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Huge Snowfall Hits Trees
Snowball fight realizes L’Enfant’s dream for US capital
February 2010
Even as storm-force winds began beating up the city’s trees Feb 6, more than 3 feet snow fell, a double whammy for weaker trees. The photo at left below shows part of an old street tree downed, by the residence of the Ambassador of Chile at 2305 Mass.
We’re to call the city’s service line 311 to report downed trees or limbs that obstruct streets and sidewalks. It is the city’s job to remove them.
The heavy snowfall bent many trees and branches “to their load limits” wrote The Washington Post’s Adrian Higgins Feb 10. Top-heavy trees with small root systems such as cypresses are most likely hurt from the weight. Along Mass Ave we saw some lower limbs of southern magnolias hammered.
Now sidewalks and alleys must be cleared. But, Higgins wrote, we should wait until the snow melts—even for months—to remove broken trunks and limbs. We should only prune once we can see the tree or shrub’s silhouette. Otherwise our cutting may leave it needlessly misshapen.
Remember: In our region most of the time—say 99.99 percent of an average year—our beautiful, useful trees are not covered in snow!
Leaving shrubs alone is a good idea. "If you start beating them free of snow, you'll do more harm than good," Higgins quoted Kevin Carr of Bartlett Tree Experts, as saying. “Azaleas, boxwood, yews and other shrubs buried or bent by snow should be left until after the thaw” when “broken branches can be cleanly removed.”
You can download our flyer "Helping Trees After Snowmageddon", with steps informed by the city’s top forester, John Thomas, who responded fast to RMA’s request for advice. The city’s snow and ice plan is at ddot.dc.gov/.
L’Enfant’s dream: a 2,000-person snowball fight
Not sure they had Twitter in 1777, when Major Charles Pierre L’Enfant stepped off the boat to join the American revolution. When the hopeful new nation formed that “united” the “states,” L’Enfant made nice with the leading celeb, George Washington (Twitter alias: @geowashKINGPIN). L’Enfant got the General to commission a capital city designed on the Paris principle of getting the populace out of crammed, dark dwellings into bright open spaces for their own good.
Dupont Circle is the largest of the “pauses” L’Enfant laid out along DC avenues. Our historical research on Mass Ave shows that his successors also wanted to encourage civic activity through formal, open landscape design. After the Civil War Dupont (then Pacific) Circles and other intersections were planted with large trees and lawns as “pleasure grounds” for residents seeking Nature.
L’Enfant seems to have been an odd, combative guy. So he might have pitched in to the snowball fight organized via Twitter on Saturday Feb 6. According to The Washington Post the next day:
“It was a flash mob with cabin fever, a giggling, hollering, exuberant crowd that spent more than an hour aggressively, chaotically and noisily lobbing snowballs…”
“it was the largest of a scattering of organized snowball fights throughout the city.”
The Post’s treatment was humorous. But among 60 comments Kitten2 wrote: “[T]he DC police should have arrested those 2,000 individuals for creating a riot in Dupont Circle and charged those throwing snowballs at vehicles with disorderly conduct as well as throwing missiles at vehicles.”
SUBMIT YOUR PHOTOS of the Dupont Circle Snowmageddon snowball fight to RestoreMassAve@yahoo.com and we’ll post a few!
Check out our program and volunteer opportunities.
Photo at left shows the fallen branch by 2305 Mass. Photo at right shows how DC streets become delightful civic space when snow alights on rows of mature trees.
Photos: Restore Mass Ave
What To Do With Old Xmas Trees
January 2010
Once again it’s time to throw out the Christmas tree. No longer can we pretend it is a verdant bit of forest in our parlors. We must face facts: our trees are dead.
But used Christmas trees are not useless. (Recall the joke about what Scotsmen do with old razor blades? Answer: they shave with them!) Dead Christmas trees can help the growth of living trees on your street. Snip some of your Christmas tree’s boughs and drape them over the soil of a street tree box. The blanket of boughs will shelter the soil from drying winter winds. And the boughs look nice.
