New Zealand Journal of Forestry (1993) 38(2): 38–40
©New Zealand Institute of Forestry
How soon does regenerating scrub control erosion
D.O. Bergin , M.O. Kimberley and M. Marden
Surveys of damage caused by Cyclone Bola which struck the East Coast of the North Island, New Zealand in March 1988, indicated a strong relationship between vegetation cover and the degree of shallow landslipping on erosion-prone Tertiary hill country. An examination of the age, species composition and stand structure of manuka/kanuka dominated indigenous scrub was carried out. Young stands contained a mixture of manuka and kanuka, with kanuka becoming dominant in older stands. Compared with pasture, there was a 54% reduction in landslipping in fully-stocked eight-year-old scrub and a 91% decrease at 16 years. Under-stocked stands gave a somewhat lower level of protection. A substantial decrease in landslipping on steep erosion-prone hill country during major storms can therefore be expected within 10-15 years of establishment of indigenous scrub.
Keywords: indigenous scrub, Leptospermum scoparium, Kunzea ericoides, Cyclone Bola, landslides, East Coast.