Forest Trees of Texas _How To Know Them_ _Eighth Edition Ninth Printing October, 1990_ TEXAS FOREST SERVICE A PART OF THE TEXAS A&M UNIVERSITY SYSTEM COLLEGE STATION, TEXAS BULLETIN 20 APRIL, 1963 CROWN TRUNK HEARTWOOD (INACTIVE) GIVES STRENGTH SAPWOOD CARRIES SAP FROM ROOT TO LEAVES CAMBIUM (MICROSCOPIC) BUILDS THE CELLS INNER BARK CARRIES PREPARED FOOD FROM LEAVES TO CAMBIUM LAYER OUTER BARK PROTECTS TREE FROM INJURIES ROOTS SURFACE ROOTS TAPROOT _Tree increases each year in height and spread of branches by adding on new growth of twigs_ _Air supplies carbon the principal food of the tree taken in on under surface of leaves._ _Leaves prepare the food obtained from air and soil and give off moisture by transpiration. Light and heat are necessary for the chemical changes_ _The breathing pores of the entire tree,—on leaves, twigs, branches, trunk and roots take in oxygen. Flooding, poisonous gases, or smoke may kill a tree_ _Root tips or root hairs take up water containing small quantity of minerals in solution_ _The buds, root tips, and cambium layer are the growing parts of the tree. Water containing a small quantity of minerals in solution is absorbed by the roots, carried up through the sapwood to the leaves and there combined with carbon from the air to make food. This food is carried by the inner bark to all growing parts of the tree, even down to the root tips_ ACKNOWLEDGMENTS The first edition of _Forest Trees of Texas—How to Know Them_ was assembled by W. R. Matoon and C. B. Webster in 1928. The sections, “Trees as Mankind’s Friends”, “Studying a Tree”, “Other Texas Trees”, drawings of twigs, leaves and fruits, and the glossary were incorporated into the fourth and fifth editions by S. L. Frost and D. A. Anderson. The sixth and seventh editions were edited by H. E. Weaver and W. A. Smith, respectively. Some of the drawings used in this publication were made available by the United States Forest Service. The eighth edition was revised and edited by John A. Haislet to conform with the nomenclature in _Check List of Native and Naturalized Trees of the United States (Including Alaska)_, Agriculture Handbook No. 41, prepared under the direction of the United States Forest Service Tree and Range Plant Committee. D. A. Anderson’s “A Guide to the Identification of the Principal Trees and Shrubs of Texas” was revised and incorporated in the eighth edition to give it greater utility to the non-technical student of trees. TREES ... MANKIND’S FRIENDS