Data from: Patterns of tree mortality in a temperate deciduous forest derived from a large forest dynamics plot

Tree mortality is one of the most influential drivers of forest dynamics,
and characterizing patterns of tree mortality is critical to understanding
forest dynamics and ecosystem function in the present era of global
change. Here, we use a unique data set of mortality in a temperate
deciduous forest to characterize rates and drivers of mortality. At the
25.6-ha Center for Tropical Forest Science—Forest Global Earth Observatory
forest dynamics plot at the Smithsonian Conservation Biology Institute
(Virginia, USA), we conducted two full tree censuses in 2008 and 2013 and
then tracked mortality over the next 2 years (2014 and 2015). Overall, the
mortality rate, m, of stems ≥10 cm diameter was 1.3–2.1%/yr. Biomass
mortality, M, was 1.9–3.4 Mg·ha−1·yr−1 at the stand level (0.6–1.1%/yr of
biomass), less than biomass gains from growth and recruitment, resulting
in net live biomass accumulation. Small stems died at the highest rate;
however, contributions to M increased toward larger size classes. Most
species had m < 2%/yr and M < 0.25 Mg·ha−1·yr−1
(<3%/yr of biomass), whereas two to four species had anomalously
high mortality rates during each census period, accounting for 15–24% of m
(n = 2, Cercis canadensis, Ulmus species) and 39–75% of M (n = 4 Quercus
species). Stems that died, whether or not in association with mechanical
damage, tended to grow more slowly in preceding years than surviving stems
and, for certain shade-intolerant species, tended to be in neighborhoods
with higher basal area. These findings show how relatively fine-scale
mortality processes contribute to stand-level compositional change and
carbon cycling. The mortality patterns reported here will provide a
valuable basis for understanding future disturbance events within eastern
deciduous forests and for comparing across forest types.