Get Involved: Centennial Woods Restoration at Union Bay Natural Area

In 2007, the SEFS Alumni Group helped organize a volunteer event to plant a wooded area, now known as the Centennial Woods, to commemorate the 100-year anniversary of the College of Forest Resources. The chosen plot was a .67-acre site along the western edge of the Union Bay Natural Area at the Center for Urban Horticulture.

Alumni volunteers originally planted 400 trees there, but without a long-term plan to maintain the site, only 40 survived. Also, some bare-root saplings had been planted in thick mulch rather than in the soil below; others were planted in less than ideal locations for the species, and they didn’t get watered after planting. These factors, coupled with the re-growth of Himalayan blackberry on the site, contributed to the very low survival rate.

View of the site in 2009, two years after it was initially planted.

View of the site in 2009, two years after it was initially planted.

During those first few years, future SEFS alumnus Jon Diemer (’14, MEH) and his wife Martha started spending varying amounts of time volunteering at the site, trying to save trees and keep the blackberry and other invasive species at bay, with bindweed and thistle among the most troublesome. Some of the other non-native grass species, as well, grow taller than six feet by late spring, blocking the sun from the young trees, and their roots often out-compete the trees’ roots. With only two people tackling these challenges, though, there was only so much they could do.

Then, in 2011 Diemer enrolled in the Master of Environmental Horticulture program at SEFS and chose creating a restoration and management plan for the Centennial Woods as his research project. With some more help from his wife, other students, and student work parties, he was able to plant most of the trees that are out there now (about 250). The native species planted, in order from greatest to least number, include: Douglas-fir (Pseudotsuga menziesii), shore pine (Pinus contorta ‘Contorta’), western redcedar (Thuja plicata), western hemlock (Tsuga heterophylla), grand fir (Abies grandis), bigleaf maple (Acer macrophyllum) and vine maple (Acer circinatum). The non-natives from southern Oregon and California include incense-cedar (Calocedrus decurrens), redwood (Sequoia sempervirens) and sequoia (Sequoiadendron giganteum).

While the woods have been better maintained than in the past, Diemer says the project would be a lot easier to manage with more help. This past summer, for example, with extended drought and record-breaking heat, proved especially challenging. Diemer and his wife spent 12 weekends trying to haul enough water to save the most stressed trees, and they did succeed in rescuing a few. Yet they didn’t have the time or resources to help as many as they hoped, and about a third of the 250 trees didn’t make it—including three larger trees (about 15 feet tall) that had survived from the original 2007 planting.

The restoration has recently picked up momentum, though, and three work parties of ESRM 100 students have helped replace about 30 dead trees. Yet they still have about 70 more to plant this fall, so they’re hoping to recruit more volunteers to help with the planting, blackberry removal and subsequent maintenance.

If you’d like to get involved, either on a short- or long-term basis, please contact Jon at jon.diemer@gmail. He would welcome any assistance you’re able to offer, whether through donations of trees, time or labor—and so would the woods!

Photos © Jon Diemer.

View of the Centennial Woods site taken in 2013.

Photo of the site taken in 2013.