184 GENERAL SUMMARY 
precocious in our climate, and late frosts take their toll of 
the young needles. South slopes of hills encourage early 
sprouting more than north slopes, but south slopes are 
not so injurious to the larch as frost hollows in which young 
larch often die outright as the result of late frosts. Next, 
the larch is extremely sensitive to shade, and whether we 
regard this as.an alpine characteristic or not, it is the 
feature which more than any other determines its sylvicul- 
tural treatment. Where grown pure the larch must be 
early and thoroughly thinned, and it is best to underplant 
it with shade bearers. When grown in mixture the other 
trees should be so chosen as to allow plenty of space for 
the larch crowns, and they should be soil-improving species, 
to compensate for the larch’s deficiency in this respect. 
The soil requirements of the larch are more physical than 
chemical, and good aeration is the most important con- 
sideration. The soil in which it is to be grown should have : 
(i) A deep, porous subsoil. 
(ii) A surface that does not cake, but allows at all times 
a free interchange of gases. 
(i) Unlike the spruce the larch has a tap-root, which, 
under favourable conditions, remains alive and penetrates 
the subsoil to a considerable depth. In addition to this, 
lateral roots send down ‘ anchor ’ roots, which not only fix 
the tree firmly in the ground, but maintain the requisite 
water-supply during a dry period. If the subsoil is hard 
or lacking in porosity these roots penetrate for -a short 
distance, but then languish and die, and, besides adversely 
affecting the general health of the trees, allow the entrance 
of the chief heart-rotting fungus, Fomes annosus. Tree 
growth is the chief agency in promoting subsoil porosity, 
and in old oak woods or beech woods little difficulty should 
be experienced in this respect. The subsoil of agricultural 
land, however, is nearly always inferior, and, where possible, 
larch should be avoided as a first rotation on such land. 
The roots of most coniferous crops suffer in the first rotation 
on agricultural land, and in Germany special commissions 
