Urban Forestry Roundtable Repository

Balling up a mature bur oak to be moved. Photo by Greg Hove
Balling up a mature bur oak in preparation for relocation. Photo by Greg Hove

A repository of more than 30 roundtables from CITY TREES magazine 2005-2017 is freely available on the home page of the Society of Municipal Arborists (SMA) website, www.urban-forestry.com.

The roundtable format was a suggestion from Dr. Nina Bassuk that City Trees took and ran with. Each roundtable contains advice and anecdotes on a theme from 8 to 10 professionals. The information will be of interest to anyone involved in the urban and community forestry (UCF) world!

The topics are: Bees, Bioswales, Building Bridges Between LAs and MAs, Building Bridges with City Depts, Part I and II, Cemeteries, Climate Change, Consulting, Contract Growing Partnerships, Drought, EAB, Fall Planting, Flood Damage, Gas Lines and Trees, Historic Trees, Invasives, Large Tree Relocation, Medians, Memorial Trees, Palms in the Urban Forest, Pruning Cycles, Pyrus Problems, Sewer Lines, Slopes, Social Networking, Teaching, Tree Boards, Tree Lights, Urban Forestry’s Location in City Departments, Urban Fruit Trees, Urban Wood, Zoos. 

Sample entries from roundtables follow. Please go to www.urban-forestry.com to take advantage of this resource and learn more about the SMA, which welcomes members from all spheres of the UCF world (paid or volunteer).

From the “Bees in Municipal Trees and Parks” roundtable: 

Monster Bee Swarm Vic MacDonald
Monster Bee Swarm in an urban tree. Photo by Vic MacDonald

Menlo Park, California is an affluent city located on the peninsula between the San Francisco Bay and the Pacific Ocean. The Menlo Park Department of Public Works is responsible for the maintenance of approximately 22,000 trees. The community’s canopy is composed of about 20% native oak species and is highly diverse in age.

Bees and other pollinators are an integral component of the health of Menlo Park’s urban forest. The Menlo Park City Arborist receives several calls each year to deal with bee-related issues. In 2013 the Department of Public Works made an operational shift to protect honey bees. To do this, staff completed a beekeeping class and formed relationships with local members of the San Mateo Beekeepers’ Guild.

In the spring of 2013, the City received ten phone calls regarding bee swarms. Swarming is when a new honeybee colony is formed when the queen bee leaves the colony, taking about half of the bees with her. As the swarm relocates, they often rest on street trees, parked cars, or street signs. Staff responded to each location with the proper beekeeping equipment to safely capture and relocate the swarm to their new hives at the City’s apiary, located at the public works corporation yard.

The apiary is composed of three to five active hives maintained by City staff. The apiary is a protected environment where bees continue to provide community benefits without the hazard of poorly located hives in public space. Along with the apiary, there are also natural hives located in trees at City parks. All of these hives have been identified and are located high enough off the ground to avoid interaction with park users. Special care is taken when performing tree maintenance near these hives to ensure the bees are not disturbed or displaced.

To raise awareness about this new program and educate residents about the importance of pollinators, Mayor Peter Ohtaki declared August 17, 2013 the Day of the Honey Bee. In honor of the day, a presentation was given by City staff and a member of the San Mateo Beekeeper’s Guild about the importance of bees and potential new ordinances that could further protect pollinators. Honey produced by the City bees was also distributed for tasting! In addition, the City established an observational hive to use as an educational tool for residents and children. The hive is equipped with glass on both sides so the queen and all the activities of the hive can be safely observed. The observational hive is easy to transport and a popular exhibit during Public Works Week and other community events.

As a result of increased awareness about honeybees in the City, in the winter of 2014 public works staff noticed bees flying at night, hovering like moths around a City building light. The bees were coming from an established hive in a nearby oak tree and ending up dead and disoriented each morning below the light. A sample of dead bees was collected and observed. After about a week, parasitic fly larvae commonly known as “zombie flies” emerged from the dead bees. The female zombie flies lay eggs on the honeybee and as the larvae develop, they attack the bee’s brain, causing them to become disoriented. The infected “ZomBees” are known to fly at night and exhibit other strange behaviors. It is believed that zombie flies are partially responsible for the disappearance of honeybees along the West Coast. Staff continues to monitor and collect samples for “ZomBee Watch,” a citizen-science project sponsored by the San Francisco State University Department of Biology.

Our City’s beekeeping program was awarded the Tree City USA Growth Award by the Arbor Day Foundation in 2014. Due to the symbiotic relationship between trees and bees, municipal arborists are often the first to respond when a swarm moves through a community. In Menlo Park, City Arborist Christian Bonner (ISA-certified Municipal Specialist and Board Certified Master Arborist) is alerted by residents and notifies the beekeepers on staff when bees require relocation. When the City’s apiary is full, hives are placed with local backyard beekeepers. The positive relationships among City staff, residents, and local beekeepers are the foundation of Menlo Park’s successful beekeeping program. —Brian Henry, Superintendent of Public Works, Menlo Park, California

From the “Large Tree Relocation” roundtable: 

Relocating a mature bur oak. Photo by Greg Hove
Relocating a mature bur oak. Photo by Greg Hove

In 1999 the City of Eagan, Minnesota purchased 120 acres (48.6 ha) of land in the city for the development of a new community center and park. The existing site included a 15-acre (6 ha) mature bur oak (Quercus macrocarpa) woodland, natural pond with creek, and open, rolling grassland. There, 36 large bur oak trees, 20 to 36 inches (51 to 94 cm) in diameter, were in the path of a proposed entrance road. One in particular, an open-grown bur oak 27 inch (69 cm) in diameter, was a cherished specimen.

