The oak is undoubtedly one of our country’s most iconic and symbolic trees. A core feature of ancient druid worship, a royal hiding place and – arguably most importantly (sorry, royalists) – a huge boon for wildlife, the oak is woven into our country’s history in a way that few other trees can match.

There are a couple of oak species native to the UK, as well as many others which have been introduced to our shores over the years. In this article, we’ll be detailing how you can tell the different species apart. So, if you want to tell your common oak from your cork oak, you’ve come to the right place.

Jump to:

• Common oak tree (Quercus robur)
• Sessile oak tree (Quercus petraea)
• Holm oak tree (Quercus ilex)
• Turkey oak tree (Quercus cerris)
• Red oak tree (Quercus rubra)
• Cork oak tree (Quercus suber)
• Pin oak tree (Quercus palustris)
• White oak tree (Quercus alba)

What are the types of oak tree?

Now, a quick disclaimer. There are over 600 species of oak trees found worldwide, so you’ll forgive us if we miss a few out, otherwise this might well have ended up being the longest piece of writing ever penned. For the purposes of this post, we’ll be focusing on some of the most common oak trees, particularly those found in the UK – both native and non-native. First up? It has to be the English oak, more frequently known as the common oak.

Common oak tree (Quercus robur)

Quercus robur, the common oak, is a magnificent broadleaf tree that can easily grow to an ultimate height of over 20 metres throughout the course of its lifetime. The timber of this native tree has long been used in furniture and flooring, while in times gone by the wood was also seen as a prime choice for sailing ships; the HMS Victory, for instance, was constructed using roughly 5,400 oak trees! It’s also known as the pedunculate oak, because its acorns are held on long stalks (peduncles).

Common oak tree identification

The common oak is most easily identified by looking at its deeply-lobed foliage, usually 10cm or so in length, the very short (almost absent) leaf petioles (stems) and stalked acorns. Flower-wise, look for dangling chartreuse catkins in early spring, and in winter, you can determine what oak you’re looking at by examining the number of bud scales. Common oaks typically have fewer than 20 scales (sessile oaks, by contrast, generally have more than 20 bud scales). Another thing worth bearing in mind is that common oaks are most often found in central and southern parts of the UK.

Sessile oak tree (Quercus petraea)

The sessile oak tree – known variously also as the Cornish, Welsh, Irish and durmast oak – derives its most popular name from the fact that, unlike the common oak, its acorns aren’t held hanging, but rather fixed directly to the branches. It is Ireland’s national tree and typically found in upland areas.

Sessile oak tree identification

The tell-tale sign you’re dealing with a sessile oak is the aforementioned acorns, affixed to twigs directly rather than dangling on stalks. Besides this, these oaks are more upright than their common oak counterparts, while the branches themselves are also a bit straighter. Lastly, look at the leaves – if you compare the common oak with the sessile oak, the former has shorter leaf stalks than the latter.

Credit: Nicholas Turland, Flickr

Holm oak tree (Quercus ilex)

Also known as the evergreen oak tree, the holm oak is native to the Mediterranean, initially making its way to British shores towards the end of the 16th century. Forming a bushy, rounded crown, these trees can easily reach 25 metres in height – the largest recorded holm oak is actually found here in the UK, in Windsor Great Park (measuring over 30 metres tall). It’s also one of the trees most commonly used to create truffle orchards, thanks to beneficial root-fungus associations. 

Holm oak tree identification

The key to identifying a holm oak lies in one of its other common names, the holly oak. The tree’s leaves are redolent of the holly bush; glossy green, slightly spiny and oval in shape, it’s easy to see how the tree got that moniker. Other things to watch out for include the more pointed acorns and, of course, the evergreen nature of its leaves, which helps easily distinguish the holm oak from its native cousins.

Turkey oak tree (Quercus cerris)

One of the most easily identifiable oaks, the Turkey oak is a fast-growing species whose nationwide proliferation has sadly led to a decline in native oaks. Why? Well, this species happens to provide home for a particular gall wasp, Andricus quercuscalicis, the larvae of which damages acorns, resulting in the formation of so-called ‘knopper galls’. These ridged, unsightly growths occur around the acorn. All that said, it’s still an attractive tree that provides some wildlife benefits (just not as many as our native species).

