Monticola rufiventris、橙胸姬鹟Ficedula strophiata和黄雀Carduelis spinus 3种为海南鸟类新纪录.与原生林和次生林相比,人工林及其林缘的鸟类多样性很低,其中人工林最低.人工林不仅对鹦哥岭自然保护区的鸟类多样性具有非常大的负面影响,而且由于人工林的种植使天然林破碎化而产生的林缘与天然林林缘不同,鸟类多样性较低.     

鹰咀界天然次生林自然保护区林地土壤特性研究

鹰咀界自然保护区位于沅水上游 ,是湘西南保存较好的一片天然次生林。它的存在对研究该区域天然林的培育、生物多样性保护具有重要意义。同时 ,也为森林类型涵水功能的研究提供了场地。为了摸清该保护区次生林的自然特性 ,为保护和研究积累技术资料 ,我们利用保护区自然科学资助基金对其林地土壤特性进行了调查与研究 ,将其结果报道如下。1　保护区自然概况鹰咀界自然保护区位于湖南省会同县东南部雪峰山山脉的西支南段。地理位置为北纬 2 6°46′～ 2 6°5 9′ ,东经 1 0 9°5 1′～ 1 0 9°5 8′。海拔最高 938ｍ ,最低 2 4 6ｍ ,一般在 3…     

中国森林覆盖度产品的差异性及不确定性分析

<正>森林具有气候调节、水源涵养、生物多样性保护等诸多生态服务功能(Millennium Ecosystem Assessment,2005;van der Werf et al.,2009),同时减少毁林和森林退化也是减缓温室气体排放协议REDD+的重要内容(DeF ries et al.,2007;Grassi et al.,2008)。为了改善日益恶化的生态状况,提高森林资源的蓄积量,自20世纪70年代以来,中国实施了六大林业重点工程,包括天然林保护工程、"三     

Multiple successional pathways in human‐modified tropical landscapes: new insights from forest succession,forest fragmentation and landscape ecology research

Old‐growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human‐modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical biodiversity, and also as a source of essential ecosystem functions and services in HMTLs. Such critical roles are controversial, however, as they depend on successional, landscape and socio‐economic dynamics, which can vary widely within and across landscapes and regions. Understanding the main drivers of successional pathways of disturbed tropical forests is critically needed for improving management, conservation, and restoration strategies. Here, we combine emerging knowledge from tropical forest succession, forest fragmentation and landscape ecology research to identify the main driving forces shaping successional pathways at different spatial scales. We also explore causal connections between land‐use dynamics and the level of predictability of successional pathways, and examine potential implications of such connections to determine the importance of secondary forests for biodiversity conservation in HMTLs. We show that secondary succession (SS) in tropical landscapes is a multifactorial phenomenon affected by a myriad of forces operating at multiple spatio‐temporal scales. SS is relatively fast and more predictable in recently modified landscapes and where well‐preserved biodiversity‐rich native forests are still present in the landscape. Yet the increasing variation in landscape spatial configuration and matrix heterogeneity in landscapes with intermediate levels of disturbance increases the uncertainty of successional pathways. In landscapes that have suffered extensive and intensive human disturbances, however, succession can be slow or arrested, with impoverished assemblages and reduced potential to deliver ecosystem functions and services. We conclude that: (i) succession must be examined using more comprehensive explanatory models, providing information about the forces affecting not only the presence but also the persistence of species and ecological groups, particularly of those taxa expected to be extirpated from HMTLs; (ii) SS research should integrate new aspects from forest fragmentation and landscape ecology research to address accurately the potential of secondary forests to serve as biodiversity repositories; and (iii) secondary forest stands, as a dynamic component of HMTLs, must be incorporated as key elements of conservation planning; i.e. secondary forest stands must be actively managed (e.g. using assisted forest restoration) according to conservation goals at broad spatial scales.     

