Yearbook^ of Agriculture 1949 



leached, and often containing a high 

 percentage of broken rock. Elevations 

 range from 1,000 to 3,500 feet above 

 sea level. The climate, typical of the 

 lower western slopes of the Cascade 

 Mountains, is wet, except for the sum- 

 mer months. Rainfall averages 87 

 inches a year, of which 1 3 inches falls 

 as snow. Nearly every night of the year 

 relative humidity approaches 100 per- 

 cent. Temperature extremes vary from 

 below zero to over 100 F., and the 

 frost-free season is short. During the 

 dry, windy summers, the fire hazard is 

 great. Forest trees grow well, but field 

 crops do not. 



The experimental forest consists of 

 many age classes of timber grown up 

 after old burns in the original forest 

 and after some recent cuttings. There 

 are approximately 4,000 acres of old- 

 growth Douglas-fir and hemlock 

 within the boundaries. An additional 

 2,500 acres of the area was burned by 

 the great Yacolt forest fire of 1902. 

 Part of that area now supports some 

 small patches of old growth, some scat- 

 tered large old-growth trees, and a 

 wide variety of stands of natural regen- 

 eration some well-stocked stands that 

 followed promptly after the burn, 

 some partially stocked areas, and some 

 areas consisting mostly of brush with 

 occasional young trees growing in it. 

 About 600 acres of this area was re- 

 burned by the forest fires of 1927 and 

 1929; about 500 acres of that was 

 promptly replanted and now supports 

 a 20-year-old plantation of Douglas- 

 fir, which will soon be large enough for 

 the cultural-cutting operations. A few 

 miles away from the main area lies a 

 3,500-acre watershed of 100-year-old 

 Douglas-fir. The forest here is ap- 

 proaching maturity, and is represent- 

 ative of the vast, older second-growth 

 stands in the region. 



Timber types vary by age and com- 

 position. The young forest which 

 seeded in naturally after the great fire 

 of 1902 is mostly Douglas-fir, but there 

 is a scattering of the western hemlock, 

 western white pine, western redcedar, 

 and balsam firs. Likewise, the 100-year- 



old stand is practically pure Douglas- 

 fir, with hemlock and cedar beginning 

 to show up in the understory. The old- 

 growth forest is now in the process of 

 transition from the intolerant even- 

 aged Douglas-fir to the tolerant climax 

 forest of hemlock and other shade- 

 loving species. The Douglas-firs are old, 

 but the other species are of all ages; 

 in addition to hemlock, they include 

 Pacific silver fir, grand fir, western 

 white pine, western redcedar, and Pa- 

 cific yew. Where the timber is of mer- 

 chantable size, volumes range from 

 20,000 to 100,000 board feet an acre. 

 One of the important features of the 

 experimental forest is the Wind River 

 natural area. This block of 1,200 acres 

 of the old-growth area was set aside to 

 preserve in an undisturbed state for 

 scientific observation and study an ex- 

 ample of the virgin timber of the re- 

 gion. Most of the stand is Douglas-fir 

 300 to 460 years old; the largest trees 

 are more than 6 feet in diameter and 

 200 feet tall. Parts of the stand are still 

 practically pure even-aged Douglas-fir, 

 while other parts are in various stages 

 of transition from Douglas-fir to the 

 climax forest of the shade-tolerant 

 species. In places the Douglas-fir has 

 entirely disappeared and hemlock is 

 the dominant tree. This tract serves as 

 an undisturbed check area for adjoin- 

 ing stands that are being placed under 

 management. It is systematically cov- 

 ered with permanent sample plots on 

 which timber growth, mortality, and 

 other ecological changes are recorded. 



MANY FOREST-RESEARCH PROJECTS 

 have been completed on the experi- 

 mental forest and many are under 

 way. They vary from single observa- 

 tions or sample plots to commercial- 

 size forest cutting operations. Early 

 Douglas-fir nursery and planting tech- 

 niques were worked out there, and 

 many fundamental studies have been 

 made that have shaped the silviculture 

 of the region. 



Seed of Douglas-fir and its associates, 

 once thought to live years in the forest 

 floor, was found to germinate or die 



