Trade-offs at applying tree nucleation to restore degraded high Andean forests in Colombia

Background

This article recognizes applied nucleation as a forest restoration strategy in many low to mid altitude forests and aims to compare applied nucleation to passive regeneration at high altitude forests. Applied nucleation is successful at accelerating the speed of forest regeneration, improving soil conditions, and shading out invasive species in many low-mid altitude forests of the neotropics. There are gaps in the literature about the performance of applied nucleation in other tropical regions as well as high attitude tropical forests.

Research Goals and Methods

This study tests how applied nucleation efforts in experimental plots compare to those of passive regeneration. The plots are established in felled Pinus patula plantations within the Embalse del Neusa restoration park in the Colombian Andes. Altitude ranges from 3,000-3,060 meters. Planted seedlings consist of an external strip of early successional species with the internal core of the nuclei as mid-late successional species. Planted individuals as well as natural regeneration is measured over the course of 26 months to determine the effect of applied nucleation on tree coverage and height.

Conclusions and Takeaways

The impact of applied nucleation on vegetation structure matches that of the low-mid altitude tropical forests. The nuclei potentially benefit carbon storage and provide resources for fauna. Nuclei do not influence the prevalence of invasive species or species richness. This study recommends a combination of passive regeneration with applied nuclei to balance the multitude of restoration benefits that each one provides. It notes that density of tree plantings should be carefully considered as not to be too dense and create an overly competitive environment. This may be the case in this study that plantings are too dense and nucleation showed to inhibit tree growth at times. This study calls for additional longer-term studies in order to make more concrete conclusions about applied nucleation versus passive regeneration in high altitude forests.