The Inside Story of Rings

Purpose:	To increase observation skills, To use inductive reasoning.
Season:	All
Materials:	Reading the Rings chart, cross section of tree trunk
TEKS:	5.2C,D,E 5.3A,C,D 5.11B,C
Background information:	Each ring is a layer of wood produced during the tree's growing season. As a tree begins growing in spring, the cambium produces a light colored band of thin-walled cells called earlywood. As growth slows down in the summer, a darker ring of thick-walled cells called latewood is formed. Together the earlywood and latewood form an annual growth ring. The thicknesses and appearances of a tree's annual growth rings often vary from year to year. Weather obviously affects growth. Other factors such as insect damage, diseases (viruses, bacteria, or fungi), fire, root damage, transplanting, and competition from other trees influence a tree's growth. Information for Reading the Rings chart Cross Section A: The uneven growth shown in the rings could have been caused by a fallen tree leaning against the tree (1). The tree grew more on one side than the other, and curved up around the fallen tree. This uneven ring pattern could also belong to a tree growing on a steep slope (6). Cross Section B: The scarring in this cross section was caused by a forest fire during the tree's sixth growth season (2). Cross Section C: The mark beginning in year six is all that's left of a branch that died and fell off (7). eventually the tree's trunk grew around the remains of the branch and covered it. (The branch could also have been broken or cut off.) Cross Section D: The narrow ring shown in this cross section could have been caused by several factors such as drought (3), heavy insect damage (4), or damage from construction (5). If a tree lost all or most of its leaves because of an insect attack or drought, it would not be able to make food and would grow very little that year. Root damage from the construction of a house or sidewalk too close to the tree would reduce the water and minerals the roots could take up. Other factors might include cold winter, a spring frost, transplanting, competition.
Procedure:	Apply knowledge of tree growth rings to sample. Record conclusions.
Questions:	How old is the tree? or How many growing seasons has this tree had? What kind of life has this tree had? What has happened in the area based on this tree?