THE IMPORTANCE OF DENSITY IN SYLVICULTURE, 7 
Apart from the case of the Scots fir, the three degrees of 
thinning result in the production of almost exactly the same 
quantity of timber. A partial exception to this almost general 
statement is furnished by beech woods, which, according to 
investigations in Denmark, may, in favourable situations, be 
made to yield an increased quantity of timber if thinnings are 
begun strongly, though cautiously, at a comparatively early age. 
In the case of Scots fir woods, on the other hand, which, even 
without interference, become naturally so thin that the individual 
trees develop large crowns, the degree of thinning that is desig- 
nated “‘moderate” results in the production of the largest mass 
of timber. 
Apart, then, from the case of the Scots fir, and, under excep- 
tional cases, the beech, the selection of the degree of thinning is 
determined by other considerations than that of production of 
quantity, One object in view is the encouragement, by early 
moderate thinnings, of the development in youth of stems which 
will ultimately furnish high-class timber. At a later period, the 
woods should be managed in such a way that the timber produced 
shall be concentrated on comparatively few trees, and in this way 
we have increase both in value per unit and in mass; and the 
intermediate returns, in the shape of strong thinnings, tend to 
raise the financial returns from the area. 
Until quite a recent date erroneous ideas were also held 
regarding the influence of light-fellings. It was generally con- 
sidered that this system of thinning resulted in the production of 
a larger quantity of timber than could be got from a continuously 
close forest. The results of careful researches prove that if Scots 
fir woods are lightened, even at a very early age, the trees are not 
able to make any very considerable use of their opportunities. 
They also go to show that it is desirable to take steps at a 
moderate age to secure cleanness of bole and the conservation of 
soil fertility, and this is accomplished by the establishment of an 
underwood. 
Even in the case of such trees as the beech, which respond 
quickly and favourably to light-thinning, the results which have 
attended the investigations were somewhat unexpected. The 
smaller class of trees, with their poorly developed crowns, are not 
able to take advantage of the more favourable conditions that are 
offered to them, while the larger trees have already developed 
such good crowns in the close wood that the admission of a 
