RESEARCH METHODS IN STUDY OF FOREST ENVIRONMENT. 25 



Annual Summary 



The annual summary of air temperatures on the "Summary" 

 form should be a tabulation by decades and months of the means or 

 totals obtained from the "Air Temperature Record," with the 

 annual mean or total, as the case may be, computed therefrom. 

 Usually a separate "Summary" form will be used for each datum 

 to be summarized. 



In addition, as a part of the annual summary, there should be 

 worked out the mean or total for each datum for the growing 

 season. The limits of the latter may be determined, as indicated by 

 the discussion in earlier paragraphs. 5 Whatever the criterion as to 

 the actual length of the growing season, it should be considered to 

 begin and end with even decades, and all means computed for the 

 growing season should be the sum of the decade means divided by 

 the number of decades. 



Form 10. 



[U. S. Forest Service, Physical Survey.] 

 SUMMARY. 



Type 



.; station No ; datum 



height or depth 



Year. 



Mean 

 grow- 

 ing 

 sea- 

 son. 



[Determined by comparing annual means for 1 foot and 4 feet.] 



Instruments. 



Approximate 

 Thermometers and shelters: range of prices. 



Mercurial thermometer (Weather Bureau pattern) $1. 25 to $3. 00 



Maximum thermometer (Weather Bureau pattern) 2. 50 to 5. 00 



Minimum thermometer (Weather Bureau pattern) 1. 50 to 3. 00 



Maximum and minimum thermometers are often supplied in 



pairs. 



Support for maximum and minimum thermometers 2. 00 to 2. 50 



Instrument shelter, complete, without supports 20. 00 to 30. 00 



a As a matter of fact the temperature conditions that delimit the growth of plants, and especiaUy of 

 coniferous trees are not known, and to attempt to fix a rule for determining when the growing season 

 begins and ends would, at this stage, be extremely arbitrary. 



