Entomological and other factors in the ecology of a Pinus radiata plantation
- Forest Research Institute, Rotorua
Kaingaroa Forest contains approximately 115,000 acres of Pinus radiata D. Don. Of this acreage there are 15,000 acres on which the trees are so poor that the areas have been scheduled for conversion to other species. These trees are short and heavily branched and many have multiple leaders; these areas were mostly understocked in the early stages. The reasons for this condition are to be found in the climatic factors, such as frost and wind, and in the soil conditions, which result from the high elevation, climatic factors and poor drainage. These soil conditions were indicated in the original flora by the presence of Dracophyllum subulatum Hook f. The adverse site factors, particularly frost damage, predisposed the trees to attack by fungi such as Phomopsis strobi Syd. and Diplodia pinea (Desm.) Kickx. It might be possible to grow a commercially acceptable crop of P. radiata on these sites after they had been drained and treated with fertilisers so as to improve the soil and increase the frost hardiness of the trees. For a forester however it is easier to change the species than to modify the site.