MANAGEMENT. 29 



compares favorably with this. Spruce is more limby, and from an 

 economic standpoint inferior, but its extreme tolerance renders it of 

 great value in cleaning the other species. It seldom comes in where 

 either yellow pine or Douglas fir would grow. 



Since the silvical requirements Of western yellow pine, Douglas 

 fir, and blue spruce are different, especially in regard to light, it is 

 necessary, in order to maintain their growth in mixture, to employ 

 a selection method of cutting. For such a method only broad rules 

 can be outlined which in a general way will suit the conditions and 

 serve as a basis for more detailed studies. 



Over most of the type are western yellow pine and Douglas fir of 

 all ages, from the seedling to the veteran stage; spruce is commonly 

 found up to the age of 150 years. As far as age is concerned, there- 

 fore, the type is uniform, but the proportion in which the different 

 species occur varies widely. Upon this, in any given situation, 

 depends the amount of timber of each kind which should be removed, 

 and that species, if any, which, on account of its limited occurrence, 

 should be favored. 



All mature and overmature timber should be removed, together 

 with that still making a good growth, but which would be over- 

 mature at the time of a second cut. All thrifty Douglas fir and 

 yellow pine'which will plainly be of more value in the future should 

 be left standing. Spruce, on areas suited to yellow pine and Douglas 

 fir, should be cut to the lowest diameter limit from which merchant- 

 able material of any kind can be obtained, except where its presence 

 would cause pine and fir to prune themselves. In the spruce-pine 

 subtype the aim should be, in the main, to produce yellow pine saw 

 timber in connection with spruce poles and stulls. In the spruce-fir 

 subtype the cutting should be regulated so that each species yields the 

 best class of material for purposes to which it is particularly adapted. 



The proportion of the stand to be left uncut will depend largely 

 upon local conditions. Enough trees must be left standing to insure 

 seed for future crops and to serve as a protection to young growth 

 not yet established. Since there is timber of practically all ages, trees 

 below the merchantable diameter limit will as a rule furnish sufficient 

 protection to young growth. Merchantable yellow pine and Douglas 

 fir left because of their greater value at the time of a second cut will 

 in most cases furnish enough seed. Spruce commonly produces 

 seed at diameters of from 8 to 12 inches. Only where reproduction 

 is insufficient or where protection is needed should mature or nearly 

 mature seed trees of any species be left standing. Broadly speaking, 

 trees of all species above 29 inches and most of those between 20 

 and 29 inches in diameter should be removed. The number of trees 

 under 20 inches in diameter cut depends chiefly upon the density of 

 the stand. In dense stands of young trees, which are not infrequent, 



