The challenge of HIV/AIDS: Where does agroforestry fit in? - World ...

98World Agroforestry into the Futuremanagement. For example, Ramadhani etal. (2002) found that 5-year-old woodlotsof Acacia crassicarpa in the Tabora districtof Tanzania produced five times as muchwood as mature ‘miombo’ woodlands.Simple calculations show that if all thewood needed for tobacco drying camefrom woodlots instead of the ‘miombo’,then 8 675 hectares of woodland would beconserved each year in the Tabora district.Govere (2002) attempted to test this substitutionhypothesis for the example of improvedfallows in eastern Zambia. His resultsare mixed: in one village the adoptersof improved fallows gathered less woodthan non-adopters; in another village adoptersand non-adopters gathered roughly thesame amount of wood.A study by Garrity et al. (2002) around theMount Kitanglad Range National Park inMindañao, the Philippines, provides supportfor a link between agroforestry and reducedpressure on protected areas. Farmersaround this area of high biodiversity wereeducated about the use of natural vegetativestrips to stabilize hillside farming areas,and improved germplasm and nurserytechniques to enhance on-farm productionof fruit and timber. The key institutionalinnovation was Landcare – farmer-ledknowledge-sharing organizations inspiredby the Landcare movement in Australia.After a number of years, this combinationof technical and institutional interventionsproduced positive impacts in terms of increasedmaize yields, greater density offruit and timber trees, reduced runoff anderosion, enhanced environmental awareness,reduced encroachments into the park,and restored stream corridor vegetation.By 2002 there were more than 800 householdsin Mindañao that belonged to villageLandcare chapters around the parkboundary.Another study of the buffer zone of theKerinci Seblat National Park, Indonesiahighlights the relationship between farmdiversification and reliance on adjacent nationalpark resources (Murniati et al. 2001).Comparing a sample of rice-only farms,mixed garden farms and a combination ofboth, the authors found that farms practisingboth rice growing and mixed gardeninghad 80 percent lower dependency on parkresources. Factors associated with a higherpropensity to extract from protected forestresources were low farm income and lowsupply of on-farm tree-based products,suggesting that agroforestry systems wereparticularly relevant in the buffer zones.ICRAF research around the Mabira ForestReserve in Uganda suggests that largerscale economic forces and forest policycan have greater impact on protected areasthan agroforestry and other developmentinterventions undertaken around them.While resource extraction by adjacentcommunities increased with proximity tothe forest, agroforesry in the buffer zonecould not have any significant impact onthe quantitatively far more significant pressuresoriginating from outside the bufferzone, particularly from fuelwood marketsfor sugar and tea processing, and for brickand charcoal making (Mrema et al. 2001a;2001b; 2001c; 2001d).Angelsen and Kaimowitz (2004) argue thatthe conservation benefits of agroforestryhave often been overstated, particularly inplaces where the forest frontier is still opento settlement and harvesting. Angelsen andKaimowitz (2004) and Tomich et al. (2001)point out there are likely to be trade-offsassociated with profitable agroforestry: onone hand, there will be pressure to convertprimary forest to profitable alternative landuses; on the other hand, degradation ofagroforestry systems may lead to conversionto less desirable land uses. A classiccase of these trade-offs is cocoa. Conversionof primary forest to cocoa productionhas been a major source of biodiversityloss in many parts of the humid tropics.However, compared to sun-grown cocoaor competing annual crops, shade-growncocoa agroforests retain much higher levelsof biodiversity (Donald 2004).3. Agroforestry and habitat for wildspeciesProposition: Agroforestry can createhabitat for wild species in landscapematrices surrounding forest conservationareas.The integration of trees into multiple-uselandscape matrices can contribute to wildbiodiversity through the maintenance oflandscape connectivity, heterogeneity andcomplexity of vegetation structure, integrityof aquatic systems, and cleaner water. Treescan contribute nesting sites, protectivecover against predators, access to breedingterritory, access to food sources in allseasons, and encourage beneficial speciessuch as pollinators. Evidence of the natureof these relationships has been generatedthrough a fairly large number of field studies,most of which have focused on birds.One caveat is that there have been limitedstudies to date on how the spatial configurationof trees on farms and in landscapesaffects the conservation of different types ofbiodiversity.Buck et al. (2004) reviewed 12 studies thatfound agroforestry systems to provide habitatfor diverse populations of birds, withthe greatest amount of evidence pointingtowards the habitat value of shade-grown