Young Trees Need Your Help Now

Tree Stewards of Arlington and Alexandria invite you to join us in volunteering to sleeve saplings with biodegradable tubes that will protect from wind, wildlife and chemicals until the trees can survive on their own in our parks. This is an easy, rewarding task that can demonstrate your deep love of Arlington trees. 

Last fall, nearly 1,000 bare-root trees were planted by contractors and local volunteers from Tree Stewards, Arlington Regional Master Naturalists and Master Gardeners of Northern Virginia. The trees did very well over the winter, but they’re beginning to tempt hungry rabbits and deer whose chomp could easily kill the young saplings. They need your help now so they can become the next generation of stream-side trees.

No experience necessary. Gloves, tools, snacks and water will be provided. Click on one or both dates to volunteer via Eventbrite:

1 to 4 p.m. Wednesday, May 15
Benjamin Banneker Park, 6620 18th St. N., Arlington
1 to 4 p.m. Sunday, May 19
Lower Bluemont Park, 401 N. Manchester St., Arlington

Posted in Arlington Tree Canopy, Benjamin Banneker Park, Bluemont Park, Community Service, Events, Growing Tree Canopy, Re-Tree, Tree Care, Volunteer | Tagged , | Leave a comment

D.C. Region Is 4th in Participants, 10th Overall, 15th for Species in Global City Nature Challenge

We could not have said it better, so here’s a report on results of the City Nature Challenge by Arlington Natural Resources Manager Alonso Abugattas from his Capital Naturalist blog.

 By Alonso Abugattas, Capital Naturalist

This year’s friendly global citizen science competition, the City Nature Challenge, ended up with 159 cities competing! These cities tried to get people out making nature observations using the free iNaturalist application to take photos that were uploaded during a 4-day competition to see who could get the most people involved, make the most observations, and identify (through crowd sourcing) the most species. These could all later be data mined by researchers and others to provide information for various projects.

Spring beauty (Claytonia virginica) bloom in the rain in Arlington’s Benjamin Banneker Park during the City Nature Challenge, April 26-29, that drew participants in 159 metropolitan areas worldwide.

   The greater Washington DC Region once again did very well, despite overall having more cities competing from the 68 that participated last year. Reporting 29,976 observations, the DC Region came in 10th overall, behind in this order: Cape Town, La Paz, San Francisco (who helped start the challenge), San Diego County, Tena (Ecuador), Klang Valley (Malaysia), Dallas/Fort Worth, Los Angeles, and Hong Kong. 
     As many other parts of the world have much greater diversity, the DC Region placed quite well coming in 15th on the globe with 2,261 species tallied. But where our area really stood out was in participation. The 1,259 observers who entered their observations placed DC 4th overall! Only the 2 original founding member cities of San Francisco and Los Angeles, followed by La Paz, placed better. What a wonderful testament to the interest in nature and the willingness to participate in citizen science the nation’s capital has to show! 

Mayapple (Podophyllum peltatum)) was the most commonly reported plant observed by citizen scientists who participated in the City Nature Challenge in the Washington, D.C., region. Photos by Jo Allen

  Locally, I’d like to feature Arlington, which while part of he DC Region team, did fairly well on its own. It contributed 4,635 observations of 803 species entered by 163 observers. The Mayapple was the most commonly reported plant while the American Robin was the most commonly reported animal.  It will take quite a while to go over all the individual species reported and see if any should be further investigated. More over, 3 Arlington County staff placed in the top 11 for species tallied. 
     I personally had my best City Nature Challenge ever, and am happy that I tallied 880 observations and topped the leaderboard with 430 species. That species count overall was good enough to place 25th in the whole global challenge. 

 So lots of reasons to be happy, with how great the DC region did, Arlington did, and my personal tallies. But more importantly, I am so happy that 159 cities decided they would participate, that 32,781 people entered data on 31,837 species. What a great commitment to citizen science, to pride in what nature is found close to them, and that they were willing to have some great fun while in this friendly global competition. Now I can’t wait until next year! 

