Data from: Interactions among trees: a key element in the stabilising effect of species diversity on forest growth

1.There is mounting evidence that species diversity increases the temporal
stability of forest growth. This stabilising effect of diversity has
mainly been attributed to species differences in their response to
fluctuating environmental conditions. Interactions among individuals could
also contribute to the stabilising effect of diversity by increasing the
mean and reducing the variance of tree growth, however, this has never
been directly demonstrated. 2.We used tree‐ring width chronologies from
temperate and boreal mixed stands of Eastern Canada to identify the role
of interactions among individuals in the stabilising effect of diversity
on forest growth. Using neighbourhood competition index and a mixed model
we compared the effect of interspecific and intraspecific interactions on
the mean and the variance of tree growth. 3.We found that interspecific
interactions are less detrimental to tree growth than intraspecific
interactions. We also found that interspecific interactions buffer tree
response to drought and thereby reduce the variance of tree growth. 4.Our
results indicate diversity may increase the mean and reduce the variance
of tree growth through interactions among individuals. Thus, we
demonstrate interactions among individuals play a role in the stabilising
effect of diversity on forest growth, and in doing so, we bring to light
other mechanisms of the insurance hypothesis.