Simulation of succession in a neotropical forest: High selective logging intensities prolong the recovery times of ecosystem functions

Abstract

There is increasing concern, to what extent production forests in the Neotropics are sustainably managed. The implementation of effective forest management strategies that are ecologically beneficial plays thus a central role to prevent forest degradation. However, to identify effective forest management strategies, there is a need for methods supporting the decision-making process. The main objective of our study is to analyze the mid- and long-term impacts of different management intensities, such as varying the minimum stem diameter of harvestable commercial trees, on the dynamic and structure of a species-rich tropical lowland forest of French Guiana. Therefore, we have applied the management module of a dynamic forest model and analyzed simulation experiments for undisturbed forest growth and selective logging. For the first time we were able to quantify the mean recovery times of multiple ecosystem functions and properties (biomass, gross primary production, leaf area index, Shanon diversity, timber volume) after selective logging. Accordingly, we validated simulation results (biomass, number of trees harvested) of selective logging with forest inventory data from the last 32 years. The forest model reliably reproduces the observed pre-logging biomass, tree-size distribution, and logging intensity (10 trees/ha, 39 m(3)/ha). In addition, it became clear how strongly management with higher logging intensities influences the forest in the long term: (1) the mean recovery times of the investigated ecosystem functions were significantly extended. With very intensive logging (116 m(3)/ha), the average recovery time of forest biomass was almost twice as long as in a moderate simulation scenario (t(int) 138 a, t(mod) 77 a). Similar patterns were observed for other ecosystem functions, e.g. timber volume (t(int) 158 a, t(mod) 62 a). (2) Additionally, the functional composition shifted, as up to 30% pioneer tree species in particular invaded the forest. This innovative use of forest growth models may help in the development of ecologically reasonable forest management strategies.