148 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY, 
and, per annum, 171 cubic feet and gt cubic feet respec 
tively. 
“ The volume of the average tree, in 1902, was :— 
Thinned wood — 722° 
I 
94 
Unthinned wood — 2394 — ‘g cubic feet. 
2540 
=, 3 cubic feet. 
° 
“Thus, while the volume per acre is almost doubled by the 
thinning, the volume of the average tree in the unthinned wood 
is only ;*,ths of that of the average tree in the thinned wood.” 
Now, what are the lessons to be learned from the above? 
The increase in volume of the ¢/izmned as compared with the 
unthinned wood is very striking, and some may be disposed to 
use this as an argument in favour of our own thinly stocked 
woods. But here they plant 8000 plants to the acre, while 
we sometimes plant as few as 2000, and we get therefore not 
stems, but scrub and branches. The great lesson for us, how- 
ever, is not to copy the methods adopted here, but rather to follow 
the principles in so far as they are compatible with common- 
sense and good management. 
It is dangerous and often impracticable to lay down hard and 
fast rules, but, in a general way, it may be said that no pure pine- 
woods should be planted at a greater distance apart than 3 feet 
(4840 plants per acre); that thinning should be deferred until 
height-growth has culminated; and that the final number of 
stems per acre should be in proportion to the size of the indi- 
vidual trees which the land will carry. 
On Friday, 18th August, we drove from Brussels to the forest 
of Soignes, which, in a general way, may be said to be a fine 
pure beech forest, thickly grown, and in many parts consisting of 
trees containing 100 cubic feet of timber on the average, and 70 
feet to the first branch (see Fig. 4). 
Here we were shown some interesting experiments in the 
thinning of beech-woods at thirty-eight years of age, and the 
effect of soil-protection on the crop. 
Various experiments had been made, but the underlying prin- 
ciple in all of them was the great advantage of creating a 
struggle for supremacy during the first thirty-eight years of 
growth, and then relieving the stronger trees. In the struggle 
the individual trees may be said to have reached three zones of 
