68 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



slow-growing species may reduce resistance to disease, hence, 

 in the opinion of the author, it appears desirable to restrict 

 this species to the higher elevations and less sheltered 

 positions. A considerable degree of shelter is necessary, and, 

 provided that is available, larch will give satisfactory results at 

 elevations up to 1500-2000 feet above sea-level, or 500-1000 

 feet above the bottoms of valleys, e.g. in Upper Deeside and 

 Strathdon. This species does not suffer excessively from late 

 frosts. Larch is not a suitable species on peat or peaty soils. 

 To summarise briefly, larch is a suitable species on fertile, well- 

 drained but well-watered sandy loams at the higher elevations 

 {i.e. 300 feet upwards above the bottom of valleys), with a fair 

 degree of shelter. 



Although this species has been grown in this country for a 

 long period, few naturally-regenerated woods exist. There is a 

 very interesting young natural larch wood on Tominourd Hill, 

 Strathspey. The previous crop was a mixture of larch and 

 Scots pine. The larch regenerated itself first, and portions of 

 the hill are covered with pure larch. Where there are gaps 

 these are filling in naturally with Scots pine. This order might 

 be explained by the relative abundance of seed immediately 

 before and during the period of regeneration. The only 

 drawback in this case is that the crop has come up too 

 densely. 



In the formation of larch plantations, the most important 

 principle is to avoid over-crowding. When a species regenerates 

 itself too densely, or is planted too closely, the canopy closes in 

 a few years. If the height-growth is rapid, as in the case of 

 larch, the struggle for existence becomes too severe unless a 

 very early thinning is made. Such an excessive struggle for 

 existence tends to weaken the whole crop, increases its liability 

 to disease, and retards the development of a good root-system. 

 On the other hand, such an early thinning rarely pays for the 

 labour of making it, as the trees removed are so small. It has 

 frequently been stated that dense planting means clean timber, 

 but after examination of many plantations of this species which 

 were planted very densely, under all conditions, the author has 

 come to the conclusion that close planting does not always mean 

 clean timber. Moreover, for economic reasons, planting costs 

 and non-productive thinnings must be reduced to a minimum. 

 One or more thousand plants less per acre is a considerable 



