KATE OF GROWTH IX SPHAGNUM BOGS 735 



some species in the Puget Sound region, but the writer cannot say 

 what may be the relative importance of this as compared with edaphic 

 factors in injury to trees in this and other Puget Sound bogs. 



It was noted that in many cases branches were better developed on 

 the south side of the trees than on the north side. It was found also 

 that the annual growth of the trunk in diameter was greater on the 

 south side than on the north. 



As previously noted, the small portion of Green Lake bog that now 

 remains is partially drained, and forest succession has progressed far- 

 ther there than in the other bogs mentioned. The growth of hemlock, 

 fir, cedar, and spruce is dense. Spruce is abundant in the marginal 

 ditch, and hemlock, fir, and cedar are common in the neighboring 

 forest. A few specimens of western white pine occur in the forest on 

 the hillside bordering the bog, but none have been found in the bog. 

 Alders 3 m. (10 feet) high are found in the sphagnum, but this tree is 

 a very rapid grower and the specimens may not have been more than 

 four years old. A species of willow is common in this bog and one 

 specimen of the western dogwood was found. All of the deciduous 

 trees found may have invaded it since it was drained. 



During the autumn of 19 16 Lake Washington was lowered about 

 2 m. (7 feet) by the opening of the Lake Washington Canal. A few 

 weeks later a ditch was cut from Mud Lake to Lake Washington, and 

 the former was thus lowered to the level of the latter and reduced to 

 about one-fourth of its former size. This has greatly modified condi- 

 tions in Mud Lake bog. Much of it is very young and has but few 

 trees on it. Hemlock is fairly common on the borders, but large areas 

 of sphagnum are entirely free from trees. The hemlocks vary in size 

 from small seedlings up to a height of 9 m. (30 feet). There is only 

 one tree of this extreme size. It has a diameter of 30 cm. (i foot). 

 It is among the largest trees found by the writer in the bogs of the 

 region. There are two specimens of western white pine in the border 

 of this bog. One of them is 7.5 m. (25 feet) tall. There are also a 

 few cedars. An occasional willow has found a foothold in the margin 

 of the sphagnum. The peat-bog birch, as previously mentioned, is 

 common along the advancing border of the bog and is a forerunner of 

 the bog rather than an invader of it. 



Fauntleroy bog is pretty thoroughly covered with a mixed growth of 

 western hemlock, Douglas fir, and giant cedar. Hemlock is much the 

 most abundant, fir and cedar following in that order. The largest trees 

 are hemlock, three individuals being especially conspicuous by reason 

 -of their size. Following are the sizes of these three trees : Thirty feet 



