Short-rotation woody crops and phytoremediation: Opportunities for agroforestry?

Agroforestry Systems - Worldwide, fuelwood demands, soil and groundwater contamination, and agriculture's impact on nature are growing concerns. Fast growing trees in short rotation woody crop...     

Ethnography and agroforestry research: a case study from the Gambia

This work examines the contribution that an ethnographic methodology can make to gender-sensitive agroforestry research. Using a Gambian case study, diverse subsistence, commercial and socio-cultural roles of forest products are investigated and the gender-based similarities and differences in their uses are highlighted. An ethnographic approach is combined with political economy perspectives to illustrate how the significance of such products, particularly for women, has markedly increased during the past two decades, especially for commercial purposes, in response to changing environmental, economic and social circumstances. Environmental management practices are used by rural individuals to regulate forest resources. Although there is potential for formal management policy to build upon these indigenous practices, a detailed understanding of local human-environmental relationships is essential for any planning mechanism to succeed. Thus an enthnographic approach can make a positive contribution towards gender-sensitive agroforestry research and practice.     

The state of the art of agroforestry diagnosis and design

Seven years ago the International Council for Research in Agroforestry set out to develop a methodology for the diagnosis of land management problems and design of agroforestry systems. Since then over 60 documents (articles, conference papers and manuals) relating to the D & D methodology have been published by ICRAF and the methodology has been used to develop agroforestry plans and identify research priorities for a wide range of ecological and cultural conditions throughout the tropical regions of Africa, Latin America and Asia. This article reviews the evolution of the D & D methodology and suggests directions for its future development.Ecological Anthropologist, ICRAF     

Structural root form and fine root distribution of some woody species evaluated for agroforestry systems

Fine root distribution and structural root characteristics of four-years-old multipurpose woody species with potential for use in agroforestry systems were investigated on an Alfisol in the forest savanna transition zone of south-western Nigeria. Rooting patterns of woody species studied differed considerably. Lonchocarpus sericeus had the lowest percentage (21%) of total fine roots confined to the upper (0 to 30 cm) soil layer, compared to 84% with Tetrapleura tetraptera. Despite the superior tap root system of Enterolobium cyclocarpum and the fine root form of Nauchlea latifolia however, their extensive distribution and very large lateral woody root volume density may pose a major problem for seedbed preparation and tillage operations in simultaneous agroforestry systems. Lonchocarpus sericeus appears to have the most desirable structural and fine root architecture among the species studied for simultaneous agroforestry systems. The total root density below the underlying distal soil layers was linearly related to the sum of square of tap root diameter and the corresponding soil depths. This revised version was published online in June 2006 with corrections to the Cover Date.     

Participatory research in agroforestry: learning from experience and expanding our repertoire

Participation has been widely touted as “the answer” to a number of problems facing agroforestry research programs. It is not enough, however, to involve rural people as workers and informants in research endeavors defined by outsiders. A truly collaborative approach will depend upon our ability to broaden our definitions of research and participation, to accommodate a wide spectrum of land users and local knowledge, and to expand our repertoire of research methods. This paper presents a critique of facile approaches to participation, outlines a more inclusive framework for who participates on what terms, and reviews a variety of methods that address the complex realities of rural life and landscapes. The final section of the paper suggest a multi-institutional model that combines the complementary strengths of several types of organizations in participatory field research.     

Directions in tropical agroforestry research: past, present, and future

Reflections on the past two decades of organized research in tropical agroforestry raise several issues. Research efforts started with an inductive and experiential approach but have subsequently followed a deductive and experimental approach that includes hypothesis testing and the development of predictive capability; agroforestry research is thus being transformed into a rigorous scientific activity. The research agenda, so far, has given high priority to soil fertility and other biophysical interactions, less priority to anthropological and sociological aspects, and little priority to evaluating costs and returns, pests and diseases, and the so-called non-timber forest (tree) products. Moreover, larger-spatial-scale issues, such as carbon sequestration, water quality, and biodiversity conservation, have been neglected because of the emphasis on field- and farm-scale studies. Overall, the high expectations that were raised about the role and potential of agroforestry as a development vehicle have not been fulfilled. In order to overcome this, it is imperative that research be focused on the generation of appropriate, science-based technologies of wide applicability, especially under resource-poor conditions and in smallholder farming systems. Future research agendas should entail a judicious blending of science and technology. Applied research should build upon the findings of basic research to generate technologies for application at the farm, regional and global levels. Such research should place increased focus on previously neglected subjects, for example, the exploitation of indigenous fruit-producing trees, the agronomic components of agroforestry systems, and the global issues mentioned above. Furthermore, an appropriate methodology that embodies economic, social, and environmental costs and benefits needs to be developed to realistically assess the impacts of agroforestry, and an enabling policy environment that will facilitate agroforestry adoption needs to be made available. Agroforestry research of the 21st century should strive to build bridges from the inductive phase of the past, through the deductive phase of the present, to the future phase of harnessing science and generating technologies for the benefit of the land and its present and future users. This revised version was published online in June 2006 with corrections to the Cover Date.     

