840 THE DISPLACEMENT OF SPECIES IN NEW ZEALAND. 



being perhaps the most frequent ; next, the bracken ; more rarely, 

 Gleichenia circinuta. The hxttcr, however, is soon overpowered by 

 the former, and the entire area is quicldy covered with a luxuriant 

 growth of "aruhe," thus affording a suggestion as to the way in 

 which the wide fern-clad "pakihis" were originally formed and the 

 timber replaced by fern. But a more striking form of replacement 

 is often to be witnessed : a dense growth of the makomako [Aristo- 

 telia race III os(i) takes the place of the pines and broad-leaved trees 

 which have fallen under the axe. Not infrequently the makomako 

 forms a kiud of coppice, the dense growth killing off most of the 

 branches, so that the plants form long, straight rods ; the stronger 

 individuals, outgrowing the others, develop branches, and, being 

 thus enabled to assimilate a larger amount of nutritive matter, 

 become more robust, and, gaining complete mastery, prevent the 

 weaker from obtaining their fair portion of air and light, so that 

 at length they die out, leaving the more vigorous specimens to form 

 a makomako grove ; these repeat the process amongst themselves, 

 the weakest continually going to the wall, until the undergrowth 

 becomes more or less open, when various shrubs and trees make 

 their appearance, and a new piece of mixed forest replaces the 

 makomako, which has become comparatively rare. In many parts 

 of the Kaipara the first tree to make its appearance after a clearing 

 has been formed is the fuchsia [F. e.vcorticata), which often occurs 

 in vast abundance, to the exclusion of almost all other plants ; it 

 grows less rapidly, however, than the makomako, and is more 

 speedily interspersed with other shrubs and trees. Another plant 

 which often makes its appearance in large quantities after clearing 

 is the poroporo {Snhnmia aviculare), which is less permanent than 

 either of the preceding. In 18G4, owing to the Maoris having fired 

 upon our troops along the line of the Great South Road, between 

 Drury and the Waikato, the heavy forest on each side of the road 

 was felled for a width of about 2 chains and burnt off, when a 

 remarkably strong growth of poroporo sprang up, and for many 

 miles both sides of the road were bordered with this plant, which 

 in its turn afforded temporary shelter for many shrubs and young 

 trees, amongst which the totara was remarkably frequent. On the 

 west coast of the South Island, much of the lowland forest when 

 burnt off is temporarily replaced by a robust growth of a large 

 native groundsel [KrechUtes prcnanthoides), which often attains tlie 

 height of 5 ft., most of it, however, disappearing before the close of 

 the third year, when its place is taken by fern or, more rarely, by 

 shrubs and trees. When the road from Nelson to the BuUer was 

 formed through the Hope Valley, about 1870, the burnt area on 

 each side of the road-line was thickly dotted with the rare pine 

 I'odocarpus acutifuliiis, although very few specimens of the plant 

 were to be seen in the immediate vicinity, it is, however, already 

 overgrown by larger trees to a considerable extent, and affords an 

 instance of a phenomenon often observed by foresters in Europe, 

 where certain plants, as Fi/rola minor and F. rotundifulia, make 

 their appearance in forests which have recently been thinned, and, 

 after increasing for three or four years, gradually die out, to re- 



