A walk through the world of trees

By Andrew Land

On the first of October, I had the privilege of joining a small group touring the Cully-Concordia International Grove with Jim Gersbach, a Concordia tree steward, longtime Friends of Trees volunteer, and a key contributor to the design of a new urban mini-forest at the north end of 42nd Avenue in Portland.

Gersbach envisions the area as a gateway to two demographically diverse neighborhoods, Cully and Concordia, from the nearby Portland International Airport. The trees represent the many lands and cultures from which the residents originate as well as native species from different parts of Oregon.

Gersbach thanked Matt Krueger and Jennifer Karps of Portland’s Bureau of Environmental Services, who sought input from local residents to guide planting decisions for the site. He credited Jim Wentworth-Plato of the Cully neighborhood for creating an initial planting plan that emphasized a mix of conifers and deciduous trees for year-round interest.

Honoring Neighborhood History

The lowlands north of the grove were the site of Vanport, a community built to house World War II shipyard workers and their families. Many of these workers migrated from the southeastern U.S., which inspired the addition of the southeastern U.S. native, the American Smoketree (Cotinus obovatus).  Smoketrees have a vibrant orange-to-red fall color.

Chinese Pistache (Pistacia chinensis) and Chilean Beech or Roble (Nothofagus obliqua) were also included for their nice autumn color. The grove includes two species native to Mexico—the Broadleaf Evergreen Oak (Quercus hypoleucoides) and the Durango Pine.

The Snow Gum (Eucalyptus pauciflora ssp. debuezzeville), a well-known and well-loved Australian native, features beautiful, smooth, light-colored bark that will show up well in headlights at night as cars drive by. Honeybees in the neighborhood will also appreciate the rich nectar of the trees’ white flowers.

The Atlas Cedar (Cedrus atlantica var. glauca), native to Morocco, was included to represent Africa. Two evergreen oak species represent Europe, though they can be found in North Africa as well: the Cork Oak (Quercus suber) and Holm Oak (Quercus ilex). Yes, the bark of the Cork Oak is used to stop bottles, but the trees must be 15 to 20 years old before their outer bark can be harvested without killing them.

Finally, two species of ‘redwoods’ were included: the mighty Giant Redwood (Sequoiadendron giganteum) and the once-thought-extinct Dawn Redwood (Metasequoia glyptostroboides). The Giant Sequoia is renowned because it is the largest species of tree by volume in the world, and one of the tallest.

Fossils of both trees have been found in Oregon, Gersbach said, though Giant Sequoias are found wild today only in California’s Sierra Nevada. Fossilized trunks of Dawn Redwoods have been found a short drive upriver from the Bonneville Dam.

Living Dawn Redwoods were rediscovered in China during World War II, and in 1948 their seeds were distributed to arboreta around the world, including Portland’s own Hoyt Arboretum.  A deciduous conifer, the trees’ needles turn a russet-orange color in fall.

Jim Gersbach’s depth of knowledge and passion for trees was evidenced by his two-hour narrative during our tour of the Cully-Concordia International Grove. He will give a series of slide shows this fall discussing the characteristics of various street trees for Portland and their suitability for different planting situations.

I strongly encourage homeowners considering buying a street tree to attend. The slide shows will be on November 3 (inner SE Portland), November 10 (N Portland), and December 8 (NE Portland). Please refer to our online calendar for details and updates about any of these three events.

– Land is a Neighborhood Tree Specialist for Friends of Trees.