36 TIMBER AND SOME OF ITS DISEASES. [CHAP. 



Freising near Munich, with young beeches growing 

 under the shade of the larches. The latter are 

 seventy years old, and are excellent trees in every 

 way. About twenty years ago these larches were 

 deteriorating seriously, and were subsequently 

 "under-planted" with beech, as foresters say i.e. 

 beech-plants were introduced under the shade of 

 the larches. The recovery of the latter is remark- 

 able, and dates from the period when the under- 

 planting was made. 



The explanation is based on the observation that 

 the fallen beech-leaves keep the soil covered, and 

 protect it from being warmed too early in the spring 

 by the heat of the sun's rays. This delays the 

 spring growth of the larches : their cambium is not 

 awakened into renewed activity until three weeks or 

 a month later than was previously the case, and hence 

 they are not severely tried by the spring frosts, and 

 the cambium is vigorously and continuously active 

 from the first. 



But this is not all. The timber is much improved : 

 the annual rings contain a smaller proportion of soft, 

 light spring wood, and more of the desirable 

 summer and autumn wood consisting of closely- 

 packed, thick-walled elements. The explanation of 

 this is that the spring growth is delayed until the 