福建集体林权制度改革对生态公益林水源涵养能力变化的影响——基于723个村的实证研究

水源涵养等生态功能是生态公益林的首要功能，维护生态安全是集体林权制度改革（简称"林改"）的重要目标。为了厘清福建林改对生态公益林水源涵养能力变化的影响，以促进生态公益林质量的精准提升。运用综合蓄水能力法测算分析了福建省5县（区）723个村林改前后生态公益林水源涵养能力变化，并运用多元线性回归模型探讨了林改对生态公益林水源涵养能力变化的关键影响因素。结果表明：（1）林改后生态公益林水源涵养量普遍增加，但单位面积水源涵养能力多数下降，少数提升。（2）产权归属通过经营管护行为对单位面积水源涵养能力产生显著影响，其中，国有权属存在正向影响，集体权属与私有权属存在负向影响。（3）面积、人工林占比、防护林占比、蓄积量变动和降雨量等因素，主要通过资源结构、经营条件和外部环境对单位面积水源涵养能力产生显著影响。据此提出，在提高生态公益林数量的同时要注重提升生态公益林质量，加大政府赎买，重点挖掘幼龄人工生态林生态潜力，做好天然林和防护林保护等政策建议。     

Post-cultivation Secondary Succession in a Venezuelan Lower Montane Rain Forest

Since tropical rain forests are widely threatened by conversion to agriculture, even within protected areas, an understanding of recovery processes is important for restoration of forest ecosystems and thus conservation of their biodiversity. Secondary succession following land clearance and crop cultivation was studied in a lower montane rain forest in a protected area of the Venezuelan Cordillera de la Costa Central. Forest recovery was studied using a chronosequence of eight 20 × 20 m plots which represented four forest types ca.10 year-old Secondary Forest, ca. 20 year-old Secondary Forest, ca. 35 year-old (uncultivated) secondary forest and mature forest. Species richness and structural complexity increased during succession, with the oldest secondary forest having a physiognomy comparable to the mature forest. Species diversity was lower in the secondary forests than the mature forest, and their floristic composition was distinct. Four phases are hypothesized to occur in the succession process, each with a distinctive species assemblage: initial colonisation by non-woody vegetation; establishment and canopy closure by short-lived small-seeded woody pioneer species; replacement by longer-lived secondary species; and gradual replacement by mature forest large-seeded climax species. Full recovery of the forests in the protected area is likely to take many years, although it may be assisted through conservation management measures.     

Co‐benefits of biodiversity and carbon sequestration from regenerating secondary forests in the Philippine uplands: implications for forest landscape restoration

Shifting cultivation is a widespread practice in tropical forested areas that policy makers often regard as the major cause of forest degradation. Secondary fallow forests regrowing after shifting cultivation are generally not viewed as suitable for biodiversity conservation and carbon retention. Drawing upon our research in the Philippines and other relevant case studies, we compared the biodiversity and carbon sequestration in recovering secondary forests after shifting cultivation to other land uses that commonly follow shifting cultivation. Regenerating secondary forests had higher biodiversity than fast growing timber plantations and other restoration options available in the area. Some old plantations, however, provided carbon benefits comparable the old growth forest, although their biodiversity was less than that of the regenerating forests. Our study demonstrates that secondary forests regrowing after shifting cultivation have a high potential for biodiversity and carbon sequestration co‐benefits, representing an effective strategy for forest management and restoration in countries where they are common and where the forest is an integral part of rural people's livelihoods. We discuss the issues and potential mechanisms through which such dynamic land use can be incorporated into development projects that are currently financing the sustainable management, conservation, and restoration of tropical forests.     

