54 J. H. MAIDEN. 
time for development; we might possibly pay a man for work of 
this kind when it would have been sounder policy to pay him the 
same sum for inaction. I hardly know a forestry operation 
requiring greater skill on the part of the overseer than that of 
thinning. Work of this kind can with difficulty be directed from 
a distance, and empiricism in dealing with a natural forest must 
be done away with as far as possible. If we had a natural forest 
on an absolutely level plain, with conditions of drainage every- 
where similar, soil and subsoil alike in every respect, the winds 
and moisture precisely similar in their effects over the entire area, 
then we could decree that the ultimate thinnings should leave 
the trees so many feet apart, which result could be attained either 
at once, or by so many intermediate thinnings. But such con- 
ditions nowhere exist, and each patch’ of forest requires the 
individual consideration of the operator. The local conditions 
require careful study in every instance, for the too abrupt 
alteration of the conditions under which a tree is living, by 
ill-advised clearing in its immediate vicinity, may do a tree harm 
rather than good, may retard its growth even if it does not induce 
actual disease. Oareless thinning may cause trees to be bark- 
bound, to send out lateral branches, instead of forming a straight 
bole free from knots, and may have injurious effects in other 
ways. Iam quite aware that it is difficult to secure the services 
of men who are capable of carrying out such work satisfactorily. 
Men should remember that the taking down of a number of trees 
in thinning operations is different in character to the removal of 
a number of stone or iron columns, and those entrusted with such 
operations must have a knowledge of the physiology of plant 
growth, and shrewd common sense to decide, under all the vary- 
ing conditions of a specific locality, what is the best action to take, 
—how to vary; in different parts of the same forest, the degree 
of thinning. 
One rule in forest-thinning should be borne in mind (i.¢., where 
merchantable timber and not merely aalaepe effects are in view) 
viz.,the necessity for keeping the g d shad h as possible, 
