Pin Oak
Quercus palustris
by Martin (Mort) Schmidt for Simply Living
Pin Oak (Quercus palustris) is one of the two most common oaks from the red oak group in Central Ohio. Though less well regarded than the other common red oak, Northern Red Oak (Q. rubra), Pin Oak has its charms.
Many people recognize Quercus palustris as an oak by its leaf shape, but leaf shape is secondary to fruits and flowers in tree classification. Pin Oaks are oaks because they produce acorns. Pin Oak leaves are alternately-attached, so the leaves and branches are not attached directly across from each other. (The Ohio trees with opposite leaves are the MADBucks – Maple, Ash, Dogwood, and Buckeye. Most of the rest are opposite). Pin Oak leaves are also simple, i.e., the blades are attached directly to the tree with their own stem, and don’t share a stem with other blades.
Pin Oak leaves are 3 to 5 inches long, 2 to 4 inches wide, with deep sinuses between narrow lobes. The veins are pinnately-arranged, or feather-like, and have a single primary vein, with secondary veins attached to it at different points. Palmately-veined leaves are hand-like, and have multiple primary veins attached at the base of the leaf.
The oaks fall into two broad groups – red oaks, with pointed leaf tips, and white oaks, with rounded leaf tips. (Remember that pointed needles draw red blood, while round snowballs are white). Pin Oak’s 5 to 7 lobes have distinct points, indicating that it’s a red oak. The leaves turn a burgundy-brown in fall, and are persistent, remaining on the tree into early winter. Like other oaks, Pin Oaks have multiple terminal buds at the end of twigs, which is a good way to recognize oaks at any time of year. Like the leaves, the buds are generally pointed on red oaks and rounded on white oaks, but the difference can be subtle.
Pin Oak flowers take the form of green catkins, which produce acorns over the course of summer. All species of oak are monoecious, having both male and female flowers on the same tree. Therefore, all oaks can potentially produce acorns at maturity. Dioecious trees have male and female flowers on separate trees, and only females produce fruit.
Although we use leaf tips – pointed versus rounded – to distinguish between red and white oaks, the classification is actually based on the acorn growth. White oak acorns are low in tannic acid, and sweet, whereas red oak acorns are high in tannins, and bitter. Subsequently, white oak acorns take root soon after falling, to prevent their being eaten, while red oak acorns wait until spring. Pin Oak acorns take root in spring, making it a red oak. It has the smallest acorns of any Ohio oak, and they’re often distinctly striped.
Pin Oaks also sprout vigorously from stumps, and William Bryan Logan’s Oak, The Frame of Civilization, tells us that, “If you look closely at some forests of pin or red oak in America’s upper Midwest, you will see that the majority of trees are stump sprouts, regenerated from a forest logged decades ago”. But then, most trees have a single trunk if they emerged from seed, and multiple trunks if they came from stumps.
Pin Oak bark is very similar to the flagship of the red oak group, Northern Red Oak (Quercus rubra). Its medium gray bark has shallow furrows, and long, smooth ridges, but generally less continuous than the ridges on Northern Red Oak. The thin bark offers little fire protection. Pin Oak’s most distinctive winter feature is its shape. The upper branches reach upward, the middle branches are horizontal, and the lower branches droop, giving the tree an hourglass shape recognizable from hundreds of feet.
Mature Pin Oaks typically have a height of 50 to 90 feet and a trunk diameter of 1 to 2.5 feet. Ohio’s Champion, located in Lake County, has a height of 104 feet, a trunk diameter of 6.5 feet, and a crown width of 117 feet. Q. palustris is fast-growing and not long-lived by oak standards, typically reaching maturity by 80 to 100 years, and seldom completing a second century.
ID Summary: Narrow, lobed leaves with pointed tips. Hourglass tree shape. Small, often striped acorns. Bark with smooth and shallow furrows.
Similar Trees: Scarlet Oak (Quercus coccinea) leaves are very similar, but the acorns are larger and their caps much deeper. Scarlet Oak is also less water tolerant and is generally not found in wet soils. Distinguishing Pin Oak from other red oaks is complicated by the fact that it hybridizes with many of them, especially Shingle Oak (Quercus ibricaria). But it’s all red oak at the lumber yard.
The Latin name, “palustris” means “of the swamp”, and Quercus palustris thrives in wetter soils and areas subject to occasional flooding, but they can also survive in upland conditions. Pin Oak does best in full sunlight, in slightly acidic, clay soils. Pin Oak tolerates pollution, soil compaction, and other common urban conditions, and because it’s normally found in wetter soils, it has no taproot and is readily transplantable.
