Northern Pin Oak
Common Names: Hill’s Oak, Jack Oak, Upland Pin Oak
Scientific Name: Quercus ellipsoidalis E.J. Hill
Family: Fagaceae (Beech Family)
Native Range: Uncommon in Canada — Ontario (west of Lake Superior, north of Lake Erie). Widespread in the Great Lakes region of the U.S.: central Michigan, northern Wisconsin, eastern Iowa, northern Illinois, northern Indiana; disjunct populations in northern Ohio, Arkansas, and extreme southeastern North Dakota.
Hybridization: Can hybridize with Black Oak (Q. velutina) and Northern Red Oak (Q. rubra).

Size & Growth
Typical Height: Up to 21 m
Trunk Diameter (Maximum): ~60 cm
Growth Form: Irregularly rounded crown, low-hanging lower branches often persist as dead stubs giving a ragged appearance.
Crown & Shade: Full sun preferred; not shade tolerant
Drought Tolerance: High; most drought-tolerant of the black oaks
Leaves
Length: 7–12 cm
Shape: Elliptic-obovate to elliptic-oblong, with 5–7 bristle-tipped lobes, lobes often constricted toward the base; sinuses rounded or U-shaped
Color: Bright green above, hair tufts in vein axils below; turn bright red to reddish-brown in fall
Petiole: 3.5–5 cm long
Special Feature: Leaves shed in autumn (unlike Pin Oak leaves, which persist into winter)
Bark
Young Trees: Smoothish, dark gray
Mature Trees: Dark gray to brown, shallow furrows with thin vertical plates; inner bark light yellow

Flowers & Reproduction
Flower Type: Monoecious (male and female flowers on same tree)
Male Flowers: Green catkins, 4–10 cm long
Female Flowers: Small, in groups of 1–3, with red tube-like structures on green stalks
Bloom Period: Mid-spring (March–May)

Fruit/Acorns:
Shape: Elliptic, slightly tapered
Size: 12–18 mm long; cup 10–15 mm across, enclosing 1/3–1/2 of nut
Maturation: Second year (late August–December)
Dispersal: Primarily gravity; consumed by wildlife
Seed Production: Begins ~20 years of age; good crops every 2–3 years
Vegetative Reproduction: Sprouts from root collar or stump if top-killed or cut

Site Requirements
Soil: Sandy, dry soils; shallow soils over bedrock possible
Moisture: Dry soils preferred
Sunlight: Full sun required
Climate Adaptability: Can tolerate nutrient-poor soils and drought
Caution: Susceptible to oak wilt; avoid pruning during peak beetle activity (April–July)

Rooting Habit
Deep taproot; rapid root development
Not easily transplanted due to deep taproot
Disturbance Ecology
Fire Resistance: Mature trees moderately resistant; smaller trees easily top-killed but resprout vigorously
Competition: Less tolerant of shade; survives in dry, open habitats

Wood Properties
Strength & Hardness: Heavy, strong wood
Uses: Furniture, flooring, interior finishing, posts, railroad ties, shingles, fuelwood, some hardwood pulp
Ornamental: Rarely planted; persistent leaves and attractive fall color

Ecological Role
Acorns eaten by blue jays, wild turkeys, white-tailed deer, squirrels
Trunk cavities used by wood ducks, eastern kingbirds, and endangered Kirtland’s warbler
Useful for rehabilitating disturbed sites

Diseases & Pests
Oak Wilt: Highly susceptible; fungal disease affecting water-conducting vessels
Spread by beetles, root grafts, and pruning tools
Management: Trench roots to isolate infected trees; remove and properly dispose of infected trees
Other Pests: Susceptible to various acorn weevils and insect damage

Sources:
Ontario.ca – Northern Pin Oak
USDA NRCS Plant Fact Sheet – Quercus ellipsoidalis
H. Clay Smith, Northern Pin Oak, USDA
Johnson & Appel, Oak Wilt Studies, 2000
Wisconsin Dept. of Natural Resources