Part 1

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

Trees have held an important place in man’s way of life since he has been on the earth. Trees provided early man with weapons to defend himself and helped provide him with food, shelter and fuel.

Trees have played an important role in the history of the United States. Timber was our nation’s first export. The forest also provided our forefathers with their homes, farm implements, rifle stocks and wagons. The forest, by furnishing ties and utility poles, made possible the expansion of railroad systems, electric power and telephone networks. Every industry depends upon forest products in one way or another.

Trees are more important today than ever before. More than 10,000 products are reportedly made from trees. Through chemistry, the humble woodpile is yielding chemicals, plastics and fabrics that were beyond comprehension when an axe first felled a Texas tree.

The American standard of living depends to no small extent on the care with which we use our forest resource. Fortunately, trees are a renewable resource. They can be grown as a crop and harvested in such a way that the stand is kept productive, and a steady supply of forest products is assured.

TEXAS TREES

A tree is generally defined as a woody plant having one well-defined stem and a more or less definitely formed crown, usually attaining a height of at least eight feet. Using water and minerals from the soil, gases from the air and energy from the sun, a tree manufactures the food it needs for growth and reproduction. Trees, like man, grow rapidly when they are young but gradually their growth decreases; they begin to deteriorate and eventually die. Nature then reduces them to the elements from which they were derived.

The terms “hardwood,” “softwood,” “deciduous” and “non-deciduous” are often encountered in tree literature. These terms are confusing and often misleading. Needle-bearing or cone-bearing trees are designated as softwoods even though the wood may be dense. Hardwoods are the broad-leaved (unlike needles or scales) trees, the wood of which may be dense or soft.

The conifers, or softwoods, generally retain their leaves more than one growing season and produce seed in cones; however, there are exceptions. Baldcypress, a conifer, is deciduous since it sheds its leaves in autumn. Cedar and juniper produce berry-like cones that scarcely resemble cones.

The hardwoods, or broad-leaved trees, are generally deciduous; i.e., they shed their leaves in autumn. Texas has many exceptions, for example: southern magnolia, live oak and American holly which retain green leaves through the winter.

More than half of the 1,100 species of native trees in the United States are found in the South. Of these, more than 200 species and varieties are native to Texas. In addition, many exotic species have been introduced and now grow in many parts of the state.

The four main forest regions of Texas include: the Southern pine forest in East Texas; the central hardwoods, the post oak and cross timbers of North-central Texas; the semi-tropical forest in the Rio Grande Valley region of Texas; and the mountain forest, the timbered areas of West Texas which are a continuation of the timber types of the Southern Rocky Mountains. In Texas, trees are the principal vegetative cover on an estimated area of 28,805,617 acres.

PINE-HARDWOOD CEDAR BREAKS POST OAK WEST CROSS TIMBERS EAST CROSS TIMBERS MOUNTAIN FORESTS

Texas also has minor tree areas which are almost restricted to Texas; the cedar breaks and the oak shinneries. Some of the shinnery trees are among the smallest in America. In places, fully matured trees are not over knee-high and resemble pigmy forests. In other areas, the same species grows 20 to 30 feet tall to form almost impenetrable thickets.