SOIL EROSION

Evening Post, Volume CXXXII, Issue 42, 18 August 1941, Page 5

SOIL EROSION

LOGGING WORK

MISTAKEN IMPRESSION

UPLAND FORESTS

Reference is made by the Di- \ rector of Forestry (Mr. A. R. Entrican) in his annual report to one aspect of the soil-erosion movement which, he says, constitutes a serious threat to the success of the general forest policy and the future development of the sawmilling and allied forest industries. "As the more accessible forests - are logged and mills move further and further into the hinterland," he says, "ardent but unobserving conservationists clamour more and more for a halt to this movement and a lock-up-keep-out policy of reservation for the more inaccessible forests. Extremists have even advocated the limitation of milling operations to country below an "--"• altitude of 1000 feet above sea ■ . level." - ' i-.Mr. Entrican expresses the opinion ; that too often the effects of abnormal and seismological disturbances are mistaken for those of milling operations, and.that enthusiastic conservationists, when faced with overturned trees ; and recently-killed standing timber in the vicinity of mills, attribute the ' damage to logging operations. Today, - he says, with effective fire regulations and conhol, forest fires even in loggedover areas have been a rarity for 20 years. It really took an expert immediately after logging to distinguish even at a "remarkably short distance the actual logged area from the sur-j rounding untouched forest. Common sense would prevail if it was remembered that often not more than five and seldom more than 50 trees out of severel hundred were actually logged per acre. BENEFICIAL DESTRUCTION. "Of paramount importance," Mr. Entrican continues, "is public recognition of the fact that by far the bulk of the virgin forests are completely unproductive in that trees are overmature and that any new growth is more than offset by decay, but that the very logging operations and abnormal climatic and seismological disturbances which are of such concern to the conservationists actually create conditions favourable to the re-establishment of a new crop and thus restore the forest to some degree of true productivity. Recent outstanding instances are the 1937 gale which uprooted many trees in the southern half of the North Island and the 1939 saltladen winds which killed so many trees throughout the great part of the North | * Island. Much of the damage done by these winds has been wrongly attri- : touted to logging operations, and in quite a number of the affected forests a young growth of beech, white pine, j etc., now flourishes where windthrown trees originally exposed the mineral soil and seeded in a new tree crop. THE MAJOR OBJECTIVE. "Conservation as applied to forestry has been defined as the preservation of forests by wise use, and with counter-erosion and watershed values unimpaired and forests restored to productivity, logging of upland forests under forest service supervision constitutes both a logical and indispensable element in the national forest effort. Its real significance lies in the fact that the major objective of the forest policy—that of supplying the •" Dominion with the bulk of its timber requirements—can only be achieved by bringing every acre of forest land into maximum productivity and by having available the entire standing timber resources of the indigenovis forests, even if this ultimately involves regulation of cutting on private and other lands. "It is therefore in. a double sense that upland stands are referred to as protection forests, since the objective of their management is the protection both of their productivity and of their counter-erosion and watershed values as well, incidentally, as of their recreational facilities. Only by the integrated use of the upland forests for all purposes may the maximum economic and social values, both direct and indirect, be derived by the public. Extension of. the State forest estates to achieve this is a corollary." LAND BURNING. Later in his report, dealing with soil erosion, Mr. Entrican says that the forest service continues to advocate a realistic approach to the problem through Dominion-wide control of land-burndng operations. "No other measure," he adds, "can give such effective results either as quickly or as economically. A conservative estimate of its effectiveness is placed at 80 per cent, of the theoretical maximum. So aggressive is the New Zealand vegetation that no ground is too barren to resist its invasion—that is, if burning is controlled. Too often observation of erosion is limited to pastured slopes heavily scarred or even deeply gullied without realising that every forest-clad hillside bears scars and gullies, though many are so healed by the ever-invading vegetation as to defy casual detection. But whereas repeated and uncontrolled burning aggravates and perpetuates the one, controlled use of fire arrests and heals the other. Even much of the harmful effect attributable to overgrazing is a direct result of indiscriminate burning and would therefore be corrected by control of firing operations. Simple as the premise is, it provides the most practicable and economic method of preventing accelerated erosion."