Reforestation with the Native Tree Alnus acuminata: Effects on Phytodiversity and Species Richness in an Upper Montane Rain Forest Area of Colombia

Background

This study takes place in the western cordillera in Colombia (Quindio). Upper montane forest is dominated by large Weinmannia (Alnus acuminata) plantations established from 1977-1978 on abandoned agricultural and grazing land (for erosion control), and secondary forest fragments that naturally colonized abandoned agricultural areas.

Research Goals & Methods

The author sampled ten 10mx10m plots in plantation, secondary, and primary forest. Secondary and plantation forest were 15 years old at the time of the study.

Conclusions & Takeaways

Secondary forest had greater tree species richness than the Alnus plantations but an average canopy of only 8-10m, whereas Alnus plantation had an average height of 20m. The author observes that while the plantation area contains similar species richness to the secondary forest, it contains low evenness of species (domination in the canopy by Alnus and in the understory by Bocconia frutescens). Importantly, the secondary forest included seedlings of the primary trees Weinmannia in the understory. (However, the study does not make any statistical tests to determine the significance of their findings.) The author suggests that the plantation area could be low in diversity due to the N-fixing nature of the Alnus and/or because of possible allelopathic behavior.