Wood Anatomy of Tree Rings
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Transcript of Wood Anatomy of Tree Rings
![Page 1: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/1.jpg)
Wood Anatomy of Tree RingsWood Anatomy of Tree Rings
![Page 2: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/2.jpg)
Tree growth begins with photosynthesis to produce new wood when the growing season begins.
![Page 3: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/3.jpg)
Trees grow upward and outward (including root tips), but…
… tree growth actually begins in the crown and moves downward due to the growth regulator, auxin.
Like “melting wax” !!
![Page 4: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/4.jpg)
Like “melting wax” !!
![Page 5: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/5.jpg)
Meristems: apical and lateral growth
D: cell division
E: cell elongation
M: cell maturation
![Page 6: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/6.jpg)
Meristems: annual growth can also be seen in the branching patterns of many tree species (esp. conifers)
![Page 7: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/7.jpg)
When we dissect the trunk, we can see this annual incremental growth, both upward and outward.
STEM ANALYSIS
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Locally Absent Rings
Rings may be locally absent along the length of the tree.
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False Ring
Cells leading into the false ring will gradually decrease in size and then gradually increase back to earlywood cells.
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Viewing wood: tangential, radial, and transverse planes. We are only interested in which of these?
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Definitions:
Cambium: the growing (generative) layer between the xylem and phloem.
Xylem: principle strengthening and water conducting tissue of the stem, roots, and branches.
Phloem: inner bark, principal function to distribute manufactured foodstuffs.
Bark: dead, outer tissue that protects the cambium from the externalenvironment and exposure to pathogens and physical injury.
Vessel: the composite, tube-like structure found in hardwoods from the fusion of cells in a longitudinal column.
Fiber: an elongated cell with pointed ends and a thick or infrequently thin wall.
Rays: ribbon-shaped tissue extending in a radial direction across the grain of the wood.
![Page 12: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/12.jpg)
Note the five major portions of the tree trunk.
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Phloem (inner bark)
Xylem (wood)
Cambium
![Page 14: Wood Anatomy of Tree Rings](https://reader030.fdocuments.us/reader030/viewer/2022033105/56812bce550346895d90262c/html5/thumbnails/14.jpg)
Role of heartwood is…?
Role of sapwood is…?
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The Wood Cell:
1. Holocellulose
a. alpha-cellulose (40-50%) = non-soluble = long-chain polymers (glucose)
b. hemicellulose (20-35%) = readily soluble = short-chain polysaccharides
2. Lignin (15-35%) – non-carbohydrate materials in cell wall, very complex chemical structure.
3. Numerous Extractives – can be removed!
a. tannins
b. oils and resins
c. other complex organic compounds
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Cell lumen
Cell wall