6.4 Improve Forestry and Agroforestry Systems as Providers of Multifunctionality
6.4.1 On-farm options
The ecological benefits of low-input agroforestry systems are more compatible with small-scale tropical/subtropical farming systems than for large farms. However, the coincidence of land degradation and poverty is also greatest in the tropics and subtropics and there is therefore considerable relevance of agroforestry for the attainment of development and sustainability goals. Disseminating and implementing a range of agroforestry practices, tailored to particular social and environmental conditions, on a wide scale will require large-scale investment in NARS, NARES, NGOs and CBOs, with support from ICRAF and regional agroforestry centers. Rehabilitation of degraded land and improving soil fertility can be accomplished by promoting a range of ecological/environmental services such as: (1) erosion control, (2) nutrient cycling, (3) protection of biodiversity in farming systems, (4) carbon sequestration, (5) promoting natural enemies of pests, weeds and diseases, (6) improving water availability, and (7) the restoration of agroecological function.
Agroforestry practices can also improve soil fertility in the future, which is crucial for achieving food security, human welfare and preserving the environment for smallholder farms (Sanchez, 2002; Oelberman et al., 2004; Schroth et al., 2004, Jiambo, 2006; Rasul and Thapa, 2006). An integrated soil fertility management approach that combines agroforestry technologies—especially improved fallows of leguminous species and biomass transfer—with locally available and reactive phosphate rock (e.g., Minjingu of northern Tanzania) can increase crop yields severalfold (Jama et al., 2006). Tree crops can be established within a land use mosaic to protect watersheds and reduce runoff of water and erosion restoring ecological processes as the above- and below-ground niches are filled by organisms that help to perform helpful functions such as cycle nutrients and water (Anderson and Sinclair, 1993), enrich organic matter, and sequester carbon. (Collins and Qualset, 1999; McNeely and Scherr, 2003; Schroth et al., 2004). Many of these niches can be filled by species producing useful and marketable food and nonfood products, increasing total productivity and economic value (Leakey, 2001ab; Leakey and Tchoundjeu, 2001). A healthier agroecosystem should require fewer purchased chemical inputs, while the diversity alleviates risks for small-scale farmers. On large mechanized farming systems the larger-scale ecological functions associated with a land use mosaic can be beneficial. As the science and practice of agroforestry are complex and comprise a range of disciplines, communities and institutions, strengthening strategic partnerships and alliances (farmers, national and international research organizations, government agencies, development organizations, NGOs, ICRAF, CIFOR, The Forest Dialogue, etc.) is crucial in order to foster the role of agroforestry in tackling future challenges. Local participation could be mobilized by incorporating traditional knowledge and innovations, as well as ensuring the scaling up and long-term sustainability of agroforestry. |
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Rights to land and trees tend to shape women's incentives and authority to adopt agroforestry technologies more than other crop varieties because of the relatively long time horizon between investment and returns (Gladwin et al., 2002). Agroforestry systems have high potential to help AKST achieve gender equity in property rights. This is especially true in customary African land tenure systems where planting or clearing trees is a means of establishing claims, on the trees, but also on the underlying land (Gari, 2002; Villarreal et al., 2006).
Reducing land degradation through agroforestry. Land degradation is caused by deforestation, erosion and salinization of drylands, agricultural expansion and abandonment, and urban expansion (Nelson, 2005). Data on the extent of land degradation are extremely limited and paradigms of desertification are changing (Herrmann and Hutchinson, 2005). Approximately 10% of the drylands are considered degraded, with the majority of these areas in Asia and Africa. In all regions more threatened by deforestation, like the humid tropics, Latin America, Southeast Asia, and Central Africa, deforestation is primarily the result of a combination of commercial wood extraction, permanent cultivation, livestock development, and the extension of overland transport infrastructure (Zhang et al., 2002; Vosti et al., 2003; Nelson, 2005). Decreasing current rates of deforestation could be achieved by promoting alternatives that contribute to forest conservation. Methods may include improving forest management through multiple-use policies in natural forests and plantations of economic (cash) trees within forests (Wenhua, 2004) off-farm employment (Mulley and Unruh, 2004); and implementing an industrial development model, based on high-value added products. Sustainable timber management implies ensuring forests continue to produce timber in long-term, while maintaining the full complement of environmental services and non-timber products of the forest. Although sustainable timber management sometimes provides reasonable rates of return, additional incentives are often needed as conventional timber harvesting is generally more profitable (Pearce and Mourato, 2004). Effective use of AKST supported by sustainable policy and legal systems and sufficient capacity is needed; the Chinese government's forest management plan implemented in 1998 offers a working example (Wenhua, 2004). However, local authorities are often inefficient in monitoring and enforcing environmental laws in large regions, as in Brazilian Amazonia where the construction of highways and the promotion of agriculture and cattle ranching facilitated the spread of deforestation. Off-farm employment can contribute significantly to forest conservation in the tropics, e.g., the tea industry in western Uganda (Mulley and Unruh, 2004).
6.4.2 Market mechanisms and incentives for agroforestry
Agroforestry is a method by which income can be generated by producing tree products for marketing as well as domestic use. There are many wild tree species that produce traditionally important food and nonfood products (e.g., Abbiw, 1990). These species can be domesticated to improve their quality and yield and to improve the unifor- |