A decade of diversity and forest structure: Post-logging patterns across life stages in an Afrotropical forest

Tropical forests are under threat of increasing pressure from
income-generating land uses. Selective logging is a compromise that allows
the use of the land while leaving much of the forest canopy intact across
a landscape. However, the ecological impacts of selective logging are
unclear, with evidence of positive, negative, and negligible effects on
forest structure and diversity. We examined the impact of selective
logging on the structure and diversity of evergreen tropical forests in
the Monts de Cristal region, a chain of mid-elevation hills in
northwestern Gabon. For three size classes (seedling, sapling, and adult)
of woody plant species, we tested whether forest structure (canopy
openness, stem density, basal area, and relative liana abundances) and
diversity were altered in forests that had been logged one year and ten
years prior, compared to unlogged forest. In general, we found no large
impact of selective logging treatment on the structure and diversity of
adult woody plant communities, but the seedling and sapling communities
were affected. Compared to unlogged forest, one-year post-logging forest
had greater variation in canopy openness and lower sapling stem density.
Ten-year post-logging forest had higher seedling and sapling species
evenness, higher sapling species diversity, and higher relative abundance
of sapling-sized lianas compared to unlogged forest. Our results show that
key differences between intact and selectively logged forests persist in
the understory at least a decade after logging. Overall, these results
contribute an additional data point in the literature on selective
logging, specifically representing the impacts of very low impact
selective logging in Central African forests. Our study highlights the
value of exploring selective logging impacts at multiple time periods of
recovery, and makes an important contribution to the knowledge of Central
African managed forests.