Why is one live oak tree suffering while companion tree is fine?

John Thomas has two mature live oaks in the front yard: one has a full canopy of leaves while the other is almost bare. John says that this happened over the last several years and wants to know what might be causing the leaf drop.

Trees lose their leaves due to stress, normally related to heat, cold, or drought, or due to infestation by a disease or insect pest. If a tree is stressed, it will drop more of its leaves, drop them earlier in the season, and will remain bare longer than surrounding healthy trees.

These trees don’t seem to have disease or insect damage and John’s keeping them deeply watered.

SO, there must be an issue with the roots and water uptake in the stressed tree. This is most likely due to soil compaction. You can check for soil compaction by taking a screwdriver or other similar metal object and trying to insert it into the soil around the tree. If the soil is compacted, it will be very difficult, if not impossible, to push down into it.

When soil is compacted, there isn’t enough pore space for oxygen and water, making it virtually the same as growing in rock. Unless the situation is remedied, the tree will continue to decline.

Although many people aerate the soil in their lawns each year, by pulling out small plugs of turf and soil, it’s much more difficult to aerate the soil around mature trees, with their large, extensive root systems. We recommend contacting several certified arborists and consider hiring someone to assist. A qualified arborist could aerate the soil around the tree safely, using special tools and techniques.