58 BRITISH FOREST TREES 



quality of soil to which this most useful tree readily accom- 

 modates itself. 



The mineral quality of the soil finds its expression rather 

 in the quality of the timber, and the duration of life of the 

 tree, than in the cubic contents produced. The attainment 

 of great height is with it, as with the other trees of the forest, 

 one of the chief outward signs of the suitability of the 

 situation. Its highest development and greatest production 

 of resin take place on loamy sand, especially if humus be 

 contained in it, and when the subsoil retains a constant 

 moderate supply of moisture. 



No other species is content with so little soil-moisture as 

 the Scots pine, which can be made to form forests on dry, 

 shifting sand, or on hot, southern slopes where even the 

 very weeds find life difficult. In such unsuitable localities 

 its growth is naturally not good, but by improving the soil 

 through the shade and shelter of its foliage preventing 

 insolation, and through the humus formed by the defoliated 

 needles, it paves the way for a better subsequent growth or 

 for other trees that could not be planted out in the first 

 instance. It also, on the other hand, is capable of being 

 grown on peat moors and bogs, and even endures stagnant 

 water better than the spruce which demands soil-moisture ; 

 but under these unfavourable circumstances its growth is not 

 vigorous. To the attainment of a long period of life, of 

 large cubic contents, and of timber of first-rate quality a 

 constant moderate degree of freshness in the soil is 

 essential ; dry soil yields good timber, but little of it ; moist 

 soil yields large cubic contents, but of inferior quality as 

 timber. It is sensitive to changes in the quantity of soil- 

 moisture, and when growing on a soil usually moist, suffers 

 in growth if either inundations take place or the soil gets 

 dried up in unusually hot seasons, or in consequence 

 of neighbouring drainage, the root-system being unable in 



