Prices and tree planting on hillside farms in Palawan

agroforesteria agroforesterie agroforestry arbre arbre fruitier cropping systems decision making farm forestry farm size fruit trees mangifera indica mango mangoes mangue multipurpose trees oferta y demanda offre et demande precios prices prix sistemas de cultivo sloping land supply balance supply response taille de l'exploitation agricole terre en pente terreno en declive toma de decisiones trees