From research to communication in agroforestry: Some insights from the MAB Programme

Attempts within the Man and Biosphere (MAB) Programme of Unesco to produce research findings and information materials useful for education and training in agroforestry are outlined. Three different field projects — one in the humid tropics of Mexico, another in an urban situation in Papua New Guinea, the third in the arid zones of northern Kenya — provide examples of the types of educational materials and training activities that can be integrated within field research projects. Lessons learned in the preparation of a poster-exhibit ‘Ecology in Action’, and their possible relevance to the development of programmes in agroforestry education, are described.     

Virtual trees and light capture: a method for optimizing agroforestry stand design

In agroforestry systems, the distribution of light transmitted under tree canopies can be a limiting factor for the development of intercrops. The light available for intercrops depends on the quantity of light intercepted by tree canopies and, consequently, on the architecture of the tree species present. The influence of tree architecture on light transmission was analysed using dynamic 3D architectural models. The architectural analysis of Acacia mangium and Tectona grandis was performed in Indonesian agroforestry systems with trees aged from 1 to 3 years. 3D virtual trees were then generated with the AmapSim simulation software and 3D virtual experiments in which tree age, planting density, planting pattern and pruning intensity varied were reconstructed in order to simulate light available for the crop. Canopy closure of trees was more rapid in A. mangium than in T. grandis agroforestry systems; after 3 years the quantity of light available for A. mangium intercrops was three times lower than under T. grandis. Simulations with A. mangium showed that practices such as pruning and widening tree spacing enable to increase the total transmitted light within the stand. On T. grandis, modification of the tree row azimuth resulted in changes in the spatial and seasonal distribution of light available for the intercrops. These results are discussed in terms of agroforestry system management.

A knowledge-based expert system for planning and design of agroforestry systems

Computer-based Expert Systems that use knowledge, facts, and reasoning techniques to solve problems, normally requiring the abilities of human experts, are increasingly being used in many activities. The United Nations University (UNU) Agroforestry Expert System (AES) is a first attempt to apply this technique to agroforestry. UNU-AES is a prototype Knowledge-Based Expert System (KBES) designed to support land-use (agricultural, forestry, etc.) officials, research scientists, farmers, and individuals interested in maximizing benefits gained from applying agroforestry management techniques in developing countries. This prototype addresses the options for alley cropping, a promising agroforestry technology which has potential applicability when used under defined conditions in the tropics and subtropics. Alley cropping involves the planting of crops in alleys or interspaces between repeatedly pruned hedgerows of fast-growing, preferably leguminous, woody perennials. The primary benefits from this technique include nutrient enrichment, soil improvement, and erosion control. UNU-AES, which is the first known attempt at the application of expert system procedures in the field of agroforestry, uses a total of 235 decision rules to develop its recommendations. With the inclusion of more climatic and socio-economic data and improved advisory recommendations, UNU-AES can be expanded to provide advice on alley cropping in more diverse geographical and ecological conditions and eventually address other agroforestry techniques.     

Analysis and evaluation of agroforestry as an alternative environmental design in the Philippines

Tabora, Panfilo C. Analysis and evaluation of agroforestry as an alternative environmental design in the Philippines.Agroforestry as a land-use concept and an environmental design was analyzed and evaluated from the Philippines setting. A historical perspective of agroforestry was presented and the study explores the direction that agroforestry has taken in recent years as a socio-economic tool, a conservation strategy and a political expediency.The concepts of agroforestry were analyzed and used as the bases for evaluation. Five general socially-oriented concepts were examined: social relevance (appropriateness); profitability; balance (equilibrium); versatility and creativity; and longevity and reliability. These were related to five agroecosystem principles: ecological integrity; productivity; stability; flexibility and resiliency; and sustainability and conservation. All these were interrelated to many attributes under a unified Agroecosystem Analysis Framework.Seven current programs in the Philippines which promote agroforestry were also examined and evaluated based on the Agroecosystem Analysis Framework. A closer look at the impacts of the programs was done and ratings were given for each program. The Multiple Cropping Program and the Integrated Social Forestry Program came out with the most positive results.For a closer focus, a site was selected and five cases from the site were evaluated based on a reconstruction of the events and experience in the area over 14 years. The Mixed-Crops Agroforestry (representing the ideal agroforestry) came out with a rating equivalent to the Coconut and Abaca-based Agroforestry. The Industrial Tree Plantation came out with the lowest rating.The study concludes that agroforestry has a role as an environmental design, but that its usefulness has limitations due to some physical constraints and social and economic values that have to be overcome. Recommendations are provided for policy-making for agroforestry.Portion of a study submitted to the Graduate Faculty of the State University of New York College of Environmental Science & Forestry, May, 1986.Presently Leader of the Diversification Program of the Honduran Foundation for Agricultural Research.     

