Hi USA-NPN,

This year's Green wave campaign has come to a close. We hope you have enjoyed making observations of leaf out 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 2023 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 the green wave, the flush of green that sweeps from south to north across the U.S. each spring as trees break buds, as well as the timing of leaf color change in the fall.

Below, we take a look at some of the patterns that emerged in your data this year, and how this year stacks up to previous years.

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, 1,660 observers reported data on Green wave species at 862 sites. Your data captured the timing of breaking leaf buds for 1,736 individual trees and the start of colored leaves for 1,536 individual trees.

This year, we had 134 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 1,660 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.

What did we learn from your reports of leaf out?

In order to better understand the timing of leaf out, we can look at when you reported "breaking leaf buds" on your maples, oaks, and poplars.

The map below generally reflects a pattern in earlier leaf out in the south and along the coasts and later leaf out in the north and at higher elevations.

Sites reporting "yes" for breaking leaf buds in Green wave species in 2023. Colors correspond to the month when breaking leaf buds were reported at the site. Shapes denote maples (Acer), poplars (Populus), and oaks (Quercus).

In the Southeast, your top observed species is red maple. Over the past six years, you have reported a peak in breaking leaf buds fairly consistently between mid-March and late April. This year the proportion of your "yes" reports was slightly lower at the peak than they have been in other years.

In the Northeast the peak is even more consistent, occurring between mid-April and mid-May in most years. this year was earlier than other years as well as a lower proportion of "yes" records.

In the Midwest, bur oak is the top observed species. The peak in breaking leaf buds was early than some years but not as early as 2021.

In the West, top observed species blue oak shows a large amount of variation between years for breaking leaf buds. The peak this year was weeks to months earlier than in some 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 2023. Colors correspond to the month colored leaves were reported at the site. Shapes denote maples (Acer), poplars (Populus), and oaks (Quercus).

In the Southeast, your reports show a fairly similar timing in peak colored leaves over the past six years. This year had a slightly lower proportion on "yes" records than other years.

In the Northeast, your reports of colored leaves in red maple are also fairly consistent. This year's peak in colored leaves was slightly later than previous years.

In the Midwest, your reports of fall leaf color were fairly consistent, though this year's peak lagged slightly behind previous years. Many of you also reported colored leaves in January, February, and March. Remember that even though young leaves in oaks and other species may appear to be red when they first emerge, you should only report colored leaves for full-sized leaves.

If you need guidance on how to correct data that you have already submitted, see this video for how to edit data on the Nature's Notebook website. On the mobile app, you can use the Review menu to find the observation date on the calendar and then update and re-submit your data.

In the West, you reported colored leaves in blue oak at several times during the year, with the peak occurring several months later than in previous years.

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.