80 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
lands of small extent, where constant care can be given, it is not 
inapplicable to the regeneration of spruce woods. 
The four systems which have been described have this point in 
common, namely, that the seed is furnished by trees actually oceupy- 
ing the ground to be restocked. 
We shall now look for a little at the other division of the subject, 
namely, natural regeneration of a clear-felled area by means of seed 
furnished by trees situated to the side of that area. Here the seed 
is borne from the mother-trees to the clear-felled ground by the wind, 
or directed by the slanting course imparted to its fall by the wing 
with which many seeds are provided. It is therefore evident that 
the system is only applicable to cases where one has to deal with 
light or winged seeds, except where, as on the side of a declivity, the 
cleared area lies at a lower elevation than the mother-trees. In such 
a case even large and heavy seeds, such as beech nuts, acorns, and 
chestnuts, may, by rolling down hill, be disseminated for a con- 
siderable distance from the trees which produced them. As a 
matter of fact, however, this system is hardly ever practised, except 
in the case of woods consisting of pines, larch, firs, spruce, elms, 
birch, willows, and acers ; but in the case of these trees, if properly 
conducted, it yields satisfactory results. 
The first consideration must here be given to the direction from 
which the prevailing winds blow, so that the area to be sown shall 
lie on the lee-side of the mother-trees. A band of trees is cleared 
only during a seed year, and the felling, dragging, and carting of the 
timber over the bare ground is generally all the preparation which 
the surface requires. One band must be carefully regenerated before 
any more felling is done, otherwise an imperfectly stocked wood will 
be sure to result. 
When it has become evident that little more is to be hoped for 
from the self-sown seed, blanks are filled up by transplanting young 
trees with ball-roots from the denser parts. 
The breadth of the band varies with the height of the trees and 
with the species. In the case of the acers, ash, and silver fir, the 
breadth should not exceed about twice the height of the trees, with 
the spruce and Scots pine it may be as much as four times the height, 
while in the case of the larch, elm, willows, poplars, and birch it may 
be increased to eight times. 
Under this system the young trees are, from the first, placed in 
the possession of ample light, even though a dense wood lies to the 
south or west, and consequently it is specially applicable in the 
