When you're strolling through the forest, you may have occasionally come across a tree or groups of trees with strange markings on them.
They can be anything from orange lines on top of each other, to ominous red crosses and enigmatic Roman numerals. These aren't the work of woodland creatures, but are used for a number of reasons in forestry management, as well as logging. So what do they mean?
While there is no standardized meaning for the symbols used across the world, different organizations of course use and understand them when they do so. In the USA, the most common markings you'll see are orange stripes. These marks are placed on trees that are due to be harvested, and have been marked for use in timber, while blue markings indicate the edge of a boundary. As well as a visual aid for loggers and tree surgeons to identify trees to be used for timber, they help forest managers keep an eye on logging activity.
"Stump paint is used to help foresters confirm that trees were properly harvested. Stumps without paint raise a red flag, especially if there are too many," Michigan State University Extension Forestry explains. "Sometimes, an adjacent unmarked tree needs to be cut in order to get at a marked tree. Foresters take this into account when marking a stand, but sometimes leave access a bit tough for a logger."
Alternatively, when a large area of forest is to be cut down, trees that are to be left alone may be marked, sometimes in a blue-green color, or a boundary may be marked in yellow.
Roman numerals are used in the UK on trees which have been measured for their height.
"These are called volume sample trees," Forestry England explains. "These trees are important for estimating the total volume, and are marked using Roman numerals to identify them."
Other trees may be marked with letters like "PL" to indicate that they are near a power line, which will need to be shut off before the tree is felled, while red crosses are another way of indicating that a tree is to be cut down. Trees that are not for timber but are diseased may be marked in the same way.