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by M. Ritter, J. Yost, W. Mark, J. Reimer
GENERAL INFO
Quercus suber has a rugged, thick bark that is deeply fissured and cork-like, making it quite unique in appearance. It can grow to a moderate height with a broad, rounded canopy that provides ample shade. The leaves are dark green and leathery with a glossy surface, often staying on the tree year-round. In spring, it produces small, inconspicuous flowers that later develop into acorns. This tree is highly adaptable to various soil types and can tolerate drought conditions, making it a resilient choice for urban landscaping. Its distinctive bark is often harvested sustainably for commercial use without harming the tree.
Native range: Western Mediterranean and North AfricaEthnobotanical Info / Tree Use: The bark of Cork Oak is the primary source of commercial cork. Cork is heat and sound insulating as well as water repellant. The first harvest usually occurs once the tree is around 25 years old with a DBH of 28in and is subsequently harvested every nine to twelve. The first two harvests are lower quality with cracking and low elasticity. The third harvest and onward is the cork that is used commercially.
The acorns are used as pig feed in a practice called acorn fattening. Citations Page
Schoolyard Use: This tree is great for learning about human uses for trees, fire ecology, and mycorrhizal symbiosis. Q. suber is best known for its valuable bark which is harvested to make cork. Cork is the outer layer of tree bark that is made up of thinly walled, irregularly shaped, waxy cells. Many trees that have peeling or exfoliating bark have cork but the cork of Q. suber is distinctly spongy and flexible making it commercially very valuable. Additionally, the spongy cork naturally insulates the tree from fire making it resilient in its native fire-prone landscapes. This could provide an interesting introduction to how plants adapt to regular wildfires. Cork Oaks also form mycorrhizal symbioses with four species for Amanita among other fungi. The vegetative bodies of these fungi, the mycelium, are in close contact with the roots of the oak. The fungi provide water and nutrients for the oak in exchange for products of photosynthesis.
Native range: Western Mediterranean and North AfricaEthnobotanical Info / Tree Use: The bark of Cork Oak is the primary source of commercial cork. Cork is heat and sound insulating as well as water repellant. The first harvest usually occurs once the tree is around 25 years old with a DBH of 28in and is subsequently harvested every nine to twelve. The first two harvests are lower quality with cracking and low elasticity. The third harvest and onward is the cork that is used commercially.
The acorns are used as pig feed in a practice called acorn fattening. Citations Page
Schoolyard Use: This tree is great for learning about human uses for trees, fire ecology, and mycorrhizal symbiosis. Q. suber is best known for its valuable bark which is harvested to make cork. Cork is the outer layer of tree bark that is made up of thinly walled, irregularly shaped, waxy cells. Many trees that have peeling or exfoliating bark have cork but the cork of Q. suber is distinctly spongy and flexible making it commercially very valuable. Additionally, the spongy cork naturally insulates the tree from fire making it resilient in its native fire-prone landscapes. This could provide an interesting introduction to how plants adapt to regular wildfires. Cork Oaks also form mycorrhizal symbioses with four species for Amanita among other fungi. The vegetative bodies of these fungi, the mycelium, are in close contact with the roots of the oak. The fungi provide water and nutrients for the oak in exchange for products of photosynthesis.
TREE CHARACTERISTICS
Tree Shape: RoundedFoliage Type: EvergreenMaximum Tree Height: 70 feetCanopy Width: 70 feetGrowth Rate: ~24-36 in/yearLeaf Arrangement and Leaf Form: Alternate, SimpleLeaf Shape: OblongLeaf color: Dark GreenFlowers: InconspicuousFlower Color: Yellow-Green or BrownFlower Time: SpringFruit: Medium Brown AcornFruiting time: Fall or WinterFruit Value: Wildlife use itBark Color: Light Green or Light Gray, FissuredLitter Type: Dry Fruit
SITE CONDITIONS
Recommended Planting Area: 4' to 7'Schoolyard Trees: YesWater Use Rating: LowSunset Climate Zone: 5 - 16, 18 - 24Shade Tolerance: NoUSDA Hardiness Zone: 8, 9, 10Soil Texture: Loam or Sand or ClaySoil pH: Very Acidic to Slightly AlkalineSalt Tolerance: Moderate
CONSIDERATIONS
Branch Strength: StrongRoot Damage Potential: ModeratePotential health issues: Allergy, PoisonousBiogenic Emissions: HighWildlife interactions: Attracts birds, squirrelsDisease and Pest susceptibility: Armillaria, Phytophthora, Root Rot and Invasive Shot Hole BorerDisease Resistance and Pest Resistance: VerticilliumUtility Friendly: NoWCISA Appraisal: Suggested LCANT 24" box, Suggested LCANT 24" box, Group Rating 2, Approx. cross sectional area 2.24 sq. in.
External Resources
CITE THIS TREE
"SelecTree. UFEI. "Quercus suber Tree Record." 1995-2025. Cal
Poly State University, San Luis Obispo. Accessed on Jun 16, 2025."
< https://selectree.calpoly.edu/tree-detail/1263 >
< https://selectree.calpoly.edu/tree-detail/1263 >
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