252 TRANSACTIONS OF ROVA[, SCOTTISH AKBORICULTURAL SOCIKTY. 



^500 was avoided by making a preliminary survey of the wood. 

 As the following description shows this consists of actually 

 measuring the timber in the wood by making use of sample trees 

 as indicators of its true volume. The extra cost involved in the 

 survey is negligible as compared with the gain. 



Survey of Woods. 



Before profitably disposing of standing timber it is absolutely 

 necessary to make a detailed survey of the crop. The best 

 method of procedure is as follows : — Strips one chain wide are 

 taken in hand along the greatest length of the wood, in these 

 every tree is callipered at breast-height and marked on either 

 side with chalk. For this it has been found that two men suffice 

 for callipering with one man booking, he in addition keeping the 

 line of the strip. The trees are entered according to species and 

 are arranged in inch diameter-classes, i.e. trees between g| and 

 loi-inch diameter are classed as lo-inch trees, trees between 

 loi; and iii-inch as ii-inch trees, and so on. The height of 

 each diameter-class is also ascertained by measuring a few of 

 the average trees in it with a hypsometer. When callipering, in 

 each inch class, a tree having as nearly as possible the diameter 

 and height of its class is marked for felling. These trees 

 represent the average stems of the various inch classes, and 

 for identification should have their diameters painted upon 

 them. 



The average trees are then felled and ringed in the middle for 

 measurement at half their length, this being usually determined 

 by the diameters 6, 7 or 9 inches at the small end. The stems 

 are ringed and girthed in order to arrive at the bark allowance, 

 which is adjusted for every third inch class. The diameters 

 mentioned above depend on the dimensions of the timber, for 

 example, heavy timber is usually sold down to 9-inch diameter, 

 medium to 7-inch diameter, and light timber to 6-inch diameter. 

 The saleable contents of these trees are then accurately obtained 

 by means of quarter-girth measurement. 



The volumes of the sample trees are booked separately and 

 multiplied by the number of trees of the same species in each 

 class. In this way the volume of the several species in the wood 

 is ascertained, and therefore by addition the volume of the whole 

 wood. 



