Park visitors have probably noticed some changes in the oak grove in the southwest corner of Bush’s Pasture Park over the past year. More leaves have been allowed to remain on the ground in the fall and, now, many oaks are surrounded by larger and more deeply-mulched “tree circles.” What’s going on?
Under the leadership of Brian Smith, a City of Salem horticulturalist who works in the Park, the City has changed the way the oaks in the upper park are managed. According to Brian, allowing fallen leaves to remain on the ground creates habitat for wildlife, including insects, spiders, small mammals, and worms. As leaves and other fallen tree debris break down over time, they release beneficial nutrients back into the soil, which in turn improve the health of the trees.
The City, Mission Street Parks Conservancy, and other volunteers are also working to improve tree circles, beginning with the oaks near the top of the Soap Box Derby track. This job starts with a small mountain of wood chips provided by the City’s tree crews. Volunteers load wheelbarrows or a small garden vehicle with chips, which are dumped near the trees. The chips are raked into place by other volunteers so that each oak tree is surrounded with about four inches of chips. Volunteers are careful not to allow chips to cover the base of the tree where it meets the ground. It’s hard work, but worth the effort. The wood chips will reduce weeds and grass; protect trees from accidental damage by mowers; and help reduce compaction of the soil.
You may also have noticed that some of the tree circles have been enlarged to create “tree islands” containing more than one tree. According to Brian, using tree islands increases protection for the trees’ roots; increases the amount of organic matter returned to the soil; and reduces the need for mowing between trees.
These management changes – allowing leaves to remain on the ground and improving tree circles – were recommended by and implemented after the release of the “Report on Bush’s Pasture Park Oak Woodland.” The Report was commissioned by the Conservancy and released in 2019, and its recommendations reflect a consensus among tree experts. By making these changes to how the oak grove is managed, the City has taken significant and important steps to preserve and extend the life of the Park’s iconic Oregon White Oak population.
If you would like to help with this important work, or other work in the Park, phone or text our volunteer coordinator Gabrielle at 503-507-1004.