Don Falk: Research Interests
Don Falk’s work focuses on three general areas: fire regimes,
disturbance interactions and
fire-climate relationships, and
restoration ecology. Most
fieldwork is conducted in western North
America, including ongoing programs in New Mexico and Arizona. New
initiatives include fire history and fire-climate analysis in the North
American Great Basin and the Sierra Madre of Mexico.
One set of questions addressed in Falk’s lab
revolves around the
mathematical foundations of fire
regime reconstruction and the
development of analytical tools for fire history (Falk &
Swetnam
2003, Falk 2004). A central case concerns the existence of scaling
relationships in fire regimes, a problem noticed by a number of
researchers but not previously studied systematically. We are also
working on the development of probability models for surface fire
regimes and mathematical theory for sample size analysis in fire
history. This model, based on discrete set theory, applies to
accumulating sets of experimental objects (such as fire-scarred trees)
and provides a basis for the common practice of creating composite fire
records in fire history research.
A new project funded by the JFSP will link fire
history, fire behavior,
and land management practices in forest-grassland ecotones of the
Valles Caldera National Preserve (VCNP), New Mexico. This project will
attempt to reconstruct the ecotonal fire regime using remnant tree-ring
evidence, and to infer spatial patterns of fire spread and climate
regulation. In addition to the VCNP, the USGS Jemez Mountains Field
Station is a central collaborator on this project.
A second emerging area of interest is in fire-climate relationships.
Collaborating with Dr. Swetnam, we use multivariate methods to
understand persistent cross-scale patterns of synchrony in fire regimes
of the western US. We are also taking preliminary steps for
meta-analysis of fire history and climate relationships using
distributed sampling designs that have been applied in a number of
locations. Collaborators include Rocky Mountain Tree-Ring Research, the
US Forest Service Fire Sciences Laboratory, Northern Arizona
University, and others.
In 2006 we initiated a program of fire history and
climate work in the North American Great Basin, the largest area of the
western United States lacking a basic network of fire history sites;
the region is also located pivotally with respect to the “dipole” of
the El Niño Southern Oscillation (ENSO) teleconnection in North
America. We are beginning fieldwork in 2007; collaborators include the
Bureau of Land Management and US Forest Service.
The Falk lab collaborates with Dr. Ann Lynch, US
Forest Service, Rocky Mountain Research Station (RMRS), to study
disturbance interactions in the Pinaleño Mountains, Arizona. The
Pinaleños are one of the highest “sky island” ranges, supporting
high-elevation spruce-fir forests as well as extensive areas of
mixed-conifer and other forest types. Our work combines reconstruction
of historical fires, insect outbreaks, tree demography, and the role of
climate variability in regulating short- and long-term forest dynamics.
Restoration ecology
is the third major area of focus in the Falk lab. A
key project during this period was a book addressing the theoretical
basis for the science of restoration ecology. Falk worked with
colleagues Joy Zedler (University of Wisconsin), Margaret Palmer
(University of Maryland), and more than 20 colleagues to assemble the
first book on this subject. Foundations of Restoration Ecology was
published by Island Press in 2006.
In the field, the Falk group has been working on
forest and fire regime restoration at the Monument Canyon, New Mexico
site since 2003. We have established a plot-based program to study
forest conditions, including annual monitoring of tree condition,
understory diversity, and other variables. The project thinned
approximately 230 ha in 2005-6, following a “process-centered
restoration” model designed collaboratively with the Santa Fe National
Forest (SFNF) (Falk 2006). We are also continuing a longitudinal study
of old-tree responses to drought and competition in collaboration with
the USGS Jemez Mountains Field Station, and a study of ecophysiological
response of old trees to competition and release in collaboration with
Los Alamos National Laboratory.
A new restoration project linking forest thinning,
fire behavior
models, ecophysiology, and restoration of the fire regime is starting
for the Sangre de Cristo Mountains, New Mexico. This project, also with
the SFNF, will use strategically-placed thinning treatments (“SPLATS”)
in heavily overgrown forest areas, followed by reintroduction of fire.
Our lab’s role includes monitoring of treatment effects on old trees,
as well as expanded fire history and post-treatment monitoring.
Organizations doing important work in biodiversity
conservation and ecological restoration:
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