Potential Growth 



Potential growth or yield is net growth expressed in cubic feet per acre 

 per year as calculated by the forest inventory computation process. The 

 estimate is based on yield tables developed for fully stocked, even-aged 

 stands of single species. These yield tables are used to construct mean 

 annual increment curves. Site indices derived from site trees measured on 

 the field location are used to choose the proper mean annual increment curve. 

 The potential cubic foot yield per acre per year is determined based on the 

 culmination point of the mean annual increment curve. The age at the cul- 

 mination point is the biological harvest age for producing the maximum amount 

 of wood. This estimate of biological potential is considered to be less than 

 the potential for intensively managed stands. 



The average potential net growth for all forest types in Working Circle 3 

 was estimated to be 54 cubic feet per acre per year (see Table 23). Average 

 gross growth per acre for softwood forest types was estimated to be 36 cubic 

 feet per year, or about 67 percent of potential net growth. The average net 

 growth per acre for softwood forest types was estimated to be 32 cubic feet 

 per year, or about 59 percent of potential net growth. Nationally, net 

 growth was 38 cubic feet per acre per year or about 51 percent of potential 

 net growth (74 cubic feet) in 1970. Net growth for the Rocky Mountain 

 region was estimated to be 24 cubic feet per acre per year or about 40 per- 

 cent of the 60 cubic foot potential net growth (USDA Forest Service 1973). 



When a forest is composed of stands in many age classes, a gap between 

 net growth and potential net growth should be expected. However, a large 

 gap between net growth and potential net growth may indicate management 

 opportunities exist to increase production. Studying the forest's growth- 

 related physical characteristics should suggest ways to reduce this gap. 



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