Tree Growth Rings Formation and Form Coder

Page 5 disturbances all can lead to an early near­ cessation of cambial growth and a renewal of growth later within the same growing season. False rings are most prevalent in branch wood down to the base of the living crown and are present only occasionally in the stem . Simple growth-ring counts can be highly inaccurate because single-growth increments can have characteristics of multi­ ple growing seasons . Careful cross-sectioning and the use of significant magnification are essential in identifying true growth-cessation points . This article was derived from , and can be supplemented with, information from the following publications by Dr. Coder at the Web site www.forestry uga.edu/warnelVservice/library under the links Tree Health Care or Commu­ nity Forestry Single hard copies of articles are also available free through the mail from the author . Secondary Growth Anatomy and Tree Rings. 1999 . University of Georgia School of Forest Resources Exten­ sion Publication FOR99 -0ll9 . 9 pp. Tree Growth Rings: Fom1ation and Form. 1999 . University of Georgia School of Forest Resources Extension Publication FOR99-020. 7 pp. Tree Growth Velocity Estimator. 1999. University of Georgia School of Forest Resources Extension Publication FOR99 -016. 2 pp. Ii-ee Ring Analysis: A Selected Bibliogra­ phy of Major Works and Information Sources. 1999 . University of Geor ­ gia Schoo l of Forest Resources Extension Publication FOR99-15. 2 pp. Tree-Ring Porosity Forms in Hardwoods. 1999 . University of Georgia Schoo l of Forest Resources Extension Publication FOR99-18 . 2 pp. A COLLECTION OF CEU ARTICLES Mi11i-Ri11gs There are conditions in which a truncated growth ring or no growth ring is produced . Marginal branches , a rapidly declining tree , areas of cambial damage , and disruption or destruction of growth-regulation zones ham­ per or prevent cambial activity Truncated growth rings occur when only the first set of cells divides and expands . These cells were set for growth at the close of the previous year, and they complete their division and growth as a first activity of the new growing season . Lack of any growth ring denotes loss of meristematic tissue, major disruption of physiological functions , or simple starvation. Cambial activity can be reinitiated by living parenchymal tissue. Co11clMsio11s A great deal of literature is available on the subject of tree rings . Tree growth increments contain many types of information . By under­ standing tree growth-ring formation and appearances , we can extract information regarding tree biology and learn more about external events that influence tree health . Kim Coder is a professor in the School of Forest Resources, University of Georgia, Athens. l. The cambium is best described as alan a. expanding cell zone in the roots b. shoot and root growth meristem c. single layer of cells d. zone of cell generation 2. Growth increments can be visualized within tree xylem because a. bark is laid down to the outside of each increment b. one year's latewood is laid adjacent to the next year's latewood c. periods of good growth are separated by periods of less growth d. sapwood and heartwood interfaces are distinct 3. Root wood and stem wood in a tree share all major anatomical parts in cross section except a. bark b. pith c. rays d. sapwood 4. Growth increments appear as growth rings in cross-sectional cuts because a. bark cambium cells force wood formation to curl around the circumference b. growth increments are hollow, nested cones in three dimensions c. growth increments are round , wooded cylinders in three dimensions d. phloem continues to be deposited into the bark 5. The radial thickness of each growth ring depends on a. how fast the shoot and root growth occurs b. how many ray cells were deposited c. resources available and last growth increment size d. stored food supplies and cell wall sizes in the last growth increment 27