Wood-specific gravity and carbon proportion of multifunctional agroforestry trees in foothills of Nilgiris,Western Ghats,India

Agroforestry Systems - Agroforestry is identified as a potential carbon sequestration strategy, involved in carbon capture and storage in woody perennials. However, the use of default values of...     

Biological significance of RNA-seq and single-cell genomic research in woody plants

RNA-seq and single-cell genomic research emerge as an important research area in the recent years due to its ability to examine genetic information of any number of single cells in all living organisms.The knowledge gained from RNA-seq and single-cell genomic research will have a great impact in many aspects of plant biology.In this review,we summary and discuss the biological significance of RNA-seq and single-cell genomic research in plants including the single-cell DNA-sequencing,RNA-seq and single-cell RNA sequencing in woody plants,methods of RNA-seq and single-cell RNA-sequencing,single-cell RNA-sequencing for studying plant development,and single-cell RNA-sequencing for elucidating cell type composition.We will focus on RNA-seq and single-cell RNA sequencing in woody plants,understanding of plant development through single-cell RNAsequencing,and elucidation of cell type composition via single-cell RNA-sequencing.Information presented in this review will be helpful to increase our understanding of plant genomic research in a way with the power of plant single-cell RNA-sequencing analysis.     

High differentiation among populations of the woody legume Sesbania sesban in sub-Saharan Africa: Implications for conservation and cultivation during germplasm introduction into agroforestry systems

Cultivation of the woody legume Sesbania sesban in agroforestry systems has been widely promoted for soil fertility improvement in Africa. Despite the existence of natural populations in eastern Zambia, considerable seed originating from Kenya has been introduced to the area, while further introductions from Malawi are planned. Large-scale anthropogenic seed dispersal raises concerns regarding genetic management, which were addressed here by random amplified polymorphic DNA (RAPD) analysis. Eleven populations of Sesbania from southern and East Africa were assessed, including S. sesban populations already or likely to be introduced into eastern Zambia and reference taxa. Seventeen primers revealed a very large number of polymorphisms (538) in surveyed material. Differentiation among S. sesban populations was unusually high for a woody perennial (70% of variation among populations), with all individuals stringently assigned to specific populations in cluster analysis, even for geographically proximate sites. High differentiation, combined with the unusually large number of polymorphisms determined, resulted in the identification of a number of population-diagnostic markers. High differentiation may reflect the restricted ecology of S. sesban, human disturbance and frequent natural fluctuations in niche availability. Hydrochory, posited as a mechanism for gene flow between populations located along the same drainage system, appears to be discounted. Geographic proximity was not always a good guide for genetic similarity among S. sesban populations. In particular, rather proximate populations from Zambia and Malawi appeared highly differentiated genetically, while Zambian populations were relatively similar to a geographically distant population from Namibia. Differentiation was consistent with the presence of two botanic varieties in the southern Africa region, vars. nubica and zambesiaca. Estimates of Nei's genetic diversity suggested that S. sesban populations from East Africa were most diverse. Overall, population diversity estimates were low, possibly due in part to frequent bottlenecks, short longevity and a short juvenile phase. The unusually large number of polymorphisms detected here provided an opportunity to test for data redundancy and primer selection methodologies during RAPD analysis. Combined data from a subset of eight primers selected according to three different approaches provided a very good overall fit to the complete data set (r_M > 0.95). Different primer selection approaches influenced the reliability of clustering and diversity analysis, with a minimum of eight primers required for reliable ranking of diversity estimates. The implications of our data for conservation, cultivation and monitoring of S. sesban in the southern Africa region are discussed. Caution is advised during the introduction of germplasm into eastern Zambia from both distant (Kenya) and relatively proximate (Malawi) sources.     

