Il6 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



excessive crowding and the crop is a second one, it is very 

 common to come across single trees and groups of trees, 

 often beside old stumps, which have been blown over by the 

 wind, or laid by snow. The wind and snow, however, are 

 not the primary causes of the damage. It is due to the 

 decay of the roots from fungal attack. Douglas fir is especially 

 liable to such damage, and in nearly every instance a careful 

 inspection of the roots of a windfall will reveal the presence 

 of Fomes annosus fructifications. 



Attempts at eradication are hopeless in a growing wood. 

 With this particular species, prevention is better than cure. 

 The most obvious way of dealing with it lies in the proper 

 selection of species. Assuming that the above theory, that soil 

 acidity is the primary cause of the attack, is correct, it would 

 have an important bearing upon silvicultural practice. It 

 suggests the following general rules, which, however, would 

 necessarily have to be modified for economic reasons : — 



1. Always remove stumps and other dead material from an 



area before planting. 



2. Burn off bracken, heather, blaeberry, etc., from an area 



before planting. These plants tend to form an 

 accumulation of raw humus, especially on dry sandy 

 soils. 



3. Some test of the soil acidity should be made. If the soil 



is basic, neutral, or slightly acid, planting of conifers 

 could be safely carried out, with due regard to species. 

 Most, if not all of these soils will be found to be either 

 residual or of that type, and are well suited for larch, 

 Japanese larch, spruce, Douglas fir, and other species. 



4. If the soil is strongly acid, this may be due to excess of 



raw humus. It might be left for a number of years 

 to allow of decomposition of the humus. This state of 

 affairs is frequently the result of clear felling a wood 

 which has been grown as dense as possible. 



5. If the soil is naturally strongly acid and sour, such as usually 



exists over Boulder tills, either pure hardwood or a very 

 large percentage of hardwood, is probably best. It 

 would not be wrong, however, to substitute Scots pine, 

 which grows very well on some Boulder tills, while 

 certain firs, notably Abies grandts, give good promise 

 under these conditions. The neglect of hardwoods is 



