140 THE PRINCIPLES OF HANDLING WOODLANDS 



Disadvantages of the System. As compared with 

 the clear-cutting systems, the shelterwood system, there- 

 fore, gives to the forester means of better controlling 

 reproduction, protecting young growth, and conserving 

 the quality of soil, as well as the appearance of the forest. 



The chief disadvantage, from a silvicultural stand- 

 point, is that the system cannot be applied when there 

 is great danger from windfall. During the period of 

 cuttings the trees are isolated, and, therefore, exposed to 

 danger from windfall. This disadvantage is partly over- 

 come in European practise by opening up the forest in 

 the first instance by a series of light thinnings, and thus 

 gradually rendering more windfirm the trees that are 

 chosen to stand. Even this measure is of no avail where 

 the danger from windfall is extreme. In this country a 

 series of light thinnings is often not feasible, and this 

 fact excludes the system not only from the more exposed 

 sites, but also from many areas where it would be practi- 

 cable if it could be intensively applied. 



A second disadvantage touches the problem of log- 

 ging. The conditions must be such as to permit the 

 restriction of the first cutting and the removal of only 

 a part of the stand in the form of a thinning; then a 

 return for one or more subsequent cuttings. 



Variation in Application. This system, like all 

 others, must be applied with wide variations in different 

 forest types, according as the forests vary in age, density, 

 and reproductive capacity. But the application of the 

 system is mainly affected by the market and logging 



