118 THE PRINCIPLES OF HANDLING WOODLANDS 



of the danger from windfall. In many instances a clump 

 of trees will resist the wind where single trees will not. 

 This is particularly the case when one or two fairly wind- 

 firm trees are in the clump. Suppose, for example, that 

 a forest is composed of two species, one subject to wind- 

 fall and the other fairly wind-firm; and suppose that it is 

 desired to reproduce the former. It might often be the 

 case that a clump of trees composed of both species would 

 resist the wind and accomplish the reproduction, even 

 if only a few of the trees in the clump were of the wind- 

 firm species. 



The clumps would ordinarily comprise from three to 

 thirty trees, and would be located and spaced on the 

 same principles as under the system of scattered seed- 

 trees. The only difference between the two systems is 

 that in the latter a group of several trees would usually 

 be left instead of single isolated trees. 



Reserving Thrifty Standards. In the two systems 

 described in the foregoing pages, the purpose of leaving 

 reserves is for. reproduction, and for that only. Under 

 the method now to be described, trees are left standing 

 for two reasons, reproduction and growth. 



The system is applied in regular, relatively even-aged 

 stands of moderate age; that is, to stands in which there 

 are many trees still capable of living a long time, and 

 capable of rapid growth. It is not applicable in very old 

 stands in which the trees have all reached their limit of 

 profitable growth. Usually the system is not applicable 

 to stands over about 100 years old. 



