Research Report from the Yale School Forests
Cross-examining White Pine History
vol. II, issue 1: February 2014
Research Highlights
• Eastern white pine shows adaptability in response to a wide
range of light and moisture environments
• Historic distribution of the eastern white pine in southern
New England was likely due to wide-ranging adaptability,
aided by human influence
S
cientists and historians have long known that the role
of eastern white pine, Pinus strobus L. in the pre-European forests of southern New England was very different than in today’s forests. However, the sources of
historical information leading to this conclusion are often difficult to compare and unexpected given tree traits
that could lead to such changes across the landscape
and through time. In his doctoral work at Yale F&ES,
Dr. Philip Marshall, PhD ’12 took a holistic approach
to compare the historical evidence of the ever-evolving
patterns in eastern white pine distribution in southern
New England. He analyzed which physical and biological traits might have given rise to these patterns.
Combining archival historical research, field investigations at the Yale-Myers Forest , and laboratory analysis, Marshall reconstructs patterns in the historical
trends of eastern white pine ecology. This examination
of distribution and ecological niche over time began by
testing its physiological characteristics and responses
to different light and moisture environments. Marshall
found a surprising degree of variability in seedling response to these tests.
This adaptability helps explain the unusually broad
ecological amplitude found in archival records of white
pines in the area, the second component of his research.
Marshall traces the earliest documentation of southern
New England’s forests via trees included as markers in
early land surveys. While not apparently a dominant
species, white pine was found in a surprising range of
locations at that time. He then used pollen-dating techniques to find clues as to how this early-successional species persisted in such a challenging range of conditions
in southern New England’s forests. Soil core samples
This pollen grain
of Pinus strobus L.
under 200x magnification shows
the air sacs on each
side, which are
necessary for the
wind pollination
of this species.
Photomicrograph by Philip
Marshall
Photo by Alex Barrett
provide information about forest species composition
via the relative proportions of pollen densities therein.
Marshall notes that this method may be biased, disproportionately representing wind-dispersers and wetland
communities. Nonetheless, pollen grains of pines were
dominant in these samples, suggesting a mostly stable
white pine population, at least in wet lowland sites.
Lastly, dendrochronology was used to test findings
of historical pine occurrence against the record found
in tree rings. Marshall’s analysis suggests that management by people, not natural ecological succession, was
responsible for most of the variation in tree growth and
development over the time period recorded in tree cores.
Marshall’s findings suggest that it is difficult to
pinpoint how the modern landscape-scale distribution
of white pine may differ from its historical distribution,
when considered from just one analysis approach alone.
He shows that examining the historic landscape using multiple analyses may yield more complete results.
While there is evidence of the continuous presence of
white pine on the landscape during the last 300 years, it
may have been more restricted to sites at extreme topographic positions such as wetlands and ridgetops.
The analysis in this study is particularly relevant
to the field of ecological restoration, which relies on
knowledge of the historical range of variability of an
ecosystem, in order to restore it to those conditions to
the extent possible.
Management Implications
• Multiple methods of gathering information about prior ecosystem conditions and historical range of variability are needed for management objectives such as ecological restoration
• Direct comparison of archival witness tree records with
modern species composition is useful in assessing impacts of
changes over time (e.g. human land management or climate)
For more information:
Visit the Yale School Forests page, environment.yale.edu/forests and click on Research.
Full citation: Marshall, Philip (2011) The historical and physiological ecology of eastern white pine (Pinus strobus L.) in northeast Connecticut, 1700-2000. Yale University.