Biomass carbon pools of Cunninghamia lanceolata (Lamb.) Hook. forests in subtropical China: Characteristics and potential

Abstract

Swedish forestry has successfully developed systems for sustained yield production of wood. Silvicultural techniques are today completely dominated (96%) by clear-felling methods. By contrast, Swedish natural forests and preindustrial cultural woodlands were ecologically and culturally diverse, with a substantial proportion having a continuous tree cover as a response to natural disturbance dynamics and preindustrial agricultural land management. If forest management systems do not mimic this diversity of disturbance regimes sufficiently well, the scope of sustainable forest management to include biodiversity and sociocultural values will not be met. This study estimated the past and present amount of one cultural and two natural disturbance regimes known to deliver continuous tree cover in two study areas located around two important biophysical and sociocultural transition zones in northern and southern Sweden, respectively. Several approaches were used to estimate the amount of remaining continuous tree cover forests. The results indicate that 9–10% of the study areas is made up by site types that historically would have held a large proportion of continuous tree cover forests. Estimates for productive site types show that only 1–2% of these sites remain in southern Sweden and 10–20% in northern Sweden. The data indicate that present management in both study areas is similar. Thus, these differences between the regions will disappear in a few decades. To achieve the aim of Swedish forest and environmental policies there is a clear need to develop and use alternative forest management methods on appropriate sites.     

Agroforestry in central,northern, and eastern Europe

Integrated management of natural resources and the multiple use of trees and forests have prevailed in most European societies since prehistoric times. In the Middle Ages, expanding and intensified agriculture resulted in the separation of trees from agricultural fields. During the last century, with the introduction of sustainable and highly productive forest management, the goal of increased wood production has been achieved in most parts of central, northern, and eastern Europe. Today, agroforestry is not considered to be an important land-use option within the region; however, there are many practices that could rightfully be classified as agroforestry. These include tree/crop systems in which trees provide products and/or environmental benefits, and tree/animal systems in which animals are grazed in forests or open woodlands.The future seems to offer some prospects for agroforestry. Large areas, hitherto used for food production, are either marginally suited to agriculture, or will probably be taken out of production due to agricultural policy considerations. Agroforestry may, at least in part, offer alternatives for the use of such lands. The availability of (surplus) fertile soils, capital, and labor may provide incentives for site-adapted forms of agroforestry, including improved fallow management. The focus of such systems would be on maintenance of biodiversity in the landscape, environmental protection, recreation, and product diversification.There are numerous expectations as to what agroforestry might provide for the land holder and for society as a whole. These expectations should be carefully analyzed and evaluated prior to political decisions on future land use. The promotion of agroforestry requires overall investment; agroforestry does not happen by itself. A set of integrated actions — not isolated efforts — must be implemented if agroforestry is to become a successful land-use option.     

An Interdisciplinary Research Initiative Towards Sustainable Management of Forest Resources in Lowland Rain Forests of Sri Lanka

Ever-wet forests of SW Sri Lanka are biodiversity hot spots with a wealth of potentially useful and currently used species. Traditional peoples surrounding these forests depend on them for a variety of focds, medicinals and the like as well as for timber. Some of these forests are being preserved as storehouses of diversity that include rare endemics and wild relatives of useful plants. Other natural forests and plantations must be managed for multiple uses including timber and non-timber products used by the forest dependent villagers. Understanding the ecological, social and economic interdependence of forests and rural communities is vital for the future forestry sector development in Sri Lanka. As many of the plants used locally are characteristic of early stages of gap regeneration, timber and non-timber products are compatible uses, given sufficiently judicious management. Anthropological and biological research is now in progress to plan for multiple use management of Sri Lankan ever-wet forests.     

Growth and yield of coffee plants in agroforestry and monoculture systems in Minas Gerais, Brazil

This research compared coffee plants (Coffea arabica L.) grown in an agroforestry and monoculture systems. Data were collected during two years, on vegetative growth, reproductive development, nutritional status and yield of coffee, besides monitoring air temperature and the tree growth. All trees in agroforestry system increased in growth, resulting in a reduction in the magnitude of the diurnal temperature variation and also maximum temperature. Coffee plants in agroforestry system had less branch growth and leaf production, more persistent and larger leaves, and presented earlier flowering, with a smaller number of productive nodes and flower buds, leading to smaller berry yield than plants in monoculture system. In both systems, the coffee plants showed adequate leaf nutrient levels, except for P and K. The yield of 2443 kg ha^-1 of coffee from the monoculture was greater than 515 kg ha^-1 of coffee from the agroforestry system.     