The DC Department of Public Works’ web site says it will pick up Christmas trees set out by street curbs through Jan 16. The trees must be stripped of ornaments, tinsel, etc. Nancee Lyons of the DPW press office told me these trees are chipped and the chips are added to leaves DPW vacuums from city streets. DPW’s map of routes and dates for collection is here.
The tree chips and leaves become compost, which DPW will offer free to residents from March through October. You shovel it into your car or truck (DC plates only) at the recycling center at Fort Totten or on Benning Road transfer stations. Questions? Call 311.
My beef is that DC’s holiday tree recycling doesn’t seem well publicized. Though Ms. Lyons said that the trees collected last year weighed 4200 tons, how many trees are tossed out in a city with 110,000 single family homes? I suspect most households put the trees out with the normal trash. So the trees go the landfill, adding to haulage costs, pollution and expanding landfills, which hurts DC compliance with federal environmental laws.
A better model is Falls Church, Virginia, a tiny city that has been recycling a long time.
The city takes dead Christmas trees to Fairfax County’s recycling center; the county grinds trees with brush into wood mulch and wood chips – and offers these free to residents (who can use it on paths or to control invasive plants). Falls Church also vacuums tons of leaves and makes these into mulch and compost. It promotes lots of outreach and education for such recycling. Start at the Recycling Center or visit the Free Leaf Mulch page or call 703-248-5176.
The National Christmas Tree Association says there are more than 4,000 Christmas tree recycling programs in the country. Its page on recycling lists some really inventive uses, such as:
• In Porter County, Indiana, calls for people to turn in Christmas trees “resulted in minimal donations.” Then a local high school and other groups announced the trees could save wildlife. They picked up and unloaded used trees at the 25-acre Moraine Ridge Wildlife Rehabilitation Center. There the trees give “cover for birds, chipmunks, raccoons and other small wild animals.”
• Near Keene, New Hampshire, the state Department of Fish and Wildlife drops the trees “into lakes, creating ‘habitat improvement structures’ where fish can hide and find food. During an experiment in a Massachusetts lake, state biologists saw a fivefold increase in the number of fish caught around sunken Christmas trees compared to other places in the lake.”
• Jefferson Parish, Louisiana, had been losing 25-35 square miles of coastal wetlands yearly. So since 1986 Christmas trees have been bundled and carried by helicopter and dropped into the swamp. The bundles of trees hold the mushy earth against tides and wind. They are credited with restoring close to 300 acres of marshland, and saved some of the area from Hurricane Katrina’s wrath.
• After Hurricane Ivan hit Alabama’s coast, the ecosystem of the dunes was mangled. The state Fish and Wildlife Service with volunteers added 3000 feet of sand fencing, placing a discarded Christmas tree at the base of each 10-foot fence.
Christmas tree holding beach, Gulf Shores, Alabama.
Photo courtesy of NTCA.
Help DC Trees Grow Bigger by Helping Their Roots
October 2009
Large, shady “street trees” between the sidewalk and street are a key goal of Restore Mass Ave. Washington has about 144,000 street trees along some 900 miles of streets; the DC Urban Forestry Administration plants about 3,000 new street trees yearly and removes half as many dead or dying ones. To be frank, the UFA does little other care; it asks nearby owners to water and mulch new street trees. Also private parties may pay for iron fences around street tree soil boxes to protect them. The UFA’s Tree Steward program is described here.
We at RMA organize care for all new and vulnerable street trees on Embassy Row, for the >60 DC has planted recently and others that are struggling. We’re delighted that now dozens of embassies, businesses, and residents help these trees. Our Treekeepers help them too.
If you have an issue concerning a street tree, call the UFA (202-673-6813) or the city’s service line (311).
RMA is also focused on helping the roots of sidewalk trees. Roots suffer when street trees are poorly planted by hurried contractors. Also, a tree’s underground space is often cramped by utilities and paving debris. You can watch young street trees stall over time because their roots can’t develop. And since this problem shows well after the 1 or 2-year warranty, the city won’t replace the tree.
