Data from: Weak edge effects on trees in Bornean rainforest remnants bordering oil palm

Many tropical forests are dominated by edge habitat, with consequences for
forest structure, carbon stocks and biodiversity. However, edge effects
are highly variable and context-dependent, and are poorly quantified in
oil palm landscapes. We studied edge effects in 10 lowland rainforest
remnants bordering mature oil palm plantations on Borneo, by surveying 0.2
ha plots along transects running perpendicular to the forest edge (ten 1.6
km transects, 5-6 plots per transect; 57 plots in total). We examined how
edge proximity affected plot-level forest structure (canopy cover, number
and size of stems ⩾10 cm diameter), aboveground carbon stocks,
microclimate (air temperature and light intensity), and tree community
composition and richness. The largest trees were significantly smaller (up
to 21% reduced diameter) in plots near edges, and plot-level carbon was up
to 30% lower (model-fitted average = 64.7 Mg ha−1 at 50m from the
edge, versus 92.3 Mg ha−1 at 1600 m), with the strongest effects
within 300m of edges. However, these significant effects of edge proximity
were relatively small in the context of existing variation, with
distance-from-edge explaining <13% of the total variability in
maximum tree size or carbon. Additionally, there were generally no effects
of edge proximity on any other component of forest structure, composition
or diversity, and only a weak effect on microclimate. We conclude that
limited edge effects in this system may reflect low structural contrast
between forest and mature oil palm, and limited invasion of pioneer trees
from plantations, which diminished edge influence in highly heterogeneous
forest remnants.