川西米亚罗林区森林恢复的影响因子分析

地处青藏高原东南缘的川西亚高山林区,地形复杂,新构造运动活跃,岩体松散,地震频繁,是一个生态环境非常脆弱的地区。川西亚高山暗针叶林是该区主要的森林类型,这些森林集中分布于金沙江、雅砻江、岷江、大渡河等流域及其支流,是我国西南高山林区水源涵养林的重要组成部分。20世     

Time and Distance: Comparing Motivations Among Forest Landowners in New England, USA

Parcelization and shifting landownership are critical forces reshaping forested ecosystems in the USA and elsewhere. These forces create a mosaic of new and long-time landowners as well as differences in residency. Using survey data (n = 879) of landowners in Massachusetts and Vermont, USA, we begin the process of sorting out time (i.e., length of landownership) and distance (i.e., distance of primary residence from forest holding), and their relationships to motivations for continued landownership and management. Both time and distance, and their interaction were significant in explaining three motivations for landownership: enjoyment, production, and protection as well as the number of neighbors with which respondents were acquainted. Distance is the statistically more important factor—negatively related to all dependent variables, but time and its interaction with distance offer the more useful insights for intervention.

Drivers and Barriers to Change to Governance in Small-Scale Forestry

The progressive introduction of new modes of governance promoted by the international dialogue on forests during the last 20 years has resulted in a concrete change of the management of the forests, with a new style of relationship between the public authority and the local actors. The change has been considerable in some specific situations, for instance when the State plays a major role in public decisions and when the continuing economic transformation increases the importance of private estates. In both cases, small-scale forestry is especially concerned. Based on detailed examples selected in various situations where this change is significant, in western Europe (Belgium, France, Germany) and in transitioning (Kyrgyzstan, Ukraine) and developing (Marocco) countries, this special issue of the Small-scale Forestry sheds a new light on the capability of small-scale forestry to adapt to a transformation of the system of public decision-making. In most cases analysed, the barriers to adaptation, usually presented as resulting from fragmentation of the management decisions and a great number and diversity of stakeholders, also appear as drivers to change, in a global process where networks of actors are recomposed and power redistributed along a new scheme of national and regional links.     

Multistoried agroforestry garden system in West Sumatra,Indonesia

The agroforestry garden system in Maninjau in West Sumatra is characterized by an intensive integration of forest species and commercial crops, forming a forest-like system. The intimate association of different species provides both subsistence and commercial products which supplement rice production. This complex agroforest is managed by the combination between cultural practices and respect of natural processes of vegetation production and reproduction. It represents a profitable production system and constitutes an efficient buffer between villages and protected forest. It is a good model of association between integration of forest resources and cultivation of cash crops in the form of a sustainable and flexible system.     

美国国有林经营及对中国的启示

在介绍美国国有林经营政策的基础上, 针对中国国有林经营现状, 提出应借鉴的经验:减轻税费负担, 加强营造林基础; 提高林业科技水平, 发展高效林业; 构建国有林资源法制化管理体系; 重视跨部门跨学科的交流和合作; 采用生态系统管理方法, 开发和保护并重。     

Forest carbon storage in the northeastern United States: Net effects of harvesting frequency,post-harvest retention,and wood products

Temperate forests are an important carbon sink, yet there is debate regarding the net effect of forest management practices on carbon storage. Few studies have investigated the effects of different silvicultural systems on forest carbon stocks, and the relative strength of in situ forest carbon versus wood products pools remains in question. Our research describes (1) the impact of harvesting frequency and proportion of post-harvest structural retention on carbon storage in northern hardwood-conifer forests, and (2) tests the significance of including harvested wood products in carbon accounting at the stand scale. We stratified Forest Inventory and Analysis (FIA) plots to control for environmental, forest structural and compositional variables, resulting in 32 FIA plots distributed throughout the northeastern U.S. We used the USDA Forest Service's Forest Vegetation Simulator to project stand development over a 160 year period under nine different forest management scenarios. Simulated treatments represented a gradient of increasing structural retention and decreasing harvesting frequencies, including a “no harvest” scenario. The simulations incorporated carbon flux between aboveground forest biomass (dead and live pools) and harvested wood products. Mean carbon storage over the simulation period was calculated for each silvicultural scenario. We investigated tradeoffs among scenarios using a factorial treatment design and two-way ANOVA. Mean carbon sequestration was significantly (α = 0.05) greater for “no management” compared to any of the active management scenarios. Of the harvest treatments, those favoring high levels of structural retention and decreased harvesting frequency stored the greatest amounts of carbon. Classification and regression tree analysis showed that management scenario was the strongest predictor of total carbon storage, though site-specific variables were important secondary predictors. In order to isolate the effect of in situ forest carbon storage and harvested wood products, we did not include the emissions benefits associated with substituting wood fiber for other construction materials or energy sources. Modeling results from this study show that harvesting frequency and structural retention significantly affect mean carbon storage. Our results illustrate the importance of both post-harvest forest structure and harvesting frequency in carbon storage, and are valuable to land owners interested in managing forests for carbon sequestration.     

