The Oaks

Overall view of large oak tree in open fields.

Description

The Oaks (Quercus spp./Fagaceae) are made up of 275 to 500 species 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 is white to very light brown, and the heartwood is dark brown in the White Oak group and red brown in the Red Oak group. Oak wood 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, flooring, mining timbers, pallets, paneling, plywood, railroad crossties, ships, tannin dyes, timber bridges, truck and trailer beds, and veneer.

Close view of oak Leafs on a branch with acorns.

Tech Sheet

https://research.fs.usda.gov/silvics/white-oak

Characteristics

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
Microscope slide of Tangential section of white oak group wood. Arrows identify wide ray types and uniseriate rays.

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

Microscope slide of transverse section of red oak group wood. Arrows point to lightwood vessels and early wood vessels.

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

Microscope slide of radio section of red oak group wood. Arrows point to the vessel ray and vasicentric type tracheids within the vessels.
Microscope slide of radial section of red oak group wood. Arrows point to axial parenchyma and fiber tracheids.
Microscope slide of tangential section of red oak group wood. Arrows point to wide type rays, uniseriate rays, and latewood vessels.
Microscope slide of tangential section of red oak group wood. Arrows point to wide rays, uniseriate rays, and vasicentric tracheids.

White Oak

Microscope slide answer section of white oak group wood. Arrows identify earlywood the ray and Lakewood

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.

Slides (Click on each image to view a larger image)

WOOD SLIDES

Microscope slide of radial section of white oak group wood. Arrows point to vessels and rays.
Microscope slide of radial section of white oak group wood. Arrows point to vessels, ray, axial parenchyma, and tylosis.
Microscope slide of tangential section of white oak group wood. Arrows identify wide ray type and uniseriate rays.
Microscope slide of tangential section of white oak group wood under greater magnification. Arrows identify the wide ray type, uniseriate rays, axial parenchyma, and tracheids.
Microscope slide of tangential section of white oak group wood under greater magnification. Arrows identify the wide ray type, uniseriate rays, axial parenchyma, and tracheids.

CHARCOAL SLIDES

Red Oak

Microscope slide of transverse section of red oak group charcoal. Arrows point to wide rays and the growth ring boundaries.
Microscope slide of transverse section of red oak group charcoal under greater magnification. Arrows point to wide rays and growth ring boundaries.
Microscope slide of transverse section of red oak group charcoal under greater magnification. Arrows identify wide rays, early wood vessels, and Lakewood vessels.
Microscope slide of radio section of red oak group charcoal. Arrows point to vessels and rays.
Microscope slide of radial section of red oak group charcoal under greater magnification. Arrows point to vessels and rays.
Microscope slide of radial section of red oak group charcoal under greater magnification. Arrows point to the vessel ray vessel pits and the ray.
Microscope slide of the radial section of red oak group charcoal. Arrow points to rays.
Microscope slide of tangential section of red oak group charcoal. Arrows identify wide ray type.
Microscope slide of tangential section of red oak group charcoal. Arrows identify vessels and a wide ray.
Microscope slide of tangential surface of red oak group charcoal. Arrows identify the wide ray.
Microscope slide of tangential surface of red oak group charcoal under greater magnification. Arrow identifies the wide ray.
Microscope slide of tangential surface of red oak group charcoal under greater magnification. Arrow identifies the wide ray.

White Oak

Microscope slide of transverse section of white oak group charcoal. Arrows identify the growth ring boundaries and a wide ray.
Microscope slide of transverse section of white oak group charcoal. Arrows identify a wide ray and the latewood and earlywood vessels
Microscope slide of tangential surface of white oak group charcoal. Arrows identify the wide array
Microscope slide of tangential surface of a white oak group charcoal. Arrows identify the location of a wide ray.
Microscope slide of radial section of white oak group charcoal. Arrows identify the vessels and the rays.
Microscope slide of radial section of white oak group charcoal. Arrows identify the rays, vessels, and tyloses.
Microscope slide of radial surface of white oak group charcoal under greater magnification. Arrows Identify the vessel, the simple perforation type and wall of the vessel, ray vessel pits, and a fungal hyphae.
Microscope slide of the radial section of white oak group charcoal. Arrows identify the width of the ray.
Microscope slide of tangential surface of white oak group charcoal. Arrows identify the wide rays and vessels.
Microscope slide of tangential surface of white oak group charcoal at higher magnification. Arrows identify the location of the wide rays.
Microscope slide of tangential surface of white oak group charcoal at higher magnification. Arrows identify the vessel and location of wide rays.
Microscope slide of tangential surface of white oak group charcoal at higher magnification. Arrows identify the vessels and the wide rays.