Forest responses to climate change
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. Specific projects
under this theme include:
- The Clearwater Refugium of northern Idaho. Was this area of disjunctions and endemism in the "inland temperate rainforest"
established by long-distance dispersal from coastal populations or in situ persistence in refugia? Funding from the National Science Foundation.
- Fire-mediated forest compositional change in infrequent-fire ecosystems on the Olympic Peninsula, Washington State.
Forest disturbance regimes: a long-term perspective
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 provide unique long-term data
for reconstructing disturbance regimes.
- Precedent for fire in primary dipterocarp forests and forest peatlands of West Kalimantan, Indonesia, using radiocarbon dating of soil charcoal across several habitat types. Funding by the NSF.
- Climate Change, Fire History and Redwood Abundance across Space and Time. Methods focus on soil-charcoal dating in Humboldt County. Funding by the Bureau of Land Management.
- A research-coordination-network, the Novus RCN focuses on reconstructing ecosystem processes with respect to past disturbances. Led by Kendra McLauchlan at Kansas State University.
- Mountain pine beetle outbreaks linked to forest governance and climate change. Co-PI on an NSF Coupled Human and Natural Systems grant.
- Erosion history and variability:
- Other projects and collaborations:
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.