68 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 
performed, in order that the trees which are left may develop new 
roots, and so gain stability sufficient to enable them to withstand 
the action of wind. 
In the early part of this preliminary stage, supposing it to embrace 
several years, the felling must not be so heavy as to cause inter- 
ruption to any considerable extent to the leafy canopy, for were such 
brought about, sufficient light would reach the ground to enable 
strong weeds to gain a footing which would make the surface very 
unsuitable for the reception of the seed, and, besides, owing to direct 
insolation and the entrance of drying winds, great loss of fertility 
would result. 
If the wood is rather thin, a proper advance felling may be 
altogether dispensed with. There is, however, one case in particular 
where very considerable felling is necessary, namely, in very dense 
woods of broad-leaved trees, especially beech. In such a case the 
ground is covered by a thick layer of humus, which is only partially 
decomposed. Such a covering would not interfere with the ger- 
mination of the seed, but would be apt to bring about the death of 
a large number of the seedlings during the first few weeks of their 
existence. This is due to the fact that a layer of raw humus is 
subject to great variations in the degree of moisture, so that, if the 
rootlets of the young plants ramify in this material alone, they are 
not so able to withstand any considerable spell of dry weather as 
they would be were they fixed in the mineral soil lying underneath. 
So long as the layer of leaves and twigs is shaded from the sun, 
sheltered from the wind, and protected from the rain by a dense 
mass of umbrage, decomposition goes on but slowly, especially on 
cold stiff soils; but the process may be much accelerated by the 
removal of a considerable number of trees, and the consequent 
admission of light, air, and rain. 
If the desired result is not attained by thinning alone, recourse 
must be had to the removal, by means of rakes, of part of the sur- 
face covering where densest, or the mineral soil may be stirred up 
and mixed with the raw humus by the aid of mattocks or heavy 
hoes. The former of these operations involves a cost of about 10s. 
per acre, the latter costing about twice as much, and both may 
generally in great part be avoided by bringing the wood into such a 
state that the natural processes of weathering can be utilised. If 
artificial aid must be adopted, it should not be put into force till 
there is an immediate prospect of seed being borne, for if some 
years elapse between the preparation of the soil and the seeding, 
