SOME OBSERVATIONS ON THE RELATION OF SOIL 



MOISTURE TO HEIGHT GROWTH IN YELLOW 



PINE SAPLINGS 



By WAI.TER J. Perry 



It is interesting to note how the wetness or dryness of a season is 

 directly reflected in the height growth of pine saplings. Knowing the 

 precipitation figures for any one of recent years, the figures for any 

 one of the remainder could almost be set down simply by observing the 

 annual growth of the young trees for the corresponding year. 



The figures given herewith, covering a dozen years, are the result 

 of recent observations and measurements along this Hne, and supple- 

 ment and confirm my general observations for many years. The most 

 remarkable thing they show is that the growth for 1920 is some 113 

 per cent greater than the average for the previous 11 years. It is 

 also notable that no evidence is to be found of any year's growth during 

 the past 40 or 50 years, or indeed at all, even approaching that of 1920. 

 This enormous growth is, without doubt, to be credited to the heavy 

 snows of the winters of 1918, 1919, and 1920, and the rains which con- 

 tinued through the summer of 1920. Many springs and arroyos, which 

 ordinarily would have been dry, were flowing that year. 



Trees selected for measurement ranged from 20 to 32 years of age, 

 with an average of 27 years. Total heights ranged from 8 feet 7 inches 

 to 16 feet 5 inches, with an average of 12 feet 3 inches. 



Special care was taken in selecting trees, with reference to having 

 all types of density of stand represented, from open-grown, isolated 

 specimens to badly crowded ones, the object being a study on rate of 

 perpendicular and lateral growth under varying conditions. 



Observations were made in pure yellow pine type at an elevation of 

 approximately 7,200 feet. The type site is fair to excellent ; timber is 

 a rather sparse stand of mature and overmature 2-3-log trees with an 

 occasional 4-log tree ; there is an understory of 8-14-inch black jack and 

 saplings 20 to 30 years old, the latter being principally in groups sur- 

 rounding old trees ; younger seedlings are infrequent, and the site may 

 be considered fully stocked as it stands. 

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