So how can street trees grow large and shady? Only when their roots grow well. It is crucial that new street trees be planted right. You can monitor city tree planting by snapping a photo of an open tree hole and calling the UFA to get them to drive over and inspect.
You can help the roots of sidewalk trees. Download our Root Rescue flyer. Pass it on to your neighbors. Post it at your office.
Our flyer lists five simple steps:
• Remove mulch piles around tree. Remove weeds, lariope, grass, etc. Soaking the entire tree box with water will make it easier to pull up plants.
• Break up hard top layers of dirt. Turn and mix soil throughout the tree box. Add a bit of topsoil or compost.
• When the soil is loose and enriched, water the area before spreading a 3” layer of shredded hardwood mulch.
• Keep mulch AWAY from tree. Form it in a collar about 3’ across, shaped so rain flows to the trees main roots. A high mulch collar also blocks mowing machines from wounding the tree, which can be fatal.
• Water weekly in warm weather. Do not water when soil is wet.
Green Treegator® bags or brown Ooze Tubes®, available from hardware stores, can help hard-to-reach trees; refill weekly when there’s little or no rain. See also Casey Trees’ helpful tree care page.
Learn Advanced Help for roots by joining our Root Rescue Project Oct 25. Sign up through our Volunteer page.
Left: Treekeeper Cody Oliphant yanks weeds and lariope that rob nutrients from a mid-sized street linden in the 2200 block of Mass Ave. Right: RMA Treekeepers soak a tree box after weeding and amending the soil. We're grateful to Glass Construction (at 2344 Mass on right) for safeguarding this young linden with an orange fence; otherwise it would have died.
The honey scents of linden blossoms
June 2009
Be sure you stroll the sidewalks of Massachusetts Avenue, west from Dupont Circle, soon. OK to run or bike, but by walking you can nuzzle the drooping blossoms of our grand avenue’s famous linden trees.
Look up, and you’ll see creamy blossoms hovering beneath the pale undersides of leaves of American lindens (Tilia Americana) and silver lindens (Tilia tomentosa).
In the late 19th century Massachusetts Avenue was planted with four miles of linden allées – purposefully longer than Berlin’s grand thoroughfare Unter den Linden. Franz Schubert celebrated this evocative tree in his famous song “Der Lindenbaum.”
Linden blossoms can be harvested to make honey and fragrant oils. You can smell them at counters selling candles or skin care products.
After blooming, linden flowers fold into papery clumps. Now is the fruit’s turn. You can see the little rounded fruits or nutlets maturing from the base of the flowers. Each is the seed for another tree – Nature’s point in evolving the flowers and scents in the first place.
When I began gazing up into the lines of Massachusetts Avenue lindens I wondered: Why don’t the blossoms hang directly from the twigs and branches, like the leaves? Rather the flower clusters hang from their own, elongated leaf.
In the first photo below, these white, wingy leaves are bracts. From the bracts hang nutlets formed from the flowers. Also below is a Polly Alexander drawing of the structure.**
The dictionary says ”bract” means a metal plate. But I think of bracts as arms bearing gifts of blossoms, fruit and nuts. Bracts are the main attraction in some plants. The red “petals” of poinsettia are bracts; so are the white or pink “blossoms” of dogwood trees; in both, colorful bracts invite pollinators to the little central flowers.
You can vote for the linden’s blossoms, or fruits, or pale leaf undersides.
But I prefer it’s curious bracts for adding architectural ornaments -- grace notes to the strolling ensemble.
Massachusetts Avenue in June is one more reason we volunteers care for its trees and historic landscape; our stretch of Embassy Row is the last intact Grand Avenue in the nation.
** Melanie Choukas-Bradley and Polly Alexander, City of Trees, Third Edition, University of Virginia Press, p. 276.
We’re planting. Everyone can!
March 2009
March has blown in and the chill’s great for tree-planting. Join us for our fourth big planting March 21, based at Mass Ave and Whitehaven St NW. Thanks to Casey Trees, we’ll increase to 63 the lindens, oaks, elms and other trees added to Embassy Row yards. All our new trees have loving caretakers - usually an embassy - to help their journey upward, so all will enjoy the shade and beauty that large-crown trees provide as gifts.
