A scarred tree or scar tree, also known as a canoe tree and shield tree, is a tree which has had bark removed by Aboriginal Australians for the creation of bark canoes, shelters, weapons such as shields, tools, traps, containers (such as coolamons), or other artefacts. Carved trees may also be created as a form of artistic and spiritual expression by some Aboriginal peoples, to mark sites of significance such as burial sites. Trees in some areas are culturally modified in other ways that change their form, including "trees-in-trees".

Bark was removed by making deep cuts in a tree with a stone pickaxe or other similar tool. The area of bark removed is typically regular in shape, often with parallel sides and slightly pointed or rounded ends, and the scar usually stops above ground level. Australian native Eucalypt species such as box and red gum (especially in Victoria), swamp mahogany, river box, or whichever species are native in the area. Scars remain in trees that are often over 200 years old. Sometimes there is exposed sapwood at the base or at the top of the scar, showing axe cuts.

Aboriginal people removed bark from trees to make things like canoes, axes, tools, containers and shields, as well as to build temporary shelters. Sometimes they cut toe holds for ease of climbing, with the trees used as lookouts or to hunt for bush foods. Wrapping meat or seafood in layers of moistened paperbark (melaleuca) and nestling it into the hot coals is one of traditional aboriginal way of cooking.

Bark canoes were mainly used for fishing or crossing rivers or lakes rather than long journeys. They were usually propelled by punting with a long stick.

To remove bark, the Aboriginal people cut an outline of the shape they wanted using stone axes or, once Europeans had arrived, steel axes. The bark was then levered off. Sometimes the axe marks made by Aboriginal people are still visible on the sapwood of the tree, but usually the marks will be hidden because the bark has grown back. The amount of bark regrowth may help you tell the age of the scar. Sometimes, if the scar is very old, it will be completely covered by regrowth

Aboriginal people made several kinds of bark canoes. Bark canoes were made from the bark of certain trees, notably red gum, stringybark, swamp mahogany and river box and were made during summer.

Bark canoes were made from massive single piece of bark. They were softened over fire, tied at both ends to make a canoe shape and used sticks or spars to keep it open. The resin from Xanthorrhoea (grass tree) was used to waterproof the base and were also used to repair any leaks or small holes. This bark canoe is called Nawi. A small fire was kept alight in the bark canoe on a bed of wet clay or seaweed. This kept people warm in the winter and also allowed them to cook the fish they had caught. Yuki is another form of bark canoe, the bark on the tree was cut-out in a shape of a canoe, it was then propped up all round the edge with the help of sticks and weighted in the middle with stones and logs of wood, then a fire is made inside and under the bark to heat the sap and make it pliable and soft. It is then left to dry in the canoe shape. Bark strips could also be sewn together to make larger canoes, known as Gumung derrka and Na-riyarrku or sewn bark canoes.

Non-Indigenous Australians called the trees thus marked as scarred trees, scar trees, canoe trees or shield trees.