Accession Number : AD0664014

Title :   TREE-RINGS AND CLIMATIC CHANGES IN WESTERN NORTH AMERICA.

Descriptive Note : Final rept.,

Corporate Author : ARIZONA UNIV TUCSON

Personal Author(s) : Schulman,Edmund

Report Date : 20 JUN 1953

Pagination or Media Count : 153

Abstract : Based on about one-third million annual rings in selected, drought-sensitive trees from semi-arid sites, regional indices have been derived for the upper basins of all the major streams of the western United States. Almost all indices are statistically well-based for about 500 years; the Colorado and Missouri indices are well documented for about 800 years. Three series of maximum length are: Colorado, 2,009 years, including the extension in archaeological beams; Snake, 1494 years; Missouri, 973 years. A major element in the construction of these indices was the discovery and extensive sampling of a category of drought-recording, stunted conifers growing with extreme slowness on the most adverse sites and attaining ages twice or more the normal for the species on optimum growth sites. The oldest tree thus far discovered in each of the principal species is: limber pine, 1510 years; pinyon pine, 975 years; Rocky Mountain Douglas-fir, 880 years; ponderosa pine, 850 years. The much longer-lived Sequoia, growing in a relatively moist environment, were not sampled for this report.

Descriptors :   (*TREES, GROWTH(PHYSIOLOGY)), (*CLIMATE, NORTH AMERICA), AGING(PHYSIOLOGY), THICKNESS, ECOLOGY, CORRELATION TECHNIQUES, RAINFALL, PERIODIC VARIATIONS

Subject Categories : Forestry
      Meteorology

Distribution Statement : APPROVED FOR PUBLIC RELEASE