/^/6;?^^EST SERVICE RESEARCH NOTE NE-275 



1979 



^^rthea8tern Torest 

 Txperiment Statioit 



.if- '-now 



FOREST SERVICE, U.S. DEPARTMENT OF AGRICULTURE, 370 REED ROAD, BROOMALL, PA. 19008 



TREE GRADE DISTRIBUTION IN ALLEGHENY HARDWOODS 



—RICHARD L. ERNST 



Research Forester 



—DAVID A. MARQUIS 



Principal Research Silviculturist 

 Northeastern Forest Experiment Station 

 Warren, Pennsylvania 



Abstract. Estimates of the distribution of tree grades by diameter 

 class were developed for six hardwood species on the Allegheny 

 Plateau. These estimates can be used to calculate present and pro- 

 jected stand values when actual tree grade measurements are not 

 available. 



INTRODUCTION 



From information developed as part of a 

 series of financial maturity studies in north- 

 eastern hardwoods it is possible to calculate 

 the value of a stand if one has data on the 

 numbers of trees by species, diameter at 

 breast height (dbh), merchantable height, and 

 tree grade. (DeBald and Mendel 1976a; Men- 

 del et al.; DeBald and Mendel 1976b; Grisez 

 and Mendel 1972). Unfortunately, informa- 

 tion on tree grade often is not included in data 

 collected during stand inventories, or in data 

 developed from yield tables or stand growth 

 simulators. 



However, if tree grade, which is an indica- 

 tor of suitability for various wood products, 

 can be correlated with size class for each spe- 

 cies, estimates of stand quality and value can 

 be made for typical stands where specific tree 



grade data is unavailable. We collected data 

 to develop empirical tree grade distributions 

 by dbh and species for typical cherry-maple 

 stands on the Allegheny Plateau. 



METHODS 



Empirical grade distributions were derived 

 from summaries of data on species, diameter, 

 and tree grade. Two sources were used: tim- 

 ber sale cruise data from the four districts on 

 the Allegheny National Forest, and data from 

 complete inventories of seven sample stands. 



The timber sale data consisted of informa- 

 tion on species, dbh, and tree grade for about 

 12,500 trees, all of which were grade 3 or bet- 

 ter; trees that were not at least grade 3 were 

 not recorded. These data were from syste- 

 matic samples of trees to be included in clear- 

 cutting sales over a 3-year period. We used 

 grading rules described by Hanks (1971). 



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