JAMES C. SPACE 



1 . 9622 i 

 I2R312 2 



UNITED STATES DEPARTMENT OF AGRICULTURE 



FOREST SERVICE 



FOmT * RAHE EXPEmEUT STATlOfi 



OCDEN 



UTAH 



No. 76 



AERIAL VOLUME TABLES FOR PONDEROSA PINE TYPE 

 IN THE ROCKY MOUNTAINS 



May L960 

 cr 



Karl E. Moessner 

 Division of Forest Economics 



These aerial photo volume tables for ponderosa pine type result from the ! 

 continuing research in direct photo estimating conducted at the Intermountain 

 Forest and Range Experiment Station, Ogden, Utah.J^/ 



Volume estimating by direct photo measurement requires a different \ 

 approach from ground cruising. Individual trees have little meaning to the 

 photo interpreter; he sees and measures plots or stands. His estimates are 

 most reliable when he has learned to think in terms of mean per acre volumes 

 as they relate to the direct photo measurements of stand height, crown dia- 

 meter, and crown coverage. i 



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Photo interpreters have difficulty in identifying species on the small i 

 or medium scale photos usually available, and since many forest types contain I 

 a mixture of hardwood or conifer species, aerial stand volume tables usually j 

 are prepared as composite tables. Such tables may be for either conifer or I 

 hardwood, depending on the predominant cover, and usually are compiled from 

 plots having a random grouping of species. 



Ponderosa pine, however, occurs as a relatively pure type over extensive 



areas throughout the West. Although Douglas- fir and a few other conifers may i 



be found on some north slopes, they rarely constitute more than 20 percent of j 



',:he per acre volume in this so-called pure type. ' 



! 



The type is easy to recognize on aerial photos. Its identifying charac- 

 teristic is the tendency to grow even-aged in small groups with crown cover i 

 of the dominant stand often less than 55 percent of the acre. In the more j 



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1^/ Moessner, Karl E. Preliminary aerial volume tables for conifer stands 

 in the Rocky Mountains. U.S. Forest Sew., Intermountain Forest and Range 

 Expt. Sta. Research Paper 41, 17 pp. illus. 1957. 



