Girding

Girding a tree is a way of efficiently killing a tree. The idea is to destroy the path for nutrients to return to the tree roots from its leaves, while leaving intact the ability for leaves to get water and nutrients from the roots. While this can take a couple of years to kill the tree, it works well.

Just cutting down a Norway Maple tree will not hurt the roots. They will immediately start regrowing shoots, and if these are not cut multiple times the tree will eventually regrow. If it is instead girded, it will need to be checked in three months to ensure that it didn't grow back over the gird, and to remove the small amount of shoot growth from below the gird, then it will be completely dead in a couple of years.

Species that can be managed by girding include Norway Maple, Glossy Buckthorn, Common Buckthorn, Winged Euonymus, Autumn Olive, and other woody invasives.

How to Gird

When girding a woody plant, you want to make a cut through the bark and the cambium layer all the way around the tree trunk. Then make a second cut about 8 inches above or below the first one. Finally, remove the bark between the two cuts. If you've cut to the right depth, the bark should peel off easily. Ideally the cuts should be as low on the tree as possible, to minimize the places where shoots will form.

Recommended tools depends on the tree. Norway maple, with a thin bark, is easily cut with the cutting edge of hand clippers, and peels off in a thin layer. Black Walnut requires cutting with a bow saw to get through the thick outer bark, then using a chisel for the vertical cut to allow one to peel off the bark.

After girding, it isn't uncommon in some species (like Norway Maple) for the tree to make an attempt to regrow the cambium layer in vertical stripes. These will need to be cut and removed to kill the tree.

Signage

Girding is a very visible attack on a tree. If done near a trail, it is recommended that a sign be posted indicating why a tree is being girded, and that it is being done with the approval of the Acton Town Natural Resources Dept.