292 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
to plough, or dig, or manure the forest, but by preserving a close 
canopy of foliage in the plantation, a natural substitute is pro- 
vided for the cultural operations mentioned. Natural pruning is 
more efficient and more economical than any scheme of artificial 
aid that can be devised. When trees are planted at 3 or 4 feet 
apart, all the lower branches, after they attain the length of 2 feet, 
begin to press upon one another, and check each other’s growth. 
Then when the branches above close, and exclude the light, the 
lower ones die and drop off before they grow to a size sufficient to 
occasion appreciable defects in the timber. This is the only prac- 
ticable system of pruning when dealing with plantations of large 
extent—say a thousand acres or more. 
In managing plantations for timber purposes, the thinnings 
should be so moderate as to ensure the fulfilment of the conditions 
above indicated. A definite rule cannot be laid down as to when 
thinning should commence. The condition of the plantation only 
can decide this. There is, of course, a danger of the trees being 
drawn up too much, and their stems becoming too long and bare of 
branches for their girth, but by cautious and timely thinning, this 
danger can easily be averted. The margins of the plantations 
should always be more severely thinned, in the early stages of 
growth, than the rest of the wood. This is necessary in order that 
the trees may become well branched and firmly rooted, so as to 
be able to resist the force of the storms which so frequently sweep 
across the country, and occasion so much damage to the woods. 
In the after management of the plantations, the margins should be 
left entirely undisturbed. 
