October 23, 190S] 



SCIENCE 



541 



will increase faster tlian the growth. But 

 even the more conservative calculation 

 shows that our forests can not last more 

 than thirty-five years on the present basis 

 of cutting. Long before that time the cost 

 of lumber will largely increase and at the 

 end of that pei'iod there will be no timber 

 fit to cut. When we consider the extent 

 to which wood is used at the present time, 

 how much it means to all men, this is a 

 most serious question. 



The government has tried to check this 

 depletion of our forests by establishing 

 forest reserves in different parts of the 

 country. It is estimated that at present 

 there are in forests about seven hundred 

 million acres, of which twenty per cent, are 

 in national and state hands. This does not 

 mean that all of this land is fully covered 

 with forests, for large sections of it may be 

 totally barren, but surrounded by forests 

 in such a way* that it is necessary to call 

 the whole forest land, until a very accurate 

 survey has been made. The National Bu- 

 reau of Forestry of the United States De- 

 partment of Agricvilture and a number of 

 state departments of forestry have done a 

 great deal towards arousing public interest 

 in the subject and establishing scientific 

 methods of cultivation. Many of the state 

 universities have established departments 

 of forestry which are training foresters to 

 take charge of the development of the for- 

 est interests of state and nation. 



It is evident that in the future lumber 

 must be considered as a crop to be planted 

 and tended and harvested with the same 

 care that other crops receive. It differs 

 from them only in the methods of cultiva- 

 tion and the length of time necessary for 

 its development. Under this scientific 

 treatment trees will be planted on waste 

 areas or other sections where ordinary 

 crops are not profitable; thej^ will be 

 thinned out imtil only those which are 

 likely to attain a mature growth are left, 



and they will be guarded against the de- 

 structive effect of forest fires. When a 

 certain proportion of the crop is ready for 

 harvesting the lumbermen will go in, cut 

 the proper trees, carry away or burn the 

 tops and branches, and then the forester 

 will plant new trees in place of those felled. 

 In a few years another crop will be ready 

 and the same treatment will be repeated. 

 The older forests will be treated in a sim- 

 ilar way except that the first stage of plant- 

 ing will not be necessary. In this way th(= 

 forests will yield a regular crop of lumber 

 once in so often. Under this treatment the 

 forests become profitable to a very much 

 greater degree than under the old method 

 of cutting off all trees large enough for 

 lumber at one time and practically destroy- 

 ing all the young growth. 



In some European countries where this 

 method of forestry is in use the entire pub- 

 lic expenses of many townships are met by 

 the sale of timber from the public forest 

 lands. Our government reserves now yield 

 but a very small income, but in time, as 

 they are brought under the proper cultiva- 

 tion, they will yield large results. As soon 

 as forest planting is taken up on a large 

 scale by national and state governments and 

 by individuals, the lumber question of the 

 future will be settled. This process, how- 

 ever, is a slow one and we must expect that 

 before that time comes the present forest 

 reserves will be largely exhausted. The 

 danger, however, has been seen and the 

 necessary methods for its correction have 

 been developed. This has been the work 

 of the scientific forester, but the labor can 

 only be done by those agencies which can 

 supply the necessary funds. 



The engineer is greatly interested in this 

 question because he needs timber for many 

 of his operations. He also has a hand in 

 the conservation of our forest areas because 

 of the use which he makes of steel and con- 

 crete in structural work. The amount of 



