3rd February 2019

A national trout and rivers advocacy is concerned at adverse impacts by a pine forest monoculture on rivers, streams and their ecosystems.

Concern in Marlborough by the Marlborough Tramping Club about the high country spread of pine seedlings known as wilding pines and the question of the pine monocultures effect on river life, was supported by the Federation of Freshwater Anglers (NZFFA). Graham Carter president of NZFFA said the federation had long held deep concerns over the detrimental environmental effect of planting large scale pine plantations.

He pointed out that several years ago a NZ Federation of Freshwater Anglers (NZFFA) annual meeting, a paper on the subject was presented and adopted, detailing the adverse impact of forestry on stream and in particularly trout spawning streams.

“Pine trees use much more water than native trees so from the first stages of planting exotics, runoff is decreased and increasingly less water flows in streams. The adverse effect continues as pine plantations cause acidification of soils. Invertebrate aquatic insect larvae are greater numerically in alkaline waters(opposite of acidic) and provide food for both native and trout and salmon species. So acidic tending waters will carry less fish,” he said.

The practice of clear felling at logging harvest stage, often on steep slopes, exposed soil to rains with resultant heavy silting of streams which in turn smothered important native invertebrate larvae.

“In summary exotic plantations mean much less water flow, much less food for fish and destruction of the freshwater aquatic ecosystem,” said Graham Carter.

He said adverse impacts on rivers by development varied significantly from region to region. Fish and Game NZ has rightly highlighted the nitrate leaching and water abstraction for dairying, a major problem in many regions.

“This occurred particularly in low rainfall areas like Canterbury and the MacKenzie Basin where large scale corporate dairying interests were given an open door by the previous government, notably John Key, Steven Joyce and Nick Smith,” said Graham Carter.

NZFFA viewed with considerable apprehension, current Minister Shane Jones mega billion tree programme which inevitably would contain much exotic forestry. He said the Resource Management Act failed to protect the environment and had allowed dairying and forestry to have uncontrolled expansion.

Graham Carter said the silence from the Department of Conservation was of concern as native aquatic invertebrates were adversely affected while the silting of rivers was adverse to both trout and native fish. In some Marlborough valleys the department had done little or nothing to control the spread of wilding pines.

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