The potential value of agroforestry to dung beetle diversity in the wet tropical forests of the Pacific lowlands of Colombia

In tropical regions where agricultural activities are limited, agroforestry is an alternative for both economic development and for the management and conservation of biodiversity. The potential role of different types of land use as reservoirs of dung beetle diversity in the wet tropical forest of the Pacific lowlands of Colombia is evaluated in three agroforestry systems that differ in canopy cover and the sowing density of Borojoa patinoi crops associated with timber forest. Although total species richness was similar among land use types, differences related to the decrease in the abundance and biomass of the species were remarkable, and reflected in turn by the diversity and structure of the guilds. The general pattern observed was one in which the structure of the dung beetle assemblage of B. patinoi growing below a diversified and permanent tree cover was similar to that of the primary and secondary forest. Beetle diversity in management systems with less tree cover or a high sowing density of B. patinoi was lower and very similar to that of abandoned agricultural fields. This suggests that B. patinoi agroforestry systems can be viewed as valuable instruments for biodiversity management and conservation in the wet tropical forests of the Pacific lowlands and not just as substitutes for forest, though we must be aware that structural changes in the beetle community may in turn affect the ecological processes regulated by these insects in the agrosystems under study.     

Emulating natural disturbances: the role of silviculture in creating even-aged and complex structures in the black spruce boreal forest of eastern North America

Ecosystem-based forest management is based on the principle of emulating regional natural disturbance regimes with forest management. An interesting area for a case study of the potential of ecosystem-based forest management is the boreal forest of north-western Québec and north-eastern Ontario, where the disturbance regime creates a mosaic of stands with both complex and simple structures. Old-growth stands of this region have multi-storied, open structures, thick soil organic layers, and are unproductive, while young post-fire stands established following severe fires that consumed most of the organic soil show dense and even-sized/aged structures and are more productive. Current forest management emulates the effects of low severity fires, which only partially consume the organic layers, and could lead to unproductive even-aged stands. The natural disturbance and forest management regimes differ in such a way that both young productive and old-growth forests could ultimately be under-represented on the landscape under a fully regulated forest management regime. Two major challenges for ecosystem-based forest management of this region are thus to: (1) maintain complex structures associated with old-growth forests, and (2) promote the establishment of productive post-harvest stands, while at the same time maintaining harvested volume. We discuss different silvicultural approaches that offer solutions to these challenges, namely the use of (1) partial harvesting to create or maintain complex structures typical of old-growth stands, and (2) site preparation techniques to emulate severe soil burns and create productive post-harvest stands. A similar approach could be applied to any region where the natural disturbance regime creates a landscape where both even-aged stands established after stand-replacing disturbances and irregular old-growth stands created by smaller scale disturbances are significant.     

Silviculture for old-growth attributes

Silviculture to maintain old-growth forest attributes appears to be an oxymoron since the late developmental phases of forest dynamics, described by the term old-growth, represent forests that have not experienced human intervention or timber removal for a long time. In the past, silvicultural systems applied to old-growth aimed to convert it into simplified, more productive regrowth forests substantially different in structure and composition. Now it is recognised that the maintenance of biodiversity associated with structural and functional complexity of late forest development successional stages cannot rely solely on old-growth forests in reserves. Therefore, in managed forests, silvicultural systems able to develop or maintain old-growth forest attributes are being sought. The degree to which old-growth attributes are maintained or developed is called “old-growthness”. In this paper, we discuss silvicultural approaches that promote or maintain structural attributes of old-growth forests at the forest stand level in (a) current old-growth forests managed for timber production to retain structural elements, (b) current old-growth forests requiring regular, minor disturbances to maintain their structure, and (c) regrowth and secondary forests to restore old-growth structural attributes. While the functions of different elements of forest structure, such as coarse woody debris, large veteran trees, etc., have been described in principle, our knowledge about the quantity and distribution, in time and space, of these elements required to meet certain management objectives is rather limited for most ecosystems. The risks and operational constraints associated with managing for structural attributes create further complexity, which cannot be addressed adequately through the use of traditional silvicultural approaches. Silvicultural systems used in the retention and restoration of old-growthness can, and need, to employ a variety of approaches for managing spatial and temporal structural complexity. We present examples of silvicultural options that have been applied in creative experiments and forestry practice over the last two decades. However, these largely comprise only short-term responses, which are often accompanied by increased risks and disturbance. Much research and monitoring is required still to develop and optimise new silvicultural systems for old-growthness for a wide variety of forest ecosystem types.     

