Elm Expectations for Eastmoreland

History and Costs

The year 2008 will see the ninth annual elm inoculation against Dutch Elm Disease (DED) in Eastmoreland. Since 2000, the neighborhood has raised and spent nearly $80,000 to inoculate DED-susceptible elms, treating one third of the trees at a time on a three-year rotation. Don and Darlene Carlson worked with Save Our Elms and Portland Parks’ Urban Forestry Division to plan inoculation events and account for over one hundred donations, about 40 volunteers, and over two thousand vials of inoculant the first fours years of the program. Eric Smith took up the mantle the second four years. For 2008, Denny Stenzel has volunteered to lead this important work.

The Urban Forestry Management Plan: Jennifer Karps, Botanic Specialist

With such a tremendous effort required year after year, and with such significant sums involved, it seemed appropriate to speak to Jennifer Karps, Botanic Specialist with Urban Forestry, to gain perspective on Eastmoreland’s elms. Some residents may have become acquainted with Jennifer during the five summers she monitored elm trees for Urban Forestry while she earned her master’s degree from Portland State. Since then, she has moved on to become a Botanic Specialist for the newly renamed City Nature Urban Forestry. After producing the 2007 Urban Forest Canopy Report, she has been involved in implementing the Urban Forestry Management Plan which has three main goals: to increase and enhance the urban forest canopy, to improve urban forest-related educational resources, and to achieve parity in how all city residents are served by the urban forest.

Urban Forestry’s Ordinary Street Tree Care as Applied to Elms

What happens to the elms in Eastmoreland and how they are managed is partly sorted out in relation to Urban Forestry’s Management Plan. At the very least, they and their adjacent property owners receive all of the services that Urban Forestry provides to any tree and property owner in the city: the educational outreach, the inspection services that precede pruning, planting, and removal permits, and the mitigation of hazards created by failing limbs or even whole trees. In these respects elms receive equal treatment.

Urban Forestry’s Special Care for Elms

Elms also receive special treatment. Karps says that elms make up about one percent of the city’s 236,000 total street trees. However, as mature trees (those over ~60 years of age), elms make a greater contribution to the urban forest canopy--providing more environmental and aesthetic benefits (see the Canopy Report on the city’s web site for more detail)--than do smaller and shorter-lived trees. Currently, the additional level of care and attention Portland’s elms receive is funded by the 2002 Parks Levy which expires this June 2008. Elms are the only trees that are assigned a special, seasonal monitor from late May until late September, and Urban Forestry staff spend several days each elm season assisting neighborhood groups in inoculating their elms to reduce the spread of disease among them. In addition to hiring an elm monitor who checks for symptoms of disease, collects and submits samples to the lab, keeps records, and communicates with the public, Urban Forestry crews are mandated to remove right-of-way trees and grind their stumps if they test DED positive at the Oregon Department of Agriculture lab. Karps notes that, “Although removing and replacing street trees is the responsibility of the adjacent property owner, Urban Forestry is currently funded to remove elms that test positive for DED to alleviate the hardship that the abbreviated time frame for removal would cause.” Timely removals can reduce the spread of the disease to adjacent trees via root grafts.

Best Results Can Be Expected from Inoculation and Good Sanitation

When asked if inoculation works, Karps notes that, while it is not a silver bullet, it provides a measure of protection that varies with local confounding factors (like individual tree health and local elm density), stressing that good sanitation pruning (removing and destroying dead and dying limbs to reduce elm bark beetle habitat) is also essential. This accords with a statement made by a group of scientists from the University of North Dakota:

“The value of a good sanitation program is often underestimated because some people believe that, "The elms will die anyway." Although this may be true, the rate of dying can be dramatically affected. The experience in Illinois is an example. When DED was first found in 1950, certain communities established excellent sanitation programs. Some communities that maintained these programs still had 75 percent of their elms 25 years later. In contrast, communities with no sanitation programs had lost all of their elms.

Indeed, many university scientists suggest that good sanitation as well as inoculation is essential for elm preservation.

Sanitation Necessary for Dutch Elm Disease Resistant Elms in Eastmoreland

Good sanitation means deadwood pruning and eradicating all elm woodpiles: even woodpiles and dead branches from disease-resistant trees can harbor the elm bark beetle and thereby the fungus that causes DED.

In Eastmoreland, 287 of the original elms planted between 1917 and 1920 remain. According to Karen Williams who has meticulously maintained Eastmoreland’s planting records, from 1997 to 2007, we planted a total of 117 disease-resistant elms:
    Homestead Elms - 93 (planted from 1997 to 2001)
    Accolade Elms - 16 (2003 - 2007)
    Frontier Elms - 7 (2004 - 2005)
    Prospector Elms–one remains from the four planted by Reed College in 1999 along Woodstock; a car knocked down three of them, along with a telephone pole one summer before 2002.

