WESTERN HEMLOCK - INCENSE-CEDAR / SALAL- Tsuga heterophylla - Calocedrus decurrens / Gaultheria shallon TSHE-CADE3/GASH

EXTENT: TSHE-CADE3/GASH is associated with FOREST FLOOR: Forest floor litter (needles, the Western Cascades Subprovince. It occurs on leaves, branches and decomposing logs) covers the North Umpqua and Tiller Ranger Districts. about 98 percent of the forest floor and usually less N = 9 plots. than 5 percent of the surface is covered by gravel, bare ground, rock, or exposed bedrock. Moss usu- IDENTIFYING CHARACTERIS- ally covers some of the rock or litter and averages about 6 percent. The occurrence of moss in TICS: TSHE-CADE3/GASH differs from other as- TSHE-CADE3/GASH is comparatively low for the sociations with consistent and moderate cover of Series. incense-cedar, and the lack of Western redcedar and western white pine. Low herb cover is also char- FOREST FLOOR MEAN S.D. acteristic of the Association. It is unlike most other TSHE associations in the Northwest. Litter (%) 98.3 2.5 Moss (%) 5.9 6.6 ABIOTIC ENVIRONMENT: Parent rock type is Bareground (%) .2 .4 basalt or andesite. Soils are deep, slopes are gen- Gravel (%) .3 .7 tle, and there are no operational constraints related Rock (%) 3.6 5.1 to site conditions. Aspects generally are east, but Bedrock (%) .6 1.7 can also be hot, south facing and steep. More infor- mation is presented in the discussion on the West- ern Cascade and High Cascade Subprovinces. VEGETATION: Sugar pine is indicative of the better sites in the Association. It often occurs with Pacific ABIOTIC MEAN S.D. madrone, where fire has been part of recent stand history. Whipplevine and baldhip rose decrease with time since disturbance. Whipplevine is associ- Elevation (ft) 3422.0 195.0 ated with drier sites in the Association. Salal and Aspect (deg) 100.4 106.5 Slope (%) 25.2 18.4 Pacific rhododendron seem to be constants regard- less of seral stage. They are common and well Total soil depth (in) 43.0 13.8 adapted to most conditions. Rooting depth (in) 44.88 10.6 Total basal area (ft2 /ac) 244.4 85.9 SILVICULTURE: Douglas-fir and incense-cedar are the most productive conifers. Western hemlock, CLIMATE: TSHE-CADE3/GASH is close to the western white pine, and white fir, in descending order, are less efficient. Big-leaf maple, Pacific center of the TSHE environmental grid (see Figure madrone, and golden chinquapin are efficient in 10). It is slightly drier than the average association early stages of succession. Incense-cedar will sur- as indicated by the complement of plants, and un- vive well on the drier sites although biomass pro- like most other associations, it commonly occurs duction may be slightly lower than Douglas-fir, if a ridgetops or upper third slope positions. near the mixture is not used. Incense-cedar has additional Annual and dry season precipitation are lower than advantages of being resistant to drought, insects, average. Moisture, soil and atmospheric, are limit- and disease. Western white pine and white fir are ing to biomass production. High summer tempera- most appropriate on the higher, cooler sites. Warm, tures and winds create a high transpirational de- exposed conditions lower regeneration potential mand. along with the high cover of Pacific rhododendron and salal. Removing shrubs is a two-edged sword. CLIMATE MEAN S.D. Competition and physical barriers are removed, but the microclimate becomes more extreme, possibly Mean annual temp (F) 46.3 .5 hostile, for seedlings, and nutrient cyclers are lost. Maximum month temp(F) 80.9 .8 Pacific rhododendron, big-leaf maple, and snow- Mean annual ppt (in) 58.6 6.9 -brush are the most intense competitors. Vine maple Dry season ppt (in) 7.6 1.0 may be competitive on some sites.

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