File:Bulletin (Pennsylvania Department of Forestry), no. 11 (1901) (20313895410).jpg

Title: Bulletin (Pennsylvania Department of Forestry), no. 11
Identifier: bulletinpennsylv11pennx (find matches)
Year: 1901 (1900s)
Authors: Pennsylvania. Dept. of Forestry
Subjects: Forests and forestry
Publisher: Harrisburg, Pa. : The Department : WM. Stanley Ray, state printer of Pennsylvania
Contributing Library: Penn State University
Digitizing Sponsor: Lyrasis Members and Sloan Foundation

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42 The bark may be of considerable technical value. Hemlock and some of the Oaks and Spruce have bark which is rich in tannin. The bark of these trees is used extensively in the leather industry. The bark of a European Oak is highly prized on account of the large quantity of cork which it produces. The inner bark of some trees yields dyeing material while that of others is used in the manu- facture of fibre cloth. Formerly the bark of the Paper Birch was used in the construction of canoes. 3. Twigs: Twigs are the terminal parts of branches. The term twig usually refers to that portion of the terminal part of the branch which grew in the last season. Those portions of the branch which began their growth a few seasons ago are usually spoken of as older twigs or branchlets. The twigs have their origin in the vegetative buds which may be located on the terminal end of the twig of the previous season's growth or along its side. If they emerge from terminal buds they become leaders, and if from lateral buds they will develop into lateral branches. The lateral branches may be alternate, op posite, or whorled (Plate II). The method of branching is very helpful in distinguishing our common trees. The lateral branches of most of them alternate with each other, while a fair number are opposite and a few whorled. The terminal twig elongates rapidly while the lateral ones usually remain shorter and occasionally are compressed to a stub or spur. When the vegetative buds burst open in spring young twigs, which are often covered with developing leaves, emerge from them. These twigs are, at first, usually delicate, greenish in color, and often hairy. As they develop during the season they become firmer and often lose their green color and their hairs. The direction of The new growth is variable. In many trees it takes at first a drooping direction and later, as its elements become firmer, it as- sumes a horizontal or ascending position. The new growth of the Pines is conspicuous in that it grows in an erect direction at first and later becomes horizontal or drooping. The taste, smell and color of the twigs are helpful in distinguish- ing some of our common trees. The twigs of some such as the Black Birch, Spice Bush, Sassafras, and Wild Cherry have a char- acteristic taste and smell. The color of the twigs may be green as in the Sassafras, red as in the Basswood and Red Maple, or brown as in the Sugiir Maple. Many other different colors and combina- tions of color aid materially in distinguishing our trees. Some twigs are rough while others are rather smooth. They may be roughened by hairs, lenticels, raised leaf-scars, bud-scale scars, •I
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