20 FORESTRY INVESTIGATIONS U. S. DEPARTMENT OF AGRICULTURE. 



more complicated matter than most people would .suspect, especially since our measurements can 

 only be made on trees and stands of trees which have grown in nature's unattended forests, while 

 with the application of knowledge and skill in the management of the crop quite different results 

 may be secured. A bulletin of the Division, No. lilt, has been published describing the methods of 

 measurement of standing trees and forests and of the rate of growth of trees and forests. 



There have been many misconceptions abroad as to the rapidity of tree growth and the amounts 

 that may be harvested from an acre in a given time. If wood alone were, to be produced the mat- 

 ter would be much more simple. We could, from the experience which has been gathered in other 

 countries and in our own, soon arrive at a statement as to the amount of wood which an acre of a 

 full-grown dense forest crop could produce, just as we know the productive capacity of an acre of 

 wheat or barley. 



In an average of a hundred years the yearly growth, according to species, soil, and climatic 

 conditions, would vary between :>0 and 180 cubic feet of wood per acre each year. I Jut, unless fire- 

 wood is the object of forest cropping, it is not quantity of wood merely, but wood of given si/.e 

 and of given quality, wood fit for the arts, that is to be grown. It will only pay to raise wood of 

 this kind. Hence, it is necessary not only to know what sizes can be grown in given periods of 

 the life of the crop and what sizes can be profitably handled at the mill or in the market, but also 

 what qualities are desired and under what conditions they can be produced. Trees develop very 

 differently at different periods of their life. Thus, \vhile a white pine tree may in the first fifty 

 years have grown on an average one-third of a cubic foot of wood per year, if we had waited till 

 the hundredth year the average rate per year would appear as more than 1 cubic foot, and the 

 total volume four to five times what it was at fifty years, although the diameter has only about 

 doubled. Again, while at fifty years hardly more than 15 per cent of the total wood volume would 

 have furnished saw timber, perhaps making 50 feet B. M., at one hundred years the proportion of 

 the more valuable milling material would have risen to "10 per cent and more of the whole tree, 

 and the output of timber would have reached 500 feet B. M. On the other hand, an acre of pine 

 fully stocked which at .one hundred years may have produced at the rate of 140 cubic feet per 

 year could under the same conditions have produced for the first fifty years at the rate of 180 

 cubic feet per year, or nearly one third more. Yet the value of the wood on that same acre at one 

 hundred years is very considerably more than the fifty-year old wood, on account of the increased 

 proportion of highly useful material that can be got from it. Similarly, we find that not more than 

 1 to 2 per cent of the wood produced in the coppice sprouts of twenty to twenty five years' growth, 

 in which New Kngland abounds, is serviceable in the arts, while 50 to 75 per cent and more may be 

 thus profitably utilized from the same acre if grown from seed and allowed to grow one hundred 

 years. 



It will be readily seen from these few glimpses into the subject that this knowledge of the 

 rate of development and yield of our timber trees is indispensable for the discussion of the profits 

 of forest cropping, and also furnishes hints for rational methods of silviculture. This same white- 

 pine tree, for instance, could have made much more wood if it had been allowed to grow without 

 interfering neighbors, but it would not only have assumed a less useful conical shape, but would 

 have put much of its energy into branches, which not only do not furnish serviceable wood, but 

 produce knotty lumber, an inferior or unsalable article. Moreover, the wood of most or many of 

 our trees changes in quality with age, so that with size, form, and freedom from knots not only 

 the technical value, but the money value also, grows disproportionately. 



It will then appear at once that these measurements must precede the discussion of the ques 

 tiou most momentous to him who is to be induced to engage in the business of forest cropping, 

 the first and last question asked: 



IS FORESTRY PROFITABLE! 



It is claimed that if this question were answered in the affirmative, forestry practice would at 

 once be established in this country. Unfortunately it is a question that nobody can answer in 

 general terms. No business is profitable per se; one railroad fails, another pays; for profitable- 

 ness depends upon a complexity of conditions which are local, and hence without given conditions 

 it is useless to attempt to answer such a question. It has been shown that under the economic 

 and populational conditions of Germany (see Appendix) forestry is not everywhere, by any 



