Abigail the Green Ash in Alexandria

On July 22, VDOF’s urban & community forestry (U&CF) manager Lara Johnson traveled to Alexandria, Virginia to visit a well-known green ash tree. This ash, located in a courtyard between two apartment buildings, is likely hundreds of years old and is one of largest ash trees in the nation.

IMG_1409
Abigail’s trunks (right and left) each had a circumference of 12’ 9” and 11’ 6” respectively. The tree’s base measured 21’.

Abigail (so named by property managers Mike and Olivia) is the current Virginia State Champion and was once the National Big Tree Champion in the ash category (dethroned only because of qualification adjustments for multi-stemmed trees).

During this visit, Lara was able to remeasure the tree with the assistance of Andrew Benjamin, an arborist with the City of Alexandria. Abigail’s trunks (right and left, as in the photo) each had a circumference of 12’ 9” and 11’ 6” respectively. The tree’s base measured 21’. Lara will report these measurements, along with the tree’s height (78’ 6”) and crown spread, to the Big Tree program.

Protecting Ash
But remeasuring Abigail was not the primary reason for the visit. Lara was there to support the tree’s on-going treatment against emerald ash borer (EAB) – an invasive pest threatening ash trees across the state and beyond. Insecticidal treatment can protect individual trees from the damage and eventual death caused by EAB.

The City of Alexandria had been providing treatment for the tree, but in recent years VDOF was able to offer financial support toward trunk injection treatment of this tree through a grant program developed to protect ash. Using this funding, Lara and Fairfax County staff first treated the Champion tree in 2018. But such funding is limited, and the chemicals and labor required to perform treatment can be costly for landowners, particularly for large trees like this ash.

IMG_20180705_110953995
Abigail the green ash tree & the 2018 EAB treatment team.

Fortunately, plant health company Arborjet offered to take over treatment of this historic ash tree. Through their “Saving America’s Iconic Trees” program, Arborjet donates treatment against pests and disease for high-profile, iconic trees, like this ash, across the country. Community leaders and homeowners can nominate iconic trees for potential inclusion in the program. These treatments with an Arborjet technician serve as educational opportunities and are open for other professionals to observe.

IMG_1425
A panoramic view of Abigail. To the right in the photo is local arborist Mike Cochran, on-site to observe the application of the injection system and chemical for potential use in his own operation.

Arborjet’s Eastern Technical Manager and International Society of Arboriculture-certified arborist Trent Dicks was on-site to perform the treatment with Lara’s support. Treatment began early in the morning to increase effectiveness. Both Lara and Trent agreed that the high temperatures that Virginia has recently experienced could make treatment challenging because it relies on transpiration – the tree drawing up water (and the chemicals) through the roots into the phloem.

Trent first measured the tree to determine how much chemical was needed for treatment. Then, a series of 34 holes were drilled into the tree’s base as close to the root flare as possible. This presented a challenge, as the tree is below grade and surrounded by a small retaining wall and has very thick “alligator bark” which can be difficult to penetrate.

A plug was placed in each hole, into which a needle would be inserted and pressurized tubes pump insecticide into the tree. The plugs remain in place and a healthy tree readily heals over them.

The duo finished the work quickly as temperatures rose. After less than two hours, treatment and measurements were complete and the small crowd that had formed to observe had dispersed.


Historic Trees
While almost any ash tree in the landscape has potential to be a good candidate, it is the large, historic and rare ash specimens that are often prioritized for on-going treatment because costs can be high.

Did you know?: Green ash trees are a riparian species, and this historic tree is indicative of the relic wetland landscape that once covered northern Virginia.

Abigail is a beloved tree on a “charming, historic property” says property manager Olivia. In the 1940s, the buildings were essentially built around the tree, which serves as a centerpiece in the courtyard and provides shade for residents enjoying time on the patio. “It’s remarkable that this tree survived construction of the buildings. Normally that activity would damage a tree’s root system, but this tree was obviously well-established and the roots were able to recover,” says Lara.

Olivia and Mike explained that they frequently have to clean out the gutters because Abigail’s canopy extends over the roof, and although a bit “high maintenance”, the ash tree is well worth the effort.

Abigail receives other care (such as pruning) from arborists during the year, and although there were historically some signs of EAB impacts (i.e. dead wood), the tree has healed nicely since the 2018 treatment. Thanks to treatment and continued care from certified arborists, there’s hope this tree will stand tall in the neighborhood for many years to come!

Field Notes: Bottomland Forests and Flooding

By Scott Bachman, senior area forester

I will confess, when I moved to Isle of Wight County as a much younger forester, I was concerned about the “swamps” and how I would ever work in this environment.  Three decades later I have learned to enjoy the bottomland forests and to appreciate the ecosystem services they provide.

One such service is floodwater storage and energy dissipation.  In mid-February this year, much of the Commonwealth experienced significant rainfall.  VDOF personnel in the mountains were tasked with missions to assist with flash flood recovery.  In the coastal plain of Virginia, we received similar rainfall but no significant flash floods.  As you undoubtedly guessed, that is because we do not have mountains!

Nevertheless, water still must run off the land. An inch of rain on an acre of land equates to a bit more than 27,000 gallons.  Where does it all go if it cannot run off rapidly?  It spreads out into our floodplains!

