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