RESEARCH METHODS IN STUDY OF FOREST ENVIRONMENT. 171 



Date. Date. 



1 . Swt lling of buds 9. End of leaf falling 



2. Bursting of buds 10. Beginning of seed ripening 



3. Begin n ing of leafing out 11 . General seed ripening 



4. General leafing out 12. Beginning of seed falling 



5. Begin n ing of blossom ing 13. End of seed falling 



6. General blossom ing 14. Quantity of seed 



7. Chang, in color of foliage 15. Quality of seed 



8. Beginning of leaf falling 



General remarks 



Instructions on hack of this form should be followed strictly. 



Under the name " dendograph ' McDougal 22 has designed a new 

 instrument for measuring and recording the diameter growth of tree 

 stems. This instrument is bring thoroughly tried out. It will 

 probably be a very valuable adjunct. It is not simple in construction 

 or operation, however, and will always be too expensive to be exten- 

 sively used. It would seem that a beginning must be made in a more 

 simple way, perhaps through circumferential measurements, even 

 though a number of complicating factors must be taken into account, 

 such as the expansion of the tree and of the tape with increased tem- 

 peratures. 



INTERNAL OR PHYSIOLOGICAL OBSERVATIONS. 



Although the forester is prone to think of growth as the major 

 reaction of interest, it is entirely possible that there may be positive 

 gain in studying the more fundamental reactions which lead up to 

 growth. For example, in the conifers, the outward evidences of 

 growth may disappear by midsummer, so far as height accretion is 

 concerned: yet diameter growth continues longer, and this period 

 of relative inactivity is of great importance in accumulating a reserve 

 for the effort of the following season. Is it not logical, therefore, 

 that the growing season for trees should be considered to be the 

 entire period in which materials for growth are being produced ? 



Again, while growth is a large factor when competition begins, 

 the critical conditions which have the greatest bearing on the success 

 of the individual and species, and thereb}^ affect most acutely the 

 character of the plant formation, may, in the case of all perennial 

 plants, be encountered not in the growing season but in the dead of 

 winter. Through neglect of this period erroneous conclusions may 

 again be reached as to the importance of various conditions in 

 building up the plant formation. 



It should therefore be most desirable to be able to determine the 

 physiological conditions of the plant frequently in order that its 

 reaction to every change in environment may be followed. The 



- MacDougal, D. T. Growth in Trees. Pub. 307, Carnegie Inst. Washington, 1921. 



