The leaves of the red oak are larger, and the lobes more pointed, than those of the native oak (Quercus robur). Their strong red autumn colour dominates the landscape in their native range, the eastern parts of North America, but in Finland they aren’t usually as strongly coloured, usually a brownish red.
The oak is perhaps the most highly valued of all European trees. The strength of its timber, its size and resistance to decay (for example in ships, furniture and wine barrels) have been contributing factors. Trees can live for over a thousand years and large old oaks are important landmarks. Old oaks are rarely seen in Finland because for hundreds of years oak forests have been destroyed to make way for farming, and for their valuable timber.
Mongolian oak (Q. mongolica) grows over a large range throughout East Asia and several subspecies and forms have been described, some of them even awarded the status of separate species. The most successful of these in Finland has been the maritime Japanese subspecies called mizu-nara (Q. mongolica subsp. crispula) because it is hardier in the Finnish type of climate, which is unsettled and changeable. The northern provenances from Hokkaido and Sakhalin Island are also hardy to severe frosts.
More than 70 oak species grow naturally in North America, the most widespread being the large majestic burr oak, also called mossy cup oak. The edge of the cup holding the large acorn resembles the burrs of the burdock, hence the common name.
On good sites the burr oak can grow to 40 metres but on less fertile soil remains small and twisted. Corky wings often develop on the branches, which emphasize the tree’s generally bare and spiky appearance.
The Northern pin oak, one of the most promising of the American oaks, was first brought to Finland by the Mustila collecting expedition of 1993. It grows naturally in the cold-winter climate belt west and south-west of the Great Lakes, where many other American oak species struggle to survive. It grows in mixed forest on poorish hillside soils with, among others, (American) red pine (Pinus resinosa).