Tree dating activity
The meristematic activity of the traumatic phellogens increases with tree age until a maximum is attained and decreases afterwards.In the case shown the maximum was obtained in the 6th periderm, corresponding to a tree age of approximately 90 years.) represent an important source of paleoclimate information, in some instances with very fine resolution, for example, major atmospheric disturbances (Miller et al., 2006).This approach has been utilized successfully by Parrish and Spicer in their work on Late Cretaceous floras from the North Slope of Alaska (Parrish and Spicer, 1988; Spicer and Parrish, 1990).More recently, Taylor and Ryberg (2007) have examined tree rings in Permian and Triassic woods from Antarctica.
Students can also infer similar information by using various wooden objects.
Once these corrections are made, recent variations in ring widths are correlated with recent climatic measurements, and inferences are made by extrapolation of older ring chronologies to climatic variation in the distant past ( attempted to extend tree-ring analyses to whole forests of Douglas-fir in the Pacific Northwest and concluded that, once climatic variation was accounted for, no additional response could be found in relation to rising atmospheric CO demonstrated the ability of a process model, FOREST-BGC, to achieve improved accuracy over conventional statistical analyses by predicting annual variation in growth recorded in a 50-year dendrochronological record extracted from pine trees in Montana ().
To take account of likely continual changes in atmospheric composition, it is almost a requirement that more sophisticated analyses be developed to interpret dendrochronological records. The discovery that sapwood converts to heartwood after a fixed number of years allows a retrospective analysis of tree leaf area, which together with stem diameter growth provides a reconstruction of individual tree and stand growth efficiencies backward in time.
The aspects of cork productivity are discussed in more detail in .
In the usual exploitation practice, the cork is extracted from the tree stem around June or July.