170 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
first quality for the Scots pine would be very much lower in the 
scale for the oak, and vice versa. It will thus be seen that soils 
are classed, apart from their general constitution, according to their 
situation and capacity for producing to perfection or otherwise one 
or more species of tree. The choice for one soil, therefore, may be 
limited to a single variety which would produce the desired result, 
and it would therefore be necessary to form a pure crop of it alone. 
Other soils, again, are capable of meeting the requirements of a 
variety of species, and it is here that some difficulty arises as to 
whether one or more should be chosen to form the crop. Probably 
in one locality it might be desirable, for financial reasons, to fix 
upon a pure crop, while in another, for a similar reason, a mixed 
one would be favoured. 
If one is to judge by the appearance of the crops, the German 
foresters seem to thoroughly understand this question, and to 
adapt the crop to the soil, and, unless something unforeseen occurs, 
each crop is of similar composition to its predecessor. 
On the Harz, pure woods of spruce form the prevailing crop, up 
to an elevation of 3300 feet. Above that level the ground becomes 
peaty and swampy, and the trees thinly scattered and stunted, and 
attain only the form of bushes. The greatest portion of the forest 
area is worked on the even-aged high forest system, with a rotation 
of 120 years. At the end of the rotation the trees stand about 
220 to the acre, and average something like 30 cubic feet each 
of clean measurable timber. Under this system, when clearing 
is commenced, a strip 30 to 40 yards in width, but which may be 
of any length, is cut on the east side, and each successive felling 
is made against the prevailing west wind. As felling is done 
in winter, the trees are cut level with the surface of the snow. 
Clearing, however, may start, simultaneously or in successive 
years, in the same way at various points about 1000 yards apart, 
so as to accelerate the work of regeneration, and at the same time 
obviate the denuding of too large an area in any part at one time, 
which would tend to deteriorate the soil by exposure to drying 
winds, and thus interfere with the growth of the young trees used 
in restocking the cleared section. When the wood, including top- 
wood, is removed from the ground, the roots are grubbed up and 
split into firewood. ‘The sum realised for the firewood obtained 
by this operation is about two-thirds less than the cost, but that 
apparent loss is counterbalanced by the absence of beetles, which 
would prey on the young plants used in restocking the cleared 