韩国山林农业概况与类型

"山林复合经营项目"是韩国在1999年为了增加林业从业者的收入而正式实施的,主要包括短期收入、木材生产和复合山地管理3种类型。截至2005年,该项目在韩国国内的168个市(区)都得到了推广。文中主要介绍韩国山林农业系统,分析该系统存在的问题并探讨与之相应的解决方案,提出应在开发更可行的复合农林经营模式的基础上加大对林业从业者的培训和奖励力度并改善对复合农林业的支持制度。     

The effects of management and plant diversity on carbon storage in coffee agroforestry systems in Costa Rica

Agroforestry systems can mitigate greenhouse gas (GHG) emissions, conserve biodiversity and generate income. Whereas the provision of ecosystem services by agroforestry is well documented, the functional relationships between species composition, diversity and carbon (C)-storage remain uncertain. This study aimed to analyze the effects of management (conventional vs. organic), woody plant diversity and plant composition on aboveground and belowground C-storage in coffee agroforestry systems. It was expected that organic farms would store more C, and that an increase in plant diversity would enhance C-storage due to complementarity effects. Additionally, it was expected that steep slopes decrease C-storage as a result of topsoil erosion. Woody plants were identified on 1?ha plots within 14 coffee farms (7 conventional and 7 organic). C-stocks in trees, coffee plants and roots were estimated from allometric equations. C-stocks in litter and topsoil (0?C25?cm) were estimated by sampling. On average, farms stored 93?±?29?Mg?C?ha^?1. Soil organic carbon accounted for 69?% of total C. Total C-stocks were 43?% higher on organic farms than on conventional farms (P?<?0.05). Conventional and organic farms differed in vegetation structure, but not in species diversity. It was found that the combined effect of farm type, species richness, species composition and slope explained 83?% of the variation in total C-storage across all farms (P?<?0.001). Coffee agroforestry in general and organic farms in particular may contribute to GHG mitigation and biodiversity conservation in a synergistic manner which has implications for the effective allocation of resources for conservation and climate change mitigation strategies in the agricultural sector.     

An economic analysis of improved agroforestry practices in the Amazon lowlands of Ecuador

Since 1985, Ecuador's Ministry of Agriculture has undertaken a demonstration project to promote improved agroforestry practices in already cleared lands of Ecuador's Amazon lowlands to promote regeneration of deforested areas. An important expected outcome of this project is to ameliorate growing population pressures on remaining national forests and natural reserves. These practices include managing natural regeneration of marketable timber trees intercropped to Coffea canephora var. robusta and grass-legume associations, using adequate techniques of coffee pruning, and planting Desmodium ovalifolium CIAT 350 as a ground cover crop or a forage legume in paddocks of the genus Brachiaria. This research was conducted to assess the potential economic impact of such a strategy and to feed back information on research and policy issues.Improved agroforestry practices in this region are not only technically practicable but also economically feasible. Proposed technologies enhance long-term productivity of both land and labor while saving on external inputs and hired labor, making on-going systems more adoptable and sustainable. Future land-use policies should consider on-farm primary forest preservation and controlled natural regeneration of high-value timber in secondary forests as socially efficient land-use patterns. Future research must address germplasm of grass and forage legumes both shade tolerant, and less field management-demanding than current ones.To have a lasting effect this technology should probably be incorporated into a Regional Forest Management Plan, for sustainable production at the secondary forests created with agroforestry technology.in cooperation with Fundación para el Desarrollo Agropecuario del Ecuador, FUNDAGRO, Casilla No. 219, Suc. 16 CEQ, Quito, Ecuador     

Adaptive risk management for certifiably sustainable forestry

The past decade has seen a global surge in forest management certification, with over 200 million hectares of the world's forest now certified as sustainably harvested. Because forests are some of the most species-rich environments on earth and more than 90% of the world's forests occur outside formal protected area systems, forest management certification will be one of the pervasive influences on global biodiversity for the foreseeable future. We find that current forest certification schemes are largely deficient because they fail to demand: (i) measurable management objectives for biodiversity, (ii) formal risk assessment of competing management options that integrate impacts on biodiversity, (iii) monitoring that directly addresses management performance requirements and a clear plan for how monitoring information will be used to make better management decisions, and (iv) ongoing research targeted toward practices that enhance biodiversity in managed landscapes. We argue that the credibility of certification schemes hinges on their ability to dictate scientifically defensible management systems for biodiversity conservation. We present a framework for adaptive risk management (ARM) of biodiversity that is both responsibly proactive and diligently reactive and recommend its incorporation in all certification schemes. We highlight the need for substantial government and agency investment in fostering ARM.     

