DAMAGE TO PINUS RADIATA BY CLIMATIC AGENTS

SUMMARY From observations made, principally in the Australian Capital Territory, damage to Pinus radiata (Monterey pine) caused by various climatic agents is described. Low temperatures are considered to be responsible for needle discoloration in winter and dead tips and needles in certain cases in young trees, small frost cracks, frost rings and strangulation. Strangulation appears to be a peculiar extension of the same type of damage as that which results in frost rings. It often causes death of the bark and cambium in a girdle near the base of the trunk and is followed by symptoms of ringbarking and in many cases by the death of the tree. High temperatures are thought to cause sunscorch resulting at times in extensive lesions, while drought appears to be responsible for excessive casting of needles, and some dying in leading shoots. Hail and snow cause only minor damage in the areas in which Monterey pine has been planted in the Australian Capital Territory, but there is evidence to show that the speci...