Hi USA-NPN,

This year's Green wave campaign has come to a close. We hope you have enjoyed making observations of flowering and leaf color on your maples, oaks, and poplars this year.

We want to hear from you! Please take a couple minutes to provide your feedback on the 2022 Green wave campaign in this three question survey. Your feedback will help us improve the campaign for next year!

This year we asked you to observe flowering in your maples, oaks, and poplars to help us learn about pollen timing. We are actively exploring what your observations of flowering can tell us about the pollen season in these plants, which is a step on the path to pollen forecasts and better allergy management. Early explorations of your data have been very promising, so much so that we will be launching a national Pollen Trackers campaign next year! Stay tuned for more details.

Below, we take a look at some of the patterns that emerged in your data for both flowering and leaf color this year.

We hope that you will continue to participate in this campaign next year. Observations made on the same trees over time are very valuable as they show us how trees respond to changing climate conditions.

This year, 1,769 observers reported data on Green wave species at 1,008 sites. Your data captured the timing of the start of open flowers for 857 individual trees , the start of pollen release for 464 trees, and the start of colored leaves for 1,912 individual trees.

This year, we had 141 Local Phenology Programs (LPPs) submitting data on maples, oaks, and poplars as part of a group effort. The 10 LPPs submitting the most records this year are below.

The 1,769 observers contributing to the Green wave campaign represent nearly half of the number of all Nature's Notebook observers who have been active this year - thank you all for your efforts!

The map below shows sites reporting on maples (blue stars), poplars (yellow triangles), and oaks (red circles). The size of the icon indicates the number of records reported at that site.

Sites reporting "yes" for open flowers in Green wave species in 2022. Colors correspond to the month when open flowers were reported at the site. Shapes denote maples (Acer), poplars (Populus), and oaks (Quercus).

Now that we have focused this campaign on data collection of open flowers for four years, we can take a look at how flowering compares from year to year. In the Southeast, your top observed species is red maple. In the previous three years, we can see a double peak in open flowers. This may be due to differences in flowering timing in different parts of the region. In 2022, however, there was a single peak in flowering.

In the Northeast we see a different story, with a clear single peak in open flowers across the region that has varied by only a couple weeks.

In the Midwest, silver maple is the top observed species. The peak in flowering in 2022 was several weeks earlier than in previous years.

In the West, top observed species vine maple shows a fairly consistent pattern in open flowers, with a slightly later peak this year than in previous years.

Generally, observers reported colored leaves earlier at higher elevations and northern latitudes.

Remember that young leaves that appear early in the year in some species can appear red, but you should only report "colored leaves" in full-sized leaves. Leaves may change color due to cooling temperatures in the fall and also due to stress from drought or insect damage. Add a comment with your observation with the suspected reason for color that happens outside of the typical autumn season.

Sites reporting "yes" for colored leaves in Green wave species in 2022. Colors correspond to the month colored leaves were reported at the site. Shapes denote maples (Acer), poplars (Populus), and oaks (Quercus).

In the Northeast, your reports of colored leaves in red maple were slightly later this year and last year than 2020 and 2019.

In the Midwest, your reports of colored leaves in silver maple showed a fairly consistent peak, with 2022 similar to 2020 and 2019.

In the West, your reports of colored leaves in vine maple were later this year than in previous years, particularly in comparison to 2019.

You can explore more Green wave data in our Visualization Tool. Start with our Seasonal Stories to discover the different types of visualizations available and how to use the tool.