Climate-informed restoration: Contrasting growth and survival of white pine seedlings
from different source populations
Biology Department Seminar
Jordan S Mead, IBS Master’s Candidate
Anthropogenic climate change is causing extinction and range shifts across diverse taxa.
Species must either adapt in place, migrate to suitable climates or face local extinctions. For
long-lived species like forest trees, rapid migration is unlikely and many species will not be able
to migrate quickly enough to keep pace with changing climate. Furthermore, this long life
history, coupled with small population sizes and herbivory, hinder the ability of these
populations to adapt to current conditions. In order to mitigate the impacts of climate change on
forest ecosystems and forest tree populations, alternative management techniques have been
proposed. One such technique is assisted migration, where more southerly individuals are moved
north with the expectation that the more southern stock might be more productive as the climate
warms. Here, this technique is tested with three seed sources of eastern white pine (Pinus
strobus) planted at 20 sites in four forest types in northeastern Minnesota. White pine is wellsuited for this technique because its populations have been reduced by selective logging,
regeneration is hindered by herbivory from white tailed deer and its populations are expected to
increase with climate change. The two containerized MN seed zones (104 and 105) showed no
difference in survival over the two years following transplant. Growth for these two seed sources
was also equal in all forest types, expect the boreal mixed sites. This shows that MN 104 may be
partially adapted to cool conditions, but it can still maintain and even increase in growth in
warmer sites. The similar growth and survival patterns in MN 105 seedlings is evidence that both
of these MN seed sources can be planted in most sites with comparable success. Bare-root MI
seedlings did not perform as well as the local, bare-root MN 104 seedlings. MI seedlings were
much less likely to survive, despite growing much taller and slower than MN 104 planting stock.
Longer, warmer growing seasons in lower MI may be selecting for the accentuated growth and
delayed development of these seedlings. Overall, assisted migration had mixed results depending
on the distance the populations were moved and the type of planting stock used.