Street Tree Inventory Report Mt. Scott-Arleta Neighborhood November 2015 Street Tree Inventory Report: Mt. Scott-Arleta Neighborhood November 2015 Written by: Kat Davidson, Angie DiSalvo, Jeremy Grotbo, Jeff Ramsey, Maya Rommwatt, and Megan Van de Mark Portland Parks & Recreation Urban Forestry 503-823-4484 [email protected] http://portlandoregon.gov/parks/treeinventory Mt. Scott-Arleta Tree Inventory Organizers: Jonathan Brandt, Kate Carone, Dan Portis-Cathers, and Jed Roberts Staff Neighborhood Coordinator: Maya Rommwatt and Megan Van de Mark Data Collection Volunteers: Marisha Auerbach, Michael Babbit, Jenn Brenner, Cameron Carpenter, Don Crossley, Casey Cunningham, Ann Denies, Jennifer Duran, Mischa Egolf, Caleb Egolf, Gregg Everhart, Autumn Gallahan, Andrew Gallahan, Jim Harlan, Holly K Hein, Martha Irvine, Ben Jones, Stephen Larson, Kyle Lempinen, Jan Maas, Sherry McCreedy, Sean McMillen, Tim Moore, Matthew Nenninger, Ann Rasmussen, Emily Rintoul, Mary Rivard, Eric Rouleau, Beppie Shapiro, Kathleen Srofe, Bob Stipe, Jack Sutherland, Gabriel Trainer, Elizabeth Turgeon, Jess Tyler, and Robert Zimmerman Data Entry Volunteers: Jonathan Bailey, Tsung Hwa Sophia Burkhart, Catherine Clark, Megan Cohen- Doyle, JoAnne DiCarlo, Aiden Forsi, Jim Gersbach, Lisa Goshe, Hansford Hair, Isabel LeMeir, Kyle Lempinen, Julien Nobili, Kathryn Peterson, Gary Thompson, and Shauna Volk Arborist-on-Call Volunteers: Jim Gersbach and Fred Nilsen GIS Technical Support: Josh Darling, Portland Parks & Recreation Financial Support: Portland Parks & Recreation Cover Photos (from top left to bottom right): 1) Catkins and leaves of a golden chinkapin (Chrysolepis chrysophylla), the first inventoried in Portland. 2) The rust-colored, exfoliating bark of a redwood (Sequoia sempervirens). 3) Fall color beginning to show on a large tulip poplar (Liriodendron tulipifera). 4) An established pagoda tree (Sophora japonica). 5) Close-up view of the starry foliage of an Atlas cedar (Cedrus atlantica). 6) The unusual bark of a eucalyptus (Eucalyptus sp.) 7) A budding bay laurel (Laurus nobilis). 8) The vivid fall color of a smoketree (Cotnius sp.) ver. 10/19/2015 Portland Parks & Recreation 1120 SW Fifth Avenue, Suite 1302 Portland, Oregon 97204 (503) 823-PLAY Commissioner Amanda Fritz www.PortlandParks.org Director Mike Abbaté Table of Contents Key Findings .......................................... 1 About Portland’s Street Tree Inventory . 3 Mt. Scott-Arleta Street Tree Inventory . 5 Neighborhood Characteristics ......................... 5 Urban Forest Composition............................ 6 Species diversity and tree type composition . 6 Functional tree type .............................. 8 Size class distribution ............................. 9 Mature tree form distribution ..................... 10 Importance value................................ 10 Tree Condition .................................... 11 Planting Site Composition and Stocking Level ........... 13 Planting sites................................... 13 Stocking level .................................. 14 Right tree in the right place ....................... 14 Replacement Value ................................. 15 Environmental and Aesthetic Benefits .................. 16 The Future Forest of Mt. Scott-Arleta.................. 17 Recommendations ..................................... 21 Next Steps: Tree Plans and Tree Teams .................... 23 References ........................................... 25 Appendices........................................... 27 A: Methods ....................................... 27 B: Street trees of Mt. Scott-Arleta by tree type ........... 29 C: Street trees of Mt. Scott-Arleta by size (map) .......... 32 D: Vulnerability to key pests (map)..................... 33 E: Young street trees (trees ≤ 3” DBH) (map)............. 34 F: Large street trees (trees > 24” DBH) (map) ............ 35 G: Poor and dead street trees (map) .................... 36 H: Planting site types (map) .......................... 37 I: Planting site sizes (map)............................ 38 J: Available street tree planting sites (map) ............... 39 K: Priority street tree planting sites (map) ............... 