CXX HENRIK HESSELMAN. 
but, of course, the burning always occasions a certain loss of nitrogen, which, 
however, if the ground is not too severely burnt, should soon be able to be 
made good. When the stand raised on the burnt ground has grown up, all 
nitrification ceases (see page cIv—CvV); and sometimes one gets the impression 
that, when about twenty years old, the stand slows down its rate of growth. 
The effect gained by burning is always transitory, of course; and as the 
same thing can be obtained by increased access of light alone, the burning 
is unnecessary. 
With regard to the danger which always exists of the ground being too 
severely burnt, and taking into consideration the other risks in burning, I 
consider that burning is objectionable on ground where the humus 
nitrogen is nitrified in any case. Burning there is a costlyland 
needless measure. 
For the practical forester, then, the question will be to judge whether the 
nitrogen is converted without burning on the areas he has under his care and 
management. One method of deciding this question is an examination of the 
humus-covering in the stand. The more mould-like this is, and the more it 
is formed of mosses and needle-refuse, the greater are the prospects that the 
humus nitrogen will be nitrified owing to the increased access of light caused 
by cutting. The ground-vegetation also gives him good and easily applicable 
guidance. If without burning such plants appear on the clearing as raspberry, 
Epilobium angustifolium, Galeopsis bifida, Senecio silvaticus, dandelions (Taraxa- 
cum officinale), Arenaria trinervia, wild strawberries, rather light-green forms of 
RKumex acetosella and such plants, then he can be sure that the humus nitro- 
gen is converted into a form favourable to the development of the 
young plants. The danger of the vegetation development just mentioned 
lies chiefly in the fact that it can often be so vigorous that it overpowers 
the young tree-plants. Whether a burning of areas of the kinds I here 
have in view can diminish this vegetation development, I do not know. 
I have not seen any cases which throw full light on this matter; but there 
would seem to be reason to consider that burning can very often posi- 
tively increase the disadvantage that is apt to be caused by a vigorous clearing- 
vegetation. 
Areas of the good quality that I have just described, are well suited for 
select cutting when we are concerned with regeneration. It is indispu- 
table, of course, that the selection system was first developed in areas where even 
gap-cutting produces a transformation of the humus covering that is favour- 
able for the germination and early development of the plants. In south Ger- 
many and in France, the real homes of a rational selection system, forest land 
has usually this favourable quality; and in their forests, with their mixture of 
of deciduous and coniferous trees, the formation of raw humus is rare. If one 
reads through a description of the forests in those districts where a rational selec- 
tion system has been practised, we find that the ground, so far as we can judge, 
must belong to the type where gap-cutting produces or increases the nitrification of 
the soil. The accounts of the nature of the ground are far from satisfactory, it is 
true; but from the wealth of the true leaf-trees that are usually found in these 
forests, one can indirectly, so to speak, infer the good quality of the humus- 
covering (see, for instance, ENGLER, 1905). My own experience of those woods 
tends in the same direction. Nor would it seem to be a mere coincidence 
