Western hemlock

Wood Delignijication. The production of wood pulp (qv) for the paper (qv) industry consists of removing lignin (qv) from wood chips, thus freeing the ceUulose fibers. An aqueous solution containing 30—70 wt % sulfolane efficiently extracts the lignin from aspen. Western hemlock, and Southern pine wood chips. Pulp yields are from 50—75% (43,44). 

The Native Lignin from Western Hemlock Tsuga heterophylla). J. org. 

Follow-up ground studies involved the analysis of outer bark from western hemlock collected at 100 m sample spacing over the Tl anomaly south of Tsuius Creek. This permitted more clearly defining the extent of the Tl anomaly (600 m X 600 m) and its relationship to other trace elements. Figure 1 shows the Tl anomaly and the spatial relationship of Hg which appears to define a conjugate set of lineaments interpreted as leakage from structural weakness. The multi-element association at this locality suggests that Tl and Hg may be pathfinder elements to concealed base-metal mineralization. 

Fig. 1. Thallium (3D plot, viewed from south) and Hg in dry western hemlock bark - Tsuius Creek, BC (Dunn Thompson 2009a).

The brown stain on western hemlock sapwood is not controlled by sodium azide (18). A number of chemicals (reducing agents and acids) prevent the colour formation in laboratory experiments but... 

This type of discoloration is less important in British Columbia than the discoloration caused By fungi. Surface dis coloration can be readily removed by surfacing of lumber, and usually objection is raised only when it s observed on an unfamiliar wood species as was the case with western hemlock. 

The flame-spread number is derived relative to red oak (with an arbitrary flame-spread rating of 100) and to asbestos-cement board (rated zero). Natural wood products (1-inch lumber) usually have flame-spread ratings of 100 to 150 in the test furnace of Underwriters1 Laboratories, Inc. (35). Some exceptions are poplar (170-185), western hemlock (60-75), redwood (70), and northern spruce (65). 

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