Urban forest gets a trim
Closely cropped downtown street trees are a sure sign that spring’s on the way.
As part of its annual tree maintenance program, the City of Campbell River prunes street trees along the Shoppers Row sidewalk from 13th Avenue to the Pier Street.
Two pruning methods are used downtown, says the city’s parks foreman and certified arborist Tom Clarke.
The London plane trees will be pollarded, a pruning technique that might look unusual to some people. “The first time we pruned the downtown trees this way, some local gardeners were surprised and even concerned by the look,” Clarke says. “We’d like to assure everyone that pollarding is the proven pruning technique for this type of tree in this type of location.”
Pollarding involves cutting back all branches to control the size of the tree and limit the reach of the tree canopy. Pollarding promotes a dense head of foliage and toughens the tree, making branches sturdier in high winds. Pollarding has been common in Great Britain and Europe since medieval times and is practiced today in urban areas worldwide, primarily to maintain trees at a predetermined height.
“London planes are very vigorous, and can produce long, heavy branches. Pollarding protects nearby buildings and signs and keeps the branches light, to prevent them from breaking off and falling on the sidewalk,” Clarke explains. “By reducing the canopy, we also reduce the risk of the tree falling over in heavy storms.”
Pollarding has been done several times on the London planes along Shoppers Row, the last time about three years ago. People can expect to see the trees sprout new branches by mid to late May and leafing out in June.
“The London planes downtown will be a bit less bushy this year, and the full green canopy will be out by mid July, or sooner, if we have the right spring and early summer conditions,” Clarke says.
The London plane trees, which were two or three years old when planted, were installed during the downtown revitalization work about 25 years ago. The pruning program began when tree limbs grew too long and heavy for their location.
“The trees have been consistently healthy, and with continued regular maintenance could live well beyond 80 years old,” Clarke says.
One London plane tree, across from Robert V. Ostler Park, has already been pruned using the pollarding method this year.
“Downtown street trees are part of the urban forest, and the benefits of this significant investment by the community include carbon capture, shade, cooler temperatures and the attractive streetscape,” says Ross Milnthorp, the city’s general manager of parks, recreation and culture.
Japanese flowering cherries and other trees will be pruned in the manner people are used to seeing for ornamental trees, Clarke says.
“The regular pruning on the cherry trees encourages lots of blossoms later in the spring, which so many people enjoy downtown,” he adds.
The city sped up tree pruning significantly this year. Three crews, made up of city and contractor staff, used a lift bucket to access branches and then chip the cuttings on location.
“If we had one team working and had to drive each load of branches to a chipping site, it could increase our time on this job by several more days,” explains Milnthorp. “Saving time means saving money, and getting the work done as quickly as possible minimizes any disruption downtown.”
The tree trimming equipment will take up some parking spaces where the work is being done, and sidewalk areas could be briefly and temporarily closed when branches are being cut.
The work was originally scheduled to take place over three Sundays this month. In an effort to minimize disruption to the downtown business core, the Parks Department made the most of an opportunity to add another team of pruners on its first day of work on Sunday.
The combined efforts of the three pruning teams increased efficiency, leaving only three to be pruned at the end of the first shift.
Because these three trees were in locations away from business entrances (two on the Chevron property and one in Tyee Plaza), the work was finished Monday.
Pollarding, the removal of the main stems, releases the growth of many dormant buds under the bark on the lower part of the tree.
Planes are among the trees that do well as pollards. Pollarding is used in certain urban areas for tree size management, safety and health concerns. It removes rotting or diseased branches for the overall health of the tree, living and dead branches that could harm property and people, as well as expanded foliage in spring for aesthetic, shade and pollution concerns. In some cases, trees may be rejuvenated by pollarding. The London plane is used as an urban parkland and street tree in cities throughout the temperate regions where a tough and adaptable tree is needed.