An objective approach for classifying precipitation patterns to study climatic effects on tree growth

This study applied the simple, quantitative method of statistical cluster a nalysis to the task of objectively classifying precipitation patterns over northern California into paternally homogeneous regions. The statistical cl ustering results were then combined with geographical information to genera te regional precipitation indices and study the relationship between precip itation levels and tree growth over specific areas. Generating regional ind ices replaces the often-used practice of associating growth rates with prec ipitation data from a single, 'remote' weather station, a station located o utside the tree growth plot. Use of regional precipitation information gene rated in this manner can significantly improve the accuracy of growth predi ctions. (C) 2000 Elsevier Science B.V. All rights reserved.