35 



larch are saved from exclusion only by the short life of the lowland 

 fir, which is quite susceptible to disease. Plans for the future forest 

 which contemplate cutting the second growth at a period less than 

 the average life of lowland fir must take into consideration the 

 aggressiveness of this species. 



Since both white pine and Douglas fir are active in restocking 

 burns, a heavy thinning followed by a light surface fire, immediately 

 preceding a good seed year of these species, is advisable wherever 

 there is no need of keeping the stand intact for protective purposes. 

 Where heavy thinnings can not be practiced, reduction of the pre- 

 ponderance of seed trees of undesirable species must be accomj^lished 

 gradually by successive cuttings in which the preferred species are 

 favored by high cutting limits, w^hile the others are cut to the lowest 

 merchantable diameters. Such management must necessarily be 

 gradual on account of the unwillingness of purchasers to take a large 

 proportion of the poorer grades. 



CENTRAL ROCKY MOUNTAIN REGION. 



The value of Douglas fir for mining and flume timbers renders it 

 the species to be encouraged above all others in this region. It grows 

 here chiefly in mixture, and competes, according to situation, with 

 lodgepole pine and yellow pine. In both cases the selection method 

 of cutting is likely to increase the proportion of Douglas fir. 



The dense, pure stands of lodgepole pine which characterize this 

 region are peculiarly adapted to clean cutting in strips, with surface 

 burning to provide a mineral seed bed. Where Douglas fir mixes 

 with lodgepole pine in sufficient abundance and quality to warrant its 

 perpetuation as a type, selection cuttings should be conducted with a 

 view to remo\dng a maximum of the pine and a minimum of the fir. 

 The former should be thinned to the maximum amount consistent 

 with security of the remaining stand against windfall, while the 

 latter should be cut only to a relativel}^ high diameter limit, so as to 

 retain a reserve of seed trees sufficient to establish an even and 

 abundant second growth throughout the thinned forest. The fact 

 that Douglas fir is often found in nature coming up under mature 

 stands of lodgepole pine indicates that the mountain 'form of Douglas 

 fi.r is sufficiently tolerant to grow in light shade, and further, that the 

 humous soil conditions of such stands afford a satisfactory seed bed 

 for the fix- without the ground burning so essential for the best re- 

 production of lodgepole pine. For protection against fire it will 

 probably be necessary to pile and burn the brush resulting from log- 

 ging, but to prevent exposing mineral soil — the best seed bed for 

 lodgepole pine — such burning should be restricted to the smallest pos- 



[Cir. 150] 



