Lodge Pole and YcUon' Pine Distribution. 513 



where the water table is deep and the drainage thorough, Yellow 

 Pine grows abundantly, its long taproot being able to draw suf- 

 ficient moisture from the deeper strata. 



Because Lodgepole Pine is not at all dependent on drainage 

 this factor should not affect its distribution. That it forms the 

 complete stand on the pumice fiats is due to the fact that Yellow 

 Pine cannot grow on such sites and the whole field is, there- 

 fore, left to the Lodgepole Pine. On the slopes, where conditions 

 are favorable for Yellow Pine, this species on account of its 

 longer life, greater height and superior fire resistance, is usually 

 able to maintain itself. Lodgepole Pine occurs on such sites but 

 it is either as a scattering understory or as an even-aged stand, 

 following fire. It may have seeded in from the side but more 

 likely has come from an understory of Lodgepole Pine in the 

 old Yellow Pine stand. 



On the edge of a bench there is usually a strip of Yellow Pine. 

 For example, along the road leading southwest from Crescent 

 toward Odell Lake. Here Lodgepole Pine forms a pure stand 

 on the level upper bench and on the flat along the river below. 

 The difference in elevation is not over 15 or 20 feet and the 

 soil appears to be identical, but the water table along the edge 

 must be lower than on either bench and it is along this edge 

 that the Yellow Pine occurs. There must be some cause for 

 this and what is more reasonable than to suppose that it is the 

 dift'erence in the soil moisture? 



In the Upper DesChutes Valley, in Ranges 8 and 9, East, 

 Lodgepole Pine forms almost a complete stand but further east 

 the percentage of the Yellow Pine area increases until near the 

 eastern boundary of the Forest, in Township 23 S., Range 16 

 East, there is no Lodgepole Pine whatever. If we assume that 

 the theory just outlined is the correct one this condition is what 

 we should expect since the pumice layer is deepest in the upper 

 DesChutes country and becomes thinner toward the east, until it 

 practically disappears at about the eastern limit of the Lodgepole 

 Pine. Occasionally Yellow Pine may be found on a Lodgepole 

 Pine flat but it is always near the bottom of a slope or where rock 

 outcrops are frequent. It is probable that the pumice cover in 

 such places is thin and that the moisture conditions are similar 

 to those on the slopes. 



In connection with a study of the distribution of these species 