Root architecture of provenances, seedlings and cuttings of Melia volkensii: implications for crop yield in dryland agroforestry

Agroforestry, as one of integrated approaches to biodiversity conservation, has received attention. But the methods to evaluate this contribution are rare. The present study focuses on the method development for quantification of effects of agroforestry on biodiversity conservation. It includes identifying the functional groups of agroforestry components, defined as a set of species with similar impacts on a system process, and quantifying the distinctness of these groups, as related to wise use of resources and increasing well-being of local people. Combining with functional group-based Analytic Hierarchy Process (AHP) analysis, the present work gives a useful way for an integrated evaluation-planning of agroforestry management relative to biodiversity conservation. It also provides a means to improve our knowledge on the potential roles of agroforestry in biodiversity conservation of nature reserves. The analyses, using the distinctness index of functional groups, demonstrated the impacts of various land-use systems on biodiversity conservation. The analyses, using AHP, ranked the priorities of various agroforestry and plantations on the protection of nature forests, aiming at the long-term solution for the resource support. The present study suggests that agroforestry development for biodiversity conservation should take into account the impacts of functional groups in strategic planning.This revised version was published online in November 2005 with corrections to the Cover Date.     

Seasonal variation of soil respiration rates in a secondary forest and agroforestry systems

Agroforestry systems are widely practiced in tropical forests to recover degraded and deforested areas and also to balance the global carbon budget. However, our understanding of difference in soil respiration rates between agroforestry and natural forest systems is very limited. This study compared the seasonal variations in soil respiration rates in relation to fine root biomass, microbial biomass, and soil organic carbon between a secondary forest and two agroforestry systems dominated by Gmelina arborea and Dipterocarps in the Philippines during the dry and the wet seasons. The secondary forest had significantly higher (p < 0.05) soil respiration rate, fine root biomass and soil organic matter than the agroforestry systems in the dry season. However, in the wet season, soil respiration and soil organic matter in the G. arborea dominated agroforestry system were as high as in the secondary forest. Whereas soil respiration was generally higher in the wet than in the dry season, there were no differences in fine root biomass, microbial biomass and soil organic matter between the two seasons. Soil respiration rate correlated positively and significantly with fine root biomass, microbial biomass, and soil organic C in all three sites. The results of this study indicate, to some degree, that different land use management practices have different effects on fine root biomass, microbial biomass and soil organic C which may affect soil respiration as well. Therefore, when introducing agroforestry system, a proper choice of species and management techniques which are similar to natural forest is recommended.     

天然林的保护与管理

对天然林的概念,世界天然林资源状况及分布,天然林保护的迫切性、保护措施及天然林管理与育林的新近发展,作了较系统的阐述.对天然林保护的现状,天然林减少状况及原因作了分析,并提出了天然林保护的三个发展趋势:扩大被保护森林,对生产性天然林进行可持续经营(包括制定标准与指标,法规及森林产品证书制等),改变木材供应的森林类型.     

Tree Culture of Smallholder Farmers Practicing Agroforestry in Gunung Salak Valley,West Java,Indonesia

This paper investigates the types of agroforestry system that exist in Gunung Salak Valley, West Java, Indonesia in order to characterize the differences in their basic structure and associated crop plant diversity. Data were collected through rapid rural appraisal, field observation and focus groups, followed by household survey of a sample of 20 agroforestry farmers. Five main agroforestry systems (homegardens, fruit tree system, timber tree system, mixed fruit–timber system, and cropping in the forest understory) exist in the study area, and all of them exhibit a noticeable diversity in terms of both species composition and utilization. Products from farming accounted for an average 24 % of household income. They comprised agroforestry products which contributed IDR 3.25 million/year and other agricultural products contributing IDR 1.66 million/year. The observed agroforestry systems include not only a form of forest dominated by ‘cultivated trees’, but also an anthropogenic vegetation formation derived from agricultural antecedents. In land-use classifications agroforestry systems are not recognized as forestry, but like forests they provide tree products and services. Classification will always be disfunctional if a binary system is applied, thus a more sophisticated approach should be adopted that incorporates the economic and environmental characteristics of a wider range of systems.     

印度东北部南梅加拉亚邦摈榔复合农林生态系统植物多样性(英文)

在南梅加拉亚邦摈榔复合农林生态系统内,农民种有多种具有重要经济价值的植物。调查了摈榔复合农林生态系统内植物组成情况,共发现160种植物,其中木本植物83种,灌木22种,草本41种,攀缘植物14种。研究表明,摈榔复合农林生态系统为当地农民带来了经济收入,提供医药、木材、燃材和食用品以及外售。这些复合农林生态系统有利于保护重要经济价值的植物物种、保持生物多样性,并在结构组成和生态经济功能上模拟自然森林。     

Traditional agroforestry systems and biodiversity conservation in Benin (West Africa)

