66 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
be best protected by regenerating under overhead shade. This 
protection can be procured as well when the young generation is 
formed by artificial sowing or planting under a shelter wood, as 
when from self-sown seed, but if the trees which give the shelter 
can also yield the seed, it is a manifest advantage to utilise them 
in this way as well. To the two species just named may be 
added the spruce, which, on account of its shallow roots, is apt 
to perish on dry land during the first few years of its existence, 
unless the surface soil be kept sufficiently moist, and nothing 
conduces more to this end than the shading of the ground by 
overhead foliage, and the exclusion of drying winds. As we 
shall see afterwards, the natural regeneration of spruce woods is 
attended with great difficulty in windy regions, but where a 
locality is sheltered from violent gales the system may frequently 
be advantageously adopted. 
4. Where young trees are liable to be destroyed by insects, it 
has been found advantageous to rear them for some years under the 
shade of an older generation, for insects prove much less destructive 
under shade than on a cleared area. Here, again, the shading trees 
may also be the mother-trees, if no serious obstacles interpose to 
their being used as such; and the ravages of the cockchafer grub 
and the pine weevil may often in this way be successfully combated. 
Where any return can be got from the roots and stools, the 
practice of felling conifers by stubbing their roots is strongly to be 
recommended, as it is very effective in keeping down the increase of 
all sorts of destructive insects, and, at the same time, the ground is 
brought into a suitable state for the reception of the seed. 
5. Trees which grow well under the shade of others are much 
the most suitable for natural regeneration, and now the system is 
being more and more applied in their case alone. Such trees are 
known as shade-bearers, and include the silver fir, beech, spruce, 
lime, and one or two others of minor importance, notably the yew, 
which develops almost as rapidly under considerable shade as in an 
open situation. 
There are two distinct cases in which an area may be supplied 
with self-sown seed, and where consequently a system of natural 
reproduction may be put in force. The one is where the seed is 
furnished by trees (the shelter-wood) occupying the area to be 
restocked, and the other where the mother-trees stand at a greater 
or less distance from it. Inthe former case, the general conditions 
of the situation and the growth of the seedlings are influenced by 
