Here are the pictures he later sent to me via email:
|Note the twine/plastic girdling the base of the tree.|
As it turns out, Travis and I both were correct. A few trees that had been described by the client as "runts" or smaller trees had twine/plastic left on the base of the tree when planted. As these trees grew, the twine/plastic girdled the base of the spruce, causing tree death. Other trees did not have an injury at the base, but must have been stressed, because they were clearly infected with Cytospora canker. You can see in these pictures where the white sap is running out cankered areas on the trunk. These oozing cankers are sometimes confused with bird droppings. Some things that may have stressed these trees: heat, drought, clay soils, ???? If branches are infected with Cytospora canker, they may die, and you can trim/destroy them. However, if the trunk of the tree becomes infected with Cytospora canker...... that can be bad news! Cankers on the trunk/stem of a spruce can cause tree death.
The Cytospora fungus invades weakened or stressed wood. We can't always determine the cause of stress from the lab, but any site or environmental conditions that are not good for the species could be the actual cause of the problem. Spruces do not do well in hot, dry, poorly drained soil with high clay content. Sometimes problems do not develop on spruce until roots outgrow the area, grow into poor soil, or until weather stress aggravates the situation. Fungicides are not effective. You need to help tree vitality by pruning out dead wood now, watering in periods of drought lasting two weeks, and fertilizing in the fall or early spring with a balanced tree fertilizer. If you can determine the cause of stress, of course, correct that as well. A fact sheet on Cytospora Canker of spruce can be found at the following link: