500 



SCIENCE. 



[N. S. Vol. VIII. No. 198. 



planting a new crop just as wanted appears 

 the simplest system. Yet, aside from other 

 flaws which adhere to this method, it would 

 under our conditions of labor be too expen- 

 sive to employ, except on such areas as are 

 now denuded or devoid of desirable species, 

 or else for demonstration of methods and 

 results. In such cases other species adapted 

 to the locality and promising both silvicul- 

 tural and financial success, among which 

 especially is the white pine, would be 

 favored. 



The other class of management for repro- 

 duction, which depends upon natural seed- 

 ing from the trees on or near the area to 

 be reproduced, offers several methods, 

 among which the method of selection in 

 which mature trees here and there selected 

 through the forest, or certain parts of it, 

 are taken resembles most the lumbermen's 

 present method, except that he is influenced 

 only by the marketableness of his trees, 

 while the forester keeps foremost the benefit 

 to the young growth that is left. This 

 method is especiallj^ adapted to those por- 

 tions which are situated on the high eleva- 

 tions, crags and heads and wherever it is 

 dangerous to expose the soil. Modifications 

 of this system, for instance one in which 

 groups of trees are removed and the repro- 

 duction, therefore, is secured by clumps 

 rather than by single individuals, may be ac- 

 ceptable in other parts of the property, and 

 finally for the sake of demonstration all 

 other systems of management, such as the 

 strip system, the nurse-tree system, etc., 

 may be practiced on smaller or larger 

 areas. 



One of the most difficult and important 

 questions to be determined, especially with 

 regard to financial results, is the rotation, 

 i. e. , the age to which the crop is to be al- 

 lowed to grow before utilizing it. Unlike 

 other crops, the harvest time of which is 

 determined by natural limits, their ripeness, 

 the harvest of the wood crop is not so 



circumscribed. There is a choice as to 

 when to harvest it, into the making of 

 which a number of considerations enter. 

 First, of course, useful size is the main con- 

 sideration; the production of hoop poles, 

 hop poles, vineyard stakes may be satisfied 

 by a ten to twenty years' growth ; railroad 

 ties may be secured in thirty to forty years, 

 and so on. "Where reproduction from seed 

 is expected, the age at which frequent and 

 prolific seed production takes place, ma- 

 turity in the sense accepted for animals 

 will set the lowest limit ; finally, however, 

 since the business of forest production is 

 mainly carried on for financial results, the 

 financial rotation must be determined, i. e., 

 that time at which it pays best to harvest 

 the crop. Quantity of production as well 

 as change in quality, both of which are 

 vai'iable witli age of the crop and market 

 conditions, influence its choice. A series of 

 measurements of the rate of growth of the 

 wood crop and calculations based on them 

 and on cost of production and administra- 

 tion and consideration of market require- 

 ments, present and conjectured future ones, 

 lead to the adoption of this regulator of the 

 time element in reproduction. 



These calculations may lead us to adopt 

 a rotation of eighty years for parts of our 

 school forest of spruce with hardwoods and 

 100 years or more for other parts ; that 

 means we would distribute our fellings in 

 such a manner that by annually or period- 

 ically equal or nearly equal amounts we re- 

 move all the wood that has been produced 

 during the period of 80 or 100 years re- 

 spectively, taking care that as much wood 

 is left to form what is called the normal 

 stock of wood, the working capital of wood 

 necessary to secure by annual accretions the 

 most desirable and profitable production of 

 which the property is capable. 



These calculations also lead finally to the 

 conclusion as to the amount of wood that 

 may be annually or periodically cut without 



