| Summary
Fossil wood is abundant in many high-latitude sedimentary
sequences. It represents the remains of forest vegetation
that once thrived in polar regions in past greenhouse climates.
These forests occupied a unique ecological niche that has
no counterpart on Earth at present, but future global warming
may allow the spread of forests back into high latitudes once
more. Studies of the ancient forests help answer crucial questions
about the survival of polar trees, such as how they tolerated
the unusual polar light regime and whether leaf lifespan (evergreen
versus deciduous) was a critical adaptation for their survival.
The wood is a significant source of information about tree
types and forest composition, local and regional climates,
and environmental conditions within a growing season. Studies
have shown, for example, that productivity in past polar latitudes
as equal to, or exceeded, that in tropical regions today because
trees can successfully utilize long hours of sunlight during
the polar summer. Fossil tree ring studies have yielded critical
information about high latitude greenhouse climates from the
pattern of cells within growth rings.
Our research goals are to obtain quantitative climatic reconstructions,
from growth ring analyses of fossil woods, leaf life span
of the conifers, from morphological analyses of cells within
growth rings, and the reconstruction of palaeovegetation maps.
We will be looking at fossil woods from Australia, the Canadian
Arctic and Spitsbergen. The project will be to provide palaeoclimatic
and palaebiological information from the fossil record to
constrain the model simulations
of polar climates.
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This section
of fossil conifer wood from Cretaceous of the Antarctic
Peninsula, showing good preservation and well defined
tree rings.
(The round holes, filled with brown mudstone or white
crystals, were formed by wood-boring bivalves that bored
into the log while it was floating on the Cretaceous
seas as driftwood). |
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