Ecology and management of South Island beech forests: Mammals and beech (Nothofagus) forests.
- Protection Forestry Division, Forest Research Institute, Rangiora.
At some time in the past almost of all of our beech (Nothofagus) forests have contained higher numbers of red deer (Cervus elaphus) than could be supported by the annual growth of palatable plants within browse range. During this period the natural balance of the forest understorey composition was upset by losses of seedlings and saplings of palatable plants, including the beeches. As long as seed sources of the palatable species are present the understorey composition tends to revert to the original situation whenever deer numbers are reduced. Additional growth of unpalatable or browse tolerant plants partly compensates for the losses, but the understorey still shows no real stability in composition even though deer have been present for over 50 years. Prediction of the future composition of the understorey while deer numbers continue to fluctuate is therefore difficult. It is easier to determine whether the present densities of deer are hindering the rate of forest regeneration. This work is one of the main tasks of the Watershed (condition and trend) Surveys made annually by the Forest Research Institute in important high country catchments. Over the past 17 years, 20 initial surveys have been completed, of which 11 have been resurveyed—some three times. The area of beech forest covered is approximately 900,000 ha. The results of individual surveys are available in several publications (Holloway 1963, Wardle 1967, 1970,1971 a&b, Wallis and James 1972), and in unpublished Forest Service reports.