20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I40 



III. THE METHODS USED 



The work that forms the basis of the present report was done from 

 1939 to 1950 upon complete sections cut from the branches of trees or 

 shrubs, except for eight trunks which were dissected in whole or in 

 part. 



Both macroscopic and microscopic methods were used, the former 

 including for the most part labehng, observations, measurements, and 

 artificial freezing, and the latter the preparation and analysis of micro- 

 tome sections. In actual detailed experimentation and measurement 

 more branches were always chosen than would ordinarily be necessary 

 in order to allow for damage by man, ice storms, and incidental haz- 

 ards. Exploratory samples were taken from diverse trees in diverse 

 habitats for the purpose of comparing them with the trees from which 

 the majority of the specimens was taken. With the exception of those 

 methods devised for special purposes in the development of our work, 

 the remainder were, of course, those common to botanical and silvi- 

 cultural practices. 



All experiments, observations, measurements, and thin-section 

 analyses were made by Clock and Studhalter working together at the 

 same time. This joint work holds true except for the years 194J2 to 

 1945, when each one carried on independently work applicable to the 

 common problem. 



MACROSCOPIC METHODS 



Simple descriptions based on locality were sufficient in the Lubbock 

 area to maintain the identity of individual trees. With branches, how- 

 ever, it was quite different. Their identity was maintained in two ways : 

 first, by a band of twine at an appropriate place ; and second, by close 

 measurement from the ground up the trunk and out the branch, es- 

 pecially from significant crotch to crotch, until the exact place of 

 measurement or experimentation was reached. With these details 

 recorded, we found it possible to return to an exact spot on a partic- 

 ular branch at any time. 



Each tree was given a letter symbol and a number, as has pre- 

 viously been explained. Branches used from any one tree were num- 

 bered consecutively. For instance, TTP 20-43 refers to Texas Tech- 

 nological College pine tree Number 20 and to the 43d branch selected 

 therefrom. When a branch was removed for dissection, blocks were 

 cut at intervals throughout its length, the innermost being labeled a, 

 and those successively outward, h, c, and the like. The final designa- 

 tion of a block reads, therefore, as follows : TTP 20-43-a. If a hand 



