Data from: Field to a forest: patterns of forest recovery following shifting cultivation in the eastern Himalaya

The patterns of vegetation recovery in shifting cultivation landscapes
that undergo a cycle of clearing, cultivation and forest regeneration are
not well understood in Asian tropical forests. We determined forest
recovery patterns by comparing species composition, richness and forest
structure in early and late fallows formed following shifting cultivation
and in an uncut forest site in a mid-elevation subtropical forest in the
Indian Eastern Himalaya. We also examined changes in functional traits of
tree species to understand recovery processes with succession. Tree
species richness in the 12, 25 and 50-year old sites was 37%, 54% and 82%
the value of the richness in uncut forest, respectively, while basal area
was 33%, 25% and 41% of the value in uncut forest, respectively. Species
composition recovery, however, was low; with even the oldest fallow
(50-year fallow) being less than 50% similar to uncut forest in terms of
composition. Successional sites that recover over long periods may differ
compositionally from uncut forest within a shifting cultivation landscape
as these forests are often prone to other anthropogenic disturbances.
Functional trait analysis revealed that early fallows were colonized by
tree species that are animal-dispersed, insect-pollinated with small
fruits and seeds, whereas uncut forest and late successional forests were
dominated by species that were tall, self-dispersed, wind-pollinated and
of high wood density that are dominant mature forest species in the
Himalaya. These results are in contrast with the patterns in functional
traits of tree species in successional sites from the Neotropics. This
points to the importance of site-specificity in succession following
shifting cultivation.