THE APPLICATION OF RECONNAISSANCE DATA TO 



THE PROBLEM OF MARKING TIMBER 



FOR CUTTING 



By Richard H. Boerker 



The object of this study is to inquire into the number of trees 

 to the acre, the density, the representation of age classes and 

 the contents of trees and stands in our Western Yellow pine 

 forests, with the idea of securing data that might be of use in 

 the management of these stands. About 60 per cent of the mer- 

 chantable timber on the Lassen Forest is Yellow pine ; the largest 

 and most continuous stands are found in the eastern and central 

 parts of the Forest. 



This study is confined to pure Yellow pine stands, i.e., stands 

 in which Yellow pine represents 80 per cent or more of the 

 merchantable timber. The data used were taken from the forms 

 made out in the reconnaissance work of the last two years. 

 Owing to the fact that these data include only those trees above 

 5 inches D.B.H. the study involves only trees above that diam- 

 eter. Investigations have shown that on the basis of the number 

 of trees per acre the average Yellow pine stands are composed 

 about as follows : 



Other species 10% 



Yellow pine: 



Under 5 inches 10 



Over 5 inches 80 



Total 100 



The stand on each form, representing two acres — usually a 

 fair average of the entire forty — , was classified into 5 diameter 

 groups, namely : 6-10", 11-20", 21-30", 31-40", and over 40". This 

 was done with 350 forties. These were taken by groups of sec- 

 tions and were representative of the pure Yellow pine stand in 

 17 townships. These data represent 700 acres actually calipered, 

 and if we assume that the ordinary strip taken through the 

 center of a forty is fairly representative of the entire forty, 

 then this study is based on 14,000 acres. 



The Average Number of Trees Per Acre 



After the stands had been classified into the 5 diameter groups 

 mentioned before, it was found that the 700 acres in question 



457 