As Karps states, “because bark beetles are the primary vector that spreads DED, reducing bark beetle populations by removing dead and dying wood—habitat that is necessary for overwintering and reproduction—should reduce the likelihood of new DED infections.”

Elm Failures

These disease-resistant elms have replaced both elms and maples from the original 1917-1920 planting and filled in where no street trees existed. Street-tree elms do endure many stresses, such as limited root runs, bad pruning, and too much or too little water, and particular trees may have structural problems that cause them to fail. Using data supplied by Jennifer Karps, Dan Dettmer, an ENA Tree Committee member, compiled figures documenting the elms lost to DED in Eastmoreland. Before 2000, 18 DED deaths were recorded; between 2000 and 2006, 28 deaths; in 2007, a total of ten deaths. This loss rate is variable from year to year, for example, eight trees in 2005 and four in 2006.

Life Expectancy of Elms in Cultivation

If we take care of the elms through inoculations and good sanitation, how long can we expect them to live? Older elms in cultivation in other cities and towns provide a clue. A comparison with wild trees makes less sense, not only because they grow in conditions so different from those in cities, but also because wild elm populations (with the exception of those in northern Alberta) have been decimated by DED. To look for older cultivated elms, one can follow the building of small towns and campuses on the East Coast which, as it happens, provided a model for the development of Eastmoreland. For example, twelve elms in the Scott Arboretum at Swarthmore College are thriving at 120 years old, and the curator Andrew Bunting expects them to live to be at least 150. Such colleges follow careful sanitation practices and inoculate their elms.

Contacting Urban Forestry

Careful vigilance, sanitation practices, and yearly inoculations are a big commitment for Urban Forestry and Portland’s neighborhood volunteers. It is a lot to think about. The ENA web site provides more food for thought regarding its elms and detailed summaries of the services provided by Urban Forestry. Several other websites are generally useful as well: the International Society of Arboriculture (www.ISA-arbor.com) provides tree care information and lists certified arborists by zip code. The city’s own website (www.ci.portland.or.us) provides information regarding DED. During the growing season, any property owner with an elm exhibiting suspicious symptoms (e.g., leaf yellowing, wilt and dieback known as ‘flagging’), whether on the street or in the yard, can call Urban Forestry (503-823-4489) to arrange for the elm monitor to inspect the tree. To reduce the spread of DED, there is a moratorium on elm pruning between April 15 and October 15.

Expectations of Property Owners

Property owners whose lots are adjacent to parking strips with elms can expect a lot of special services for trees that amount to one percent of Portland’s canopy. A great deal is expected of them as well. As with all property owners in Portland, elm neighbors are responsible for the care and maintenance of their street trees. Many have taken responsibility for the special care their elms require as well, both by giving substantial donations to elm inoculation efforts, by volunteering on inoculation day, and by having their trees pruned of dead wood and removing all elm debris from their grounds. Everyone owes these homeowners a debt of gratitude.

Expectations of the Neighborhood as a Whole

Because DED can easily spread throughout a grove, DED prevention is not just an individual property owner’s concern, but rather is the concern of the whole neighborhood. Denny Stenzel is currently planning for the 2008 elm inoculation. Once again, the neighborhood will have to raise the funds to inoculate ~90 trees and have seed money for the next year A fundraising and inoculation-organizing letter will be delivered by the ENA tree committee foot delivery system to all the houses in Eastmoreland. If you want to walk up to your neighbors’ beautiful front doors, this is your chance. Many members of the original ENA tree committee have moved away from the neighborhood, all are ten years older than when we started planting trees in 1997, and several simply need to give more time to aspects of life other than trees. New volunteers will be needed to continue to think carefully about preservation efforts and to help the elms flourish. . If you enjoy the shade and the majesty of the old elms, call Denny at and sign up early to help with the inoculation, 503-777-6651.

Environmental and Aesthetic Values: Investments and Expected Returns

Elms are listed as the most valuable trees in the Urban Canopy Report, the quantitative and qualitative analysis of Portland’s urban forest produced by Jennifer Karps and her colleagues at Urban Forestry in October 2007. One mature elm provides hefty benefits in a year’s time: $13.36 in energy savings, $1.94 in CO₂ sequestering, $5.16 in air quality improvements, $78.52 in stormwater abatement, and $98.72 in aesthetics, for a total of $197.00 per tree each year. Generally, Portland’s publicly owned trees provide $3.80 in benefits for every dollar spent on them. The Eastmoreland street trees comprise your part of the whole urban forest. If you have not thought of pruning your elms for deadwood and joining in the elm inoculation effort, perhaps now is the time to protect an investment that benefits you and the entire city.