Expanding opportunities for agroforestry education in the U.S. and Canadian universities

A telephone survey of 39 U.S. and Canadian University forestry schools accredited with the Society of American Foresters, conducted in November 1988, showed that 25 had courses in tropical and international forestry, and 14 university faculties had been conducting research in agroforestry. Field-oriented training in agroforestry is also offered in North America, especially for voluntary and relief organization personnel. Many of the agroforestry courses have been established recently in response to desires of students with international interests and/or experience. Most of such courses are integrated programs, initiated by forestry faculty, and most of these are seminars or colloquia incorporating the experience of both faculty and students with focus on systems and issues rather than technical proceses. Ideas for agroforestry course content offered by North American forestry faculty include: integration of social and technical aspects of agroforestry and social forestry, involvement of multidisciplinary teams, focus on managing marginal, lands and consideration of the importance of agroforestry systems in North America and other temperate zones.     

Comparisons of Mayan forest management, restoration, and conservation

Numerous communities associated with at least five distinct ethnic Mayan groups in southern Mexico and Central America continue to rely upon forested areas as integral components of their agricultural systems. They carefully manage these areas so that forests provide food, raw materials, and animals. Management practices include removing and planting of woody and herbaceous species, apiculture, and seed harvest. Mayan agroforestry systems in geographically and ecologically distinct areas of Mesoamerica were evaluated to better understand traditional agroforestry system components and how indigenous Mayan agroforestry could be a part of regional forest conservation and restoration. Systems were within Mexican land grant areas (ejidos) or on contested land. Although these systems rely upon different woody species and management techniques, common among them are: (1) the use of multi-stage and successional pathways with forest as a part of the larger system, (2) species that are believed by traditional ecological knowledge (TEK) to accelerate forest regeneration - more than 30 tree species are recognized and managed as potential facilitators of forest regeneration and (3) direct human consumption of forest products at all stages of regeneration.     

西双版纳现有混农林系统的主要模式

本文在对西双版纳现有混农林系统进行广泛调查的基础上,根据国际混农林研究委员会(ICRAF)P.K.R.Nair的分类方法,将其进行了分类和评价。结果表明,该地区现存混农林系统的模式极为丰富,并以经济植物为主体的模式占较大优势。这些模式,有的已经发挥出较好的生态、经济和社会效益,有的仍处于实验阶段,有的则对合理利用当地自然资源造成不良的影响。提出了必须合理开发利用当地自然资源,积极创立和引进以粮食作物为主体的混农林系统模式的见解。     

Reducing financial risk in agroforestry planning: a case study in Costa Rica

We used fluctuations in net income from alternative cropping systems to assess the financial risk associated with an agroforestry system. Mean-variance analysis was used to derive a set of minimum-risk farm plans for a 15-hectare farm in Costa Rica. Monocultural coffee production provided the highest expected net income, but also had the greatest economic risk. As risk was reduced, the optimal agroforestry system diversified to include other cropping systems in addition to the coffee monoculture. Risk aversion was, however, accompanied by significant reductions in expected net income for the cropping systems studied. The inclusion of additional cropping systems whose net incomes are negatively correlated with the systems considered here could help reduce the economic risk facing rural agriculturalists in this region.This research was supported by the Utah Agricultural Experiment Station, Utah State University, Logan, Utah 84322-4845. Approved as journal paper no. 4211.     

Combining the socio-economic-cultural implications of community owned agroforestry: The Winnebago Tribe of Nebraska

Agroforestry systems usually are examined for their biological components and somewhat for economic feasibility but rarely for their sociocultural merits. A relatively young agroforestry system was examined in view of sociocultural, biological, and economic factors through the use of decision matrices. Decision criteria were used to evaluate an agroforestry system against two alternative landuse options, a corn-soybean rotation and renting the land to an agricultural producer. Economic, sociocultural, environmental, and risk criteria were considered simultaneously with a scaled Z-statistic and then compared by using four weighting schemes. When all criteria were weighted equally, the agroforestry system had the greatest Z-score (3.4), indicating the better alternative. Placing weights on economic criteria resulted with renting the land being the best alternative (Z-score 6.6). When sociocultural factors were weighted alone, or when greater weights were placed on sociocultural factors along with moderate weights on economic and risk factors, or when community weighted objectives were used, the introduced agroforestry system had the greatest Z-scores (11.5, 6.3, and 1.1, respectively). Use of weighted decision criteria allowed for sensitivity analysis between alternatives to be explored. This is especially important when using techniques that have a greater emphasis on economic parameters that are not equally important or appropriate cross-culturally. Use of decision matrices provides a more comprehensive method for comparing the multiple, interactive, and long-term benefits of the agroforestry system and competing land uses. This revised version was published online in June 2006 with corrections to the Cover Date.     

The scope and potential of agroforestry in Central America

Although agroforestry practices have been used in Central America since pre-Columbian times, scientific initiatives in agroforestry began only about 15 years ago in this region. This paper describes the evolution of agroforestry in the Central American region, and discusses the relative merits of generating new procedures or encouraging traditional practices. This is followed by an analysis of several particularly promising practices—use of N-fixing trees to shade cacao and coffee, timber trees in pastures, and living fenceposts. Finally, a list of research gaps and recommendations for future efforts is presented. It is concluded that, from the perspective of scientific knowledge, agroforestry in Central America has taken off but the link between scientific knowledge and effective field application is still lacking.     

