Data and R code for “Individual-level variation in reproductive effort in chestnut oak (Quercus montana Willd.) and black oak (Q. velutina Lam.)”, Forest Ecology and Management, 2022

Masting is a population-level reproductive strategy, where
individuals synchronize large but intermittent seed production.
Despite the high degree of synchrony at the population level, there
can be considerable variation in reproduction among individuals
(intraspecific variation). Here, we use 18 years of acorn production
data from individual chestnut oak and black oak from control and
thinned stands, to understand what factors influence individual
differences in reproductive effort and variability. We included a
variety of tree-level measurements, environmental characteristics,
and measurements from tree cores to determine if certain
characteristics were associated variations in reproduction. We
considered both mean annual acorn production per m2 crown and
interannual variation in acorn production (CV) as response
variables. We also classified individuals as super producers (i.e.,
those that consistently produce more acorns than others), good, fair
and poor producers (i.e., those that consistently produce less or
have a higher number of failure years). In chestnut oak, 14% of the
individuals were classified as super producers and contributed 34%
of the total acorns, while poor producers made up 35% of the trees
and contributed only 16% to total acorn production. In black oak,
super producers (14% of the individuals) contributed 31% of total
acorns and poor producers (24% of the individuals) contributed only
9% of the acorns. Diameter at breast height (DBH) was the most
consistent variable for explaining intraspecific variation in
reproductive effort and variability (i.e., larger individuals had
higher mean acorn production for both chestnut oak and black oak,
and lower CV for black oak). Other variables that influenced
reproduction and variation included elevation and clay content for
chestnut oak, and slope for black oak. We found no significant
effect from the thinning treatment on acorn production. Our results
illustrate how tree-level and environmental characteristics can
distinguish acorn production groups, which can be used to inform
management and selective harvesting decisions.