40 Portland Parks & Recreation i Volunteers, guided by Portland Parks & Recreation Urban Forestry staff, collected data on all 2,460 street trees within Mt. Scott-Arleta neighborhood to compile the neighborhood’s first complete street tree inventory. The data are being used to inform the creation of a Neighborhood Tree Plan to guide volunteers in caring for their community’s trees. ii Street Tree Inventory Report – Mt. Scott-Arleta Neighborhood 2015 Key Findings This report provides the results of a street tree inventory conducted in the Mt. Scott-Arleta neighborhood in 2015, along with Portland Parks & Recreation (PP&R) Urban Forestry staff recommendations for the Mt. Scott-Arleta tree team. Over the course of four work days, 40 volunteers contributed more than 160 hours collecting data on each of the neighborhood’s 2,460 street trees. URBAN FOREST STRUCTURE • Mt. Scott-Arleta’s street tree population is dominated by cherry, plum, and pear and does not meet recommended species diversity guidelines. While 95 tree types were found in this inventory, only two families, Rosaceae and Sapindaceae, account for more than 53% of the street tree resource. Furthermore, both the Acer (maple) and Prunus (plum, cherry) genera are over represented leaving Mt. Scott-Arleta’s street tree population vulnerable to pests, pathogens, and effects of a changing climate. • The dominance of broadleaf deciduous trees (90%) points to a need to plant more evergreen trees for year-round benefits and to help create a more resilient, sustainable urban forest. • There are many young trees in Mt. Scott-Arleta – 42% of trees are 3” or less in diameter. This is likely the result of successful tree planting efforts in recent years and provides an opportunity for inexpensive young tree maintenance activities that will reduce future costs and ensure the longevity of these trees. If young trees are properly cared for today, Mt. Scott-Arleta will have a healthier age distribution of street trees in the future. • Only 15% of Mt. Scott-Arleta’s street trees are large form varieties. Large form trees are necessary to increase canopy cover and the benefits they provide for Mt. Scott-Arleta’s residents. Planting the estimated 218 large available spaces identified in this inventory will maximize tree canopy in Mt. Scott- Arleta 's rights-of-way. TREE CONDITION • The majority (87%) of trees inventoried in Mt. Scott-Arleta are in fair or good condition. However, nearly half of the trees that are rated poor are in the Rosaceae family and more than 23% of the trees in the Prunus (plum, cherry) genus are in poor condition. PLANTING SITES AND STOCKING LEVEL • Only 54% of street tree planting sites have trees in Mt. Scott-Arleta. Planting efforts should focus on the largest sites with no overhead high voltage wires first, as large form trees will provide the most long-term benefits to the neighborhood. • Less than one-quarter of large planting sites contain trees large enough for the site. Small form trees planted in large planting sites are a missed opportunities because larger trees contribute many times more benefits than do smaller ones. URBAN FOREST VALUE AND BENEFITS • Mount Scott-Arleta’s street trees produce an estimated $160,800 annually in environmental and aesthetic benefits.The replacement value of this resource is $4.5 million. Planting efforts focused on appropriately sized trees distributed across the neighborhood will ensure that future benefits are equitably distributed among all residents. Portland Parks & Recreation 1 Clockwise from top left: 1) A more diverse canopy can better withstand pests and diseases. This rare hickory (Carya sp.) is helping to increase diversity in the Mt. Scott- Arleta neighborhood. 2) Broadleaf evergreen trees, such as these myrtlewoods (Umbellularia californica), are very uncommon in the neighborhood. 3) At 50.5" DBH, this black walnut (Juglans nigra) is the largest diameter street tree in Mt. Scott-Arleta. It is also Portland Heritage Tree #31. 4) Another good example of a rare species, the evergreen elkhorn cedar (Thujopsis dolabrata) exhibits showy white patches of stomata on the underside of its foliage. 2 Street Tree Inventory Report – Mt. Scott-Arleta Neighborhood 2015 About Portland’s Street Tree Inventory THE IMPORTANCE OF STREET TREES Street trees are an important public asset in urban environments, serving as a buffer between our transportation corridors and our homes while enhancing the livability of our city. As integral components of a community’s green infrastructure, street trees provide multiple economic, environmental, and social benefits such as cleaner air and water, cooler summer temperatures, safer streets, and increased property values. Unlike traditional, “grey” infrastructure, which begins to deteriorate the moment it is installed, the benefits that street trees provide increase over the lifetime of the tree, making their planting and maintenance one of the best investments a city and its residents can make. While street trees are only one component of Portland’s urban forest, they are particularly important because they are the trees that residents Urban forests are complex, living interact with most. Having adequate information resources that interact both about the street tree population allows a community to make informed decisions about