I have noticed that some of my trees are showing autumn colours. The Trident is getting redder, and my Field Maples have a few leaves dying. The Silver birch also is starting to lose some leaves. Seems early, the trees are fine otherwise.
This is most likely because we had a warmer and dryer period than usual. Especially spring was cold the reaction might be stronger. This make some try trees withdraw the green chlorophyll earlier to protect them from being exhausted.