Use of LiDAR and supplemental data to estimate forest maturity in Charles County,MD, USA

This study evaluated the utility of remotely sensed data to estimate forest maturity within Charles County, MD. We calculated tree canopy height using airborne scanning LiDAR (light detection and ranging) data over the entire county, and compared this to crown top height, stand age, and other data collected from randomly selected plots on the ground. Canopy height was a strong predictor of forest age, and we improved predictive power by including other variables such as land cover, slope, stream proximity, wetlands, and floodplains. These comparisons allowed us to construct a spatial model classifying forest in the study area into three age categories: ≤30 years old, 30–70 years old, and >70 years old, corresponding to young, intermediate, and mature. This spatial model was used to help characterize ecosystem condition and wildlife habitat, and help prioritize conservation decisions in the study area.     

Tree regeneration responses to microsite characteristics following a severe tornado in the Georgia Piedmont, USA

For 3 years following a severe, November 1992 tornado, abundance and growth of tree regeneration in intact forest-floor and windthrow-pit microsites were studied in three mixed pine and hardwood stands in the Georgia Piedmont, USA. The research had two objectives: (1) determine if performance of tree regeneration differed between microsite types and between pre- and post-tornado cohorts on intact forest-floor microsites, and (2) determine if variation in light and soil water availability from the disturbance affected performance of eight species artificially seeded into intact forest-floor microsites. Near each of the 42 sample points (12–20 per site) spaced on 15 m grids, species and height of tree seedlings were recorded within a 1 m radius plot of intact forest floor and the nearest windthrow pit. Intact forest-floor microsites were dominated by two late-successional species, Acer rubrum (3.5 pre-tornado stems per m² and 1.8 post-tornado stems per m²) and Ostrya virginiana (2.6 post-tornado stems per m²), while windthrow pits were dominated by an early successional species, Liriodendron tulipifera (1.7 stems per m²). Although seedling survival did not vary significantly among species or microsite types, first-year height of seedlings in intact forest-floor microsites (24 cm) was significantly greater than those in windthrow-pit microsites (19 cm). Second-year height growth of new seedlings of Cornus florida in intact forest-floor microsites (52 cm) significantly exceeded that of many other combinations of species and microsite type. Species artificially-seeded into intact forest-floor microsites in 1994 and 1995 varied considerably in emergence (<1–24%), survival (<1–16%), and height (5–15 cm), and those with the heaviest seed survived best. From 1994 to 1995, average gap fraction, an index of light availability, decreased 17% from 0.23 to 0.19. Soil water content in 1995 under gap fractions of greater than 0.3 (21%) averaged significantly less than under gap fractions of either 0.1–0.3 (24%) or less than 0.1 (26%). Significant positive correlations were detected for relationships of emergence and survival of several species to soil water content. Overall rankings of seedling performance between microsites (intact forest floor>windthrow pits), between cohorts (pre-tornado>post-tornado origin), and among species (mid- to late->early-successional species) indicate that advanced regeneration and new seedlings of A. rubrum, O. virginiana, and C. florida will be long-term dominants of the understory because of their high abundance, initial growth responses, and shade tolerance.     

Attitudes of small-scale forest owners to their properties in an ageing society: Findings of survey in Yamaguchi prefecture, Japan

Populations of most developed countries have been ageing, and the populations of Japanese mountain villages are estimated to have reached into a super-ageing society. In particular, because forestry is unprofitable and due to the economic recession in Japan, many small-scale forest owners face the problems of ageing. For policy-makers, it is important to assess the socioeconomic impacts of forest owners’ ageing in order to ensure the sustainable management of forests. A survey was conducted of forest owners in Yamaguchi Prefecture, which is famous for overall depopulation and ageing of the rural population. It was found that 83% of 687 plantation forest owners who responded in the survey were 60 years or older and 76% did not have forestry income over the past three years, but 81% had kept up ownership of their forest as the traditional family property. In terms of forest management intentions, the respondents were found to consist of four types, namely ‘family management’, ‘commissioned management’, ‘de-accession’ and ‘possession without proper management’. Differences in evaluations of hypothetical policies were found among the four types.     

湾沟林业局退耕还林工程实施情况及几点做法

湾沟林业局在退耕还林实施过程中，不断加大退耕还林力度，努力加强退耕还林工程的科技创新，逐步提高退耕还林工程的科技含量和总体水平，取得了生态效益、社会效益和经济效益的和谐统一。     

Vegetation community responses to different establishment regimes in loblolly pine (Pinus taeda) plantations in southern MS,USA

