168 NATIVE FOREST AND PLANTATIONS OF INTRODUCED TREES. 
some £65 per acre; it will be at once objected that the plantations 
may yield two or three times as much timber per acre as the indigenous 
forests and in half the time. But this is a one-sided calculation if, with 
natural regeneration and a sprinkling of planted standards, from 
20 to 30 acres of wild forest can be put into good yielding condition 
for the cost, with interest (£65), of making 1 acre of plantation ! Why 
pull a house down when all it wants is some repairs? asks the prudent 
man ! 
It is difficult to say which may have the greatest value in fifty years— 
the forest put into order by funds from the sale of its mature timber and 
now growing up into a well-stocked forest fit to cut in another thirty 
or fifty years, with its natural regeneration certain; or the plantation 
with its doubtful natural regeneration and fivefold risk. Broadly 
speaking the matter should be presented more in this way : Every tree 
cut by foresters in the working of a forest is so much gain, every tree 
planted is so much cost piling up at interest to a ruinous figure 
where labour is as high as in New Zealand. When a forester thins 
a forest there is a double gain—the value of the timber from the 
trees that are thinned, and the increased increment put on by 
the remaining trees after thinning. If a dozen trees standing close 
together really want thinning, and if the forester takes out four 
of the most crowded, he gets the timber from his four trees, plus 
a better production of timber than he had before from the remaining 
eight trees. (See note on Trounson’s Kauri Park in ‘‘ Waipoua Kauri 
Forest.’’) 
Within very wide limits, an acre of ground covered with trees will 
have the same timber-production whether the acre has more or less trees 
on it. The first forest valuation survey I ever did was a good illustration 
of this. It was Blue-guin planting in southern India. The bulk of the 
forest was tall, straight, clean poles running some two thousand to the 
acre; but there was also a piece of poor, sparse planting with only about 
a hundred trees to the acre. Yet the yield of timber from the two was 
about the same: the difference lay in the quality of the timber. Sparse 
Blue-gum timber is often not worth the cost of felling and breaking up 
for firewood. 
FOREST OR GRASS. 
The point, discussed in the ‘‘ Balance-sheet of a Kauri Forest ’’ 
(p. 95), that it may cost about as much to destroy the native forest 
and put it under grass as to plant up the native forest to the extent 
required to give it a full stocking of good timber, shows that the choice. 
as a matter of national policy and production, is not between grassing 
and the present forest of New Zealand, with its partial timber stocking. 
but between the cultivated forest fully stocked with timber ana the same 
area grassed. 
Going a step further, there may be doubt about the permanency of 
the grassing; there is none about the permanency of the forest. There 
are lands where the grassing is easily permanent ; other lands where 
with every care, it dies out. Over large areas of what was once cond eras 
land on the fertile southern coast lands of South Africa the native 
grasses with sheep-grazing have died out and been replaced iy ** Rheno- 
sterbosch ’’ and other weeds, as has happened in many districts in New 
Zealand. But the forest, which has existed for geological time, will 
