72 BRITISH FOREST TREES 



be damaged by the whip-like twigs of the former. Under 

 certain circumstances, however, the birch is a welcome guest 

 in pine woods, only its stay must not be too prolonged. On 

 soils of somewhat inferior quality, which suffice for the birch 

 but are hardly good enough to ensure the thriving of other 

 species, an admixture of birch protects the pine against insects, 

 snow, and fire. Where, again, the pine is likely to find difficulty 

 in establishing itself, an admixture of birch as a nurse often 

 yields good results, as on very dry, almost shifting, sandy 

 soils and on moors and marshes, on which experience shows 

 that such mixed forests thrive better during the younger 

 stages of growth. But in these cases the birch should be 

 removed early in the way of thinning, especially on the 

 more sandy varieties of soil. 



The admixture of larch with Scots pine was formerly 

 not at all infrequent, but has now pretty generally fallen 

 into disrepute in most countries except Scotland, as might 

 from the very first have been expected from the natural 

 characteristics of the two species. Even on soils below the 

 average in quality, the larch is the quicker in growth till 

 between the tenth to the twentieth year, when it is caught up 

 by the pine, and the one condition of its growth absolute 

 freedom of crown can no longer be satisfied unless at the 

 sacrifice of the surrounding pines ; at such a stage of growth 

 the almost inevitable measure to be adopted is the removal of 

 the larch poles before they fall a prey to canker (Peztza 

 Willkommii). But in any case the poorer classes of pine 

 soil are no suitable situation for the larch, which requires a 

 deep, fresh, and strong soil, such as will seldom be best utilised 

 by being planted up with Scots pine. Where, however, 

 the larch is desired in pine woods, it can better be reared 

 and tended if planted in patches or groups than individually 

 or in rows. 



On peat-moors or sour boggy soils Scots pine has often 



