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Climate variability in Tasmania based on dendroclimatic studies of Lagarostrobos Franklinii

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Buckley, BM (1997) Climate variability in Tasmania based on dendroclimatic studies of Lagarostrobos Franklinii. PhD thesis, University of Tasmania.

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Abstract

Four new Huon pine ring-width chronologies complete a seven-chronology
network from western Tasmania, and span an elevationial
range from 200 to 950 metres above sea level. The new chronologies are
from relict stands in the Frenchmans Cap area of western Tasmania, and
range from 451 to 1925 years in length. Two are from rare subalpine sites
above 800 metres, and two are from 550 and 700 metres, respectively. The
sample depth in the earliest portion of the 950 metre-high chronology
from Mt. Read, from which a 2792 year reconstruction of warm season
temperature was previously derived, is substantially improved through
the inclusion of several subfossil logs. The crossdating of ring sequences,
and the climatic responses of the three earlier chronologies is confirmed.
The chronology network enables a more complete analysis of Huon
pine's climatic response throughout much of its latitudinal and
elevational range. An improved temperature time-series (a composite of
9 coastal or near-coastal records surrounding Tasmania) is used for the
calibration and verification of the climate response. Response function
analyses clearly define the seasonal influence of temperature and
preciptiation on Huon pine growth. An elevation dependence of the
temperature response is revealed, reflecting the stratification of the
climate in mountainous western Tasmania. This vertical structure is due
to the effects of orographic uplift of westerly and southwesterly airflow,
combined with a persistent subsidence-inversion layer above 700 metres.
Apparent changes in the mean height of a persistent cloud zone (from
820 - 930 metres) are coincident with recent warming in the region. These
changes appear to be associated with a poleward migration of the mean
latitude of the Subtropical High Pressure Belt, and slackened zonal
circulation. New reconstructions of temperature help define the regional
extent of the climate signal from this region. Several unique qualities
make Huon pine a valuable resource for palaeoenvironmental research,
in particular the tremendous preservation properties of its wood which
can survive for many thousands of years. The abundance of subfossil
logs at most sites allows for great sample depth through time. Very long
ring sequences allow for the preservation of low-frequency signals in the
chronology indices, normally not afforded by dendroclimatological
reconstructions. Such low-frequency signals are critical for the detection
of natural climate variability on timescales of centuries to millennia, and
allow for a more accurate assessment of recent trends in regional climate.

Item Type: Thesis (PhD)
Copyright Holders: The Author
Copyright Information:

Copyright 1997 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).

Additional Information:

Analyses the ring sequences in Huon pines from relict stands in western Tasmania to determine climatic responses, and thence to reconstruct variability in climate on timescales of centuries to millennia. Library has additional copy on microfiche. Thesis (Ph.D.)--University of Tasmania, 1997. Includes bibliographical references. Analyses the ring sequences in Huon pines from relict stands in western Tasmania to determine climatic responses, and thence to reconstruct variability in climate on timescales of centuries to millennia

Date Deposited: 25 Nov 2014 00:47
Last Modified: 03 Jun 2016 01:48
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