The Oaks

The Oaks (Quercus spp./Fagaceae) are made up of 275 to 500 species that can be split into three groups based on their cellular structure; the Live Oak Group, the Red Oak Group and the White Oak Group. Species within each group look alike at the cellular level. Oak trees can attain heights of 125 ft with large, sometimes irregular diameters. Oak sapwood white to very light brown and the heartwood is dark brown in the white oak group and red brown in the red oak group. The wood of Oak has a rough texture and is heavy, hard, stiff and strong with good working properties. The oaks vary with respect to decay resistance from nonresistant to very resistant. Oak is used for barrels, kegs and casks (white oak group), boxes, caskets, containers, fuel wood, furniture, hardwood dimensions and flooring, mining timbers, pallets, paneling, plywood, railroad crossties, ships, tannin dyes, timber bridges, truck and trailer beds, and veneer.

http://www2.fpl.fs.fed.us/TechSheets/HardwoodNA/pdf_files/quercuseng.pdf.

Characteristics found in the Oak (Quercus spp.)

• Ring Porous
• Dendritic latewood
• Simple perforations
• I/V pits medium (8-12)
• Rays of two types [Wide rays – can be seen with the naked eye & uniseriate rays]
• Rays homocellular

Tangential section of White Oak   Group (Quercus sp.) showing   numerous, small uniseriate rays   and one wide ray (center).

Three species groups:

• Live oak group semi-ring porous to diffuse porous
• Red Oak Group (Erythrobalanus) ring porous
• White oak group (Leucobalanus) ring porous.

Separation of Red/White Oaks

Feature	White Oak Group (Leucobalanus)	Red Oak Group (Erythrobalanus)	Combined Accuracy (estimated)
Tyloses in Heartwood	Yes	Sometimes	~50%
Ray Height	> 1 1/4"	< 1"	95%
Latewood Vessels	Numerous & Indistinct	Few & Distinct	99%
Latewood Vessel Cross-section	Thin Walled & Angular	Thick Walled & Round	100%

Red Oak

Cross-section of Red Oak   Group (Quercus sp.), showing   earlywood vessels and latewood   vessels.

White Oak

Cross-section of White Oak Group   (Quercus sp.) showing a wide ray,   earlywood vessels, latewood vessels   and the growth ring boundary. Note   tyloses in earlywood vessels.

CHARCOAL SLIDES

Red Oak

White Oak