Hey, all you DC residents, businesses and embassies: your help is critical to expand the city’s tree canopy.
Many think adding trees is the city’s job, not theirs. Wrong.
DC’s Urban Forestry Administration (UFA) has jurisdiction only over trees along roads, alleys, and lately in city parks. DC’s roads, intersections and sidewalks are just 19% of its land area (61.3 square miles or 39,000 acres). The UFA (budget $7 million; staff 51) is valiantly planting new street trees with the goal of filling all 144,000 street tree spaces. And it just took on the ~100,000 trees in city parks.
Bottom line: 44% of Washington’s land is in private hands. So private owners hold the key to the future tree canopy - also of our city’s air quality, drains and sewers.
Washington has tree canopy over 36% of the land (it helps to have Rock Creek Park flowing through our middle). A 2004 US Forest Service survey showed we have much more canopy in relation to area than Baltimore, New York or Boston.
But even when the UFA has planted its areas, tracts of private DC land could remain bare or nearly bare. As for the cement heavens slated for business development, such as around the stadium, the city now asks developers to add trees and permeable paving so future commercial sites will be greener.
Ultimately, yards around homes are the key. Residents need to add lots more trees for DC to achieve the 5% canopy expansion it wants to meet EPA air standards for 8-hour ozone, the persistent health scourge of cities. Thick-leaved canopy must also expand to absorb significant carbon emissions. Finally, DC has a combined storm water-sewer system for its two big catchments. (In public works jargon they’re MS4 and CSO. Even NPDES, the EPA permit under which DC operates, sounds scary.) The city faces big penalties if it can’t slow the runoff from even small storms from adding stinking river sludge.
Plant a Tree, get a $50 rebate
You might figure this out by drilling down the DC Department of Environment web site, to the Green DC page.
The DDOE and Casey Trees offer a rebate to anyone who buys a new tree for a DC residence. The tree can be of any type, except for invasive species.** To get the rebate, the purchaser must plant it, or have it planted, and sign a form saying they’ll care for it for two years.
The new Casey Trees web site has user-friendly info on choosing the “right tree, right place” near a house. Other one-pagers show how to plant a tree and how to plant on a slope.
Restore Mass Ave is getting large-crown trees wherever we can. In addition to the 63 we’ve brought to yards, we reckon the UFA has added 60 along Embassy Row streets. The total’s 120 and more are planned.
Stay tuned. In an upcoming issue of Urban Tree News we’ll compute the greenhouse gas offset and pollution and storm advantages of our trees.
**Rebates are not offered for Norway maple, Bradford pear, Sawtooth oak and Siberian elm.
Xmas Trees, Inaugural Trees, Gift Trees
January 2009
Xmas trees don’t have to become wards of the city, waiting on the freezing sidewalk to be removed at taxpayer expense. If you have a wooded area near your home, lay your Xmas evergreen there on its side, so it can provide shelter for small animals and birds.
Saving elms from inauguration crowds
The Inaugural Parade’s biggest moment comes when it passes the presidential reviewing stand in front of the White House (white structure at right in upper photo). Note the bare branches of elm trees poking up between the stands. Both sides of the 1600 block of Pennsylvania Avenue were planted with Princeton elms in 2005 and dedicated by First Lady Laura Bush.
For the parade, wood boxes ~ 5 feet high were built around every elm. The boxes have solid sides so crowds can’t trample the soil or push against the slender trunks. Can you make out the chicken wire across the top of each box, to prevent parade-watchers from falling in?
Below right shows one of these Pennsylvania Avenue elms last summer in full leaf.
Historic trees at the swearing-in
Melanie Choukas-Bradley, an authority on Washington trees, notes the historic trees in the panoramic views of the West Porch of the Capitol, where the President-elect will take the oath of office. As you look at the West Porch, to the left is a very tall willow oak tree. In front of the porchis a huge pecan – bare in January, of course. Her “City of Trees” now hitting bookstores describes the history of the Capitol Grounds and other DC landmarks, including Massachusetts Avenue. Restore Mass Ave is described on page 276.