According to Lucy Braun’s The Woody Plants of Ohio, Pin Oak grows in all but 6 of Ohio’s 88 counties. The Columbus, Ohio Street Tree Inventory indicates that Pin Oak is the 29th most abundant tree on the City streets, making up 0.89 percent of the total. A number of white oak species are native to Europe and Asia, but nearly all red oaks are native to North America. Interestingly, Pin Oak and other red oaks are generally valued here, but they can be invasive overseas.
Pin Oak lumber has a Janka hardness of 1,500 lbf and a density of 0.71 g/cc, according to the Wood Database, compared to the median of my list of 73 Ohio trees of 1,075 lbf and 0.64 g/cc. This makes Pin Oak one of the hardest oaks native to Ohio, but its lumber is limited by the presence of numerous small knots. Additionally, as a red oak, it’s not water-tight, so it has low rot resistance and is less suitable for outdoor use than white oaks. On the other hand, the higher permeability of red oak lumber makes it easier to inject with chemicals for treated lumber. Consequently, the hard wood of Pin Oak makes good railroad ties. Pin Oak is also excellent for flooring, where hardness means long wear, and knots don’t much matter. Q. palustris is also used for the unexposed parts of furniture, and for pallets. Pin Oak splits readily, and like other dense woods, burns hot, so it makes excellent firewood. And finally, Pin Oak is well suited for mine reclamation, due to its hardiness, water tolerance, and preference for acidic soils.
According to the Native American Ethnobotany Database, Pin Oak was not nearly as widely used by the Natives as many other trees, but the database indicates that the Cherokee used Pin Oak to make wooden pegs or pins used as fasteners, and the Delaware made an infusion of inner bark to relieve gastrointestinal problems. Some white oak acorns were sweet enough to be a staple food for the American Indians, but Pin Oak acorns were too small and tannic to be used as a human foodstuff.
Pin Oak’s greatest economic value is perhaps its use for landscaping. Its distinctive shape, and persistent, colorful winter leaves make it very attractive. The shallow root system – unusual for oaks – makes it easy to transplant. The diminutive acorns are more convenient than larger fruits (like Hedge Apple), stinky fruits (like Gingko), or overabundant fruits (like Cottonwood). And Quercus palustris tolerates city conditions, such as pollution and soil compaction.
Pin Oak also offers greater environmental diversity than many other trees used for landscaping. According to the 10/20/30 Rule, urban areas should have no more than 10% of one species, 20% of one genus, or 30% of one family of trees. The Columbus Street Tree Inventory indicates that the species/genus/family percentages for Red Maple (Acer rubrum) are 9.3/30/31, but for Pin Oak only 0.89/7/8. And it’s native to boot.
Because Pin Oak acorns are small, they are especially important food for birds, including blue jays, ducks, wild turkeys, and nuthatches. Bluejays are more likely than other birds to store fruits for later consumption, and therefore responsible for planting more trees. White-tailed deer, squirrels, and chipmunks also eat the small acorns in great numbers. White-tailed deer also browse on the leaves and twigs. Dozens of species of moths and butterflies consume Pin Oak leaves in their larval form. Treehoppers, aphids, and gall wasps consume Pin Oak sap. An extensive list of faunal associates that live on oaks can be found at Illinois Wildflowers.
The myths and folklore surrounding trees are fascinating. Unfortunately, many of these stories originated in Europe or Asia, and since most red oaks are New World natives, the literature is sparse. But I have a story of my own.
I spent most of my career as an environmental geologist, and one of my regular clients operated a limestone quarry. To them, the boulders brought down from Canada during the Ice Age, overlying the limestone, were waste, and were dumped in the spoil pile. Whenever I visited, I brought home a couple of boulders, and made a rock garden in my back yard. One spring, a tree sprouted from the middle of the rock pile, and since I hadn’t planted it, I snipped it off. The following spring, the tree, or one like it, sprouted up again, and again, I snipped it off. The third spring, I recognized the tree as a Pin Oak, and realized that it was perfectly placed, so I left it alone. Decades later, the Pin Oak is over 30 feet tall, over a foot in girth, and drops numerous small acorns for wildlife. The critter that planted it was smarter than me, and when I finally got out of the way, I was gifted with one of my favorite trees.
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You can also listen to my talks on Ohio Broadleaf Tree Identification on YouTube, Part 1 and Part 2.
