Trees thermometers

Tree Thermometers and Commodities Historic Climate Indicators... 

In four modern trees, we find that the carbon, hydrogen, and oxygen isotope ratios track the modern temperature records namely we find that trees are recording thermometers. 

Long term changes in precipitation, caused by changes in climatic temperature, are well documented in polar ice caps the heavier of the stable isotopes is depleted in ice laid down in the ice age by comparison with present day ice. In 1970 we extended this concept to trees, suggesting that they, also, are thermometers. Trees grow from water and atmospheric C02. In trees which grow on rain water, isotope variations in their rings should be climate indicators because the isotope composition in rain and C02 varies with temperature. 

For measurement of the oaks we used, per force, a mass spectrometer of somewhat low accuracy, and achieved the accuracy to demonstrate that trees are thermometers by making many measurements on each sample. On the tree sequences which we measured later, we used high precision spectrometers with accuracies of 0.1 parts per thousand (ppt) for 180/160 and 13C/12C, and 2 ppt for D/H. The measurements are expressed in terms of 8D and 6 g. 

If the stable isotope ratio of 13C/12C is to be further measured in tree rings and interpreted as an indicator of climate variation, (and we have barely begun to initiate its use as a thermometer in the present work, confining our measurements to the stable isotopes in water, because water is so abundant compared to carbon dioxide and because the dependence of its isotope ratios is relatively simple compared with those of carbon dioxide), some more sophisticated considerations must be given to the distribution of carbon dioxide among the reservoirs on the surface of the earth. 

Libby, L. M., Pandolfi, L. J., Calibration of Isotope Thermometers in and Oak Tree Using Official Weather Records, Colloques Internationaux du Centre National de la Recherche Scientifique, Gif-sur-Yvette, France, June, 1973. 

Tent caterpillars, 330,330 Baltimore orioles and, 7 Eastern, 330 Fagus and, 96 pruning and,431,432 on trees, shrubs, and vines, 236 Tetranychidae. See Spider mites Texas root rot, herbs and, 117 Thalictrum, 225 Thalictrum aquilegifolium, 225 Thermometer, 360 Thinning cut, 103 Thrips, 331,331... 

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