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2 - DATA ANALYSIS
- Edited by M. K. Hughes, P. M. Kelly, J. R. Pilcher, V. C. LaMarche, Jr.
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- Book:
- Climate from Tree Rings
- Published online:
- 05 October 2010
- Print publication:
- 17 June 1982, pp 32-77
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Summary
INTRODUCTION
The Editors
In the previous chapter, various methods of enhancing the climate signal in tree-ring chronologies have been mentioned. In order to reconstruct climate, it is necessary to extract this signal – to separate climatic factors from the many other environmental variables limiting the plant processes which control growth. The climate-growth response is complex, and reliable theoretical models have yet to be developed. Semi-empirical techniques have, therefore, been developed in order to extract the climate signal. Response functions are used to describe associations between climate data and annual ring measurements. Transfer functions are used to calibrate the ring measurements with climate data in order to provide regression equations for climate reconstruction. Both techniques employ multivariate statistical methods such as principal component or eigenvector analysis and canonical correlation and regression.
The response of the growth of trees to climate and other environmental factors is discussed by Fritts. He highlights the need for semi-empirical techniques to define and extract the macroclimatic signal from tree-ring chronologies. The response function provides an empirical method of describing the nature of the climatic factors that influence tree growth. As Hughes and Milsom point out, the response function does not measure the climategrowth response but rather the effectiveness of a particular statistical model at predicting the element of tree-ring variation forced by external factors. The response function has proved to be a valuable tool for analysing the climate-growth relationship. Guiot, Berger and Munaut review various methods of calculating response functions.
5 - CLIMATE RECONSTRUCTIONS
- Edited by M. K. Hughes, P. M. Kelly, J. R. Pilcher, V. C. LaMarche, Jr.
-
- Book:
- Climate from Tree Rings
- Published online:
- 05 October 2010
- Print publication:
- 17 June 1982, pp 159-198
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- Chapter
- Export citation
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Summary
INTRODUCTION
The Editors
The aim of dendroclimatology is to extract the climate signal in the annual rings of trees and use it to provide a proxy record of climate for times and places where the instrumental record is absent or inadequate. These proxy records are used to produce reconstructions of one or more climate variables in the time, frequency, and sometimes the spatial domains. Reconstructions from tree rings are of potential value in four main fields. First, they may be used to provide an extended climate data base to be used in the testing of models of climate. Second, they may provide a longer and more representative data base for the calculation of climate and climate-related statistics. Third, they may provide detailed descriptions of climate in distant periods which may be used as analogues of possible future changes in climate. Fourth, they may be used in the verification of other proxy records of climate, including historical (or documentary) data, for pre-instrumental times.
The bases of the methods currently available for the preparation and testing of climate reconstructions from tree rings have been discussed in Chapters 1 and 2 of this book, whilst the existing data base, and the potential for its improvement, has been described in Chapters 3 and 4. In order that the reader may see the potential of dendroclimatology, short accounts of a number of dendroclimatic reconstructions are brought together in this chapter.