* Melanie Choukas-Bradley and Polly Alexander, “City of Trees: The Complete Field Guide to the Trees of Washington, D.C.,” Third Edition, University of Virginia Press, 2008.
How citizens can stop illegal cutting of DC trees
September 2008
What to do if you see someone preparing to cut down a tree in DC? Or know of someone who plans to do so?
I faced this quandry last March. I utterly failed to stop a Maryland tree service from cutting down a magnificent magnolia along Mass Ave. The fellow mocked me and went on cutting. The tree was down in minutes, it seemed. The incident roils me so much that, since then, I’ve asked DC police, the folks at Urban Forestry Administration (UFA) and others: What can we citizens do?
The DC Urban Forest Preservation Act* (UFPA) covers trees in DC on public and private land. The ‘private land’ bit means that you can act if you see suspicious activity in a neighbor’s yard, or hear of someone planning to take down a big tree on their land. Trees on ‘public land’ include city land, such as ‘the parking’ which is the strip between sidewalks and buildings along Mass Ave and other streets. Though DC owns this land, by law and tradition owners maintain it in accordance with city rules. So the good news is the UFPA’s large area coverage.
But the law only protects ‘special trees.’ It defines ‘special trees’ as having a circumference of 55” or larger, i.e. 17.5” in diameter or larger. The measurement is made 4.5’ above ground. (The 4.5’ standard used to be called DBH - Diameter at Breast Height. Then female arborists came along....) If you want to monitor tree-cutting, for practice, carry around an 18” ruler and hold it against tree trunks (at BH) and guesstimate which are ‘special trees.’
You don’t need a precise measurement to call the authorities. The UFA has professional arborists assigned to each ward. They’re your first line of defense; their job is to judge if a tree proposed for takedown (or being cut) is a protected ‘special tree.’
Get the names of your local DC arborist by calling 202-671-5133. Call that number to have an arborist sent to the scene.
(Ward 2’s lead arborist is Ms. Munever Ertem.) The dispatcher can send another arborist if ‘yours’ is not available and the situation is urgent.
Inform the would-be tree cutter that their work may be illegal. They or their client could get into trouble – besides ruining a fine specimen. Ask: Why do they need to take it down? Ask: Have they applied for a permit? If not, they could be in more trouble. If they applied for a permit, ask to see it, since the permit is a public document. Write down the name and phone number shown on the contractor’s truck. Call the contractor directly to warn them. Take photos that show the tree’s diameter.
Note the tree’s health. People sometimes claim a tree is unhealthy to justify taking it down. They hire an arborist to say its unhealthy, so UFA will issue a permit for removal. But theperson must to get a permit to take down an unhealthy or hazardous tree in advance. Upon receipt of such application, the UFA is supposed to notify the local ANC 15 days ahead of the project. (Permit applications are at .)
If things seem desperate, call the police. Carry the number of your District and your local patrolmen.
Our part of Mass Ave is MPD Second District, main # 202–715-7300. We’re PSA 208. Our patrolmen are Lt. Erich Miller 202-715-7344 and Roland Hoyle 202-715-7356. Or, simply call the city service line 311 and ask for the police.
Destruction of trees on public land may be destruction of public property – a crime. Though DC police aren’t trained in the details of the UFPA, a policeman on the scene can deter action until UFA arborists arrive. Also It may deter perpetrators from cutting a tree, if you tell them police are on the way..
Follow up:
We of Restore Mass Ave hope DC authorities will heed our calls, even when we’re guessing and turn out to have been wrong. Okay! Take the tree down! Its DBH’s only 16 inches! Oops! Turns out it is an exempt species! **
Polite followup is a good idea – such as an email report to UFA and anyone involved. Thank the “suspect” who turned out to be acting legally. (Maybe next time, they’ll check out the law.) Thank city officials for promptly responding to your passionate concerns for the canopy.
