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Cork insulation; a complete illustrated textbook on cork insulation ...

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CHAPTER II.<br />

CORK STRIPPING.<br />

6.—Removing the Outer Bark.—The <strong>cork</strong> of commerce, or<br />

<strong>cork</strong>wood, is the outer bark of the <strong>cork</strong> tree, which bel<strong>on</strong>gs to<br />

the oak family and which has been described. This outer<br />

bark can readily be removed during the summer m<strong>on</strong>ths, gen-<br />

erally during July and August, without harm to the tree,<br />

although c<strong>on</strong>siderable skill is required if injury to the inner<br />

or sap-carrying bark is to be avoided. French strippers some-<br />

times use crescent-shaped saws, but Spanish strippers in-<br />

variably use a l<strong>on</strong>g-handled hatchet, the handle tapered at<br />

the butt in the shape of a wedge.<br />

When <strong>cork</strong> oak trees attain a diameter of about five inches,<br />

or measure forty centimeters in circumference according to<br />

the Spanish practice, which fixes the age of the tree at about<br />

twenty years, the virgin outer bark is removed. It is customary<br />

to cut the l)ark clear through around the base of the<br />

tree and again around the trunk just below the main branches,<br />

the two incisi<strong>on</strong>s then being c<strong>on</strong>nected by probably two vertical<br />

cuts. By using the l<strong>on</strong>g handle of the hatchet as a wedge<br />

and lever, the tree's outer bark is easily pried off. The lower<br />

porti<strong>on</strong>s of the limbs are stripped in like manner, frequently<br />

yielding a liner grade of <strong>cork</strong>wood than that of the trunk.<br />

The thickness of this virgin outer bark varies from about <strong>on</strong>e-<br />

half to two and <strong>on</strong>e-half inches, while the yield per tree also<br />

varies from a half hundred to several hundred pounds, depending<br />

<strong>on</strong> both its size and age when the virgin stripping is<br />

accomplished.<br />

7.—Virgin <str<strong>on</strong>g>Cork</str<strong>on</strong>g>.—This virgin <strong>cork</strong> bark, called "borniza"<br />

in Spain, is rough, coarse and dense in texture. It is there-<br />

fore of limited commercial value, except as used by florists<br />

10

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