490 Forestry Quarterly. 



will be twelve inches, requiring a rotation of ninety years. The 

 dense reproduction which follows cutting should develop into 

 stands of clean boled, slightly tapering trees well suited for ties 

 and rough lumber. It may be noted that the crowns occupy only 

 a small proportion of the total area. In Western Yellow Pine 

 the chief competition is in the roots, but it is believed that the 

 crown measurements indicate the relative demands on the situ- 

 ation of trees of different sizes. The growth is too slow to war- 

 rant holding more than a very small proportion, if any, of the 

 stands as reserves for quality. Western Yellow Pine in this 

 region will produce only ties and rough lumber. 



Although an approximate twelve inch diameter limit may be 

 adopted in the future, the business of the School in its cutting now 

 is to improve the vigor of the stand by removal of mature and 

 defective trees, — in other words to cut on a silvicultural rotation. 

 The silvicultural rotation is from about one hundred and twenty 

 to one hundred and fifty years, and requires a diameter limit of 

 from fourteen to sixteen inches. This diameter limit, in practical 

 forestry, would, of course, be considered approximate only, in 

 actually marking trees for cutting, and the vigor of the trees 

 would determine very largely whether or not they should be cut. 



The silvicultural method is simply shelterwood. If only the 

 mature and defective trees are cut, immature trees will be left in 

 sufficient numbers to insure seed and to insure protection for 

 seedlings. The mature and defective trees comprise about 50% 

 of the stand. In marking, the only question, therefore is, whether 

 or not each tree is more valuable now than it will be later. Trees 

 with spike tops, cat faces in which decay is liable to begin, mistle- 

 toe infestation, irremediable crooks, small, unproductive crowns, 

 and trees showing signs of maturity, should be cut. Trees with- 

 out defect, with crooks that in time will be somewhat corrected 

 by diameter increase, and with large vigorous crowns, should 

 be saved. 



Douglas Fir on account of its durability is in greater demand 

 than Western Yellow Pine. It occurs in limited quantities and 

 as its stumpage value is probably about $1.00 higher than that of 

 the pine, it should be disposed of conservatively. 



One of the chief purposes in the preparation of the working 

 plan was the determination of the annual cut necessary for a sus- 

 tained yield. Computation based on the abundance of repro- 



