i8o BRITISH FOREST TREES 



acquire in Britain, although as undergrowth in copse the 

 latter is often welcome. 



Wherever birch finds broken soil in young beech-woods, 

 it is apt to assert a foothold, and to become more of a 

 noxious weed than anything else, giving trouble, through its 

 reproductive capacity, with regard to the introduction of 

 more desirable species, and when springing up in any con- 

 siderable numbers, despite its light foliage, often interfering 

 greatly with the development of the beech. As groups of 

 birch thin themselves out strongly between the twentieth to 

 thirtieth year, this species should be grown only as single 

 individuals, or in small knots on favourable situations, so as 

 not to interrupt the canopy too much when they become 

 mature at forty or at most fifty years of age. Its introduction 

 takes place preferably by planting rather than by sowing, but 

 under many circumstances the cutting out of all self-sown 

 seedlings is alone requisite to have a sufficiency of birch. 



The other softwoods, of which lime, aspen, and sallow 

 are, next to birch, the chief species to be found in admixture 

 with the beech, have much in common with the birch. They 

 very usually find their way into beech forests during repro- 

 duction as self-sown growth, or as stoles from former trees ; 

 and where they do not occur in such numbers, or so dis- 

 posed over the area in groups, as to damage the development 

 of the ruling species, they perform good service as nurses, 

 quickly form marketable timber, and yield at an early date 

 fairly appreciable returns. But where allowed to form large 

 patches, they tend like the birch and pine to branching 

 growth, neither congenial to the ruling species nor profitable 

 to the development of their own boles. Such groups have 

 the further disadvantage of being difficult to fill up with any 

 remunerative species when these quick-growing trees have to 

 be removed, long before the ruling species has approached 

 maturity. If the proper time for their removal has not been 



