Pin oak

Leaves

Form

• Base wedge-shaped
• 5–7 lobes
• Wide-spreading, separated by deep, wide, U-shaped notches
• Upper edge of lobes at right angles to the midvein
• Basal lobes often recurved
• A few tufts of hairs in the vein axils

Length

• 7–15 cm
• Central lobe 3 times as long as the width of the leaf between opposite notches
• Petiole 2-5 cm

Colour

• Upper surface shiny dark green
• Lower surface paler

Margin

• A few bristle-tipped teeth on the larger lobes

Petiole

• Slender

Buds

Form

• Terminal bud ovoid, small, sharp-pointed
• Almost hairless

Length

• 2–4 mm

Colour

• Light chestnut-brown

Twigs

Form

• Slender, hairless

Color

• Reddish-brown

Flowers

Form

• Pollen flowers small
• In many-flowered drooping catkins
• Seed flowers small
• Solitary or in few-flowered clusters (spikes)

Structure

• Monoecious

Floral timing

• With the leaves

Fruits

Form

• Acorns small
• Short-beaked at the tip
• Cup shallow, saucer-shaped, enclosing one-quarter of the nut
• Scales tight-fitting, thin
• Pointed, hairy

Length

• Acorns 9–13 mm

Width

• Acorns almost as wide as long
• Cup 12–16 mm

Colour

• Cup reddish-brown

Structure

• 1-seeded nut

Bark

Form

• Thin and smooth when young
• Divides into narrow inconspicuous ridges with age

Colour

• Greyish-brown
• Inner bark reddish

Wood

Colour

• Light brown

Size

Height

• To 20 m

Diameter

• To 60 cm

Maximum age

• 100 years

Tree form

Forest-grown

Trunk

• Straight, with a gradual taper
• Distinct well into the crown
• Small, stiff, dead branchlets often project from the trunk and larger branches

Crown

• Principal branches slender
• Ascending in the upper crown
• Horizontal in the centre of the crown
• Curving downward in the lower crown

Root system

• Shallow

Habitat

Site

• Mainly on poorly drained soils
• In swamps and along streams
• On well-drained loamy soils
• Frequently planted as an ornamental
• Tolerant of urban conditions

Light tolerance

• Intolerant of shade

Associated species

• Mixed with other oaks, elms, and willows

Range

Southern Ontario at the east and west ends of Lake Erie
Locally abundant