46 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



preparation, vrithout which conditions never rise above the 

 moor type. Such an area would be considered somewhat 

 unsuitable for spruce in this country, and in replanting the risks 

 from temporary summer drought, with accompanying insect 

 pests, would be so great that the area had best be left fallow 

 until the stumps ceased to render facilities for the breeding of 

 beetles. 



In this consideration of the effects of soil preparation on 

 natural regeneration, again correlated with improvement in 

 soil conditions, Hesselman mentions several conditions which 

 can be confirmed by observations in this country, such as 

 better growth round decayed stumps and rotten brush, which 

 are perhaps of less practical interest ; but of greater value are 

 his observations on the improvement obtained by artificially 

 "wounding" the soil, which might be (and is) duplicated in 

 this country by the herding of heavy cattle or pigs on a 

 regeneration area. The beneficial effects are not entirely due 

 to the burying of seeds in the soil, since soil improvement, as 

 evidenced by increased nitrification, also occurs. 



The effects of burning were also investigated with similar 

 results. Where burning has occurred regeneration has been 

 promoted, and for similar reasons growth after planting would 

 be promoted. Where light burning of heather has been carried 

 out in this country it is quite noticeable that regeneration is 

 improved, and there seems to be no reason why burning should 

 not be practised where possible as an operation preparatory to 

 planting. Heavy burning, however, whether of peat or of 

 grass, is totally to be avoided, as although small amounts of 

 ash improve the texture of the soil, heavy burning and the 

 production of much ash not only may remove the valuable 

 humus from the soil but produce a condition of peat somewhat 

 similar to the puddling of clay, and cause further deterioration 

 in the direction of sphagnum moor, through the incrustation of 

 the surface by an impermeable pan-like "muck." This fact 

 probably explains in part the opinion held against burning as 

 a preparatory operation. 



Another factor mentioned by Hesselman as producing nitri- 

 fication in peat is the flushing action of running water. Hill 

 streams running into or through peaty areas produce a distinct 

 improvement of soil reaction, the equivalent of drainage. This 

 fact has been utilised in the improvement of permanent hill 



