Address correspondence to Chief U.S. Weather BureauU. S. DEPARTMENT OF AGRICULTURECENTRAL OFFICE OF THE WEATHER BUREAUOFFICE OF THE EDITOR WASHINGTON, D. C. June 23, 1914.Dr. John Muir,Martinez, Cal.Dear Sir:A recent memoir by Prof. Ellsworth Huntington on the use of trees as an index to climatic changes. pays especial attention to the annual rings of growth of the sequoias. Knowing your great interest in the preservation of these trees and in botanical studies in general, I should be glad to publish in the Monthly Weather Review a short article by yourself summarizing what we really know about the laws of growth of sequoias or other trees.It seems to mo that it is not enough to simply assume that the so-called "annual rings" depend upon temperature or rainfall or other details in the atmospheric conditions; apparently the soil and the soil temperature should have some influence. Are the annual rings each individually continuous and of uniform breadth? Does the darker part of each ring represent growth during or just after some special season of the year, such as the dry season or the wet season or the time of blossoming?Does the sap of the sequoias form the dark part of the annual ring when sap is ascending or when it is returning downward after exposure in the leaves to the action of sunshine and evaporation? Do not fresh cut branches or trees05782
Washington, D. C.
1914 Jun 23
Original letter dimensions: 26.5 x 20.5 cm.
Reel 22, Image 0429
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