Titre :	Tree rings as indicators of climatic change and the potential response of forests to the Greenhouse effect
Type de document :	texte imprimé
Auteurs :	Edward R. Cook, Auteur
Editeur :	Chapman and Hall
Année de publication :	1991
Importance :	p 56-64
Langues :	Anglais (eng)
Résumé :	The boreal and eastern deciduous forest examples have provided insights into the large-scale background fluctuations of climate and tree growth that must be considered when searching for the occurrence of CO2-induced climatic change and its effect on forests. The boreal example shows that substantial , long-term changes in tree growth have occurred. These changes are believed to reflect long-term changes in surface air temperature. This complicates the statistical assessment of future changes in both instrumental temperature data and ring widths, making the identification of an anomalous greenhouse effect difficult . Given the high year-to-year persistence in boreal forest tree-rings seen in Fig 4.1B, an anomalous climatic effect on tree growth might have to last several years or decades before it emerges from the background variance and trend also exist in the hemispheric temperature data. However, it appears to be amplified in the boreal tree –ring series used here by the physiological processes of the trees. Yet given these problems, the temperature-sensitive nature of latitudinal and elevational timberline tree species still makes such sites highly appealing in the search for temperature-sensitive nature of latitudinal and elevational timberline tree species still makes such sites highly appealing in the search for temperature-related effects on tree growth. General circulation model estimates of regional climatic change are considered much more reliable for temperature than for precipitation. This means that there may be a reliable expectation of CO2-induced temperature change that can be used to predict the way in which boreal timberline trees will grow in the future. Thus, it may be possible to reduce the uncertainty in interpreting future ring-widths trends in the boreal forest. The eastern deciduous forest example indicates that past large-scale changes in climate and tree growth have been less extreme and persistent compared to the boreal example. Potentially, this makes the identification of CO2-induced climatic change and its effect on ring width easier to identify in this forest region because an unusual series of climatic events caused by greenhouse warming might emerge more quickly from the natural background variance.
Numéro du document :	A/MAC
Niveau Bibliographique :	2
Bull1 (Theme principale) :	METEOROLOGIE ,ATMOSPHERE,CLIMATOLOGIE
Bull2 (Theme secondaire) :	ATMOSPHERE,CLIMATOLOGIE-CONSIDERATION GENERALE

Tree rings as indicators of climatic change and the potential response of forests to the Greenhouse effect [texte imprimé] / Edward R. Cook, Auteur . - Chapman and Hall, 1991 . - p 56-64.
Langues : Anglais (eng)

Résumé :	The boreal and eastern deciduous forest examples have provided insights into the large-scale background fluctuations of climate and tree growth that must be considered when searching for the occurrence of CO2-induced climatic change and its effect on forests. The boreal example shows that substantial , long-term changes in tree growth have occurred. These changes are believed to reflect long-term changes in surface air temperature. This complicates the statistical assessment of future changes in both instrumental temperature data and ring widths, making the identification of an anomalous greenhouse effect difficult . Given the high year-to-year persistence in boreal forest tree-rings seen in Fig 4.1B, an anomalous climatic effect on tree growth might have to last several years or decades before it emerges from the background variance and trend also exist in the hemispheric temperature data. However, it appears to be amplified in the boreal tree –ring series used here by the physiological processes of the trees. Yet given these problems, the temperature-sensitive nature of latitudinal and elevational timberline tree species still makes such sites highly appealing in the search for temperature-sensitive nature of latitudinal and elevational timberline tree species still makes such sites highly appealing in the search for temperature-related effects on tree growth. General circulation model estimates of regional climatic change are considered much more reliable for temperature than for precipitation. This means that there may be a reliable expectation of CO2-induced temperature change that can be used to predict the way in which boreal timberline trees will grow in the future. Thus, it may be possible to reduce the uncertainty in interpreting future ring-widths trends in the boreal forest. The eastern deciduous forest example indicates that past large-scale changes in climate and tree growth have been less extreme and persistent compared to the boreal example. Potentially, this makes the identification of CO2-induced climatic change and its effect on ring width easier to identify in this forest region because an unusual series of climatic events caused by greenhouse warming might emerge more quickly from the natural background variance.
Numéro du document :	A/MAC
Niveau Bibliographique :	2
Bull1 (Theme principale) :	METEOROLOGIE ,ATMOSPHERE,CLIMATOLOGIE
Bull2 (Theme secondaire) :	ATMOSPHERE,CLIMATOLOGIE-CONSIDERATION GENERALE