19

C.—B

CHAPTER IV.—RESEARCH AND EXPERIMENTS. ]. FOREST-MANAGEMENT. Forest-management—broadly defined as the application of forestry in the conduct of the business of forest-production —to be carried out in a definite and systematic manner requires an exact knowledge of the fundamental factors affecting the forest and the growing stock therein. Collection of data concerning growth and yield of exotic timbers established in the Dominion has made steady progress during the period under review, thirty-six yield tables covering seventeen species of conifers being constructed. Established plantations in the North Island have now reached the point where systematic control is possible. The detail inventory of the 8,500-acre Waiotapu Forest Plantation, embodying yield tables and volumes of timber by both diameter classes and species was completed, together with the field-work of a similar stock-taking of the 9,940-acre Whakarewarewa Plantation. Valuable data concerning adaptability, growth, and yield of naturalized timber-producing trees grown under forest conditions in New Zealand has been obtained from these investigations, which will be continued during the current year in other State plantations. Initial examinations preliminary to the establishment of planting working-plans were inaugurated during the year for the Riverhead, Kaingaroa, Wellington, Sounds, Nelson, North Canterbury, and Southland projects. An area of 4,000 acres, portion of the current season's planting programme at Haumer Springs, was mapped topographically, so that the lay-out of roads and fire-breaks, and the distribution of planting, could receive the necessary consideration. Topographical surveys of all areas to be planted during the 1927 season arc being executed during the current year. Exhaustive preliminary studies in the indigenous forest relating to the rate of growth of the important species of native taxads, totara, matai, silver-pine, miro, kaikawaka, were brought to completion. ■2. ECOLOGICAL RESEARCH. Tawa Forests. During the year 1925 26 Dr. L. Cockayne, F.R.S., Honorary Botanist to the State Forest Service, continued his investigations of the tawa (Beilschmiedia tawa) forest, studying such (I ) near Lake Rotoma, (2) in the Urewera country, (3) in the neighbourhood of Ohakune, (4) near Wellington, and (5) in Marlborough-N elson. The investigation —quite complex in character —is not yet complete, but it is hoped that sufficient knowledge of the subject will be acquired to enable a fairly full report to be furnished at the end of 1926. Up to the present the following facts, amongst others, have come to light: — (1.) That the tawa forest is a climax association following after that group of associations in which taxads, or even kauri, play a prominent part; (2.) That this final dominance of tawa is owing to that tree being essentially shade-tolerating, whereas taxads and kauri require far more light for their proper development; (3.) That, compared with Nothofagus, tawa is of slow growth, but in this respect, however, probably faster than most of the forest-trees, the kauri excepted ; (4.) That tawa forest left to itself will regenerate naturally into tawa ; (5.) That the undergrowth is usually too dense for the employment of rapidly growing exotic trees for restocking the forest, but that it may be possible, subject to future investigations, to use kauri for that purpose, while Nothofagus can certainly be established where the light is suitable. During the current year Dr. Cockayne will pay particular attention to the moss and liverwort (bryophyte) content of New Zealand forest in general, since these plants function as seed-beds and as recorders of climate, and an accurate knowledge of the species present in the associations is fundamental in forest classification. It is proposed to send specimens, of which a good many have already been procured, to British and American specialists for their determination—a necessary preliminary towards their ecological study from the standpoint of silviculture. 3. FOREST ECONOMIC RESEARCH. Ever-increasing values of forest-products and rapidly decreasing stocks of native timber demand careful investigation into the use of timber, its supply, and all other factors pertaining to its national economic status. Mr. F. E. Hutchinson, B.Sc.F., of the School of Forestry, Canterbury College, has undertaken such an investigation on behalf of the Forest Service, and completed " The Economic Forest Survey of Canterbury," Part I, which deals principally with the forest resources and the use of forest-produce in that province. The part received is splendidly written, contains a fund of valuable statistical data, and is illustrated by forty-three excellent full-plate photographs, together with a large number of graphs and maps. Building on the results of the investigations in Part I, a forest policy for Canterbury—a plan of future action having for its objective the satisfaction of the forest-produce requirements of the community —will be formulated by the Canterbury School of Forestry, and will comprise the second part of " The Economic Forest Survey of Canterbury."