As the days grow shorter in early fall, the increasing periods of darkness trigger leafy plants to slow down photosynthesis and stop growing. They do this through a process known as photosynthesis, using the energy of the sun to produce food. Science Behind the Leaves Changing Colors:ĭuring the short summer months, broad-leafed trees such as maples, oaks and birches produce food to nourish themselves for growth. As such, there are many 'peaks' so that you can make your plans based on the timing and location that works for you. Color change begins in mid-September and runs through the first two to three weeks in October and varies by elevation, progressing from north to south and higher to lower elevations during the course of the season.

There is no one 'perfect' time to visit Vermont to see peak foliage.