Greetings!
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.
This year for the first time we asked you to observe flowering in your maples, oaks, and poplars to help us learn about pollen timing. We are collaborating with researchers to explore the potential of using your pollen data to create predictions of allergy season.
We are also working on a new set of maps that will predict the timing of fall color, similar to our
Spring Leaf and Bloom maps
. Your observations of fall color in your maples, oaks, and poplars are an important part of creating this new product!
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.
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What did you report on maples, oaks, and poplars?
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This year, 1,504 observers reported data on Green wave species at 878 sites, up from 1,144 observers at 662 sites last year. You recorded onsets of open flowers for 1,600 individual trees, onsets of pollen release for 532 trees, and onsets of colored leaves for 2,722 individual trees.
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In total we had
1,504 observers
contributing observations at both LPP sites and personal sites, which is nearly half of the number of observers who have been active this year! One observer in New Hampshire submitted 8,279 records this year on Green wave species - wow! Thank you all for your efforts!
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In order to better understand the timing of pollen release, we can look at when you reported "open flowers" on your maples, oaks, and poplars. We also have a phenophase on the
Nature's Notebook
datasheet for "pollen release". However, this can be difficult to record, especially in large trees where flowers are far off the ground.
The map below generally reflects a pattern in earlier flowering in the south and later flowering in the north. Some higher-elevation oaks (
Quercus
, denoted by the hexagon shapes) in the Appalachian mountains and western Oregon had later flowering.
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Sites reporting "yes" for open flowers in Green wave species in 2019. Colors correspond to the first day of year open flowers were reported at the site. Shapes denote maples, oaks, or poplars. Green outlines indicate more than one genera observed at that site.
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In the Southeast, you started reporting open flowers first for Green wave trees in the maple (
Acer
) genus. The peak in open flowers occurred in early February. Green wave trees in the oak (
Quercus)
genus had open flowers starting in late January with a peak in April.
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In the Northeast, open flowers in maples (
Acer
) started in February, peaked in April, and ended in July. Open flowers in poplars (
Populus
) started in March, peaked in April, and ended in July. Open flowers in oaks (
Quercus
) started in March, peaked in May, and ended in July. You reported similar flowering timing in the Midwest.
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In the Southwest, oaks (
Quercus
) first flowered beginning in January, with a peak in April. Poplars (
Populus
) started flowering in late January and peaked in March. Maples (
Acer
) started flowering in March and peaked in April.
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You reported colored leaves both early in the year and in the late summer and fall. Some maples and oaks have young leaves than can appear red, which may be why some of you reported colored leaves early in the year. Remember that you should only report colored leaves in full-sized leaves.
You should report leaves that change color due to cooling temperatures in the fall and also leaves that may change color 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.
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Sites reporting "yes" for colored leaves in Green wave species in 2019. Colors correspond to the first day of year colored leaves were reported at the site. Shapes denote maples, oaks, or poplars. Green outlines indicate more than one genera observed at that site.
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In the Midwest, you reported colored leaves in oaks (
Quercus
) from January to March, with another larger period of leaf color from August to December. You reported colored leaves in maples (
Acer
) and poplars (
Populus
) from July to December.
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In the Great Plains, you reported colored leaves in a small number of maples (
Acer
) in March with a larger period from August to December. You reported colored leaves in oaks (
Quercus
) from June to December with multiple peaks in the fall. You reported colored leaves in poplar (
Populus
) from August to November.
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In the Northwest, you reported a small number of maples (
Acer
) with colored leaves in January, with a larger period of colored leaves from June to November. You reported a small number of oaks (
Quercus
) with colored leaves from April to June, with a larger period of colored leaves from August to December. You reported multiple periods of colored leaves in poplar (
Populus
) from June to November.
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The maps and activity curves in this message were created in the new version of our Visualization Tool, which will be available next month for you to explore data!
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Did you earn your Tree Tracker badge this year? See it on your
Observation Deck
.
We hope you will join us again next year to continue tracking flowering and leaf color in your maples, oaks, and poplars.
Thank you for your contributions to this important project!
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Contact
Erin Posthumus
erin@usanpn.org
520-621-1670
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