» § 
40 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
better-grown to remain as the young timber-crop. This would 
then, of course, have to be underplanted with whatever kind of 
shade-enduring tree local experience shows to be most suitable, 
and likely to be most profitable—just exactly as is done at 
Novar. 
But it is an entirely different matter when one deliberately, and 
of purpose aforethought, as we say in the North, forms, year by 
year, pure larch plantations at 34 feet by 34 feet, with 3556 
plants per acre, knowing quite well— and, indeed, expecting—that 
the vast majority of these are bound to become infected with the 
canker-producing fungus to such an extent as to plainly exhibit 
the outward and visible signs of this disease. Now we know, 
beyond all question of any doubt about the matter, that the 
formation of pure larch plantations is the surest way of exposing 
them to outbreaks of this disease; and, consequently, pure 
plantations must also be the most direct way of encouraging 
and fostering the fungus, and of enabling it to fructify and to 
disseminate its spores. 
I could point to larch plantations varying up to over thirty 
years of age, which I have recently visited in Worcestershire 
and Gloucestershire, and which were, up to within the last few 
years, remarkably free from canker; but, with the planting of 
larch almost pure, even in comparatively small plantations, the 
result has been a striking increase in the appearance of canker 
throughout the plantations made within the last fifteen years, as 
compared with those made from fifteen to thirty years ago. The 
local conditions are such that it seems to me warrantable to 
believe that the sources of infection have been spores from the 
older plantations, even though these were themselves not badly 
attacked by the fungus. And the risk of increase in cankerous 
attacks throughout new plantations must, in my opinion, be 
greater now than it was over fifteen years ago—while, of course, 
the danger of its occurrence in a permanent epidemic form must 
increase if large pure plantations be made. 
And yet the formation of large pure plantations is, we are told, 
precisely the step that Mr Munro Ferguson takes, apparently in 
the belief that it is the best means “of combating larch disease” :— 
“‘ He now plants pure larch woods, and when the trees are 16 to 20 years 
old he removes all the stems except the soundest and most promising, of which 
300 to 500are left peracre. Needless to say, the system is inapplicable to cases’ 
where all, or practically all, the trees are attacked by disease at this early stage, 