Management treatments involving multiple herbicide applications are standard procedure on most industrial pine plantation sites in the southern USA, raising concerns about biodiversity impairment. Management decisions impact not only plant communities but also the habitat potential they create for wildlife. We tested the effects of five intensities of stand establishment treatments on vegetation communities in loblolly pine plantations (n = 4) to age 5 in the Middle Coastal Plain (MCP) of Mississippi. Measurements were species richness, diversity, coverage, and community composition. Treatments were combinations of mechanical site preparation (MSP), chemical site preparation (CSP), and herbaceous weed control (HWC) both banded or broadcast for 1 or 2 years using the same herbicide mixtures. Tree richness and diversity were reduced by increasing treatment intensity; tree coverage, which included crop and non-crop trees, was less in moderate-intensity treatments. Vine richness and coverage were less in more intensive treatments, but 2 diversity indices differed on whether vine diversity was likewise affected. Richness and coverage of forbs and graminoids was lessened by broadcast HWC, with effects mostly limited to the year of application. Plant communities differed in all 5 years, with CSP acting as the primary factor for years 2–5. Early seral communities were favored by CSP, but broadcast HWC suppressed resulting herbaceous plants. Though CSP may somewhat reduce stand-level plant diversity, it may increase overall biodiversity within plantation-dominated landscapes by creating early succession plant communities that enhance wildlife habitat.     

Patterns of Liana Abundance,Reproductive Traits and Liana-Tree Relationships in Relation to Forest Management in a Tropical Forest in Ghana

The study determined the impacts of three forest management regimes—logging treated (LT), tropical shelterwood system (TSS) treated, and untreated forest (UF)—on liana abundance, reproduction and climbing guilds, and liana-tree relationship patterns in the Asenanyo Forest Reserve, Ghana. The first two regimes involved liana cutting over 20 and 53 yr ago, respectively. Lianas and their hosts were sampled in 10 randomly demarcated plots (40 × 40 m²) in each regime. Liana abundance and infestation were significantly lower in the LT forest than the UF, whereas these attributes were comparable in the TSS treated and the UF. Overall, the patterns of liana reproduction and climbing guilds were similar in the treated and untreated forests. Tree diameter was positively and significantly correlated to liana load, basal area, and degree of colonization in the treated and untreated forests. Mean liana load was the same on different tree bark types in the forest management regimes. These findings suggest that the impact of liana cutting on liana abundance was still apparent in the LT forest but not in the TSS treated forest. Again, the impacts of liana cutting on patterns of liana reproduction and climbing guilds and liana-tree relationships were not noticeable in the treated forests.     

从法正林转向近自然林:德国多功能森林经营在国家、区域和经营单位层面的实践

简要介绍德国林业的发展历史、多功能林业的法律规定和实现多功能目标的近自然林业理论和技术, 分别从经营单位、区域和国家层面分析总结了德国作为林业发达国家开展多功能森林经营的具体实例和初步结果, 提出了在各个层面上多功能森林经营的工作要点和评价效果的方法、指标和标准等可学习借鉴的要点。认为多功能近自然林业的理论是中华民族一直倡导的"真、善、美"的文化理念在林业经营中的具体表达, 我国开展多功能林业有良好的历史文化基础和现实需求动力。     

Retained Woody Structure in 1- to 2-Year-Old Loblolly Pine (Pinus taeda L.) Plantations in Mississippi,Louisiana, and Arkansas: Implications for Wildlife Conservation

Information regarding how site preparation techniques affect residual woody structure is lacking for the southern United States in spite of the importance of such structure for many wildlife species. Therefore, we documented retained structure in young loblolly pine (Pinus taeda L.) plantations established using four common site preparation regimes: mechanical only, chemical only, chemical + mechanical, or chemical + prescribed burning. Herbicides reduced live tree density and increased snag density relative to mechanical methods. Prescribed burning reduced density of coarse woody debris (CWD) along with density and volume of piled CWD relative to chemical and mechanical methods. Our results provide a baseline for further studies of wildlife and retained structure in southern pine forests.     

Historical fire and vegetation dynamics in dry forests of the interior Pacific Northwest,USA, and relationships to Northern Spotted Owl (Strix occidentalis caurina) habitat conservation

Regional conservation planning frequently relies on general assumptions about historical disturbance regimes to inform decisions about landscape restoration, reserve allocations, and landscape management. Spatially explicit simulations of landscape dynamics provide quantitative estimates of landscape structure and allow for the testing of alternative scenarios. We used a landscape fire succession model to estimate the historical range of variability of vegetation and fire in a dry forest landscape (size ca. 7900 km²) where the present-day risk of high severity fire threatens the persistence of older closed canopy forest which may serve as Northern Spotted Owl (Strix occidentalis caurina) habitat. Our results indicated that historically, older forest may have comprised the largest percentage of the landscape (∼35%), followed by early successional forest (∼25%), with about 9% of the landscape in a closed canopy older forest condition. The amount and condition of older forest varied by potential vegetation type and land use allocation type. Vegetation successional stages had fine-grained spatial heterogeneity in patch characteristics, with older forest tending to have the largest patch sizes among the successional stages. Increasing fire severities posed a greater risk to Northern Spotted Owl habitat than increasing fire sizes or frequencies under historical fire regimes. Improved understanding of historical landscape-specific fire and vegetation conditions and their variability can assist forest managers to promote landscape resilience and increases of older forest, in dry forests with restricted amounts of habitat for sensitive species.