Reforestation of Abandoned Pastures: Silvicultural Means to Accelerate Forest Recovery and Biodiversity

Background

Despite the 2736 native tree species in Ecuador, the majority of forestation activities in the country are based on exotic pines and eucalypts. In this book chapter, the authors describe the reason for this neglect being the lack of knowledge on the ecology and silvicultural treatment and the lack of nurseries growing these species.

Goals & Methods

The authors examine the reforestation of woody plants by both natural regeneration and plantation establishment. To evaluate the effects of distance to forest edges on natural regeneration the authors studied ten transects within a patch of an abandoned cattle pasture presently covered by secondary forest; diameter at breast height was measured in each transect. For plantations, the authors tested the suitability of five native species (Alnus acuminata, Cedrela cf montana, Heliocarpus americanus, Juglans neotropica, and Tabebuia crysantha) and two exotic species (Pinus patula and Eucalyptus saligna) to grow in recently abandoned pasture, abandoned pasture dominated with bracken fern, and abandoned pasture covered with shrubs. The exotic species exhibited high growth and survival.

Conclusions & Takeaways

For natural regeneration, the authors found that the abundance of anthropogenically valuable species was not common in natural regeneration plots, except some regeneration along the edge of the forest. They found that species diversity and abundance decreased with distance from forest edge and suggest that dispersal is limiting beyond 20m from the forest. With herbicide application, differences between species in biomass allocation were minimal, while in areas without herbicide, some trees (Tabebuia) invested more biomass in roots that others (Cedrela). The authors suggest that root competition is a factor in the allocation and early development of the trees. Overall, they suggest that native species can tolerate harsh conditions when planted in abandoned pasturelands, but in some cases the use of exotics as "nurse trees" may be valuable for the subsequent enrichment planting of natives.