The city will enforce the UFPA more effectively with local citizen help. The law is accomplishing much, officials say. In a few years, the number of permit applications has grown -- particularly filed by large construction projects which used to chop down trees whenever. Now anyone taking down ‘special trees’ must plant ones of comparable size or pay into a Tree Fund UFA uses to add new trees. The UFA staff has grown from 26 to 51; its budget is more than $7 million.
Washington’s green cover is growing by addition.
You can help lower the amount of green cover that’s taken away.
We've had a lot of rain. So are DC trees home-free?
July 2008
Heavy rain in May and June helped fend off the drought. Rainfall this year at Reagan Airport is one–third above normal (for further information see the back page of The Washington Post Metro section). But Post columnist Joel Lerner wrote recently that trees now leafing out may conceal the stress of the city’s "cumulative six year deficit" in rain. Rebecca Feldberg, the arborist for Baltimore, told Lerner that many young trees planted last season had been so hard hit by drought they haven't come back. As for mature trees, Lerner passed on advice and two warnings:
Advice: You should water mature trees – 10 gallons, twice per week – but slowly. Deluging the roots with tap water does not oxygenate them as well as will slow, steady rain.
Warning No. 1: Some mature trees may be so weakened by past drought they could fail this season, even with lots of rain.
Warning No. 2: Watch the white pines. They're still suffering from drought
if their needles drop, or if their new light green growth shoots (delightfully called "candles") are less than six inches.
Bottom Line: We're not out of the woods yet.
How to Monitor DC Tree Planting
Part 1
January 2008
We’ll have better street trees growing in “tree boxes” in city sidewalks if we citizens are watchful while trees are planted. And keep phone numbers handy. And a camera.
Though my latest tree planting drama had a happy ending, it shows the value of watching, phoning the city’s foresters if one is doubtful, and insisting on answers. Citizens can catch DC contractors planting new trees wrongly, which hobbles their growth. Citizens also learn when the city does things right and say thanks.
On a recent cold morning on the 2000 block of P Street, I found a contractor plopping new trees in holes in tree boxes in the new brick sidewalk. It was the culmination of more than a year of city renovation of these busy commercial blocks.
But they were digging little holes able to hold the root ball and a thimbleful of new soil.
Whoa! Hadn’t I just heard DC’s top forester say that contractors are required to dig out the entire tree box to the depth of the root ball – a volume about 9’ by 4’ by 2’ deep? For too long new DC street trees have grown stunted or died due to poor and compacted soil in the tree boxes. The young roots can’t get traction being walled-in underground.
I called the city forester for our part of town (202-671-5133). I called the number on the truck of the contractor, F& F. I asked the workers to stop until a city official arrived: otherwise in minutes their planting would be covered (why a camera helps).
When our area forester Ranjit Babra arrived, he had good news.
All the soil is new in the tree boxes in the renovated blocks of P Street, he said. It was installed under the sidewalk before the brick was laid. The new soil is not just in the tree boxes; it extends in a 4-foot wide strip in from the curb, forming a continuous, fresh, growing medium for the trees’ roots. And longer roots will strengthen the young trunks against wind, bikes, vehicles, etc.
Ranjit also said the growing medium is “structural” soil. It contains stone that make a matrix or foundation for the load of paving overhead. The matrix is supposed to help roots to push through loose soils between the chips.
Structural soils have been tested for some time and are one approach. A newer technique is the “structural cell.” These are frames which leave room for more soil underground while the top or deck of the frame prevents compaction from above.
While DC Urban Forest Administration tests structural soils along P Street, the agency plans to install structural cells near a building site on Constitution Avenue. We citizens can monitor how new trees fare under different test planting conditions. Stay tuned!
Part 2: Sweetgums are Nice.
You don’t need a sweet tooth to like sweetgums.
City foresters picked Liquidambar styraciflua 'Rotundiloba,' the fruitless sweet gum, for the renovated blocks of P Street. If I count right there are 33 new sweetgums of 3” caliper, perking up from their fresh soil and starting to root underground.
