September 2, 2008
Oh, here’s another nasty,” says Denis Underhill, 84, hacking away with his mattock, a WWII infantry trenching tool. He brandishes a spear of Japanese knotweed—not his main foe here in Pacific Spirit Regional Park (that honour goes to English holly), but he can’t resist the opportunity to kill it. Knotweed is a non-native plant, and leaving it to propagate will only lead to more problems for indigenous species.
On this sunny day in mid May, the foliage that flanks the bike path along West 16th Avenue is in a period of accelerated growth. To a passerby, the sylvan landscape may appear verdant and healthy. Not so to Underhill and his work partner, Ed Chessor, 63. Together, they’re the Holly Haulers, a subfaction of the park’s Invasive Species Working Group. “I have nothing against holly,” explains elfin Point Grey resident Underhill. Chessor, a long-time Dunbar inhabitant, adds: “In England, it’s a wonderful plant.” But this isn’t England, and in this forest holly has the potential to overwhelm other species.
The two men met when Underhill brought the results of an informal experiment to the Pacific Spirit Park Society, headed at the time by UBC mechanical engineer Chessor. Underhill, who’s been coming to the park since he moved to the West Side in 1928, had undertaken an experiment with his daughter, Margaret, after his wife died. “I had to do something, so I walked every trail in the park, made notes of every invasive.” Survey in hand, Denis and Margaret chose a test plot, removed all the foreign species, and kept an eye on the land; after two seasons, it was still mainly invasive-free. With those results in hand, Underhill approached the PSPS with a proposal to launch something a little more robust, and the Holly Haulers were born.
If Stanley Park is the heart of the city, then Pacific Spirit Park might be its soul. At 784 hectares it’s nearly twice the size of Stanley Park, and it encloses a native forest composed mainly of Douglas fir, western red cedar, and hemlock. It’s also home to coyotes, pileated woodpeckers, barred owls, ravens, hawks, eagles, and a colony of great blue herons.
Over the years the area has withstood assaults of all kinds. The southern part of the park was logged in the 1890s. In 1919, fire destroyed much of the forest. The remaining northern section was logged in the 1930s. Today it faces a less obvious but potentially even more pernicious threat from plants such as English holly. According to Nick Page, a biologist with Raincoast Applied Ecology, many of the invasive plants in the GVRD are in the “colonization” phase: they’re not yet abundant enough to reduce native plant diversity. But there’s a distinct possibility that, left unchecked, they will do just that; invasive plants can displace native ones. According to a 2001 report by the International Union for Conservation of Nature, invasive species are second only to habitat loss as a threat to biodiversity.
Fighting the battle are volunteers like Underhill and Chessor. “They sort of fill the niche because we don’t have a lot of municipal folks dedicated to the issue,” says Tasha Murray, coordinator of the Greater Vancouver Invasive Plant Council. “Pretty much every municipal and regional park in the area is dealing with some sort of invasive infestation.”
Underhill says he and Chessor take on the park twice a week with their arsenal of equipment. For about three hours at a stretch they disarm (“First we cut off all the branches so we can’t get hurt”), then destroy (“You drag the roots out of the ground”). Holly trees are the main target, but Scotch broom, European mountain ash, laurel, English ivy, and Himalayan blackberry have also taken hold there.
Their tactics combine elbow grease and physics, and their tools include saws, loppers, pruners, and shears. Underhill’s old-school hand-logging techniques involve ropes, pulleys, and hand pulls. The tallest holly tree they’ve brought down stood more than 42 feet; even larger ones are rumoured to be in here. “I want to tackle some of those big ones,” says Underhill. “We got equipment that I think can handle anything I’ve seen in the park.”
Where do invasive species come from? “A vast amount of material is dumped by gardeners,” Underhill explains, “and it’s taken off. That’s where this holly probably stems from.” Discarded Christmas wreaths are culprits; so are the birds that feed on holly berries in people’s gardens and then distribute the seeds.
Over the last four years, the Holly Haulers estimate they’ve removed four tonnes of holly, less than a tenth of what they believe is in there. “Extreme pruning,” Underhill calls it.
“It’s just a case of keeping this as a place where the native species can thrive,” says Chessor. “These things may belong in a decorative cultured garden, but this is a park for preserving what Mother Nature provided.