CHAPTER XXXII 



COORDINATION OF FOREST SURVEY WITH GROWTH DETER- 

 MINATION FOR THE FOREST 



343. Factors Determining Total Growth on a Large Area. The 



solution of the problem of determining the amount or volume of wood 

 which will be grown on a forest or area of forest land in a given period 

 depends upon six factors: 



1. An analysis or classification of the forest into the areas included' 

 in each of the site qualities present. 



2. The areas occupied by stands of given type and mixture of species. 



3. The actual present density of stocking, volume and number of 

 trees per acre, and size of diameters of the present stand on the forest. 



4. The actual age classes present, and the area which each occupies. 



5. The length of the period for which growth is desired, whether 

 for a short current period, or for permanent management and a rotation. 



6. The rate of growth, to be determined by whatever method can 

 best be applied to the forest as a whole by obtaining the actual growth 

 on the stands which compose it. 



344. Data Required from the Forest Survey. The first four of 

 these elements require the collection of data in connection with the 

 forest survey. Studies of the rate of growth (6) for the period deter- 

 mined (5) will not solve this problem in the absence of quantitative 

 data to tie this growth study to the tract in question. 



Unless a forest is to be cleared for farms, the prediction of future 

 growth is a basic consideration of its future management. A forest 

 survey that is so conducted as to fail to obtain the necessary data on 

 which growth for the forest can be determined must later be repeated 

 to obtain this data, or supplemented in some way, while if the need 

 were recognized at the start, the information could be obtained in final 

 form with trivial extra cost. 



The character of this data depends upon the form of the forest as 

 to its age classes. It may be itemized as, 



1. Site classification. 



2. Age of stands. 



3. Area of stands. 



4. Volume of stands. 



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