Plants & Human Affairs

Objectives: At the conclusion of this exercise/unit you should be able to:

Wood Identification
Each group will be given several numbered blocks of wood. Match each block with the appropriate description. You can also use a dichotomous key to help with your identifications. As you study each particularly note the characteristic features and wood structures. Confirm your identifications with me.

	_______ Ash heartwood brown to grayish-brown sapwood creamy �white rings distinct, abrupt change from early to latewood ring porous rays barely visible to naked eye handles, baseball bats, oars		_______ Red Oak early wood pores in heartwood usually open latewood pores visible large rays visible to naked eye furniture, flooring, millwork
	_______ Black Cherry semi-ring porous sapwood whitish to light red heartwood cinnamon-brown to dark reddish-brown rings distinct, delineated by narrow band of pores in early wood pores small and indistinct rays plainly visible wood dull, but takes fine luster when finished color darkens with age easily machined		_______ White Oak early wood pores filled with tyloses heartwood light-brown to dark-brown large rays visible to naked eye latewood pores small and indistinct barrels and kegs, flooring, furniture wood tough and resistant to wear
	_______ Maple rings distinct, delineated by dark line denser fibrous tissue diffuse porous small pores, uniform in size sap wood wide, white or light rays � barely visible or wide as or wider than largest pore on tangential surface rays appear as very fine but distinct lines furniture, flooring		_______ Walnut distinct growth rings pores scattered, those in early wood readily visible sapwood whitish to yellowish-brown (sometimes steamed to darken to match color of heartwood) heartwood dark to chocolate-brown furniture, cabinets, gun stocks, caskets most valuable timber tree in the US
	_______ Southern Pine rings very distinct; delineated by pronounced band of darker latewood contrast from early wood to latewood very pronounced sapwood is nearly white to yellowish heartwood is distinct, shades of yellow to orange to brownish resinous odor straight but uneven grain, medium texture rays fine and not visible to naked eye resin canals appear as whitish or brownish flecks distinct with handlens pulpwood, plywood, dimensional lumber		______ White Pine distinct, but not pronounced rings each ring marked by a dark band in the latewood resin canals - whitish flecks - visible in center of rings rays very fine construction, ship masts, millwork

Annual Rings:
Each year a new layer of wood is produced by a tree. By counting the number or layers, or annual growth rings, the age of the tree can be determined. The width of the ring provides an indication of the growing conditions in that year. Study a wood block or sketch.

Wood Cuts:
The three standard cuts of wood are transverse (cross sectional), radial and tangential. Can you draw a section of wood and then:

Quarter Sawn vs. Plain Sawn Boards:
By examining the figure (= appearance) of a board, it is possible to tell if it was plain‑sawed or quarter‑sawed.

Heartwood and Sapwood:
If given a transverse section of a tree, can you distinguish the heartwood and sapwood. Sketch a pie shaped section of this specimen and label heartwood, sapwood, bark, annual ring, ray, vascular cambium.

Cell Types of Wood:
The two major water conducting cells in wood are tracheids and vessels.

Wood Porosity:
The vessels in wood are also termed the pores. The distribution of vessels in wood is species-specific and can be useful for identifying wood. Ring-porous refers to wood in which the vessels are arranged parallel to the ring. In diffuse-porous wood, the vessels are scattered throughout the ring. Using the wood samples provided, do you observe any vessels or pores in the wood of spruce, oak or pine?

Wood Forensics:
Wood played a major role in solving the murder of Charles Lindbergh's infant son. Describe this case and the type of information derived from wood that was used to solve it.

Tyloses:
Vessel cells can become plugged by outgrowths from the parenchyma cells called tyloses. These bubble-like structures can accumulate a variety of resins and other materials that effectively plugs up the vessel. Tyloses are usually formed when sapwood changes into heartwood, but can be formed at any time (Sharp, 1990). Tyloses are common in white oak and black locust and a characteristics of wood used in tight cooperage (barrel making).

Obtain a twig (1/4 to 1/2 inch diameter) from red oak and white oak. Attach a rubber hose to one end of the twig and attach the other end to a water outlet. Slowly turn on the water and observe the end of the twig. On which twig, in either, do drops of water appear? Explain why. Which wood would make better barrels?

Last updated: 12/13/2005 / � Copyright by SG Saupe / URL:http://www.employees.csbsju.edu/ssaupe/index.html

Red pine__________		Sugar maple__________
Oak__________		Blue spruce__________