THE FORMATION OF FORESTS 139 
be cheaply reaped in this way, and then one can plant 
whatever he pleases on the place it occupied. No 
special supervision is necessary. The work may be 
safely placed in the hands of a contractor. He can 
donoinjury. After the slash is removed, the forester 
may conduct his plantings. The soil is exposed to 
the action of sun and wind, and might in some in- 
stances be seriously damaged, especially if located on 
a steep mountain side, or in places where water or 
wind might do injury. Burning over the soil is often 
an advantage, especially in northern districts where 
duff often accumulates to such extent that it inter- 
feres with forest-growth. 
The successive cutting system is applicable only 
to pure even-aged forests, or in pure even-aged groups 
or clumps. When the forest approaches maturity, 
regeneration is effected by a series of carefully con- 
ducted cuttings. These must be begun in anticipation 
of a seed-crop, and the soil must be prepared in such a 
way that the seedlings may reach mineral soil. Large 
accumulations of humus are often a great hindrance 
to the application of this system in many northern 
districts. The system is similar to the common cus- 
tom of leaving seed trees, although the seed trees, 
in this case, are evenly distributed over the whole 
area. They are left also for the purpose of affording 
shelter to the young trees. As the young trees ap- 
