274 Studies in Forestry [CHAP. xn. 



of humification of the dead foliage shed from the crop, and 

 consequently with the stimulation of the formation of fresh 

 nutrients within the soil. Thus, gradual natural regeneration 

 under parent standards, though perhaps merely in groups or 

 patches here and there, will prove much more prudent than 

 extensive clear-fellings laying bare large areas at one time ; 

 and this precaution is all the more necessary on steep and 

 on rocky slopes, where, in addition to the powerful inimical 

 influences of sun and wind, there also comes the mechanical 

 danger of the surface-soil being washed away by heavy rainfall. 



All of the above considerations, individually and collectively, 

 lead to the simple result that the fullest utilization of the 

 soil and the most effective safeguarding of its productivity 

 are obtainable by one and the same means, viz. by the continuous 

 protection of the soil through the maintenance of a good leaf- 

 canopy of normal moderate density^ and through the retention 

 of the soil-covering of dead foliage for the beneficial formation 

 of forest mould by the usual process of humification. Where the 

 timber-crops stand too thin, as seems to me the general fault 

 in British woods, the productive capacity of the soil is neither 

 utilized to its fullest extent for the formation of the longest and 

 straightest boles of timber, comparatively free from branches, 

 nor is it husbanded as it should be in accordance with the first 

 fundamental principle of Economy in general, and of Sylvicul- 

 ture in particular. Where, on the other hand, the timber-crops 

 are too thick or crowded, nutrients may be drawn in excessive 

 quantity from the soil, and squandered in the individual struggle 

 for existence, instead of being utilized to anything like the best 

 advantage in the more rapid development of the predominant 

 individual stems ; and at the same time the process of humifi- 

 cation of the dead foliage is interfered with. These dangers 

 are of course greatest on poor lands that are either too moist 

 or too dry. Just, in fact, where an admixture of humus is 

 most requisite, its formation is most difficult. 



A good canopy of foliage protects the soil from any excessive 



