AgEBB-MU CAFNR Extension

Green Horizons

Volume 22, Number 3
Fall 2018

Species Spotlight

Species Spotlight: The Ozark Chinquapin

Michael Gold| University of Missouri Center for Agroforestry

Ozark chinquapin single nut in bur

The Ozark chinquapin (Castanea ozarkensis), sometimes called Ozark chestnut or chinkapin, is a drought tolerant hardwood tree that once grew up to 65' in height and up to 3' in diameter. The Ozark chinquapin is closely related to the American chestnut (Castanea dentata) and the Allegheny chinquapin (Castanea pumila) found further north and east.

Not as large in stature as the American chestnut, the Ozark chinquapin is the lesser known "cousin" to the towering Castanea dentata. Prior to the arrival of the chestnut fungal blight (Cryphonectria parasitica) the Ozark chinquapin inhabited the rocky upper slopes and ridge tops of the Ozark and Ouachita Mountains in Missouri, Arkansas, Oklahoma and Eastern Texas. Similar to the American chestnut, the Ozark chinquapin produces prolific nut crops that both humans and wildlife found delicious (note that the nut size of the Ozark chinquapin is much smaller than the American chestnut). Ozark chinquapin blooms in late May to early June after the threat of frost has passed. Fruits are spiny burs (to 1 1/4" diameter) that appear in small clusters, with each bur encasing one small rounded seed.
Similar to its larger American chestnut "cousin" the wood of the Ozark chinquapin was highly prized for its rot-resistance and made excellent lumber for barns, furniture, railroad ties and fence posts. Unregulated logging practices (which were the norm prior to WWII) and later the chestnut blight wiped out the most of the Ozark chinquapin (see map below). With rare exceptions, only blighted stumps remain of this once important Ozark tree.
Chestnut blight attacks the above ground parts of the tree. Fortunately, the fungus dies at the soil surface. The surviving roots can produce new stump growth of sprouts that will develop into small trees (to 15-20' tall) until reinfection inevitably reoccurs. Within 4-6 years, the blight again strikes killing the sprouts, and the cycle is repeated. The number of surviving stumps and the historic range of the tree continue to shrink.

Size comparison of chinkapin, American, and Chinese chestnuts

Ozark chinquapin male catkin and female flower (at base of catkin)

The blight spread throughout the natural range of the American chestnut from ~1900-1940, and eventually reached the Ozarks in the 1960's. Within a decade, the Ozark hills were littered with the carcasses of Ozark chinquapin trees that reached up to 60 feet high. Today, the chinquapin survives mostly as root suckers that re-sprout after the above-ground portion of the tree is killed, and therefore very few seeds are produced to re-populate the species.

Ozark chinquapin restoration efforts are currently led by the Ozark Chinquapin Foundation (OCF) https://ozarkchinquapinmembership.org/. OCF efforts include:

locating blight resistant trees

distribute resistance seed for growing

cross pollination

DNA Analysis to confirm pure native strands

nut grafting/twig grafting

establishing research farms

Spread of the Chestnut Blight. Credit: Ozark Chinquapin Foundation

This restoration work is a collaborative effort involving University researchers, student volunteers, local, State, and Federal cooperators, as well as outdoorsmen and women participating in field research and education. The Center for Agroforestry, in conjunction with the Missouri Dept. of Conservation, is becoming more involved in the overall restoration effort and will be an active partner in coming years.