My Story 4: Starting Young: Middle School Students Pull Yellow Starthistle to Improve the Environment
Students in the Environmentally Concerned Kids Club (ECK) of Foothill Middle School in Walnut Creek, California have been clearing weeds from Pine Canyon, a local recreational area, for over a decade. This is one of many ecological projects the club engages in under the direction of teachers Jeff Parrish and Ariel Owen. The goal of the Pine Canyon project is to remove non-native plant species and return the area to its native condition. A recycling program run by students and a grant from the East Bay Regional Park District support the activities of the ECK club. In addition, parents transport students to and from Pine Canyon, and provide supplies and contacts needed for some of the environmental tests conducted by the group.
Pine Canyon rises from an elevation of about 30 feet at Pine Creek directly behind the school to about 200 feet moving up towards the summit of Mt. Diablo. Its native vegetation is primarily scrub oak and grassland but it has become infested with many species of non-native thistle over the years. One of these species is yellow starthistle (Centaurea solstitialis), a widespread invasive plant in northern and central California. Jeff is unsure how the original infestation in Pine Canyon occurred, but believes that horse traffic through the canyon is one of the primary means by which the weed continues to spread. As horses are ridden through the canyon, thistle seeds attach to their legs and are transported throughout the area.
Students work during the spring and summer months to pull the weeds up by their roots and haul them out of the canyon in large garbage bags. Best results are achieved by removing the weeds before they produce seed, although this is not always possible. Younger weeds can usually be removed successfully while older, larger weeds that cannot be uprooted are cut down at the base. In order to minimize contact between the weeds and horses traveling through the canyon and prevent seeds from “hitching a ride,” students strive to maintain at least a three-foot wide clear area around the horse trails. In areas where young weeds are removed, few yellow starthistle plants return the following year.
Restoring Pine Canyon to its native vegetation is an ongoing battle but Jeff sees his students making definite progress in managing yellow starthistle. The sharp spines of yellow starthistle discourage hikers and horseback riders from using the canyon but by removing the weeds from areas adjacent to paths and trails the EKC students enable people and horses to enjoy the canyon in spite of the infestation. In addition to its practical ecological aims, Jeff says, he and Ariel view the ECK as an opportunity to "to instill in our students the knowledge that they can make a difference in their environment." The ECK club and its sponsors hope to maintain the monitoring and care of Pine Canyon well into the future, protecting the canyon’s health, preserving its use for the community and providing the chance for middle school students to learn about and take responsibility for the care of their environment.
See the Yellow starthistle species profile for more information.