io8 



here and that the forest would perpet- 

 uate itself if it were left undisturbed. 



The problem of silviculture in this 

 case is to harvest the crop with as little 

 disturbance as possible. The procedure 

 is therefore to imitate the way indi- 

 vidual trees die in the natural forest 

 and cut a mature tree here and there. 



To round out the picture, consider 

 land that has been abandoned for agri- 

 culture in an area once covered with 

 forests. Eventually this land will revert 

 to forests. But if there are no seed trees 

 nearby of pioneer species that can start 

 on dry, shadeless land, it may take a 

 thousand years. Natural succession can 

 be hurried along by planting such 

 abandoned fields to pine. 



All of these examples are oversimpli- 

 fied. But more details of silvicultural 

 methods are given in later articles. 



REAL SIMPLIFICATION of silviculture 

 can come only with more knowledge of 

 how forest communities behave. The 

 very richness of the forests in these 

 United States multiplies the problems 

 of the silviculturist. For many forest as- 

 sociations, we know little about nat- 

 ural succession; for some, we can only 

 guess at the climax type toward which 

 the association tends. So much of our 

 original forests has been destroyed or 

 cut over that it is hard or impossible to 

 find undisturbed areas of many types. 

 Belatedly we are establishing, on the 

 national forests and elsewhere, natural 

 areas in the few remaining virgin- 

 forest communities. These areas are to 

 be protected from all cutting and other 

 artificial alterations so that we can 

 learn from them the nature of our cli- 

 max or near-climax forests. 



Most bothersome of unsolved silvi- 

 cultural problems are those that deal 

 with the effects of modifications that 

 must necessarily be made when the tree 

 crops are harvested. To work in the 

 direction of natural succession is usual- 

 ly easy and inexpensive. To work 

 against it is harder and may be costly. 

 For instance: Will it be possible con- 

 tinuously to keep back the hardwoods 

 in the Carolina Piedmont and raise 



Yearboo\ of Agriculture 1949 



pine without eventually having to fer- 

 tilize the soil artificially? Can we man- 

 age to tolerate just enough of the soil- 

 enriching hardwoods without letting 

 them get the upper hand? Or will we 

 have to go to the expense of plowing 

 and planting trees if we insist on rais- 

 ing pine? Such questions probe deeply 

 into the underlying laws of ecology. 



We seek ever the best balance be- 

 tween the ways of nature and our 

 wants. To make the forests yield useful 

 products while maintaining and im- 

 proving their natural vigor requires 

 continuous, painstaking research. 



FORESTERS MUST be forward-look- 

 ing. A single tree crop may require 200 

 years to mature. But the single crop is 

 not the only concern; there must be 

 provision for successions of them. Fur- 

 thermore, we cannot wait a century or 

 two between harvests. Things must be 

 arranged so that some trees can be 

 harvested each year or every few years. 

 That requires foresight and planning, 

 and leads to another branch of for- 

 estry forest regulation. 



The basic rule of forest regulation 

 is to cut each year a volume of timber 

 no greater than the volume that grew 

 during the year. If the layers of wood 

 added to the trees on an acre of north- 

 ern hardwood forest in Michigan total, 

 say, 250 board feet each year, then 

 trees with a volume of 250 board feet 

 or less can be removed from the acre 

 annually without reducing the growth 

 capacity of the forest. Thus yield can 

 be sustained indefinitely. 



But sustained yield of our forests 

 depends on more than making plans. 

 It depends on how well we are able to 

 work with nature and get her to work 

 with us. Wherever this cooperation is 

 attained, communities of men and 

 communities of trees are in harmony. 



JESSE H. BUELL is assistant chief of 

 the Division of Forest Management 

 Research in the Forest Service. He was 

 formerly engaged in research in sil- 

 viculture at the Southeastern Forest 

 Experiment Station. 



