 |
Forest responses to climate change
Tree species will shift their ranges in response to future climate change, but the mode and tempo of such
changes is largely speculative. The duration of migrational lags depends upon
dispersal rates, dispersal distances (existence of refugial or disjunct populations), and colonization success. We address
these biogeographical questions using a retrospective approach involving statistical treatment of pollen and
macrofossil data and quantitative climate reconstruction using a variety of paleoclimate proxies from lake sediments. |
 |
Scale-dependent
controls of disturbance regimes
The historical range of variability of
disturbance regimes is an important baseline to guide ecosystem
management and to aid studies of
ecosystem dynamics and species coexistence. For forest disturbances,
the observational
record does not adequately characterize this variability over time
spans
relevant to tree life cycles. Paleoecological methods, using proxy
evidence from lake sediment and soils, provide unique long-term data
for
reconstructing disturbance regimes. |
 |
Tree-ring
records of forest growth and disturbance dynamics
A persistent challenge to the study of
growth rates of tree species is attributing causal factors to long-term
growth trends. Factors affecting growth rates vary from simple
mechanisms such as stand dynamics and the natural growth trends of
trees, to insect outbreaks, soil nutrition, climate, and interactions
of all these factors.
» Interactive effects of insects, fire and climate on fuel loads and fire behavior in mixed conifer forest |
 |
Bioclimatic envelope modeling
A study of climatic controls on forest composition during the Holocene should begin with an assessment of the current
controls on species distribution. One way to study climatic controls of
species distribution is bioclimatic envelope modeling: the prediction
of species occurrence as a function of a small number of biologically meaningful
variables. |