52 STATE BOARD OF AGRICULTURE. 



to compare the results obtaiued by these "valuation surveys'' with the 

 actual cut taken afterwards from the area for which they furnished an 

 estimate. The comparison has shown for them a degree of accuracy not 

 only quite sufficient for the ])urpose in hand, but which bids fair to prove 

 the entering- wedge in inducing lumbermen to abandon cruisers' estimates 

 for a similar system of measurement. 



To determine the amount of merchantable timber which the forest will 

 produce in a given period, it is necessary to know the rate of growth of 

 the different kinds of trees and the size and number of the immature 

 trees now standing. The latter is taken from the valuation surveys, the 

 former from what are called stem aual3'ses. These consist in the deter- 

 mination of the age of felled trees by counting the rings. The age and 

 diameter are taken at the end of each log; the length of the merchantable 

 stem, the percentage of heart and sap wood are found and other meas- 

 urements are made which aid in determining the rate of growth of the 

 tree in age and in diameter, and other points in its life history. A number 

 of these analyses are made of each kind of timber trees present in the 

 forest. The results are worked up, averaged and thrown together into 

 tables, of which the most important in fixing the future yield are those 

 which show the number of years required by trees of different sizes 

 and kinds to grow one or more inches in diameter. Knowing the present 

 stand per acre of trees below a merchantable diameter, the forester now 

 has a record of the rate of growth of other trees of the same size and 

 kind and grown under the same conditions, from which to determine how 

 long it will be before these immature trees reach marketable size; and 

 from his volume tables he can calculate what their contents will be. 

 From the knowledge at his command he can show the comparative advan- 

 tages of cutting to different diameter limits, can determine the annual or 

 periodic yield which the forest is actually producing, and can show just 

 what the results will be in the production of future crops of timber, pro- 

 vided the young trees which will form them be preserved. 



Such, brierty outlined, is the scope and the basis of a working plan ; its 

 purpose is to fix after a thorough expert examination, upon the best 

 business policy in the management of forest land, whether it be a timber 

 tract containing many thousands of acres, or a wood lot containing less 

 than one hundred ; the principle is the same— ^the conservation of a sus- 

 tained yield from a forest through conservative lumbering, or practical 

 forestry. 



A PLANTING PLAN. 



In circular 22 the bureau proposes to give practical assistance to tree 

 planters. This comprises personal assistance to farmers and others by 

 cooperation with them in establishing plantations, wood lots, shelter 

 belts and wind-breaks. 



The bureau of forestry is prepared so far as its appropriation will 

 permit, to render practical and personal assistance to farmers and others 

 by cooperating with them to establish forest plantations, wood lots, 

 shelter belts and wind-breaks. 



Applications for such assistance are considered in the order of their 

 receipt, but the bureau reserves the right to give preference to those 



