August 10, 2017 |
A Linden Tree in the City
Subject: Something wrong with my tree
Question: We have a tree in front of our house – not sure the type (someone once called it a “trash tree.”) It’s lost a ton of leaves recently – and they look like they have been eaten through or something.
I’ve attached some photos of the tree, the lost leaves, close ups of the leaves, and some odd growths we are seeing on other leaves.
Any clue what is going on? Is there a cost to having someone come out and take a look?
Arborist’s Answer: Your tree is a linden, although this tree has problems, I wouldn’t call it a trash tree. In ascending order of the severity of the tree’s problems. Picture 5, leaves with appendages, shows a gall caused by a eriophyid mite, the gall has a baby mite inside it, unsightly but not a concern for the tree’s health. Picture 4, leaves with the surface removed (skeletonized) by Japanese beetles feeding – not a big concern either and they’re almost done feeding for the year. You can spray for Japanese beetles with many different insecticides if you want to get some revenge. The main problem is stem girdling roots (SGR’s) visible at the base of the tree in pictures 1 and 2. SGR’s cut off sap flow in the main stem by forming a tourniquet around the trunk. The trunk gets thicker and the root expands slowly restricting the movement both up and down the stem. The canopy starts to thin and the leaves are smaller as the tree adjusts to the reduction in water and nutrient movement. In the worse cases the weakness in the “pinched” area makes the stem brittle and the tree breaks off in windy conditions. Removal of the girdling roots should be done with great deliberation because the SGR is also benefitting the tree by transporting water, etc.