92 AORIM OR TIMBER-GROWTH FIGURE. 
the tree-growing period averages some five months against about eight 
months in mid New Zealand. = 
(2.) Dr.* Henry, the premier English tree expert, describing the possj- 
bilities of the ‘“ New Forestry in the British Isles ”’ (Scotch-pine being 
replaced by better trees), estimated a general all-round acrim of 200, 
(3.) It has been announced that Jarrah, a tree growing so slowly that 
it cannot be profitably planted, will have at eighty years a Stand of 
8,000 c, ft. in cultivated Jarrah forest. (Forest Bill, Westralia; second- 
reading speech by Hon. Rh. T. Robinson.) This means an acrim the same 
as my estimated Kauri acrim—viz., 100 c. ft. 
In the plan for a normal Kauri forest sketched here the acrim, it 
is evident, will be low till the better growth produced by the foresters’ 
regeneration methods have taken effect, and the revenue will not be 
benefited till that timber is fit to cut. I will assume that a few years 
after regeneration there will be an acrim of 100 c. ft., and that this 
acrim will spread gradually over the whole forest as the present crop 
of timber is cut and the forest regenerated. Jt will be 100 years before 
the first of the regenerated Kauri is fit to cut; and if twenty years be 
taken to work through and regenerate the old virgin-forest timber, it will 
be 120 years from now before the improved regrowth forest is all fit to cut. 
In the meantime the fellings and revenue will only be from thinnings 
and from the mid-rotation Kauri reserved trees left over when cutting 
out the old timber of the virgin forest mentioned above. Then, from 
100 years the revenue will be rising rapidly as the first of the improved 
forest matures. 
As mentioned above, I assume for the normal Kauri forest, after 
the virgin-forest timber is cut, and during the 100 years of the “‘ transi- 
tion period ’”’ that must elapse before the regrowth timber matures, an 
average yield of 35 c. ft. q.g. of millable timber per acre per year— 
15 Kauri and 20 other. After that, 100 c. ft. q.g. Kauri per acre per 
year of millable timber, This 100 c. ft. q.g. is the normal yield. It 
will never be less than 100 and may rise gradually to 200. 
During the 100 years of the ‘‘ transition period’ there will be less 
than 35 ¢. ft. q.g. to cut at first, more afterwards. 
Forty Lean Yuars, wira Fat Years avr tue Eno. 
The 35 c. ft. acrim will be made up at first of light thinnings among 
the secondary species and some deferred regeneration fellings of the 
Kauri virgin forest. These at first will yield nothing like the 35 c. ft. 
per Acre per year, the average yield estimated for the whole period. 
This, in fact, will be the lean period in the working of every Kauri 
forest, just as seventy or a hundred years later there will be a fat 
period with a plethora of mature Kauri. It will be the business of the 
 working-plans”’ forest officer to so anticipate and ‘defer fellings that 
the yield will be more equalized, and with it, of course. the distribution 
of the age-classes. He can help the lean years by runnine some of the 
virgin-forest fellings into them ; he can help the plethora years by 
anticipating or deferring the felling of the 100-vears rotation : and in 
doing this he is helped by nature, for that is the time when Kauri 18 
growing rapidly and holding up its acrim against any rapid decline. 
In other words, there will be large supplies of Kauri timber on hand, 
and it will depend on the timber-market and on Government demands 
whether the timber is harvested twenty years sooner or forty years later. 
What the forester will be looking at will be a good distribution of age- 
* Courtesy title. 


