Transcript TREE GROWTH
Tree Growth Topic 1114 Mr. Christensen Objectives • Learn how woody plants grow • Know where growth occurs in a tree • Understand the relationship of tree ring growth and environmental conditions • Describe limiting factors for tree GROWH How Does A Tree Grow • • • • MERISTEM tissue in the Bud--crown Root tips--roots Cambium--trunk From the MSU AGRSCIENCE WEB PAGE Roots • Apical MERISTEM protected by a root cap (cells divide and differentiate) • Permanent roots—anchorage • Feeder roots • Root hairs—water and nutrient absorption Roots • Absorbing roots are concentrated in the top 6-18 inches of soil (water, nutrients and oxygen) • Roots cover 4 to 7 times the area of the crown From the MSU AGRSCIENCE WEB PAGE Tree Root Classes • Heart root (red oak, honey locust, basswood, pines) • Tap root (hickory, walnut, butternut, white oak and hornbeam) • Flat root (birch, fir, spruce, sugar maple, cottonwood and silver maple) From the Iowa State University Forestry Extension http://www.ag.iastate.edu/departments/forestry/ext/pubs/F-308.pdf Trunk • Growth in diameter of plants is due to cell division in the cambium • Located just under the bark • Inside—xylem –conducts water and nutrients • Outside—phloem—transports sugars, amino acids, vitamins, hormones and stored food *Sapwood Heartwood Xylem From the MSU AGRSCIENCE WEB PAGE Outer Bark Phloem Cambium From the MSU AGRSCIENCE WEB PAGE From the University of Georgia School of Forestry http://www.forestry.uga.edu/warnell/service/library/index.php3?docID+172 From the MSU AGRSCIENCE WEB PAGE Wood Types • Spring wood (early wood) • Summer wood (late wood) • Heart wood—old xylem tissue (provides structure and infection resistance) • Sapwood—living xylem active in fluid transport • Phloem—inner bark nutrient transport, outer bark—dead phloem Factors Affecting Ring Growth From the University of Georgia School of Forestry http://www.forestry.uga.edu/warnell/service/library/index.php3?docID+172 Crown • • • • • • Buds—apical MERISTEM 3 types Mixed—shoots—leaves and or flowers Leaf buds Shoot buds Terminal buds--apex of MERISTEM (trunk) Lateral buds—branches and flowers From: Iowa State University Forestry Extension Notes F-308 www.ag.iastate.edu/departments/forestry/ext/pubs/F-308.pdf Types Of Buds • Fixed growth—the number of leaves and nodes for next year is fixed by this years resource availability (length of nodes is dependent on next years conditions (pine, oaks hickory) • Free growth—buds containing leaves are preformed but additional leaves can be added depending on that years CONDITONS (cottonwood, willow, and silver maple) Tree Form • EXCURRENT—strong apical dominance (conical—pines) • DECURRENT—lack of strong apical dominance—deliquescent (large spreading crowns) From: Iowa State University Forestry Extension Notes F-308 www.ag.iastate.edu/departments/forestry/ext/pubs/F-308.pdf What Have We Learned Today • Learned tree growth occurs in Meristem tissue of Roots (tip), trunk (cambium) and crown (buds) (Down, Out and Up) • Water is the most restrictive factor affecting tree growth (Light, Temperature and Relative humidity)