172 



Forestry Quarterly. 



ience. Before the actual work of estimating was begun hypso- 

 meter height measurements were taken on about 4,ocx) standing 

 trees on the tract to be cruised. From these data three height 

 curves were constructed for each species, showing the average 

 height of trees of each diameter class on site I, II and III. 

 Cruise strips one chain wide were then run 10 chains apart, giv- 

 ing the 10 per cent, estimate of the area. All trees on the strip 

 more than 12 inches in diameter were tallied by species in 2 inch 

 diameter classes. Trees 32 inches in diameter or less were esti- 

 mated, but the eye was checked several times a day by taking 

 actual measurements. Trees more than ;^2 inches in diameter 

 and less than 60 inches were measured by means of a Biltmore 

 stick. Trees more than 60 inches in diameter were measured 

 by means of a diameter tape. Every strip on each "forty" was 

 classified by the cruiser into its proper height class. The re- 

 sult of this cruise was two 5 per cent, estimates which, when 

 combined, gave a 10 per cent, estimate. 



The 100 per. cent, estimate was made by a four-men party as 

 follows : One man ran compass and lightly blazed the trees along 

 his course; a second man ran through the center of the strip 

 tallying the trees and watching the cruisers to see that no trees 

 were omitted. The other two men measured or estimated all the 

 trees on the tract and called them out to the tallyman. A strip 

 2j chains in width was taken on each trip, which necessitated 

 32 trips for each section. The height class of each species was 

 determined from the height curves as in the original estimate, 

 the hypsometer being frequently used to check the eye. 



Table 2 shows the results of this check-cruise. 



