56 FOREST REGULATION 



the normal average yearly growth of ripe timber, two figures 

 useful in the development of the Working Plan. 



Similarly in mixed stands and many age stands, the actual 

 Growing Stock of a fair number of the best stocked acres seems 

 still the best basis for a provisional Normal Growing Stock and 

 Normal Average Growth in these stands. 



In all cases the yield table results may well be checked by the 

 use of Volume tables and by a comparison with established tables 

 for the same kind of timber. A goqd set of Volume tables, especially 

 where attention has been paid to the ''growing space'' or area of 

 land occupied by the trees of different sizes, deserves attention. 



In setting the average age of the best mature stands it is well 

 to keep in mind that the ordinary stand of timber (pure and even 

 aged) does not increase, materially, in volume after a certain age, 

 and that this age for most species is far within the limit of the 

 natural Rotation or life of the tree. 



In the field work of gathering data for Yield tables, a task 

 well done by the valuation survey crew, it is well to select the stands 

 carefully and to be satisfied even with areas of one-half acre, rather 

 than complicate conditions. In hard pine, etc., stunted, dense stands 

 must be avoided ; preferably also very old stuff, since future rota- 

 tions will rarely consider stands over 150 years old, and the majority 

 not over 100 years. 



Considering the many difficulties in the preparation of Yield 

 tables, the question may well be asked: Why prepare these tables 

 at all ? The answer is : Just as a farmer wants to know, and needs 

 to know how much wheat or corn he can raise on a given farm, so 

 the Forester should know, and the owner wants to know how much 

 pine timber will this property produce per acre and year. 



This is the function of the Yield table ; and while the figures 

 from wildwoods may never be very accurate, they will at least be 

 near enough right to prevent foolish investment and utterly mislead- 

 ing statements, such as have already been circulated about Eucalyp- 

 tus. Jack Pine, Norway Poplar, etc.. in our country, and they will 

 also prevent costly planting on miserable sites and equally so the 

 unwise penury of leaving good lands idle for want of proper plant- 

 ing. In the regulation of large forest properties, even approximate 

 figures, if rationally based, will give assurance of continued supply, 

 by preventing thoughtless overcutting of the forest. 