Agroforestry systems in China: a survey and classification

We classified agroforestry systems in China by system type and system unit. A system type is defined as a homogenous group whose major components are closely related economically, socially, and environmentally. A system unit is defined as a basic functional unit that reveals the specific biological relationships among the major components and requires similar management strategies and techniques. Seven system types and 26 system units are recognized in China. Among them, agrosilvofishery, silvomedicinal and agrosilvomedicinal systems have values unique to Chinese. Each system type is discussed in the context of its geographical extent in China, main species components, and system units.     

How to take advantage of a new crop? The experience of Melanesian smallholders

Coconut-based agroforestry systems have a central role in livelihoods on Malo Island in the South Pacific. These mixed plantations provide households with both food and a cash income, thanks to the association in space and time of root crops, vegetables, and cash crops (coconut, cocoa and vanilla). Vanilla has been developed on the island since the year 2000. Farmers have tried to adapt their production systems to include it, with some choosing to do so by associating vanilla with their main cash crop, coconut. A survey of these innovative practices and their economic results conducted in 2005 resulted in an economic modelling of this new agroforestry system with the software Olympe. This study illustrates the use of economic modelling with Olympe to simulate and test new agricultural practices in complex agroforestry systems. The software proved to suit agroforestry systems very well and provided useful information, particularly on economic aspects.     

Multipurpose leguminous trees and shrubs for agroforestry

These are various ways in which farmers deliberately incorporate trees and shrubs on farm production fields. Many of the species so incorporated are legumes. The role of such woody perennials in agroforestry systems can be productive and/or protective. Legumes offer by far the maximum range of choice of woody species for agroforestry in terms of their economic uses as well as ecological adaptibility. In addition to the several leguminous woody species that are well known in agroforestry, there are many more whose potentials have not yet been fully understood. An evaluation is presented of the agroforestry potentials of a few leguminous species from the point of view of their growth characteristics, ecological adaptability, combining ability with other species and uses/functions. The science of agroforestry is still in its infancy. There exists no research data on the various management aspects of these potentially promising group of plants. ICRAF, in its capacity as an international research council, has assembled several multipurpose leguminous trees and shrubs of agroforestry potential at the Council's recently-established Field Station in Machakos, Kenya, primarily for demonstration and training purposes. Initial results from these trials are presented in the paper.Adapted from a paper presented at the International Symposium on Nitrogen Fixing trees in the Tropics, 19–24 September, 1983 Rio-de-Janeiro, Brazil.     

Agroforestry: a profitable land use. An overview of the 12th North American Agroforestry Conference

This special issue features papers contributed by presenters at the 12th North American Agroforestry Conference held June 4–9, 2011 in Athens, Georgia, USA. The conference brought together agroforestry researchers, educators, practitioners, and students to highlight agroforestry research, implementation, policy, education, and entrepreneurial opportunities across North America. Eight papers cover topics ranging from adoption of silvopastoral systems across eco-regions and countries; economics of pine straw production; and timber and alley crop production in the Southeastern U.S.; reduction of sublimation of snow with shelterbelts in Canada, carbon offset incentives for agroforestry practices; consumer and market dynamics for chestnut and elderberry specialty crops; and web-based graduate degree and certificate programs in agroforestry.     

Modelling species and spacing effects on root zone water dynamics using Hydrus-2D in an Amazonian agroforestry system

Modelling the root zone water dynamics in a tree crop agroforestry system is a useful approach to understanding small-scale effects in tree crop systems and may be helpful for optimizing tree spacing in agroforestry system planning. The agroforestry system in this study consists of the species Theobroma grandiflorum (Willd ex Spreng) Schum (Cupuaçu), Bactris gasipaes H.B.K. (peach palm) and the cover crop Pueraria phaseoloides (Roxb.) Benth (Pueraria). The soiltype is an oxisol. Calibration was conducted for each of the three species separately. Calibration results show good conformity between simulated and measured data. Simulated scenarios examine the influence of different spacing between trees on root water uptake, evaporation and drainage. Mean interception and crop factors of the whole flow region vary with spacing or are held constant to examine below-ground effects only. Also a fictitious scenario of an older agroforestry system with deeper roots is calculated. In order to overcome restrictions of the computer program Hydrus-2D, correction factors in the root zone were introduced and a calculation scheme for root water uptake of a flow subregion was developped. Below-ground effects of spacing between trees are not or almost not present, but the depth of the tree roots has a significant influence on root water uptake, evaporation and drainage. When mean interception and crop factor vary, drainage increases and root water uptake decreases slightly with spacing. The modelling approach has been found promising for optimizing agroforestry systems although it can only be seen as a first beginning. In an agroforestry systems under drier conditions differences in results will probably be larger.     