In the past, the conservation of biodiversity has been mostly understood in terms of the management of protected areas and natural forests, ignoring the possible role of farm areas and the ways through which rural communities have promoted biodiversity in their subsistence agricultural production systems. The present study focused on the floristic diversity within traditional agroforestry parkland systems around the Pendjari Biosphere Reserve in Benin and showed the diversity of tree species in the area as well as socio-economic factors which affect the practice of this farming system. We used questionnaires and interviewed a total of 118 households to collect data. Respondents were interviewed on their farms and during the interview; we inventoried the number of tree on the farm and determined the farm size. Twenty-one tree species belonging to 14 botanical families were recorded during the surveys and the average stand density of the woody component of farmlands was 7.97 ± 5.43 stems/ha. A number of both native and exotic tree species occurred in the parkland agroforestry systems with dominance of indigenous tree species. Species richness varied with the size of household where households with small land holding conserve more tree species in their field than households with large land holdings. 64% of households surveyed were making deliberate efforts to plant tree species on their farmlands. The most important reasons which determined household ambitions to conserve woody species on farmland were tree products contribution to food and medicine. Results also showed that respondents who noticed that trees were decreasing in the wild conserve more tree species on their farmlands. This research highlights the role of traditional agroforestry practices to support tree species richness and provides evidence of the farms’ role as biodiversity reservoirs.     

Coffee agroforestry systems in Central America: I. A review of quantitative information on physiological and ecological processes

Research on coffee agroforestry systems in Central America has identified various environmental factors, management strategies and plant characteristics that affect growth, yield and the impact of the systems on the environment. Much of this literature is not quantitative, and it remains difficult to optimise growing area selection, shade tree use and management. To assist in this optimisation we developed a simple dynamic model of coffee agroforestry systems. The model includes the physiology of vegetative and reproductive growth of coffee plants, and its response to different growing conditions. This is integrated into a plot-scale model of coffee and shade tree growth which includes competition for light, water and nutrients and allows for management treatments such as spacing, thinning, pruning and fertilising. Because of the limited availability of quantitative information, model parameterisation remains fraught with uncertainty, but model behaviour seems consistent with observations. We show examples of how the model can be used to examine trade-offs between increasing coffee and tree productivity, and between maximising productivity and limiting the impact of the system on the environment.     

Coffee agroforestry systems in Central America: II. Development of a simple process-based model and preliminary results

Research on coffee agroforestry systems in Central America has identified various environmental factors, management strategies and plant characteristics that affect growth, yield and the impact of the systems on the environment. Much of this literature is not quantitative, and it remains difficult to optimise growing area selection, shade tree use and management. To assist in this optimisation we developed a simple dynamic model of coffee agroforestry systems. The model includes the physiology of vegetative and reproductive growth of coffee plants, and its response to different growing conditions. This is integrated into a plot-scale model of coffee and shade tree growth which includes competition for light, water and nutrients and allows for management treatments such as spacing, thinning, pruning and fertilising. Because of the limited availability of quantitative information, model parameterisation remains fraught with uncertainty, but model behaviour seems consistent with observations. We show examples of how the model can be used to examine trade-offs between increasing coffee and tree productivity, and between maximising productivity and limiting the impact of the system on the environment.     

Ecosystem services in human-dominated landscapes: insectivory in agroforestry systems

Despite of being structurally simpler and species-impoverished than natural forests, agroforestry plantations can act as a secondary habitat for native species and sustain some biodiversity. In particular, insectivores can provide important ecosystem services such as insectivory, indirectly benefiting plants through the reduction of herbivory and increasing productivity, by diminishing herbivores abundance. The lending of these services could occur in agroforestry systems, and in the same magnitude that in natural environments, however it has not yet been assessed whether the direct effect of insectivores over insects and indirect effect on plants differ between natural and agroforestry environments depending on possible modulating factors such as climatic region, type of insectivore, trophic group of the preyed arthropod and length of insectivores experimental exclusion. In this study, through a meta-analysis, it was assessed the provision of ecosystem services by insectivores in agroforestry systems compared to natural systems, contrasting it with the modulating factors mentioned. In general, insectivorous species reduced arthropod abundance and plant herbivory, and increased plant productivity. The magnitude and direction of these effects did not differ between natural and agroforestry systems, and neither did between different climatic regions, type of insectivore, preyed arthropod trophic groups nor experiment length. The effect of insectivores on productivity can vary based on the variable used to measure productivity. Our results evidence the provision of services by the insectivores present in plantations, independently of factors that could modulate its magnitude and direction. In this way, enhancing the existence of these important interactions within plantations could represent a win–win scenario.