PIPER FLORA OF THE STATE OF WASHINGTON. 41 



the rod fir {Psendotsu ga inurronafa) which in the Puget Sound roii'lon 

 often makes up over 90 per cent of the forest over hirge areas (PL 

 VIT), and \\^ to an altitude of 1,000 meters seldom forms a smaller 

 element of the total forest than 60 per cent. Nearly all of western 

 AVashington l)elow the altitude mentioned i^ossesses this character- 

 istic red fir type of vegetation, except a narrow strip along the 

 Pacific Ocean, Here the Sitka spruce {Pieea sitchensis) becomes 

 the dominant tree, making up from '25 to 75 per cent of the forest, 

 while the red fir falls to 10 per cent or less. This narrow strip has 

 he(m considered as I)elonging to the next higher zone, the Canadian, 

 hut for reasons hereafter expressed we would include it in the Humid 

 Transition. 



The i^rincipal features of the vegetation of western Washington 

 may be discussed under the three heads of the principal types of soils, 

 namely, the Uplands, the Bottom Lands, and the Gravelly Prairies. 

 Plant associations of lesser importance, but of marked character, are 

 those of the seashores and of sphagnum bogs. 



UPLANDS. 



The vegetation of the uplands thi-oughout the Pacific area in 

 AVashington is a plant association in which the red fir predominates. 

 The size of this tree and the luxuriance of the associated i)lauts 

 varies with the character of the soil, l)ut otherwise the formation is 

 remarkably uniform. In forests in dry or sterile soils the connnonest 

 undershrubs are salal {GdiiJfJu'ria slialJon) aiul Oregon grape {Ber- 

 hcris )i(')-rosa)^ while the liracken fern {Pf('j'/<Jn/m)\s the most con- 

 spicuous herb. Shrubs or trees of Scouler willow {Salix !<eoulcriana) 

 are also constantly associated. 



In better soils the same shrubs remain, but the salal especially 

 becomes much more luxuriant, often forming almost .impei:etrable 

 thickets. AATien, however, the red fir is at its best, forming dense 

 forests into which the sun scarcely penetrates (PI. VIII) the salal 

 and Oregon grape are usually much less conspicuous. Under such 

 circumstances the ground is covered with a thick layer of mosses and 

 scattered crowns of Chamisso's shield fern {PoJi/stichum munifiim). 

 Among the few shrubs which thrive in such dense shade is the red 

 huckleberry {Vaceiniiim parrifoJium). Following the destruction 

 of a red fir forest by logging and subsequent ])urning, as has been too 

 connnouly tjie case, there is a marked sequence in the plants that 

 appear, usually as follows: The first are nearly always the fireweed 

 (EpUohh/?n i^pirafum) and the bracken {Pteridium) . These are 

 closely followed by the dewd^erry {R>/hus macro petalvs) which the 

 following year fruits heavily and then gradually disappears. The 

 thimbleberry {Puhus paroiflorm) is often abundant also, as is red- 



