Creative Woodworks & crafts 2003-09, страница 37
Hemlock, Tsuga Canadens, also callcd Canadian Hemlock Hemlock Spruce. K grows from .vToimdIarKi across southern and Ontario, south through 1 of New England, down the Mountains into ia and Alabama, and in the States, li is a site-specific in thai it will only grow in of its own liking. The site have cool moist soil Lhat is well-drained and a flow of cool moist air. Such sites arc usually found in upper elevations on slopes near creeks and glens. The trees are nearly unmistakable due to their shape, color and size, with the Eastern White Pine somewhat similar. When they are in pure stands, they grow much slower; size is not relative to the age of a tree. In our country's earlier times, some relatively small trees were well over 500 years old and a few over 1000. When a stand is thinned either by man or nature, the trees arc released and growth rates can increase 10 times, with some specimens attaining heights over 100 feet and diameters over 3 feet; however, most today are somewhat smaller.
The needles of hemlock are unique; there is no confusion between this species and other conifers. They are flat and fastened to the twig by a very short, thin stalk, and when healthy, have a deep green color with a slight silvery shade to the underside. The cones may stay on the tree for two years, although the seeds are released during the first autumn. The seeds do not cany far from the mother tree and provide food for birds and forest rodents.
At the present time, the Wooly the little fuzzy specs in the are decimating stands Eastern Hemlock throughout its They got here from Asia in early 1920's, and kill or weaken tree by sucking the sap from the and twigs. However a few do . Spraying is effective for hemlock, but too expen-for forest tracts. The spray has thoroughly cover the entire height the tree, and bccause most are so there is no effective method of application that is affordable.
As you can see in this photograph, the death of these magnificent trees will have an altering effect on woodland microclimates bccausc of the warming and drying of areas that up until now have been cool and moist. This particular stand is 40% dead and the forest composition is beginning to changc. Fortunately, the trout stream that Hows through it has not. been affected - yet!
^ Historically, the bark of hemlock has |:been its most valuable commodity t.because of its high tannin content. iTrom the time the earliest settlers |camc to this country and up to the | disco very of the chrome tanning ^process in the middle 1800's, thousands of acres of hemlock were cut ^yand stripped of their bark for the (aliening of leather. In many cases, the £.logs w;crc left to rt>L. The bark is still ;;uscd in vegetable tanning methods ^because that method provides the ^.leather different wear characteristics I'than those of the mineral recipes.
The wood of this tree has commercial value, but because of shake, extra care must be taken in the grading process. Shake is a condition whereby the growth layers separate in a condition is caused by wind fas in wind-shook), but it is actually caused by bacterial action in the moisture between the growth rings. The separations arc evident when the tree i.s felled; however, the extent cannot be determined until the tree is on the sawmill. We have sawn a number of beautiful Eastern I lemlocks on our mill only to experience losses of as much as 65%' due to shake. They can be short or as long as the log and when the board is removed from the mill it will fall into several new widths that are never straight. The older the tree, the more prevalent the shake condition is, and it is not limited to this specics.
is little if any color separation the sapwood and hcartwood, closer inspection reveals that the is slightly lighter in color, hcartwood runs from tan to a brown with a reddish hue. The is coarse with an uneven tex-lairly lightweight, and moder-hard-but the knots are brutal, wood is also fairly stiff, but low strength and shock resistance. It is a "pitchy" wood like Eastern Pine, and lakes paint, stain and finishes well. It has accepted all glues we have used, but be sure •'^.ffl'^^w^wsKw^^.w t() get enough on the surfaces bccause it will soak in fast and could leave a "starved joint". Working the wood with machine or hand tools is not a problem except for the knots, and it holds screws and nails very well.
The wood, when sound, finds use as construction lumber, pulp-wood, shipping boxes, pallets and crates. The tree also has use as a food. Our early settlers were taught by the Native Americans to brew a tea from the needles that is very high in vitamin C, and the cambium layer could be used as an ingredient, in bread, soup, or mixed with meat, suet, and berries to make pcmmican. Uft
Creative Woodworks & Crafts September 8003 • 37