CAUSES OF JUVENILE INSTABILITY OF PINUS RADIATA IN NEW ZEALAND

The effects of root configuration and soil cultivation on stability of juvenile Pinus radiata D. Don were studied in New Zealand plantations. Roots of toppled and stable trees were excavated, and morphological features of the two sets were assessed and analysed in pairs. It was concluded that straight-grained taproots and sinker roots reduced the likelihood of toppling. The amounts of toppling in seven cultivation trials were assessed between ages 1 and 5. Cultiva­ tion varied in its effect on toppling frequency, because of differences in tree