150 BRITISH FOREST TREES 



larch forests ; in respect to the first, this is so energetic 

 that rank growth of grasses or weeds is soon outgrown, 

 and complete canopy is often formed in five or six 

 years with close planting. Shortly after the formation of 

 close canopy,' the period of its liveliest growth in height 

 is entered on, the maximum being attained on low-lying 

 situations and uplands as early as between the tenth to 

 twentieth year, although not till much later in its Alpine 

 home. On favourable situations with fresh, deep soil 

 the energy of growth in height is maintained till about the 

 thirtieth to fortieth year of age, with shoots averaging two 

 to three feet in length and sometimes more ; but on less 

 favourable soils and situations this has often sunk so far by 

 the twentieth to thirtieth year of age that further growth in 

 height is less than with most other conifers. In regard to 

 no other species of forest tree do soil and situation make 

 their combined influence more evidently felt than with 

 respect to the cultivation of the larch in pure forest, an 

 influence likewise equally visible in the density of the crop, 

 and in the degree to which close canopy is formed and 

 maintained. Under no circumstances can these latter 

 ever be so complete as in forests of shade-bearing conifers, 

 or even of Scots pine. Early in the pole-forest stage of 

 growth the total number of larch per acre becomes re- 

 duced by more than 50 per cent., and by the time the 

 twenty-fifth to thirtieth year has been completed, the canopy 

 is very much more broken than in forests of Scots pine, 

 often to such an extent, indeed, that, except on soil of 

 exceptional quality, its deterioration and a diminution of 

 productive capacity must be feared. Henceforward, the 

 appearance of the crop affords no pleasant sylvicultural 

 picture. The canopy becomes more and more interrupted 

 and broken by stems dying off when interfered with by 

 more energetic neighbours, tufts of beard-mosses (Usnea) 