Virginia has two types of floodplains: red river bottomlands and blackwater river bottomlands. Red rivers have their headwater in the Piedmont or above.  Their waters contain clay sediments and tend to be brown or “red”.  The James River is one. Blackwater rivers have their headwaters in the coastal plain.  The waters of in these rivers tend to be dark and tannic, nearly like dark tea.  The Blackwater River in Isle of Wight is one.  There are implications for fish and aquatic systems, but that is a post for the Virginia Department of Game and Inland Fisheries.

0-1

There is an incredible amount of energy held in moving water, especially floodwaters.  We are reminded, when flooding is eminent, to never try to drive or walk across a flooded road.  In flash floods, this energy is expended in uprooting trees, sweeping away cars and homes, and washing out bridges and culverts (thus the need for proper best management practices in timber harvest operations.)  In the wide, flat floodplains of the coastal area, this water energy is stored and slowly released by spreading out over the flat lands adjacent to the river bottoms.

The friction from the water striking the buttressed roots of the wetland-adapted trees slows the water, dropping sediment and releasing energy.  This water, clearer of sediments, will slowly leave the river bottom and eventually reach an estuary before finally making it to the ocean.  These can be slow-moving, long-duration flood events.

Unfortunately, some of our oldest towns and cities are built close to these floodplains, as they were the superhighways of the earlier times.  When the floodplains are not able to hold all the rains, these communities can be inundated with flood waters for extended periods.

It is important for us to recognize the ecosystem services that our forests provide.  Most of us know about the more obvious services forests provide – clean air, wildlife habitat and carbon sequestration.  Floodwater storage and sediment reduction may be other services that you had not considered.

Field Notes: What’s in the Woods Today? Jan. 31, 2018

by Area Forester Lisa Deaton

Those Hidden Roots

Homeowners often contact our local Department of Forestry or Virginia Cooperative Extension offices when they are worried that a yard tree might be diseased or dying.

dying pine

This loblolly pine (above) is located on the shore of a tidal creek that flows into the Chesapeake Bay.  The needles and branches in the top of the tree have been dying for the past several months.  We initially thought that the harsh growing conditions of a saltwater shoreline and repeated flooding had finally taken its toll on this tree.  Then we found out that the tree’s roots had suffered through the construction of a home addition and the installation of a lawn irrigation system.  The homeowners thought that as long as the taproot directly under the tree was undisturbed then the tree would be fine.

While pine trees do have a central taproot, evident in the two tree stumps on the right, (below) they also have a large network of smaller roots and fine root hairs like the stump in the center of the photo.

roots 2

The fine roots of live trees are located in the first few feet of soil. Just driving over them with heavy equipment can compact the soil enough to damage those roots. Cutting through tree roots for irrigation systems or utilities (electric wire, cable, etc.) eliminates part of the original root system and creates wounds where diseases can enter the tree.
A general rule of thumb during home construction is to leave the ground underneath a tree undisturbed for at least the breadth of its canopy. A tree’s roots can extend away from the tree a distance of 1 to 3 times its height, which is a consideration for landscape planning, also.

These photos (below) provide a glimpse of the underground root system of hardwood trees.

roots 3roots 4

Here are a few more photos from an eroded shoreline on the York River  (Most of the fine root system of these dead pines has weathered, decayed and fallen off).

roots 5roots 6

Last, but not least, this is an interesting look at root competition.

roots on top of roots

The American beech tree in the upper left is crossing over roots of the sweetgum tree in the center, and another tree or vine’s roots are crossing over top of the root in the foreground.

 

Field Notes: What’s in the Woods Today? Dec. 5, 2017

by Area Forester Lisa Deaton

Baby Longleaf

Last week was finally time to plant a longleaf pine project.  The landowner had spent over a year preparing a 17-acre cutover site for these seedlings.  Longleaf pine is known for its very long needles, huge pine cones, very strong “heart pine” lumber, and the naval stores it can produce.  The longleaf seedlings are in the planters’ bags.

longleaf planting crew

As you can see, the planting crew was ready to go to work early in the morning.  The loblolly pine plantation on the left is 21 years old.  It was precommercially thinned at age 10, understory burned at age 14, and commercially thinned at age 17.  The area to the right of the road was clearcut to make room for the longleaf plantation.

planters on road

In 3-4 years, the new plantation should look something like this:

suffolk plantation

Longleaf pine used to be part of 1.5 million acres of forest in the southeastern corner of Virginia until around 1700.  Its presence allowed for the beginning of the ship-building industry in Hampton Roads.  However, the historic harvest of longleaf lumber and naval stores, the conversion of forest to farm fields, and the exclusion of fire helped lead to the decline of longleaf pine in Virginia’s landscape.  A great deal of research has been conducted on how to reestablish longleaf pine in Virginia.  Our hope is to increase species richness and biodiversity at the northern limit of where longleaf pine can grow.

baby longleaf

One discovery is that planting containerized seedlings in the fall, as opposed to bare-root seedlings in the early spring, is more successful.

open field planting

Sometimes landowners decide to plant agricultural fields back into trees.  These planting rows were “scalped” to remove the roots of grasses that could compete for water, nutrients, and sunlight with the longleaf seedlings.  A “ripper” was also used to break up compacted soil so that the longleaf roots can grow deep.  The ripper is in the “up” position in this photo.  It is the white looking piece of metal.

scalping plow n tractor