330 



Yearbook of Agriculture 1949 



able estimates of board-foot volumes; 

 a framework on which to base future 

 plans for timber cutting and from 

 which the allowable annual sustained- 

 yield cut could be calculated. On the 

 basis of forest-management formulas 

 the allowable annual cut was deter- 

 mined to be 323 million board feet, the 

 amount that the land could grow if it 

 is kept fully productive. 



With the allowable cut determined, 

 still another problem remained what 

 methods of cutting would most effec- 

 tively keep the lands productive. 



The Forest Service always has re- 

 served the right on its timber sales to 

 require that, as a fire-prevention meas- 

 ure, the slash be burned; that no mer- 

 chantable logs be left in the woods after 

 logging; that stumps be cut low to keep 

 from wasting timber; and that seed 

 trees be left to reseed cut-over areas. 



Until recently, however, extensive 

 areas of clear cutting were common on 

 national forest timber sales, with the 

 provision that seed trees be left. The 

 seed-tree method of providing for re- 

 stocking of young trees left something 

 to be desired, it was found, because lone 

 Douglas-fir trees are easily blown down 

 by strong winter winds that periodically 

 buffet the Pacific coast. The cut-over 

 land, with no seed source, consequently 

 often grew up to brush instead of to 

 young fir trees. 



The development of truck and trac- 

 tor logging made it possible to reduce 

 the size of clear-cutting areas and still 

 not make the logging cost too high to 

 permit cutting. 



Truck and tractor logging is a flex- 

 ible mode of operation. It made pos- 

 sible sales to small operators, who could 

 afford to log timber only where a lim- 

 ited capital investment in logging 

 equipment and development was re- 

 quired. Tracts of timber not large 

 enough to justify building an expen- 

 sive logging railroad could be opened. 



The first cruisers who had scouted 

 the forest observed that most of the 

 timber volume on the Willamette was 

 in old-growth, overmature stands of 

 Douglas-fir. Later cruises and the pub- 



lication of the systematic resource sur- 

 vey confirmed their observations. True, 

 in certain localities there were exten- 

 sive stands of second-growth, the sequel 

 to large fires that had devastated vast 

 areas along the Cascades in the nine- 

 teenth century. But far the greater part 

 of the volume was in overmature, stag- 

 nant stands stands that were losing as 

 many board feet each year from decay, 

 disease, and windthrow as they were 

 adding through new growth. The worst 

 of it was that losses were in the slow- 

 growing and high-quality "yellow fir," 

 from which most of the valuable clear 

 lumber and plywood is produced in this 

 region. The first need, then, was to con- 

 vert the overmature timber to a grow- 

 ing condition to utilize the old trees 

 and to harvest the trees that were likely 

 to be windthrown. 



To accomplish their purpose, for- 

 esters needed a logging system that 

 would have four characteristics: It 

 had to bypass growing parts of a stand 

 but cut the overmature trees, so as to 

 convert the stagnant forest into a grow- 

 ing forest in the shortest time. It had 

 to extend the transportation system 

 over the entire forest more quickly, so 

 as to make possible the salvage of wind- 

 falls and the fire-killed or insect-killed 

 trees, and the profitable thinning of 

 young stands at a later date. It had to 

 leave a large part of the timber as a 

 reserve to provide for natural repro- 

 duction and preserve the values of wa- 

 tershed protection, recreation, and 

 scenery. It had to avoid creating ex- 

 tensive areas of slash accumulation. 



That ideal logging system is the one 

 to use in converting forest manage- 

 ment from a virgin-timber basis to a 

 vigorously growing, second-growth ba- 

 sis in about 100 years the rotation 

 (that is, the number of years required 

 to mature a crop of timber) in which 

 Douglas-fir forests produce a maxi- 

 mum volume of wood. 



A FOREST usually consists of trees of 

 different sizes; sometimes the age of 

 trees on a single acre can vary widely. 

 Some trees are vigorous and fast grow- 



