Tree-growth-climate relationships in subalpineNothofagusforests, South Island, New Zealand

Abstract

Detailed analyses of tree-growth-climate relationships in New Zealand trees using dendrochronological techniques are presented. Principal-components multiple-regression analysis (response function analysis) was used to assess the relationship between variations in annual growth ring widths of subalpine Nothofagus menziesii and N. solandri trees, and temperature and precipitation variables in the South Island of New Zealand. In calibrating the regression equations, approximately four times as much of the variance in the tree-ring chronologies was explained by climate variables, than by previous growth. Temperature during the austral summer months (December to March) was found to be the most strongly related to tree growth with increased growth occurring during growing seasons with warmer temperatures. This result is in close agreement with the findings of phenological studies of Nothofagus tree-growth.