次生林概念与生态干扰度

近一个世纪强烈的人为干扰使世界范围内的原始林面积锐减,次生林已成为中国乃至世界森林资源的主体.虽然在文献与现实中"次生林（Secondary forest）"被广泛使用,但次生林的概念在各个国家,甚至同一国家或地区以及各种不同文献中存在相互矛盾的情况,这给次生林研究与经营实践带来诸多不便;而不准确的次生林定义也为与各个层次的决策制定者及公众之间的交流带来了障碍.本文在查阅大量国内外关于次生林概念文献的基础上,结合近年来关于次生林生态与经营研究实践,综合分析了次生林概念的不确定性,同意以往次生林定义中的基本内涵,并认为：次生林是由于人为破坏性干扰或异常自然干扰使原始林固有的林分结构、物种组成或基本功能发生了显著变化,经过天然更新或人工诱导天然更新恢复形成的林分.但该定义中仍存在着很多不确定性, 如:怎样的干扰为"人为破坏性干扰"和"异常自然干扰";"林分结构、物种组成或基本功能"发生了怎样的变化为"显著变化";"人工诱导天然更新"中"人工"参与的成分比例如何等.次生林概念是在20世纪初由植物演替学家提出,当时未考虑干扰的持续性;而实际上,无论是次生林还是原始林,均是森林生态系统演替过程中的某一状态,在现代森林生态系统研究中,应重新规范"次生林"的概念.考虑到"次生林"定义的不确定性或困难性,建议使用"森林自然度"或"森林生态系统成熟度"或"森林干扰度"来表达现实森林所处的状态,但该方面的研究与实践尚需加强.     

Wildlife Recovery During Tropical Forest Succession: Assessing Ecological Drivers of Community Change

Despite the high proportion of secondary forests in the tropics, their conservation value remains poorly understood, particularly with regard to animals. Most theoretical studies of succession have focused on plants, linking life history trade‐offs to well‐known patterns of community change. However, the same trade‐offs proposed for plants should apply to animals, and indeed, animal studies show a change in community dominance from habitat generalist to forest specialist species during succession. Focusing on the diverse terrestrial small mammals of the endangered Atlantic Forest, we assessed which ecological drivers (habitat structure and food availability) affect community changes during succession. If the change in community dominance is driven by trade‐offs between productivity and efficiency, it should be mainly associated with a decrease in food availability. As expected, from younger to older forest, habitat generalists decreased in richness and total abundance, concurrent with a decrease in arthropod biomass. By contrast, the increase in richness and total abundance of forest specialists was not clearly supported by the data; however, this group was not affected by food availability. These results are congruent with a trade‐off between competitive ability and ability to use abundant resources, and indicate that the major community change during succession involves habitat generalists. Secondary forests may thus be valuable for conservation, at least where habitat loss and fragmentation are not high, and old growth forest is available.     

Resilience of tropical dry forests – a meta‐analysis of changes in species diversity and composition during secondary succession

Assessing the recovery of species diversity and composition after major disturbance is key to understanding the resilience of tropical forests through successional processes, and its importance for biodiversity conservation. Despite the specific abiotic environment and ecological processes of tropical dry forests, secondary succession has received less attention in this biome than others and changes in species diversity and composition have never been synthesised in a systematic and quantitative review. This study aims to assess in tropical dry forests 1) the directionality of change in species richness and evenness during secondary succession, 2) the convergence of species composition towards that of old‐growth forest and 3) the importance of the previous land use, precipitation regime and water availability in influencing the direction and rate of change. We conducted meta‐analyses of the rate of change in species richness, evenness and composition indices with succession in 13 tropical dry forest chronosequences. Species richness increased with succession, showing a gradual accumulation of species, as did Shannon evenness index. The similarity in species composition of successional forests with old‐growth forests increased with succession, yet at a low rate. Tropical dry forests therefore do show resilience of species composition but it may never reach that of old‐growth forests. We found no significant differences in rates of change between different previous land uses, precipitation regimes or water availability. Our results show high resilience of tropical dry forests in term of species richness but a slow recovery of species composition. They highlight the need for further research on secondary succession in this biome and better understanding of impacts of previous land‐use and landscape‐scale patterns. Synthesis Secondary forests account for an increasing proportion of remaining tropical forest. Assessing their resilience is key to conservation of their biodiversity. Our study is the first meta‐analysis of species changes during succession focussing on tropical dry forests, a highly threatened yet understudied biome. We show a gradual species accumulation and convergence of composition towards that of old‐growth forests. While secondary tropical dry forests offer good potential for biodiversity conservation, their capacity for recovery at a sufficient rate to match threats is uncertain. Further research on this biome is needed to understand the effect of land use history and landscape processes.