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City Nature Challenge Starts Friday

Over four days starting this Friday, which cities worldwide will engage the most people to record the most observations of wildlife and plants, and find the most species? This is the City Nature Challenge, and it’s open to all, including you. Last year, 68 cities participated and tallied 441,888 observations by 17,329 people. This year, more than 160 cities around the globe will join this citizen science effort.
The free iNaturalist app ( is how data is recorded by those participating in the City Nature Challenge. First, install the app, or the even snazzier Seek version ( on your smart phone or tablet. Second, with a fully charged device, go outside from Friday, April 26 through Monday, April 29 and photograph living things with the app. Seek will tell you instantly what you have seen. The standard version can be asked to suggest possibilities. Third, be sure to upload your photos to iNaturalist. Save precious battery power by uploading your images from your home computer. Scientists and researchers will help identify your findings. To reduce their burden, do not submit photos of your pets, common birds or commonly cultivated flowers. No fido, no robins, no tulips. A short instructional video about how to use iNaturalist can be found here:
If you plan to focus on trees, take several photos: one with the entire tree and its surroundings, one of the branching pattern (alternate or opposite), one of the bark, one of the leaves and any flowers or fruit, and be sure to include any evidence of pests or disease. Submit all of the images of the same subject so that scientists have a better chance of correctly identifying what you saw. Your aim is to get “research grade” status for your work. Sometimes a piece of white paper or foil can help illuminate your subject, such as bark or a stationary salamander, so that researchers can see more detail of telltale markings.
For those fascinated by fungi, a good technique is to take a mirror with you and place it under the subject so that in one shot you can capture the base, stem, connection to the cap, gills and top of the mushroom. Detail of the area where the stem connects to the cap is crucial in identifying fungi with photos, so be sure to focus on that.
This type of crowd sourcing allows scientists worldwide, including many at our own Smithsonian Institution, to mine the data for information they need to track species. You might even find a new species! It has happened in our area before with insects, so go chase some bugs with your phone and see what turns up.
Last year, the DC Metro area did well during the City Nature Challenge, according to Alonso Abugattas, writing on the Capital Naturalist blog. He said the area’s 22,809 observations ranked it fifth overall, behind San Francisco—which with Los Angeles started the competition three years ago—(41,737 observations), Dallas/Fort Worth (34,218 observations), San Diego (33,448 observations), and Klang Valley/Greater Kuala Lumpur (25,287 observations). Just behind DC were Houston and New York. Coming in last was Palmer Station Antarctica, whose three participants had 36 observations of 27 species. Globally 124 new species were added to the iNaturalist data base that had not been present before.
     Participation by 876 individuals ranked our area fourth, behind San Francisco (1,532 observers), San Diego County (1,211 observers), Boston (992 observers), and just ahead of Los Angeles (855 observers).
The DC area came in eighth last year with 1,855 verified species observed during 40 planned events, 25 of them in Arlington. This year, more than 124 local events are planned. Check them out and sign up for events sponsored by Arlington County at Those under the auspices of Arlington Regional Master Naturalists are at For area-wide events, go to

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2018 Annual Report

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Vine Finding on a Fine Afternoon

Tree Stewards, trainees and other environmentalists headed out along Holmes Run in Alexandria Sunday to find native and invasive vines after learning how to distinguish them from a slide lecture by noted naturalist Rod Simmons.

First stop outside Beatley Library was an American elm (Ulmus americana) bursting with light-green ripening fruits on the bank of the old Holmes Run channel.

