THE DISPLACEMENT OF SPECIES IN NEW ZEALAND. 341 



appear after the next periodical thinning. Much, however, has yet 

 to be learned with regard to phenomena of this kind in New Zealand. 



Destruction of Kauri Forests. 



It is now proposed to trace the principal lines along which injury 

 has been done to the flora, and at the outset to glance at the agency 

 of man. So far as the necessary results of clearing land for culti- 

 vation are concerned, they are sufficiently obvious, and have already 

 been mentioned. But they are greatly aggravated and intensified 

 when attention is attracted to the economic value of certain timbers, 

 and the forest is felled at the demand of commerce : the giant 

 kauris, whose branches were waving high in the air long before the 

 civilization of the West was called into existence, are thrown down, 

 and these grand trees, the growth of many centuries, are in a brief 

 space made available for the thousand requirements of every-day 

 life. But before this has been done rolling-roads have been formed, 

 or tramways laid, involving the destruction of a vast amount of 

 arboreal growth, of elegant flowering shrubs, of fragrant orchids, of 

 delicate herbaceous plants, and of charming ferns, which never 

 again can beautify that scene ; for directly the last log has been 

 removed the intelligent bush-man, with a recklessness which would 

 be reprobated by a savage, applies a match to the dead branches, 

 for the mere pleasure of seeing the blaze, and not only destroys 

 thousands of promising young trees, but effectually prevents all 

 possibility of renewal, since the surface-soil, being charged with 

 resin, becomes so intensely heated that all fallen seeds are destroyed, 

 and the site of the forest becomes a desolation, Avhich, after a 

 short interval, is partially covered with an unattractive weedy 

 growth, the seeds of which have been introduced in the wool or 

 hair of animals, or the wings of birds, or blown by aerial currents, 

 after a time to be shghtly relieved by patches of bush-lawyer (Itubus 

 austmlis) or other uninviting plants. There is probably no greater 

 scene of desolation in the colony than the sites of the large kauri 

 forests in the Kaipara district and on the Cape Colville peninsula. 

 In cases like this the direct and intentional agency of man com- 

 presses into a brief space a far greater amount of destruction than 

 would be effected by natural agencies during many centuries. 



Injury caused by Cattle. 



Whenever cattle gain access to the forest they browse upon the 

 young shoots, while they consolidate the soil, thus preventing the 

 germination of seeds and consequent renewal ; this renders the atmo- 

 sphere dry, and eventually leads to the destruction of the older 

 trees, although no actual clearing may have been made by man. 



Next to man, however, the chief agents in this destructive work 

 are the sheep and the rabbits. Some districts are eaten almost 

 bare by these close feeders, little being left except the tough bases 

 of the silver-tussock [Poa caspitosa) and the wiry, ligneous stems of 

 Muhlenbeckia and similar plants ; even the woolly leaves of some 

 species of Celmisia are often closely cropped, the result being that 

 the more delicate plants are all but extirpated over large areas. 



