48. Bur Oak

Also called Prairie Oak or Mossy cup Oak

Specimen Size: 86.8ft tall, 30.5in in diameter.

Location: Massive tree filling much of the space south of the main wing of Denny Hall, on the side of the Building facing Memorial Way NE.

Historical Background: Also known as the mossycup oak for the fringe caps on their acorns, the Bur Oak’s latin name describes its large acorns, the largest of any oak in North America. It is often planted as a shade tree and its wood is used for cabinetry, construction, and flooring. Native Americans use parts of this tree medicinally for heart problems and other health conditions. The astringent bark specifically is used to treat wounds and sores. 

Non-native

Native Range: Northern and Central United States, Southeastern Canada 

Identifying Features: This is a monumental specimen of an oak. It exhibits some of the standard features of the genus. They are not evergreen as the Canyon Live oak was, but turn a coppery orange yellow in fall. Leaves are lobed, but not generally pointy like those of the Pin Oak or red Oak seen earlier on this tour. The lobes are irregular and rounded, and the acorns are very large and round, half to almost entirely surrounded by the hairy cap. The tree has a massive broad rounded crown, stemming from a thick tall trunk and large branches.

Identifying Features In Depth:

1. Form: A straight thick trunk leads up to a broad rounded crown, with large spreading branches, open inside with dense foliage on the edges. Generally this tree reaches heights of 80’ (25m) but it has been known to achieve 165’ (50m). 

2. Leaves: Leaves are obovate, thick and shiny green above and gray green and fuzzy beneath. They are almost 10” (25cm) in length, very large for an oak, with 5-9 rounded lobes occurring at irregular intervals. The petiole/leaf stem is about 1” (2.5cm) in length and very stout.

3. Bark: Bark is light gray and deeply fissured.

4. Reproductive Bodies: The acorns of the Bur oak are the largest of any oak species native to the America’s. They are up to 2” (5cm) in length and elliptical, with a hairy fuzzy yellowish capsule covering half or more of the brown fruit.