If you have a maple tree that has been slowly turning color prior to October, your tree maybe trying to tell you something. Your tree may be deficient of necessary micronutrients like manganese or an iron deficiency. No, manganese is not a foreign country, it is a micronutrient necessary for healthy foliage. Most people are familiar with the “major” nutrients found in fertilizers, nitrogen, phosphorus and potassium. The micronutrients like manganese however can have an important impact on the health of a tree, and lack of it can be very visible when looking at the foliage. The foliage will have a pale, yellow unhealthy look with dark green veins. You can purchase implants, injections or fertilizers to correct this nutrient deficiency. Before doing so however, do a soil PH test. Usually soils have the necessary amounts of micronutrients, but the nutrients are unavailable to the tree due to an improper soil Ph. Correcting the soil Ph followed up by amending the nutrients with a feeding including micronutrients like manganese and iron will give the tree the “kick in the plants” it needs.
If you have a tree like the one pictured to the right, again your tree is telling you something. Early fall color, dying branches, undersized foliage are indications of shade tree decline. The problem could be stress from enduring periods of drought, maybe old age, root competition or girdling roots, etc. etc. Scheduling some winter pruning and feeding the tree in October as the leaves are falling off with the soil warm enough for root activity will help.
Like Yogi Berra said, you can observe a lot just by watching. Be in touch with what your tree is trying to tell you, especially if change in color comes before the calendar says it should.