Tree species richness and the logging of natural forests: A meta-analysis

Forests cover much of the earth’s surface and are regularly logged. Well established ecological theory predicts, and the results of extensive silvicultural studies demonstrate the role of disturbance in maintaining species richness in forests; however, logging and other human initiated disturbance is often credited with the degradation of forest ecosystems throughout the world. Presented here are the results of a meta-analysis of 19 published studies investigating 25 distinct paired human-disturbed and primary forests in the tropical and temperate biomes. Regardless of whether studies were grouped across biomes or considered independently, the current literature indicates a significant reduction in tree species richness following logging. While the reasons for this reduction in richness are as diverse as the forests considered here, some common themes are clear. Although logging may increase the richness of early successional tree species, it also tends to reduce the richness of late successional trees. This occurs both through the altering biotic and abiotic processes regulating resource availability and through size-class and species based selection biases common in logging. Logging also makes primary forests more accessible, setting the stage for a chronic human disturbance cycle.

► We conducted a meta-analysis of 25 logged vs. unlogged forests.
► We examine changes in tree species richness in tropical and temperate biomes.
► Results indicate a reduction in tree species richness following logging.
► Results were significant whether biomes were considered independently or pooled.