1122 



Canadian Forestry Journal, May, 1917 



How Timber Is ''Cruised'' 



From ''Pointers' by Jas. D. Lacey Co. Chicago 



Having a tract of timber to cruise 

 after the most accurate manner prac- 

 ticable in consideration of cost, we 

 first send an expert woodsman, pre- 

 ferably the head cruiser who will be 

 in charge, over the tract to fix upon 

 a general plan of operations and pre- 

 pare a preliminary report on the 

 character of the timber. This report 

 is the basis of instructions issued to 

 the cruisers. Survey crews are then 

 sent to the tract to locate the corners 

 and lines, established perhaps many 

 years before by government survey- 

 ors, and to survey and plainly mark 

 out the minor subdivisions; also to 

 set "tally stakes" for the guidance of 

 the cruiser's compassmen. 



When this work is well under way 

 the cruisers are sent in and the actual 

 estimating of the timber begins. 



Before the cruiser actually begins 

 the work of estimating the timber, he 

 endeavors first to find windfalls of 

 each species, which are representative 

 types. If this is possible he measures 

 the down tree with his tape. He 

 ascertains the exact butt diameter, 

 having chopped away the bark, and 

 the diameter of each succeeding 32- 

 foot or 16-foot log according to the 

 basis of the estimate. By this meth- 

 od he is able to compute from the 

 standard log scale the exact volume 

 of the tree, taking it log for log, the 

 average taper and the number of 

 merchantable logs it contains. He 

 uses these fallen trees as a standard 

 of comparison by which to judge of 

 the contents, the height and taper 

 of those standing. His experience 

 has taught him that trees of ap- 

 proximately the same age growing 

 under the same conditions, will attain 

 to approximately the same height, 

 and will maintain the same degree 

 of I taper. It is vital to the accuracy 

 of his work that the cruiser keep care- 

 ful watch on the changing age, con- 

 ditions and types of the timber 

 through which he passes in the course 

 of a day's work. Unconsciously he 



expects to find the tall clean timber 

 in the draws or on well protected 

 benches; while on the poorer ex- 

 posures his woodsmanship prompts 

 him to look for the shorter and more 

 imperfect specimens. In a country 

 notoriously free from windfalls, as 

 is freciuently the case in the western 

 pine, the estimator often carries some 

 one of the numerous mechanical de- 

 vices designed to determine the height 

 of standing timber. His steel tape 

 is always in use as an aid and a check 

 to his trained eye in arriving at the 

 butt diameters. Experience has made 

 the expert cruiser a good judge of 

 taper — given him the ability to see 

 at a glance whether a tree holds its 

 size well up into the branches or 

 whether it tapers off rapidly and fails 

 to contain the amount of lumber that 

 its butt diameter would indicate. 



Years of practice have imprinted 

 indelibly on the mind's eye of the 

 competent cruiser certain forms and 

 types and sizes, which to him re- 

 present certain known contents, and 

 subconsciously these form standards 

 of comparison upon which he bases 

 his estimate upon given trees. By 

 frecjuent reference to his volume table 

 he has come to know, for example, 

 that a tree 24 inches in butt diameter, 

 containing three 32-foot logs with 

 an average taper of 4 inches of the 

 log — will cut 1,000 feet board mea- 

 sure, also that a tree 31 inches in 

 diameter, four logs high, with a 5-inch 

 taper contains 2,000 feet. Such stan- 

 dard trees are simply an index upon 

 which to work; a rule of thumb, as 

 it were, to systematize and simplify 

 the work of the estimator and to add 

 both speed and accuracy to his efforts. 

 In other words, they serve to stan- 

 dardize his judgment. Should he 

 find trees defective or malformed, he 

 must deduct accordingly. Further, 

 should he find trees that are seriously 

 affected by fungi or any similarly 

 serious diseases peculiar to certain 

 species, he disregards them entirely. 