Use of the iterative diagnosis and design approach in the development of suitable agroforestry systems for a target area

The process of iterative diagnosis and design with the active participation of farmers and extension agents was found effective in identifying appropriate agroforestry systems for farmers in the Bugesera and Gisaka-Migongo (BGM) regions of Rwanda. Periodic re-evaluation of research assumptions and technology designs was based on feedback from farmers and extentionists through regular visits to station trials, early initiation of on-farm testing, and interaction with farmer cooperators through informal discussions and formal surveys focused on specific agroforestry technologies. Statistical analysis is valuable for comparison between regions or periods. However, valid conclusions can be drawn without statistics, by employing several farmer-participatory approaches and pooling and properly interpreting the data obtained from them. Farmers' preferred uses of tree biomass in the BGM regions and appropriate agroforestry systems are discussed. If researchers and development agents do not consider the farmers' real needs, circumstances, available resources and management capacity with regard to tree planting, they will fail in identifying and extending suitable agroforestry systems for any region. This study was a part of the ISAR/IITA/World Bank FSR Project, implemented in the BGM regions of Rwanda during 1983–1988.     

Multipurpose tree yield data — their relevance to agroforestry research and development and the current state of knowledge

Agroforestry is not likely to be accepted, particularly by small-holders, unless it is proved superior to other forms of land use not only on ecological but also on economic grounds. It is therefore argued that economic parameters concerning the quantitative productivity of all agroforestry systems components have to be a matter of concern to both research and development in agroforestry.In the process of screening selected relevant literature and as a result of a search of ICRAF's Multipurpose Tree and Shrub Data Case, the yawning gap between the high level of knowledge on agricultural crops on the one hand and the low level on woody perennials on the other is exposed as a serious obstacle to the analysis of agroforestry systems and to the further development of agroforestry. The lack of knowledge on woody perennials, as substantiated in this paper, concerns particularly quantitative production data on trees and shrubs used in agroforestry systems.It is also argued in support of the views cited from other authors that what little there is by way of yield data on woody perennials is scattered and distributed over a vast amount of literature, and thus often difficult to access and to retrieve, and often difficult if not impossible to compare owing to different methods and parameters employed in attaining the data.Although the difficulties of yield assessment are appreciated, increased efforts to obtain more — and more comparable — data on te productivity of woody perennials are advocated. In support of this call for stepping up appropriate activities some preliminary suggestions are presented on how to standardize parameter of yield assessments to achieve better comparability and how to increase accessibility of yield data and promote retrieval of data by the establishment of supplementary data bases.     

Research methods for multistrata agroforestry systems with coffee and cacao: recommendations from two decades of research at CATIE

This paper reviews the research themes and methodologies used by CATIE in agroforestry research with shade trees over coffee (Coffea arabica) and cacao (Theobroma cacao) during the past 20 years. Initially research focused on characterization and production studies (of crop and timber including border areas) of traditional systems using temporary and permanent sample plots on private farms. The assessment area of traditional shade-coffee (or cacao) systems should be the whole plot, including the border areas, and not some subjectively selected central area which supposedly represents unit area productivity. Uncontrolled crop, tree, and management heterogeneity limited extrapolation of early on-farm research results to other farmers' fields. Replicated case studies of best bet technologies (traditional or experimental) on different farms are often preferable to the use of formal experimental designs. On-station research included the use of systematic spacing designs to test extreme shade tree density treatments of coffee. Most nutrient cycling studies were also carried out on-station, using service and timber shade species over coffee and cacao to evaluate the ability of these agroforestry systems to maintain nutrient reserves and diversify production. Plot size (even 36 × 36 m) was limiting for long term research because of inter-plot interference, both below- and above ground, when using fast growing, tall timber trees as shade. These experiences suggest a minimum plot size of 2,500 m². Individual tree designs and tree-crop interface studies (e.g. regression analysis of data taken along transects) are promising experimental/sampling approaches that need further development. The principal research thrusts proposed for the next five years are bio-physical process research on coffee responses to shade and competition with trees (growth, carbon allocation, phenology, disease-pest tolerance, yields and coffee quality effects) and socioeconomic analyses of both traditional and new or improved shade – coffee combinations vs. monocultures. This revised version was published online in June 2006 with corrections to the Cover Date.     

Adoption of agroforestry innovations in the tropics: A review

Agroforestry Systems - The period since the early 1990s has witnessed an explosion of research on the adoption of agroforestry innovations in the tropics. Much of this work was motivated by a...