Turkey oak tree identification

If you’re met with a Turkey oak, this is what you’re going to see: the leaves are in a deep green, glossy hue, they’re irregularly-lobed, cut deeply and boast a downy, felt-like feel on their underside. The acorns are a dead giveaway, too. The acorn cups look like a matted, tangled knot of hair. The tree’s bark is deeply-fissured and, in maturity, can feature orange strips in said fissures.

Red oak tree (Quercus rubra)

If autumn colour is your thing and you’ve got a large garden, then the red oak tree is certainly worth considering. Originally from North America, this species is similar to other oaks in that it develops a dense, bushy crown and boasts ridged grey bark. Often growing to an ultimate height of more than 20 metres, this tree is fast-growing and, though not as beneficial to wildlife as our common or sessile oak, still provides a valuable nesting site for birds.

Red oak tree identification

Most notable for its flaming-red autumn hues, you can also tell this oak apart from others through the more pointed nature of its foliage, as well as the ‘shiny’ stripes seen on the bark. Unlike other oak species, these bandings are seen throughout the trunk’s length, not just towards the top of the trunk.

Cork oak tree (Quercus suber)

The second evergreen oak tree in our list, the cork oak tree is a fascinating one, being the origin of, as the name suggests, cork – so if you’re partial to a glass of vino on a Friday night, this tree deserves your gratitude! A tree that doesn’t mind taking its time to grow, the cork oak develops gnarly, ridged bark which, when harvested, gives way to a bold brick-red colour while the new replacement bark develops.

Cork oak tree identification

The acorns of this oak species are pretty elongated and narrow, and held in a small, scaly cup. As with many other evergreen plants, the cork tree’s foliage is a dark glossy green colour, with a velvety (and paler) underside. Mature cork trees also often divide into several, asymmetrical spreading crowns, as opposed to the rounded, bushy singular crown that many other Quercus spp. boast.

Pin oak tree (Quercus palustris)

The first RHS award winner to grace this post, Quercus palustris holds the Award of Garden Merit, an accolade conferred upon those plants deemed by the RHS to perform particularly well in British gardens. Also known as the swamp Spanish oak, the pin oak is a lovely option for landscaping large gardens and parklands. A comparatively short-lived species, the pin oak is native to wetlands – hence its alternative name – and its bark was used by some indigenous American populations in a drink as a remedy for intestinal pain.

Pin oak tree identification

Growing from a pyramidal canopy when young to a spreading habit with maturity, this tree’s deeply-lobed foliage features teeth with bristle-like tips, changing to deep red and orange shades come autumn. Over time, the lower branches may adopt a somewhat pendulous nature, further adding to the tree’s already-sizable impact.

Credit: Daniel Arrhakis, Flickr

White oak tree (Quercus alba)

The last Quercus sp. on our list, but by no means the least important, is the white oak tree. Sometimes known as the Quebec oak, this fine species boasts light bark, while the wood, when finished and treated, is very pale in appearance (giving the tree its name). Like many other oaks, this slow-growing tree can reach between 20 and 30 metres in height, starting out more pyramidal, before becoming increasingly rounded with age. Historically, white oak has been used in basketry, shipbuilding and by coopers.

White oak tree identification

The standout feature of this oak in our books is its colour-changing foliage. Emerging an attractive pink colour, the deeply-lobed, rounded leaves then turn green, before finally adopting coppery red hues when autumn rolls around. The bark is scaly and fissured, while the acorns produced are a light chestnut brown colour.

Credit: Melinda Young Stuart, Flickr

Final thoughts

There you have it! You see now why we whittled down our list to just a few oak species… We may be biased but our favourite oak has to be the common oak; native to our shores and as majestic as they come, it’s hard not to fall in love with a tree that’s proved such a steadfast companion to our nation’s historical tapestry. So, here’s to all you oak trees out there. May you flourish and thrive wherever you’re found.