Pin oak (Quercus palustris): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Quercus palustris Muenchh. in USDA PLANTS, beech family
Other names	Swamp oak, water oak and swamp Spanish oak (Silvics)
Native status, USDA PLANTS	Native in Canada and the lower 48 states
Size, Silvics	On good bottomland sites stands normally reach 24 to 27 m (80 to 90 ft) and about 60 cm (24 in) in diameter by age 75, and individual trees may eventually attain 37 m (120 ft) and 150 cm (60 in)
Longevity, Silvics	A short-lived species that reaches physiological maturity at 80 to 100 years; trees averaged 138 years in one old-growth stand in Kentucky
Green weight of the wood, NRS-38	64 lb per cubic foot, without bark

Native range

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) says pin oak grows from southwestern New England west to extreme southern Ontario, southern Michigan, northern Illinois and Iowa, south to Missouri, eastern Kansas and northeastern Oklahoma, then east to central Arkansas, Tennessee, central North Carolina and Virginia. It calls pin oak a fast-growing, moderately large tree of bottom lands or moist uplands, often on poorly drained clay soils, with best development in the Ohio Valley. The handbook says it transplants well and is tolerant of the many stresses of the urban environment, so has become a favored tree for streets and landscapes.

Flowers, acorns and form

Silvics says pin oak is monoecious, with flowers appearing at about the time the leaves develop in spring and pollination by wind. The acorn matures at the end of the second growing season after flowering and is dispersed from September to early December.

On form, the handbook says pin oak is strongly excurrent, with even open-grown trees keeping a well-defined main trunk through most of the crown. Open-grown trees develop wide, symmetrical crowns in which the upper branches bend upward, the mid-crown branches are horizontal and the lower branches bend downward, giving a distinctive pyramidal shape. Pin oak is not self-pruning: many lower bole branches stay alive on open-grown trees, and in closed stands the dead branches are retained for many years, which causes the many small pin knots in the lumber and, in one explanation Silvics gives, the common name.

Growth and roots

In well-stocked, even-aged bottomland stands in southeastern Missouri, the handbook says pin oak crop trees averaged 28 cm (11 in) in diameter and 20 m (65 ft) in height at age 30, and more than 40 cm (16 in) in diameter at age 50. Typical 60- to 70-year-old bottomland stands yield 112 to 168 cubic m per hectare (8,000 to 12,000 board feet per acre) of merchantable sawtimber, and the handbook says pin oak responds rapidly to thinning and that growth on upland till-plain sites is much less than on bottomland. In well-aerated soils seedlings initially develop a strong taproot, but the root system becomes more fibrous with age, and bare-root seedlings and small saplings quickly regenerate an extensive, fibrous root system when transplanted.

Wood

Silvics says the wood of pin oak is similar to that of northern red oak and the lumber is marketed under the general designation of red oak, but that the numerous small knots limit its use for high quality products. It lists general construction and firewood among the uses. The Wood Handbook (FPL-GTR-282, 2021) groups it in the red oak group of the Eastern states; what it says about that group is set out once on the northern red oak page. Table 5-3b has a separate pin oak row, shown below.

Wood Handbook Table 5-3b	Specific gravity	Modulus of rupture (lbf per square inch)	Side hardness (lbf)
Green	0.58	8,300	1,070
At 12% moisture content	0.63	14,000	1,510

The Wood Handbook states that specific gravity is based on oven-dry weight and the volume when green or at 12% moisture content. The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Diseases, insects and damage the handbook names

Silvics (1990) names these agents by the names it used.

Flooding. Pin oak is very tolerant of dormant-season flooding and much less tolerant of growing-season flooding. The handbook says trees may be injured or killed by intermittent growing-season flooding over several successive years, usually survive one growing season of continuous flooding, and are killed by continuous flooding over two or three consecutive years. It rates pin oak intermediately tolerant, along with sugar maple, river birch and southern red oak. After 25 years of dormant-season flooding in a green-tree reservoir in southeastern Missouri, many trees had bole swellings at and above the flood water level, causing bark fissures up to 10 cm (4 in) wide; the cause is described as unknown.
Fire. The bark is relatively thin, so the species is especially susceptible to fire damage and the decay associated with fire wounds.
Diseases. Subject to most oak diseases including oak wilt (Ceratocystis fagacearum, see oak wilt), and particularly susceptible to the leaf blister fungus Taphrina caerulescens, the shoot-blight and twig canker fungus Dothiorella quercina and pin oak blight (Endothia gyrosa).
Insects. Host to many oak-feeding defoliators, wood borers, gall wasps and acorn weevils. It is classed as a most preferred host of the gypsy moth, also called the spongy moth (spongy moth page), and especially susceptible to the obscure scale, oak leaftier, pin oak sawfly, scarlet oak sawfly, forest tent caterpillar, a leafroller, the horned oak gall wasp and the gouty oak gall wasp. The handbook says outbreaks of the horned oak gall wasp and forest tent caterpillar severely damaged thousands of acres of pin oak stands in southern Illinois over a 25-year span.
Chlorosis. Ornamental pin oaks planted on alkaline soils often develop foliar yellowing (chlorosis) which, if severe, can kill the tree. The handbook says it was previously thought to be simple iron deficiency but involves reduced foliar concentrations of micronutrients, and is not a problem in natural stands on more acidic soils.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.