If the new rows attain good height, they’ll unify this bustling street. In spring and summer the fine-shaped leaves will be a lively sight fluttering over pink sidewalks. Their fall color is a thrilling orange-red.
But as our Treekeepers know, these trees will be tall and shady in 15 years only if they make it to their first birthday in 2009, then to year 5, then to year 10, and so on.
The P Street planting includes rails around tree boxes. Rails keep off bikes, humans, and trash so the soil stays loose to absorb water and air. Thanks go to Historic Dupont Circle Main Street for getting the city to include rails in the plan (http://www.dupontcircle.biz).
What about the city’s requirement that tree soil boxes be dug 14 x 4 x by 2 feet deep? Since all the soil was new, F & F didn’t have to excavate the whole area. Turns out the whole-box dig is specified only in new contracts, not for current plantings.
So be vigilant this spring. Contractors will plant right when they know citizens are watching and telling the city officials who hire them ‘we want the best.’
President Ronald Reagan didn’t have a cell phone. Nor did he stand around watching trees grow. But we can adopt his motto:
"Trust, but verify."
Hows and whys of trees' fall costumes
November 2007
In recent weeks we see trees shutting down at different rates around the city. Now at Thanksgiving some trees are still green (including some young lindens you’ve been watering); others are wintry bare; others entertain us in showy costumes.
Green-reflecting chlorophyll is the main pigment in leaves. Why? Because it absorbs energy from sunlight and uses it to convert carbon dioxide into sugars, i.e. carbohydrates. Inside the tree, with the help of water and nutrients taken up from the soil, these sugars are converted into new wood, bark, roots, stems and leaves.
But chlorophyil gets worn out by the hard labor of making sugars. It must keep regenerating within the leaf to keep the tree photosynthesizing . If the summer is too dry and and/or hot, photosynthesis may stop, The leaves wear out and the tree shuts down -- to save energy for regrowth in spring. (See the last E-news, “Do brown leaves mean hope?”)
The disappearance of chlorophyll lets other pigments in the leaf, which were masked by the chlorophyll all summer, to have their moment in the sun -- literally. As the chlorophylls vanish, yellows and oranges dance. These are
xanthophylls– which reflect yellow, like the color of egg yolks, and
carotenoids – which reflect orange and are in carrots and corn.
Much is known about how trees’ costumes come onstage in fall – what temperature and moisture levels create the showiest crowns, flapping leafy skirts like Rockettes at Radio City Music Hall.
Much less is known about why.
Joe H. Sullivan, a plant physiologist who is Associate Professor at the University of Maryland, explains that xanthophylls and carotenoids protect leaves. They are “antioxidants to mitigate damage from exposure of leaves to too much sunlight; yes, plants can sunburn too!”
They toiled away at this all summer. They keep going in fall perhaps because they are more stable, says Sullivan. In any event, they prolong leaf life by protection.
The red in fall leaves is more intriguing. The pigment anthocyanin shows red-purple and also colors cranberries, blueberries, cherries and plums. The anthocyanin forms inside the leaf in fall, but to do so it needs warm days, cool nights, and lots of moisture.
The drought and warmth of this fall may not have provided the ideal conditions for anthocyanin production this year, Sullivan says. Ok, that’s how but -
Why do some tree species turn red? To defend against pests, according to one of the theories listed on the US Department of Agriculture web site**.
Pests react to the dogwood’s purple, muscle-like leaves or the fire-red crown of a scarlet oak in effect see red. Scientists suspect the pests turn tail and march off to some weaker-looking tree.
So purple and red-turning species evolved this way to ward off mortal threats, perhaps.
Now when you see a blazing red tree in fall, go ahead and wonder at it.
But consider: Is it scary? To certain insects – it is!
*http://en.wikipedia.org/wiki/Autumn_leaf_color
**http://www.usna.usda.gov/PhotoGallery/FallFoliage/ScienceFallColor.html
Do brown leaves mean hope?