Tree Stewards and other environmentalists admire an American elm laden with light-green seeds. Photo by R.H. Simmons
Tree Stewards and others admire an American elm laden with light-green seeds. Photo by R.H. Simmons
Detail of American elm fruit. Photo by Jo Allen
Detail of American elm fruit, above, pointed out by Rod Simmons, hand raised, below. Photos by Jo Allen
Rod Simmons, hand raised, describes the elm fruit.
Porcelainberry's wiry tendrils dig into tree bark as the vine climbs.
Invasive porcelainberry’s wiry tendrils coil around branches, digging into tree bark as the vine climbs. Nearby, an Eastern rat snake, sunning itself near the sidewalk, found the group disturbing and slithered off.
Several wild grape vines (Vitis spp.) have co-evolved with native trees and grow up with the trees, draping themselves over limbs as they reach for sunlight. Unlike invasive English ivy (Hedera helix), with green leaves on the same tree, grapes and other native vines do not harm tree bark.
Several wild grape vines (Vitis spp.) have co-evolved with native trees and grow up with the trees, draping themselves over limbs as they reach for sunlight. Unlike invasive English ivy (Hedera helix), with green leaves on the same tree, grapes and other native vines do not harm tree bark.
A native grape vine loops over a tree branch on the north bank of Holmes Run.
A native grape vine loops over a tree branch on the north bank of Holmes Run.
On the north bank of Holmes Run, a beaver felled a tree and gnawed off the lower bark.
On the north bank of Holmes Run, a beaver felled a tree and gnawed off the lower bark.
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Learn About Native Vines and Trees

Vines and Trees lecture and walk announcement
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Top Ten Least Wanted Invasive Plants

In Northern Virginia, there are several plants we and trees would be better off without. Some strangle trees, some add enough weight to topple them, and some grow so vigorously that tree saplings don’t stand a chance in natural areas these nasty weeds have invaded.

Here they are, illustrated in slides from Sarah Archer, Arlington County’s invasive plant and natural resources specialist.

Posted in Education, Invasive plants, Training Materials, Tree Care, Uncategorized | Tagged , , , , , ,

Big Trees Need Your Help

They soak up rain, sway in wind, spread seed to create more trees. But they cannot fight off invasive plants without helping hands from humans, who benefit so much from trees’ shade and shelter.

Woman holds a large root system from a privwet plant.
Tree Stewards trainee Gretchen Crowley holds a privet root unearthed from East Falls Church Park.

Do this to help trees: Volunteer as Tree Stewards trainee Gretchen Crowley has done to rip out the roots of invaders like privet from East Falls Church Park. Tree Stewards and Master Naturalists are ripping invasive plants from 10 a.m. to noon Tuesday, March 26 in East Falls Church Park, 1730 N. Roosevelt Rd., Arlington. Meet at the basketball court to sign in and tool up. We have gloves and sharp objects to lend. We welcome teens, as long as their parent or guardian stays with them for the duration.

The big prize this month could be a delicious batch of garlic mustard pesto. You pull the garlic mustard, then make the pesto. Or just use the leaves in salad for a touch of garlic flavor.

We and Gretchen hope to see you Tuesday!

Jo Allen and Amy Crumpton
Every Last Weed, Every Last Tuesday RiP in East Falls Church Park

This RiP is sanctioned by Arlington County’s Department of Parks and Natural Resources.

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Protecting Sentinel Trees by Removing Ivy

Eileen Grant and Lynn Gas pulling ivy from trees on a hillside at Ivy Hill Cemetery.
Tree Stewards Eileen Grant, left, and Lynn Gas, right, helped trees In January at Ivy Hill Cemetery in Alexandria by removing invasive ivy. Tree Stewards, Master Naturalists, Master Gardeners and other volunteers, led by city Natural Resources Division staff, will conduct a second Invasive Removal Event (IRE) on Saturday, March 16 from 1:30 to 4 p.m. at the cemetery. Photo by Tree Steward Jane Seward

Sign up here to volunteer Saturday afternoon, March 16!

still of video on removing invasive ivy
Click here to watch a short video about the event and the dangers of ivy.

Don’t just stop at trees! Here are 40 reasons to remove ivy from your yard. Thank you, Colin Purrington, for compiling this list. The environmental destruction caused by English ivy (Hedra helix) is a classic example of why native plants, which evolved to support native bees, caterpillars, butterflies, birds and mammals, are always the best choice.

Posted in Alexandria Tree Canopy, Community Service, Continuing Education, Invasive plants, Ivy Hill Cemetery, Mature Trees Are Valuable, Protecting Sentinel Trees, Tree Care, Volunteer | Tagged , , , , ,

Dichotomous Key Update by Emily Ferguson

Click here for the key to winter tree ID with buds and twigs.

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