Will we have a colorful fall leaf season in Kentucky this year?

The questions are already coming into our department about what affect this crazy weather will have on fall leaf color in the state.  We had a very warm spring, followed by summer droughts, and then heavy rainfall in various areas and it is difficult, if not impossible to predict how good the color will be in the trees.  One thing is for certain, we will have some color in the leaves unless the leaves are already brown and the trees are dead.  Why?  The answer lies in the two factors that give rise to good color, warm sunny days followed by cool to cold nights at the time of leaf abscission (when a plant drops a part of itself, in this case the leaf).  Leaf abscission is generally triggered by changing day or night length and in some species leaf abscission can actually begin in August.  Right now the flowering dogwoods, sassafras and black gum are turning scarlet red as their process of getting ready for dormancy has already begun. In those areas where these species occur in the forest, the color has been pretty good.  Generally speaking, a warm wet spring followed by favorable summer weather, and warm, sunny fall days with cool nights produce the best color and drought often delays color change a couple of weeks.  However, the trees will still gradually lose the green pigment (chlorophyll) and the other pigments (carotenoids which give rise to orange, yellow and brown and the anthocyanins which give rise to red) will show their colors as the season progresses.  If we get rainy, drizzly, days in the coming weeks, the color may not be as spectacular as we would like.  Now is a great time to enjoy being outside and enjoy what Nature has to offer before winter sets in.