Effect of Environmental Factors on the Wood Structure of Lodgepole Pine, Pinus Contorta Loudon

Abstract

That environmental factors affect the structure of the leaves of plants is well known, and a considerable literature has grown up around the development of that fact. Some investigations have proven that such factors also measurably affect the cellular structure of the wood of trees (Adams, '28, Cieslar, 1897, Geiger, 'I5, Hartig, 'oi). Other investigations cast doubt upon this assumption (Harlow, '27). Moreover, the exact correlation, if any, of variations in cell structure with measured factors of the habitat has been investigated in but few instances. That such a probable correlation is of scientific and economic value is shown by the increased attention being given to this subject by the United States Forest Products Laboratory (Koehler and Paul, '29, Paul, '30) and the Canadian Forest Products Laboratory, as well as by research workers in the educational and research institutions of this and other countries. While studying the vegetation, successional relations and environmental factors of an isolated lava bed in the Cascade Mountains of southwestern Washington, in contrast with the vegetation just off the lava bed, an excellent opportunity presented itself for studying not only the growth rates of the trees, but also the effect of the severe conditions of the lava bed on the minute structure of the wood of the trees. For this purpose specimens of the wood of several species of trees growing on the lava bed and just off the lava bed were obtained and a study made of their structure. The general vegetational and environmental conditions obtaining on and off the lava bed will be discussed elsewhere,1 and the purpose of this article is to record the results of a study of the wood structure of one of the tree species, the lodgepole pine (Pinus contorta Loudon), as affected by varying site factors. The wood of lodgepole pine growing in sphagnum bogs in the same region was also included for the sake of comparison.