THE RELATION OF CROWN SPACE 



TO THE 



VOLUME OF PRESENT AND FUTURE STANDS 



OF 

 WESTERN YELLOW PINE. 



By George A. Bright. 



The most striking feature of a stand of Western Yellow pine 

 is its open character. This peculiarity is the first thing which 

 strikes any one looking upon such a forest for the first time. 

 Even growing on the best soils and under favorable climatic 

 conditions, it would be difficult, if not quite impossible, to find 

 a full or normal stand of Yellow pine over an area of forty or 

 even ten acres. There appear openings even where the very 

 best conditions for the growth of this tree occur, as well as in lo- 

 calities where conditions are less favorable. 



This peculiarity of Yellow pine stands is due to five primary 

 causes, as follows: (i) fire, (2) insect infestation, (3) windfall, 

 (4) root competition and (5) light competition, 



(i) In stands of Lodgepole or Engelmann spruce a fire will kill 

 most of the trees that it touches and the ground is practically 

 cleared for an entirely new stand, which generally comes in 

 quickly and evenly, the light seeds of these species being blown 

 for considerable distances. In the case of Yellow pine, on the 

 other hand, comparatively few trees are killed by a single fire. 

 Openings are only made here and there in the crown cover by 

 the destruction of one or a few trees at best. 



On deep, moist soils the damage done by fire is less than on 

 dry soils or where the soil is shallow ; also reproduction is here 

 far less precarious. For these causes primarily the openings on 

 dry soils are apt to be large and more frequent, although the trees, 

 once having obtained a start, make good growth. In a report by 

 Mr. Munger he discusses the damage done to Yellow pine by 

 surface fires. A table taken from this report follows : 



