SOME SILVICULTURAL ASPECTS AND PROBLEMS OF THE SOIL. 47 



pastures in this country, and where possible at a low cost 

 might be used in the preparation of heather or even sphagnum 

 peat as forestable land ; probably Sitka spruce, which does 

 not seem so susceptible to excess water or unstable water 

 conditions would be the most suitable species for planting. 



Th«se are only a few of the more suggestive points out of 

 many to be deduced from Hesselman's investigations, which are 

 referred to as an example of the work being done and the 

 results which may be obtained from a scientific investigation 

 of soil conditions, and only one of the two papers have been 

 referred to. Much work is being done both in this country and 

 abroad, from which might be drawn deductions of similar 

 importance, but such work often suffers, from the forester's 

 point of view, in that it is not undertaken with a special 

 silvicultural bias, and is thus apt to be overlooked, while the 

 scientific basis of the soil problem as a whole, and the inter- 

 pretation of his own observations upon that scientific basis, are 

 seldom considered by the forester. 



Even a superficial glance at a climatic and vegetational map 

 at once indicates the close causal connection between water- 

 supply and forest distribution. Since rainfall affects the forest 

 principally through the medium of the soil, soil moisture 

 conditions, whether atmospheric or telluric in immediate source, 

 may therefore be at once considered the most important edaphic 

 factor in the distribution of species of trees throughout wide 

 areas. Local moisture variations must similarly play an 

 important part in local distribution within these limits, whether 

 these local variations are ultimately affected by rock stratifica- 

 tion, slope, or other physiographical factor, or soil structure, 

 available supply of nutrient salts or other edaphic factor. So 

 that in any survey of the distribution of species in an area like 

 the British Isles, with rapid geological and physiographical 

 variation, strong telluric water movements, and localised effect 

 of the processes of rock decay, the systematic study of soil 

 conditions in themselves must certainly become exceedingly 

 complex, and any work, to be of value in the deduction of the 

 specific likes and dislikes of forest trees, must be conducted 

 either under great variety of conditions, or must include the 

 determination of a large number of characters of the soil under 

 a more limited number of varying conditions. 



In illustration of the point Bulletin No. 3 of the Forestry 



