131 



are relatively infrequent but extensive areas of peat soil are 

 common. The general features of the climate and soil- and of 

 the flora^ of this region have already been described. This 

 area lies in the humid transition zone and consists mostly of 

 very gently rolling uplands that were originally covered with 

 a dense forest in which the Douglas fir, Pseudotsuga taxifolia 

 Britt. was the dominant tree. The broad alluvial valley of the 

 Nooksack river, and to some extent the valleys of smaller 

 streams, as well as several extensive peatbogs, were originally 

 covered with forests in which the western red cedar, Thuja 

 plicata D. Don., and the Sitka spruce, Picea sitchensis Carr. 

 were the dominant trees. Practically all of the forests have now 

 been removed, the greatest activity having taken place during 

 the last thirty years. Most of the lowlands, and such peat 

 bogs as could be drained, have been cleared for farming land. 

 Much of the upland has also been cleared and the remainder is 

 mostly "logged off" or stump land used for pasture. The county 

 has two seaports, Bellingham and Blaine, and the several towns 

 within its boundaries are served by three railroad lines. Oppor- 

 tunities for bringing seeds of weeds into this county have been 

 favorable since every year large quantities of feed and seeds 

 are shipped in. 



Native Weeds 



After the removal of the forests only a few of the native 

 species persisted as troublesome weeds in the clearings. Even 

 some of these are species accustomed to the open places along 

 the banks of streams or shores of lakes where trees were absent 

 on account of the periodic fluctuations of the water level and 

 erosion. The common brake fern, Pteridium aquilinum var. 

 pubescens Underw. was the most troublesome pest on newly 

 cleared uplands. Under thorough cultivation, or with persistent 

 efforts to eradicate it, the brake fern usually survived only a few 

 years but in some pastures and grasslands, it has survived for 

 twenty years or more. In some neglected logged ofT pasture 

 lands it has even spread. In the lowlands, especially in sandy 

 soil, the common field horsetail, Equisetum arvense L., became 



2 Mangum, A. W. Reconnoissance soil survey of the eastern part of the 

 Puget Sound Basin, Washington U. S. Dept. of Agric, Bureau of Soils Bull. 

 1911. 



3 Muenscher, W. C. Flora of Whatcom County, Washington. Muhlen- 

 bergii 9: 101-132. 1914. 



