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Woolly Hophornbeam

The Ostrya Knowltonii is commonly known as Ironwood, Knowlton Hophornbeam, Western Hophornbeam, Wolf Hophornbeam, as well as Woolly Hophornbeam

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Growing Regions

Knowlton hophornbeam is found in southeastern Utah, northern Arizona, southeastern New Mexico (in the Guadalupe and Sacramento mountains in Eddy County), and northern Trans-Pecos Texas. It is not a common tree and its occurrence is sporadic even in these areas [9,10,18,23].

     

General Information

The currently accepted scientific name for Knowlton hophornbeam is Ostrya knowltonii Coville [9,10,7,23]. There are no recognized subspecies, varieties, or forms.

Knowlton hophornbeam is commonly found in oak (Quercus spp.) woodlands,
pinyon (Pinus spp.)-juniper (Juniperus spp.) woodlands, and lower
ponderosa pine (Pinus ponderosa) forest zones [9].  In Texas it is a
component of the gray oak (Quercus grisea)-true pinyon (Pinus
edulis)-alligator juniper (Juniperus deppeana) association at 5,000 to
7,000 feet (1,524-2,133 m) and the ponderosa pine-Douglas fir
(Pseudotsuga menziesii) association at 6,000 to 7,500 feet (1,828-2,286
m).  In Texas it is also associated with Texas madrone (Arbutus
texana), southwestern white pine (Pinus strobiformis), chinkapin oak (Q.
muehlenbergii), and bigtooth maple (Acer grandidentatum) [18].  In
deciduous canyon woodlands of Guadalupe Mountains National Park, Texas,
Knowlton hophornbeam will increasingly replace wavyleaf oak (Q.
undulata), alligator juniper, Riogrande cottonwood (Populus deltoides
ssp. wislizenii) and little walnut (Juglans microcarpa) as the moisture
gradient goes from xeric to mesic.  Knowlton hophornbeam is replaced by
bigtooth maple and chinkapin oak, especially on upper terraces, around
springs and in canyonheads [6,13].

Much of the information presented here is attributed to:
Tesky, Julie L. 1994. Ostrya knowltonii. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available at USDA Forest Service.

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