Moving the proposed road to a new location, and thereby avoiding tree removal, was not possible. However, through working cooperatively with staff from Eagan’s Engineering Department, the new road alignment (intersection angle and road curvature) was shifted to preserve many of the trees that had been jeopardized. Unfortunately, the 27 inch specimen bur oak tree was still in the path of the proposed road and was scheduled to be removed.

With that in mind, I began researching the possibility of transplanting. Was the tree healthy enough to withstand a major transplant? Was it physically possible to move such a large tree? Who could perform such a project, how would this project be funded, and what follow-up management would be required to ensure tree survival? As it turned out all these questions had positive answers, leading to the initiation of a highly successful and unique (to our area) Grandfather Tree preservation project.

To determine the health of the Grandfather Tree (GFT), a local private company, Rainbow Treecare, volunteered to conduct starch tests. That test had positive results, indicating that the tree was healthy and was therefore a potential candidate for transplanting. The project was on.

National Shade LLC from Houston, Texas was contracted to move the tree. Because construction dates for the new community center and entrance road were already set, the tree move needed to take place on specific dates. Fortunately these dates coincided with an early spring that year, allowing the tree to be moved following full leaf-out but before the hot summer weather started.

From the start of this project, we wanted it to be a community-based endeavor, not one that was funded through City budget. Through a chance meeting between Eagan Director of Parks and Recreation Ken Vraa and Kay Brown of the Eagan Foundation, the GFT project found an enthusiastic sponsor who would coordinate fundraising efforts. In a relatively short time, the Eagan Foundation successfully raised the $55,000 needed to cover the cost of the transplant. Donations were received from a wide variety of sources including local businesses, private citizens, and even the 2001 graduating class of Eagan High school. Additional project savings were realized through creative partnerships with cooperators such as donated housing arrangements for National Shade crews, donated labor and use of equipment from local contractors, and lunches provided by a local civic-minded group.

The actual tree move began on May 31, 2001 as the five-person National Shade crew hand dug the perimeter of the 30-foot (9.1 m) root ball to a depth of 4 feet (1.2 m). Following the hand digging, an excavator was used to move soil away. The entire root ball was then wrapped with alternating layers of burlap and wire fencing. When the root ball was secure, an entrance ramp was created. Steel pipes, 40 feet (12.2 m) long x 8 inches (20 cm) in diameter, were then set under the root ball with a hammer hoe to create a lifting platform. The platform and tree were lifted with four hydraulic jacks and set onto a specially constructed steel trailer; all the while, the tree remained in an upright position.

Together, the tree and lifting platform weighed 250 tons (227 metric tons). With the gantry system complete, the tree was ready to begin its move. This entire unit, steered with a tracked exactor and pushed with two D7 Caterpillars, moved slowly for 800 yards (732 m) across a paved parking lot to its new home near the front of the proposed community center. Eight days later, on June 8, 2001, the GFT move was completed as the bur oak was set into a prominent location in front of the new community center.

The GFT has just celebrated its 10th anniversary in its new location. The tree did suffer some minor dieback but today has good twig and leaf growth over the entire crown. City staff, with assistance from Rainbow Treecare, continues to perform management activities such as irrigation when needed (although we’re doing less and less artificial irrigation as the years go by), an application of a tree growth regulator in 2003, a couple of insecticide treatments for jumping oak gall, and an application of prescription compost in 2010.

A memorial bench has been added under the GFT’s crown as has an informational sign telling visitors about the history of this unique tree preservation project. —Gregg Hove, Supervisor of Forestry, City of Eagan, Minnesota

From the “Fruit Trees in the Urban Forest” Roundtable:

Fruit and nut bearing trees can indeed be a source of frustration when they are planted in inappropriate places. However, the food value offered by such species deserves some respect! Our own species might not be here today were it not for the figs, dates, and other nutritious fruits that kept our early kin from starvation.

We all have residents who hate messy debris from trees. While I won’t advocate for fruits that can cause concussions or broken windshields, tree fruits are usually ornamental and valuable to wildlife. The often despised sweetgum (Liquidambar) fruits are an example of an attractive fruit that is annoyingly persistent once it falls. But really, if you’re willing to mow a lawn 30 times per year, is it so much of a burden to rake “monkey balls” two or three times per year?

With the increasing popularity of locally grown foods and edible landscapes, there is almost certainly potential for great public relations and community building here. Should people eat fruits grown in sewage sludge or infused with heavy metals from exhaust? I’d say no. But if cities can find suitable soil for community gardens, then apples, cherries, pecans, and persimmons should be just as safe to eat when grown in appropriate places. And the walnuts, hickories, and the like that volunteer in our parks may someday be the only century-plus giants we have, since they are the only trees being planted as nature intended, without root balls, grafts, and buried root collars.

In Upper Arlington, we have a number of cherry trees in our parks and along streets, and I see entire families picking the fruit each summer. Despite my none-too-subtle hints, I’ve never had a pie dropped off at my office, but it’s heartwarming to see kids outside, picking fruit and bonding as people did before video games were invented. It’s a great cure for “nature deficit disorder.” The osage oranges in another local park keep kids occupied for weeks in autumn, serving as ammunition, art supplies, and spider repellants.

Many times I’ve witnessed entire families of residents picking up the fruit of the female Ginkgo from the ground. I do not drop hints about obtaining pies in such cases. I am, however, curious about how this foul-smelling fruit becomes an edible delicacy.

Working in a community adjacent to The Ohio State University, we’re besieged each fall by callers looking to collect buckeyes to make their necklaces and trinkets. So in a world where biodiversity is key, let’s not be too quick to condemn trees that can serve our residents in so many ways (but let’s use some common sense in the process). Every mighty oak is just a nut that held its ground.—Steve Cothrel, Superintendent of Parks, Upper Arlington, Ohio

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