Reforestation of Abandoned Pastures: Seed Ecology of Native Species and Production of Indigenous Plant Material

Abstract

Tropical forests are characterized by a high diversity of tree species together with a low abundance of individual species. This has far-reaching implications on strategies for a sustainable management and conservation of their genetic resources. Reforestation with native species is considered a preferable option for sustainable development, overcoming some of the ecological drawbacks of the earlier deforestation and concurrently contributing to the conservation of the region's biodiversity. Until the year 2000, 167 000 ha of plantations were successfully established in Ecuador (FAO 2003). Most of the plantation s, however, consist of introduced species , i.e. in the coastal region mainly Eucalyptus sp. and Tectona grandis , and in the Sierra mainly Eucalyptus sp., Cupressus sp. and Pinus sp. Because of ecological problems with these species, more emphasis is nowadays put on plantations with native species (Brandbyge and Holm-Nielsen 1986; Borja and Lasso 1990; Aguirre et al. 2002a, b; Leischner et al. 2004; Predesur 2004). However, lack of knowledge of the biology of the trees providing seed resources, e.g. their population densities and reproductive phenology , as well as of their germination physiology and the establishment of seedlings poses a severe challenge for any reforestation project. The permanent availability and supply of high-quality seed and plant material for any kind of planting activity (enrichment planting, reforestation, plantation establishment; see Chapter 34 in this volume) requires the establishment of production standards. To achieve such standards, the monitoring and approval of seed sources of priority species is essential, which is accomplished by seed certification and control of seed procurement. 433 Ecological Studies 198.