﻿WHITE PINE UNDER FOREST MANAGEMENT. 



21 



The rate of growth of the stand is influenced by the same physical 

 factors which control that of the individual tree. Computations of 

 future yield must, therefore, take into account conditions under 

 which the trees grow, and it is customary to classify stands accord- 

 ing to their height growth, which, as previously said, is the best 

 indicaton of the quality of the site. Quality I shows the most rapid 

 growth, and quality III the slowest. 



Stands fully stocked, that is, those which contain just enough 

 trees to utilize all the growing space and to produce well-formed 

 trunks, are said to be "normal." Too many trees result in slender- 

 stemmed, slow-growing stands; too few do not fully utilize the 

 growing space, and produce limby stands of relatively low value. 

 Since growth is more rapid and competition more keen in good 

 situations than in poor ones, the number of trees is less and their 

 size . greater in fully stocked quality I stands than in quality III 

 stands of the same age and type. 



YIELD OF SECOND-GROWTH WHITE PINE. 



The yield of a stand, that is, the amount of wood produced per acre, 

 in large measure determines the choice of species or of material to be 

 produced, the length of rotation, and other important features of man- 

 agement. Volume growth of a stand depends, of course, upon the 

 height, diameter, and volume of the individual trees, and also upon 

 the number of trees. 



Tables 3 to 6, which give the yield per acre of three qualities of 

 second-growth white pine, are based upon the results of measure- 

 ments of 196 typical fully stocked second-growth stands in New 

 Hampshire, by C. A. Lyford and Louis Margolin of the Forest Serv- 

 ice. 1 The tables are for use either as guides in predicting the future 

 yield of young second-growth or for determining the present yield 

 of existing stands. 



Table 3. — Yield per acre in cubic feet, quality I. 





Aver- 



Diam- 



Num- 

 ber of 

 trees 

 per 









Aver- 



Diam- 



Num- 

 ber of 

 trees 

 per 







Age. 



age 

 height 



eter 

 breast 



Basal 

 area 



Total 



Age. 



age 

 height 



eter 



breast 



Basal 

 area 



Total 



of domi- 



high of 



per 



yield. 



of domi- 



high of 



per 



yield. 





nant 



average 



acre. 







nant 



average 



acre. 







trees. 



tree. 











trees. 



tree. 









Years. 



Feet. 



Inches. 





Sq.ft. 



Cu.ft. 



Years. 



Feet. 



Inches. 





Sq.ft. 



Cu.ft. 



10 



7.2 



1.7 



1,728 



29 



800 i 



60 



85.5 



12.8 



311 



278 



10, 500 



15 



14.5 



2.9 



1,520 



68 



1,400 1 



65 



90.5 



13.7 



279 



286 



11, 300 



20 



24.5 



4.0 



1,322 



115 



2,100 



70 



94.5 



14.7 



249 



293 



11,900 



25 



34.5 



5.2 



1,115 



162 



3,000 



75 



98.0 



15.6 



226 



300 



12, 500 



30 



44.0 



6.4 



879 



196 



4,000 



80 



101.5 



16.5 



207 



307 



13, 000 



35 



53.0 



7.5 



710 



218 



5,200 



85 



105. 



17.4 



190 



313 



13,500 



40 



61.0 



8.6 



583 



235 



6,500 



90 



108.0 



18.2 



177 



319 



14,000 



45 



68.0 



9.7 



485 



249 



7,700 



95 



110.5 



19.0 



165 



324 



14, 400 



50 



74.5 



10.8 



408 



260 



8, 800 



100 



113.0 



19. S 



154 



330 



14, 700 



55 



80.5 



11.8 



354 



269 



9,700 















1 Tables based on these measurements have already been published in the biennial reports of the For- 

 estry Commission of New Hampshire for 1905-6 and 1907-8. The present tables din'er from the others in 

 that the separation into quality classes is made upon the basis of the height of the dominant trees instead 

 Of that of the yield itself. 



