Each fall, members of the Society of Municipal Arborists (SMA) nominate and vote for the SMA Urban Tree of the Year. Tree species or cultivars of species native to the U.S. Midwest, South, and East have dominated the Urban Tree of the Year program in its 25-year history (see past winners here).
For 2021, SMAers in the western states of the U.S. must have gotten organized; their collective might pushed the majestic giant sequoia (Sequoiadendron giganteum) over the finish line. (And yes, there are giant sequoias that have been planted and are thriving in New York State, including at Wave Hill in the Bronx, Brooklyn Botanical Garden, and New York Botanical Garden, and on private properties on Long Island. We’ve also gotten reports of giant sequoia trees doing splendidly in southeastern Connecticut.)
Although giant sequoia is native to a small swath of western slopes of the Sierra Nevada Mountains, its hardiness (given most generously as Zone 6a to 9b, with some sources constraining that range) makes it suitable for use beyond its indigenous terrain and indeed, it’s been planted in many western spaces, urban or otherwise.
Like most trees it prefers a loamy soil, even moisture, mid-range pH, adequate soil volume, freedom from soil compaction, and full sun. However, it can grow in less than these ideal conditions, and the more well-established the tree, the better it will be able to ride out periods of drought. Full sun appears to be the least negotiable condition for giant sequoia.
Addressing the elephant in the room: how can a giant sequoia, in all its massive glory, be considered for urban spaces? Gordon Matassa is the Urban Forestry Grant Project Coordinator in the Tree Services Division of the Oakland, California Department of Public Works. “If planted correctly in urban areas, this species can bridge the natural world to the cities that many of us call home,” he says. “Giant sequoia is well-suited for climate-appropriate urban areas when given enough room to grow, such as when planted in city parks. We have several giant sequoias in our parks in Oakland, California, where they stand out as sentinels in the urban landscape.”
Giant sequoias are numerous in Portland, Oregon; many of them were planted circa 1900. There are seven Portland Heritage Tree program giant sequoias in the City—some growing in parks, others in the City right-of-way or in residential front and side yards. The tallest of them is growing in Portland’s Mt Tabor Park; it’s 200 ft (61 m) tall, with a 50 ft (15 m) canopy spread and a 25.3 ft (7.7 m) trunk circumference. (The genetic potential of giant sequoia’s height, given ideal conditions, can exceed 250 ft/76 m.)
According to the Portland Parks and Recreation website, “Nearly 500 sequoias and redwoods have been inventoried in the City, and 93% were rated as being in good or fair condition. These trees thrive in our urban forest, and as large-form evergreens, they provide us with enormous public health and environmental benefits. A mature giant sequoia in Portland can store over 6 tons of carbon and scrub pounds of pollutants from the air annually.”
The City of Eugene, Oregon is celebrating the early fulfillment of their goal of planting 2021 giant sequoias by 2021. According to SMA President and City of Eugene Urban Forestry Management Analyst Scott Altenhoff, giant sequoias grow extremely quickly but, unlike so many other fast-growing tree species that tend to be high-maintenance, giant sequoias tend to be very low-maintenance if planted in the right locations.
“They are extremely resistant to drought, high winds, snow/ice, and pests/pathogens,” Altenhoff says. “In most cases, they just don’t require structural or maintenance pruning. When it comes to providing ecosystem services, giant sequoias are veritable workhorses. They are true champions when it comes to cleaning the air, providing shade, intercepting rainfall, sequestering carbon, attenuating noise, and instilling people with a sense of beauty and grandeur. It would be hard to find a species of urban tree here in the Pacific Northwest with greater net benefits for humans.”
Through the “2021 by 2021” initiative, City of Eugene planted giant sequoia in shared public areas such as parks and street medians, as well as on the grounds of schools, local businesses, and homes. Eugene originally conceived the effort to commemorate the City’s hosting of the 2021 World Athletics Championships, which have now been rescheduled for 2022.
Giant Sequoias outside Their Natural Range … and Most Notably, in Surrey, British Columbia
Redwood Park in Surrey, BC is reputed to have the largest stand of redwoods north of California, along with a collection of notable evergreens and other species from around the globe. How did this come to be?
Surrey homesteader and eventual postmaster and provincial Justice of the Peace David Brown had deaf twin sons, David and Peter. When they turned 21, David Brown gave them each 16 ha (40 ac) of land, on which the younger Browns promptly planted redwood seeds they had collected in California.
David and Peter lived on the property all their lives, eventually building and living in a tree house on stilts. The original tree house burned down but it has been reconstructed and contributes to the immense appeal of this natural attraction in the Lower Mainland of British Columbia.
For reasons of Brown Family history; tree and canopy density, maturity, and diversity; a biodiverse understory of herbaceous species; and striking views from its hilltop position, Redwood Park has been listed since 2005 on the Canadian Register of Historic Places. ?