C—3

destruction of the original forest by fire. The bulk of the regeneration is Pinus radiata, of which there are crops aged three, seven, and twelve years, but there is also a substantia area of Pinus pinaster, aged three years. Some eighty sub-plots have been laid out. 23. The sample plots mentioned in the last report, for investigation of the effects of thinning and pruning Pinus radiata at various seasons on the incidence of casualties from Sirex attack, were re-examined, but the mortality from all causes was small and did not vary significantly in relation to different treatments. Observations will continue. 24. Forest Soils.—Only a limited amount of advisory work on forest soils was possible. Assistance was given on the layout of experiments to study the effects of fertilizers on kauri seedlings in Waipoua Forest nursery, and to the Railway Forestry Officer in regard to experiments at Athenree where fairly severe needle fusion occurs on Pinus species. To study methods of remedying soil deficiencies experimental plots were laid out in naturally regenerated insignis pine at Eyrewell State Forest, Canterbury Conservancy. The trees in the plot were treated with one of the following trace elements : manganese, copper, zinc, or boron. As the district has a low rainfall and is stony, the trees in two additional plots were free from competition by other vegetation, and in addition one of these plots was given a dressing of superphosphate. From the data available to date, zinc sulphate has proved successful in stimulating extra growth on the short-needled and comparatively backward trees. It is still too early, however, to assess the true statistical or economic significance of the treatment. Applications of boron and potassium were made to sample plots in plantations of pines in Rotoehu Forest, Rotorua Conservancy, where excessive casualties in the first ten years were suspected to be due to soil deficiency. It is still too early to judge results, but mortality from the attacks of Sirex noctilio appears likely to vitiate the experiments as far as insignis pine is concerned. 25. Beech Forests. —Basic research and silvicultural investigations in the beech forests have proceeded steadily throughout the year. In broad terms the programme of work in hand may be broken down into the following problem groups : (a) Ecological studies concerned with the structure, distribution, origins, and trends of these forests, since it is only by the acquisition of a sound understanding of them that successful management for any desired purpose will prove possible : (b) The mapping and assessment of the forests through the national forest survey, in order to provide reliable data concerning the extent, condition, and quality of the forest estate : (c) The selection of forest areas of optimum potential for intensive sustained yield management for each of the timber-producing species concerned, having regard to questions of timber quality, growth rate, regeneration, prospective future demand, markets and transport, and the initiation of intensive management within these areas: (d) The development of improved techniques in the exploitation of beech forests not selected for intensive but for extensive management in order that, at least, they may be left in a better condition for growth than they were in their " wild " state ; and (e) Studies of the protection forests, particularly directed towards the elucidation of the real effects of exotic animals (deer, chamois, &c.) on the continued existence, well-being, and efficiency of these forests. 26. The field of investigation is very wide and many of the problems are complex, but real progress is being made particularly following recent improvements in the staff position. The number of qualified men available for the work is still, however, too small considering the importance, size, and wide geographical distribution of the beech forests, and in view of the very considerable physical labour involved in their survey and study. In illustration it might be mentioned that, during the year, field studies have been carried

32