The basis for a computation of yearly weather patterns, tree-ring width and maximum density is provided by chronologies from a number of sites with oak, beech, fir and spruce: Chronologies of maximum density include several sites with fir and spruce, all in the temperate region of southern Central Europe, at elevations between 250 and 1600 in a.s.l. The range of chronologies includes all ecological sites in which the four species widely occur. A uniform statistical analysis of the chronologies allows synoptic evaluation of annual extreme values (pointer values) within an altitudinal gradient in relation to climatic factors. A phenological approach allows year-by-year comparison of similar patterns of extreme values with weather diagrams. Pointer value patterns are usually specific to tree-ring parameters or sometimes to species, sites or regions. The most influential factor for maximum density of latewood in conifers on sites above 500 in a.s.l. are the mean daily temperatures in summer. Therefore many pointer value patterns are similar over large areas. The effects of weather on tree-ring width are much more specific. Some growth patterns result from very cold periods in winter, some from low precipitation in early summer. The relationship between late frosts and growth patterns is detectable but often can not be verified due to lack of local meteorological data. This heterogeneity explains why ring width patterns do not cross date so well and why pointer value patterns of ring width usually occur only over quite small areas.
Extensive geographical pointer value patterns can only be explained climatologically under three assumptions: 1. That living trees have become very well adapted to their sites, all trees unable to adapt sufficiently being eliminated during stand development; 2. that their inter annual reactions are an expression of a deviation from mean climatological conditions at the specific sites and 3. that latewood tracheids in conifers live several months so that general weather patterns are expressed in pointer year patterns.