Several centuries for forest to regenerate

Press, 16 July 1987, Page 26

Several centuries for forest to regenerate

By

OLIVER RIDDELL

in Wellington Regeneration of the burned-over area of beech forest at Mount Thomas, in North Canterbury, will take several centuries, according to research done by the Ministry of Forestry. During the last 1000 years the beech forests of the relatively dry regions east of the Southern Alps have often been damaged by fire. Since 1970, there have been at least eight fires in the Canterbury beech forests alone. Seven of these have been small (less than 30ha), but the Mount Thomas fire of October 1980 burned about 300 ha

of native forest when a fire from nearby farmland spread. Most of the Mount Thomas forest was in mountain beech. The Ministry said beech forest regeneration after fire was very slow. Good seed crops were produced only every four to six years and the climatic conditions favourable for establishment did not necessarily follow a good seed year. Those seedlings which did become established were usually found within a 20m zone around forest edges. Further spread normally occurred only when this new growth was 20 to 30 years old and produced viable seed.

a trial had been conducted by the Ministry at Mount Thomas to see if forest recovery could be speeded up. Natural vegetation change after the fire was also studied. Five years after the fire it was evident that most of the burned-over area would develop into grassy clearings with a scattering of shrubs. Beech seedlings were rare and beech regeneration was occurring only around the edges of the surviving forest.

The trial did show that during the early post-fire phase establishing beech and other woody species by seeding was possible, and would greatly accelerate forest recovery.