How Green Is My Tree?
Written by: Jean Ferdinandsen, Certified Arborist, WI-0149A
Most healthy trees should have leaves with an even green color. Leaves should also have a similar size, density, and an even distribution throughout the tree.
If a tree exhibits a yellowing of leaves with a network of darker green veins (interveinal chlorosis), this likely indicates a serious nutrient problem. In severe cases the entire leaf turns yellow and leaf size is stunted. Leaves may scorch or wither and drop prematurely. Symptoms may be on a few leaves, an individual branch, and portions or all of a tree.
This yellowing of leaves indicates a lack of the chlorophyll needed for the tree to photosynthesize properly to maintain growth and vigor. If not corrected, trees decline or even die.
Lack of iron (Fe) or Manganese (Mn) usually causes chlorosis. This can be related to high soil pH, soil moisture, poor drainage or aeration, high temperatures, root loss and compaction.
Some trees such as red and silver maple, river birch, white & pin oak, white pine, quaking aspen and bald cypress are more susceptible to chlorosis. If your tree is small and suffering from chlorosis, consider removal and replacement versus a lifetime of treatment.
Long term actions should be taken to improve the root zone to help retain a tree. Measures such as removing grass from under the tree and applying organic mulch can improve rooting and reduce stress. Root zone enhancement with aeration and soil amendments also improves rooting and nutrient availability.
Direct treatment to improve the health, vigor and color of a chlorotic tree may be needed. These may include foliar application and soil or trunk injection of nutrients. Each treatment has its place.
Contact your Wachtel Certified Arborist to evaluate your tree and help decide the most appropriate treatment and course of action.