Transcription:
Address correspondence to Chief U.S. Weather Bureau U. S. DEPARTMENT OF AGRICULTURE BR BR CENTRAL OFFICE OF THE WEATHER
BUREAU OFFICE 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 trees 05782