Adopt a Season

Created by John Pickle, DEW Educator, Arlington, MA

As autumn sets in and the amount of daylight decreases and the temperature becomes colder, deciduous trees begin their "green down" phase. Pictures taken regularly - generally once a week for a month - before and while the leaves are changing color in your area, will create a record of the timing and intensity of autumn color during green down that you can monitor over many years.

Notice the variety of trees in these pictures taken in Massachusetts and that each species has its own timing in changing leaf color and dropping of leaves. Although pictures were taken on clear days, the weekly amount of precipitation may be inferred from the changing water levels in the pond (use the large rocks as markers). Rising water levels indicate a week marked with several rain events, falling water levels occur during a week without much precipitation, and unchanging water levels indicate moderate rainfall during the week.


  • Start taking pictures while the trees are still green.
  • Identify the species of trees that are visible in the image and label them on a reference picture that may be used to study green down each year.
  • Upload the labeled picture as a reference for others.
  • Take a picture with a visible scale of known length beside trees of interest. You may then use the DEW software to measure how the tree grows over years. Since the trees don't physically relocate on their own, one picture with the scale nearby will be the reference for years to come.
  • Measure the distance and direction to each tree (or GPS the location if you have access to a handheld GPS tool). This may help community planners use the photographs with Geographic Information Systems (GIS) software.
  • Make notations about the weather and other relevant factors when you upload the pictures to the website.
  • Ask neighbors or other parties to comment on the pictures after they are uploaded - others may notice interesting things in the pictures that you may not.
  • Once you have a season or more of pictures, you can analyze the timing of seasonal changes with the greenness index.
Green down 1st picture
green down pic 2
green down pic 3
green down pic 4
green down pic 5