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We invite you to join us in tracking the “green wave”—the flush of green that accompanies leaf-out–-over the course of the spring season, as well as the spread of seasonal color across the country in the autumn.
Observations of these trees are of extra importance because they can help decision-makers develop forecast models and early warning systems for use in forest management and public health administration via pollen forecasting. In fact, researchers are already using data that have been reported for these species to validate models that predict how changes in climate will impact phenology of trees, and also to learn that deciduous trees may leaf out weeks earlier under climate warming. See what we learned from this campaign last year.
Join us for this special campaign! Make it easy on yourself...choose that tree that you see every day - either the one in your yard or the one you pass each day. Observations from just one tree can help fill critical data gaps!
How to Participate...
1. Select one (or more) individual maple, oak, or poplar trees to track from the list below.
Don't have one of the target species at your site? Your observations are still valuable! select from our list of many other maple, oak, or poplar species for which we have protocols.
2. Join Nature's Notebook. If you haven't already, create a Nature's Notebook account. See our specifics of observing if you need more details on getting started.
3. Sign up to receive our Green Wave campaign messaging (in the right sidebar of this page - you may need to scroll back up to see it). You will receive messages approximately every 4-6 weeks during the growing season, providing early results, encouragement, observation tips, interesting links, and campaign-specific opportunities. Don't miss out!
4. Take observations. We invite you to track leaf out in your trees ideally 2-4 times a week, in the spring and autumn. We are especially interested in the following phenophases, though you are welcome to report on flowering and fruiting as well.
5. Report your observations. As you collect data during the season, log in to your Nature's Notebook account and enter the observation data you recorded. You can also use our smartphone apps to submit your observations!
We have had a steady increase in the number of observers reporting on Green wave species over the last five years. Since 2013, the number of observers participating has more than doubled!
The winter of 2017 was the second warmest winter on record across the continental US. In many parts of the country, the biological start of spring arrived 3-4 weeks earlier than average. Fall also was late in arriving in 2017. In parts of the country, the period of August to October was the warmest on record (NOAA.gov).
The Activity Curve below shows the difference between 2016 and 2017 in the proportion of northern red oak trees with "yes" reports for breaking leaf buds in the Northeast US. The peak in the number of trees with breaking leaf buds occurred several weeks earlier in 2017 than in 2016.
Colored leaves in northern red oak in the Northeast peaked at about the same time this year as last year. This might reflect the similarly warm fall temperatures that the Northeast experienced last year.
On the other side of the country in the Southwest, the peak in breaking leaf buds in quaking aspen trees was several weeks earlier in 2017 than in 2016.
Quaking aspen put on their colored leaves at about the same time in 2017 as in 2016, which had similarly warm summer and fall temperatures.