135 



Oh this basis, the yield in cubic feet from an acre of woodland as 

 returned by owners, was as shown by the following table. 



YiEij) Per Acre of Wood on Farm Wood-lots 

 Based on Answers to Questionnaire 



If as shown on page 115, the total area in farm wood-lots is 

 2,668,050 acres, this area divided among the 237,181 farms of the .state 

 gives 11.239 acres of woodland per farm. 



The yield per farm, or per average wood-lot, on this basis of wood 

 material is given in the table on page 138. 



In thus endeavoring to measure production of wood crops by 

 merely recording the yields obtained on an average acre of a large total 

 area of woodland from questionnaires sent to selected individual owners, 

 two factors of error may be present. First, those responding may pos- 

 sess the better grades of woodland, or may have more recently sold or 

 cut timber crops. This would tend to raise the indicated yields above 

 the true average. Second, the amounts cut on given areas in given years, 

 even when distributed over the total area of woodland involved, does 

 not necessarily indicate what the growth was on these areas for the 

 same period, or even their average annual production, since it may mean, 

 rather, a mere removal or cutting into the accumulated capital of the 

 wood-lot. The rate of cutting may exceed the annual average rate of 

 growth, or be less than this growth. The owner may cut his crop clean 

 and entirely replant or permit sprouts and seedlings to restock the area. 

 The capital of a wood-lot is like a sum invested permanently whose 

 interest only is to be expended. If in any period, less than the interest 

 is used, the capital increases. Continual expenditure of more than the 

 interest diminishes not only the cai)ital but the annual income as well, 

 and ultimately will dissipate the resource. But unlike money, this forest 

 capital can only increase by means of the interest earned, or growth, 