October 2007
Some of you have expressed alarm about the number of lindens along Mass Ave with brown edges on the leaves. And those with full crowns of leaves - all brown. Is there hope? Geneva 12 pt
Answer: These trees need 3 things: Water, water, and more water.
I discussed the brown-ringed leaves on our street trees with Jim Urban, of Urban Tree Associates, during a walk of the route last month. (Jim, by the way, was identifying which young lindens might be part of a federal research study on how to grow bigger street trees.) Last week I reached Jim Sherald, an authority on urban trees at the Center for Urban Ecology of the National Park Service. I asked him what means these scary-looking brown leaves?
"The trees are shutting down early. Early defoliation is due to the heat,” Sherald said. If they’re watered generously, he expects most could come “piping back” next spring. We know there are a few hopeless cases along our route – mostly due to transplant shock. I have asked our city forester to identify these few. The rest need TLC.
So treekeepers, keep watering ‘your’ trees. And any others looking poorly that you can reach with hoses or green bags. Keep watering trees with green leaves that are curled: curling is an early sign of drought streets, says Jim Urban.
Bottom line: Let’s keep watering through Halloween.
The Washington Post says rainfall in 2007 has been 72% of normal.
In September just 0.6 inches fell - not enough to dip your toe in - and 1 / 6 of normal. We’re still playing catch-up for many dry months.
Even if October brings lots of rain, it may not make up the year-long drought.
You can follow the drought saga on the Post’s daily Weather page (Metro section, back page). Treekeeper Jill Howell has this tip: While out West this summer, she followed DC weather daily at www.accuweather.com.
Need bags, vests?
We have four new Treegator® bags thanks to Kim Nettles. (Kim, with husband and housekeeper are doing a great job at Mass and California Street.) Email or call me if you want a replacement– but SAVE defective ones. We’ll take inventory in November. SAFETY VESTS are available, mandatory, and très chic.
Congratulations!
Our experts have been pleased how WELL Mass Ave’s young trees look!
Keep up the good work!
Treekeeping fun when it rains
August 2007
Don't you miss mucking around in the mud when it rains, as we – or some of us - did when we were kids?
Now's your chance to relive soggy childhood moments and help trees!
A good, soaking rain loosens roots of weeds and grass around the bases
of trees. Normally we have to soak the soil with a hose or hauled buckets
of water before pulling up overgrowth around a tree.
But when Nature does our work by raining,
Take a garden tool and something to pile weeds in. Pay a medical house
call to your favorite weed-choked tree. Pull up green stuff by the roots
in a 3’ diameter area around the base – or larger. This will allow the soil to breathe and carry more water to the roots.
Your cleared area will be ready for mulch on your next visit.
If some parent-figure tries to call you in, saying ‘you’ll get dirty’ or ‘you’ll get wet,’ you can say: ‘I have to stay here and get dirty and wet to help this tree!’
Q: What’s the reward for rainy-day treekeeping?
A: An (indoor) shower.
Wangari Maathai, the Kenyan professor who earned the Nobel Peace Prize
for founding the Green Belt movement planting trees in Africa, says:
“When we plant trees, we plant the seeds of peace and the seeds of hope.”
Treekeeping 101
July, 2007
Our new non-profit arranged for many new trees to be planted along Embassy Row this past spring.
As the summer sizzles – the young trees need your help!
Join our Treekeeping program today! Send a reply email with your name, phone, place of work or residence.
Tell us the preferred time of week and summer you could give a few hours to a few trees.
Adopt – an Orphan. Embassy Row has many "orphan" trees which are hard to reach with hoses. Local embassy staff and others are adopting specific “orphan” trees to help them grow healthy and strong. Re-we supply
Treekeepers help stamp out the ‘heat islands’ which make walking, biking, driving along Mass Ave in summer
Our long-term goal is a continuous row of shade trees, to raise the quality of life and appeal of this landmark “Grand Avenue,” which may be unique in the USA.
Restore Mass Ave is a 501(c)(3) organization of residents, workers, foreign mission staff, and arborists working to re-green Embassy Row.