Managing native and non-native plants in agroforestry systems

Indigenous knowledge has influenced native species selection in agroforestry systems worldwide. However, scientific advancements in plant sciences, agroforestry technologies and trade have accelerated species movements and establishment beyond their native range. Managing native and non-native species is an important area of research in agroforestry and this thematic issue includes 13 papers that cover a range of topics from the role of non-native species in agroforestry to management interventions to improve yield. As evident from these papers, non-native plants are still an important component of agroforestry in many parts of the world. Whether native or non-native, management interventions can increase the economic, environmental and social values of these species and that of agroforestry. Collectively, these papers attest to the increasing body of foundational knowledge in agroforestry.     

Agroforestry research in India: a brief review

India's long tradition of agroforestry has been influenced by numerous religious, social, and economic factors. Several indigenous agroforestry systems, based on peoples' needs and site-specific characteristics, have developed over the years. Agroforestry research was initiated in the country about two decades ago; since then, considerable progress has been achieved. The interactions between and among the tree, crop, grass, and animal components have been studied, and several agroforestry technologies have been developed and tried on farmers' lands. Agroforestry research is now conducted under the auspices of the All India Coordinated Agroforestry Research Project of the Indian Council of Agricultural Research at 31 centers distributed over India's tropical and temperate regions. In addition to research, the program includes agroforestry training of farmers, technicians, and scientists at 28 centers throughout the country. Expectations from agroforestry are high in India in both rural and urban areas; these expectations include production benefits that are in harmony with the ecology, environment, traditions, and heritage of the country.     

Planning optimal economic strategies for agroforestry systems

Design of agroforestry systems requires a land management planning process that clearly specifies wants, needs and objectives along with the land's suitability for potential agroforestry practices. Within this planning process economic analysis can be used to analyze agroforestry alternatives to help determine the proper system to apply. Specifically, production economics coupled with capital theory and valuation techniques can provide measures of economic performance in terms of present net values, benefit-cost ratios and internal rates of return. These economic performance measures can be used to determine the best joint production level for a particular agroforestry practice. Once these best combinations have been defined, linear programming can be applied using these best joint production combinations as decision variables along with considering a wide range of additional constraints and requirements. A hypothetical example is used to illustrate the planning process and how these economic tools can be combined as a package to help determine optimal agroforestry strategies.     

Organic carbon pools in a Luvisol under agroforestry and conventional farming systems in the semi-arid region of Ceará, Brazil

Many environmental benefits have been attributed to agroforestry systems in various ecosystems around the world. However, there is a limited amount of information to evaluate this agricultural system in the semi-arid region, specifically in the region of Ceará, Brazil. The objective of this work was to evaluate five agricultural (four agroforestry and one conventional) systems in order to test the hypothesis that the agroforestry systems promote an increase in the soil organic carbon stocks and organic carbon pools, thus improving soil quality. The following treatments were tested: agrosilvopasture (AGP), silvopasture (SILV), traditional agroforestry (TRAG), intensive cropping (IC), and native forest (NF). The soil samples were collected at four depths: 0–6, 6–12, 12–20 and 20–40 cm. Total soil organic carbon stocks and the organic carbon pools (microbial biomass-C, mineralizable-C, oxidizable-C, free, occluded light fraction organic matter, and C in the humic substances) were analyzed. After 5 years of experimental cultivation, the soil under the SILV system presented the best results for the attributes studied, preserving, and in some cases, improving these attributes, when compared to the other conditions. The traditional agroforestry system (TRAG) reduced total organic carbon stocks and, consequently, C in some organic matter compartments, indicating that the fallow period was not sufficient to maintain soil quality. The AGP and IC systems presented significant losses in some of the soil organic matter (SOM) pools, suggesting that the soil environment had been degraded. The most labile SOM components were considered sensitive indicators of change in the soil quality. The silvopasture system can, therefore, be recommended as an alternative soil management strategy for food production and for the maintenance of soil quality and agricultural sustainability in the semiarid region of Ceará state.     

东部黑核桃(Juglans.nigra)在美国的栽培利用概况

东部黑核桃(Juglans.nigra)在美国是一分布广泛、适应性强、经济价值很高的树种。黑核桃木材优良、果仁营养价值高,因此可果材兼用。文中简要介绍了黑核桃的生物学特性、面积、分布;木材生产、利用和出口;坚果生产和加工利用;黑核桃的科研及推广;黑核桃在农用林业中的应用等。     

The Bioeconomic Potential for Agroforestry in Australia’s Northern Grazing Systems

Although agriculture generates 16% of Australia’s greenhouse gas emissions, it also has the potential to sequester large quantities of emissions through land use management options such as agroforestry. Whilst there is an extensive amount of agroforestry literature, little has been written on the economic consequences of adopting silvopastoral systems in northern Australia. This paper reports the financial viability of adopting complementary agroforestry systems in the low rainfall region of northern Australia. The analysis incorporates the dynamic tradeoffs between tree and pasture growth, likely forest product yields, carbon sequestration and livestock methane emissions in a bioeconomic model. The results suggest there are financial benefits for landholders who integrate complementary agroforestry activities into existing grazing operations at even modest carbon prices.