Vienna has a considerable tree canopy, but nearly two-thirds of its trees – 3,968 – need maintenance, according to a recently performed inventory.
PlanIT Geo Inc. performed the tree survey, key findings of which the company’s director of field services, T.J. Wood, presented to the Vienna Town Council on June 20.
The firm’s employees surveyed 7,224 trees at 1,222 planting sites and detected 162 tree species – which amounted to a highly diverse urban forest, Wood said.
The 10 most common species discovered were red maple (16.61 percent), tulip tree (10.89 percent), common crapemyrtle (5.23 percent), eastern red cedar (3.1 percent), Kwanzan cherry (3.05 percent), flowering dogwood (2.62 percent), northern white cedar (2.52 percent), pin oak (2.24 percent), Leyland cypress (2.21 percent) and white oak (2.2 percent). The remaining 3,563 trees (49.33 percent) consisted of other species.
Wood said he was not surprised red maple was the dominant species, saying it had appeared in each of the nearly 200 other surveys he had done, even in southern Florida.
“This is the hotspot for those,” he said.
Arborists who conducted the tree inventory measured specimens’ diameter at breast height, 4 ½ feet, and discovered the town had needed a larger percentage of smaller-diameter trees.
The town nearly could meet the goal of having 40 percent of its trees with diameters of 1 to 6 inches if it planted trees in locations suggested by the survey, Wood said.
“In all the other categories [of tree diameter], you’re doing great,” he told the Council.
The inventory examined many, but not all, trees within the town’s right-of-way. A second phase will examine specimens in Northside and Wildwood parks, said Jeremy Edwards, Vienna’s park-maintenance superintendent. Trees along the Washington & Old Dominion Regional Trail are not under the town’s jurisdiction and weren’t inspected, he said.
The inventory took a “bottom-up” approach to data gathering, but if the town wishes to measure its overall tree canopy, this will need to be done from above, Edwards said.
Data from a pilot survey of trees on a fraction of private properties in the town could be extrapolated to provide a rough estimate of how many specimens are within that category, Wood said.
The inventory rated 58 percent of the town’s trees as being in “good” condition, 30.4 percent as “fair,” 9.5 percent as “poor” and 1.4 percent as – no need for quotation marks – dead.
Wood said he was impressed by the relative health of Vienna’s tree inventory, where nearly 90 percent of trees were in “fair” or “good” shape.
“I’ve looked at a lot of data across a lot of projects and I don’t think I’ve seen one [with] as good a health as Vienna’s trees are in,” he said.
PlanIT Geo Inc. recommended the town “crown clean” – i.e., remove dead wood and hanging limbs – on 2,373 trees, or 26 percent of its inventory.
The company also suggested the town remove 25 trees rated as “high-risk,” and replant trees in those locations; monitor 689 trees that are in “poor” or worse condition; prune 829 to promote a healthy structure and another 802 that are conflicting with utility lines; and consider pruning 263 trees that pose clearance problems for pedestrians and bicyclists.
The town also should maintain or establish a routine tree-monitoring and -maintenance schedule; consider removing the inventoried stumps and planting trees there; plant trees at recommended sites; continue to use the TreePlotter application to track tree maintenance, plantings and removals; and educate local residents about the town’s tree inventory, its benefits and the tree-management program, Wood said.
Council member Ed Somers said tree removal sometimes has been overly aggressive when it comes to utility-line conflicts.
Wood responded that utility contractors do not always assess trees in the same manner as arborists.
“They might look at it and say, ‘Well, this is a tall-stature tree that’s just going to continuously grow into those power lines. It’s got to come down,’” Wood said. “What I would advise is . . . analyze it further. There are a lot of pruning techniques for large-stature trees that can go around power lines without removing the full tree. Or, if you’re going to remove the tree, as least replant the right species underneath the power lines.”
Town staff members already work with Dominion Energy on planting the right tree species in proper locations to avoid utility-line conflicts, Edwards said.
“We don’t have a lot of power, at the end of the day, to influence what they prune or if they choose to remove,” he said. “I think a lot of the decision-making is based on risk . . . They’re looking at it [for] preventing interruptions to their service.”
Somers had a starker take on the matter.
“If given their druthers, they would cut them all down so they wouldn’t have to worry about them in the future,” Somers said. “This is something that drives me absolutely crazy because I just saw it happen and the trees weren’t that close to the [utility] line. They could have been brought to a lower level. Instead, they just wiped them out.”
To check out the tree inventory, visit pg-cloud.com/ViennaVA.
