1836 Canadian Forestry Journal, August, 1918 



The Second Crop of Pulpwood 



By II. C. Belyea 



{Graduate, Forest School, Universitif of New Brunswick; Instructor in Forest Engineering, New 

 York Stale College of Forestry, Syracuse, \. Y. ) 



An Antidote to the Pessimistic conclusions 

 Based on Rate of Growth in Virgin Forests. 



The prediction of the rate of growth 

 for second growth forests after him- 

 bering, from the performance of the 

 original stand is a common source 

 of pessimism among himbermen. 

 Technical forestes have an unfor- 

 tunate tendency of basing their growth 

 predictions upon the performance 

 of the species under virgin conditions. 

 The conditions for growth after lum- 

 bering are much difTerent than they 

 were for the original forest, due 

 principally to the freedom of the 

 survivors from root and crown com- 

 petition. Attention is called to an 

 article on the reforestation of pulp- 

 wood lands, published in the Decem- 

 ber 1917 issue of the Canadian 

 Forestry Journal, in the hope of a 

 reinterpretation of some of its con- 

 clusions. 



Virgin Forest Conditions 



A forest as grown under virgin 

 conditions, consists of two main 

 divisions; an upper or main portion 

 consisting of the actual merchantable 

 and productive trees, and a lower or 

 under forest of small and young 

 trees which form the basis of the 

 potential forests of the future. While 

 the existence of the latter is depend- 

 ent upon the presence on, or near 

 the site, of trees big enough to pro- 

 duce seed, it is distinctly not a part 

 of the productive portion of the 

 forest. 



The existence of a tree, big or 

 small, in a forest, is absolutely 

 dependent on the presence or absence 

 of certain conditions for tree growth 

 which are termed the factors or 

 resources of the site. Only under 

 stimulation of these factors is tree 

 growth either initiated or continued. 

 These site factors are several in 

 number, but crown light and soil 

 moisture are the most important. 



The presence of a lower growth of 



seedling or small trees under the 

 crowns of the main trees of the 

 forest is concrete evidence that either 

 the resources of the site for tree 

 growth are in excess of the demands 

 of the trees now present, or else the 

 crown cover of the main forest is 

 temporarily less dense and represents 

 a less number of trees than the 

 potential ability of the site for tree 

 growth. This small seedling, and 

 often suppressed, growth of stunted 

 trees occupies both in the air above 

 and in the soU below space properly 

 ascribed and credited to other and 

 bigger trees. Hence it cannot be 

 reckoned as an item of the product- 

 ivity of the site, but rather as a 

 potentiality. It exists only by suf- 

 ferance of the minimum demands of 

 the overwood, and it is maintained 

 only so long as these demands are 

 not in excess of the supply. Hence 

 it cannot be counted as part or parcel 

 of the productive forest nor as an 

 actual item of the forest production. 



Growth in volume in the individual 

 tree for any site is dependent upon 

 the size of the crown, which in turn 

 is indicative of the size of the bole 

 and the development of the roots. 

 Growth in volume is also more a 

 factor of size than age. Twelve inch 

 trees in any forest will show only 

 the average growth of 12 inch trees 

 as grown in that forest, irrespective 

 of whether their age be 75 or 175 

 years. 



The life history of softwood in 

 virgin mixture is a series of struggles 

 to get light and develop a crown ; 

 struggles that are feeble in early age 

 and more progressive as the tree 

 attains size. Each phase of suppres- 

 sion and release leaves its record in 

 the alternating zones of dense and 

 wider ringed wood in the bole of the 

 tree. In virgin forest the release 



