t Projections of vegetation distribution that incorporate the transient responses of
vegetation to climate change are likely to be more efficacious than those that assume an
equilibrium between climate and vegetation. We examine the non-equilibrium dynamics of a
temperate forest region under historic and projected future climate change using the dynamic
ecosystem model LPJ-GUESS. We parameterized LPJ-GUESS for the New England region
of the United Sates utilizing eight forest cover types that comprise the regionally dominant
species. We developed a set of climate data at a monthly-step and a 30-arc second spatial
resolution to run the model. These datasets consist of past climate observations for the period
1901–2006 and three general circulation model projections for the period 2007–2099. Our
baseline (1971–2000) simulation reproduces the distribution of forest types in our study
region as compared to the National Land Cover Data 2001 (Kappa statistic00.54). Under
historic and nine future climate change scenarios, maple-beech-basswood, oaks and aspenbirch were modeled to move upslope at an estimated rate of 0.2, 0.3 and 0.5 myr−1
from 1901 to
2006, and continued this trend at an accelerated rate of around 0.5, 0.9 and 1.7 myr−1
from 2007
to 2099. Spruce-fir and white pine-cedar were modeled to contract to mountain ranges and
cooler regions of our study region under projected future climate change scenarios. By the end
of the 21st century, 60% of New England is projected to be dominated by oaks relative to 21% at
the beginning of the 21st century, while northern New England is modeled to be dominated by
aspen-birch. In mid and central New England, maple-beech-basswood, yellow birch-elm and
hickories co-occur and form novel species associations. In addition to warming-induced
northward and upslope shifts, climate change causes more complex changes in our simulations,
such as reversed conversions between forest types that currently share similar bioclimatic
ranges. These results underline the importance of considering community interactions and
transient dynamics in modeling studies of climate change impacts on forest ecosystems.