I have been thinking for while now about how Green Seattle Partnership contributes to sustainability in the city, particularly now that green cities around the United States are largely leading the way on innovation and commitment towards more robust climate action and policies that promote a healthier environment. Beyond solar panels and energy efficiency efforts, here is where I have begun to document how we build a community and a forest resilient to the new normal of a changing climate. Forêts saines, communautés fortes!
Protecting What We Have – Overarching much of the citywide forest conservation, the city’s Urban Forestry Commission in 2007 established a goal of reaching 30% tree canopy cover by 2037. Nested within that goal is the GSP program mission of restoring 2,500 acres of forested parkland by the year 2025 – a progressive timeline. We remove invasive weeds from the forest understory while planting 80,000 native plants a year to give our native forests a competitive edge. Simple things like removing invasive climbing vines from mature trees allows those trees to reach their natural lifespan. Then, we plant seedlings of a future healthy forest underneath and alongside their matriarchs.
The technology to assess our city’s forest has vastly improved and the Office of Sustainability and the Environment recently released results from the latest canopy cover study. The details show that 28% of the city is covered in tree canopy. You bet we are ahead of schedule, and I think almost everyone is interested in overachieving the 30% by 2037 goal – protecting and planting more city trees! Not surprisingly, Seattle Parks Natural Areas are largely covered in tree canopy, with 89% tree cover, which equates to 14% of the city’s urban forest. One can find some of the largest trees and concentration of groves found in our Natural Areas.
To provide some more context, below is a list outlining how our urban forest responds to the changing climate while also providing a summary of how we are doing our part as a Partnership. Please follow my links. In an effort to keep this piece somewhat succinct, I have referred to some past GSP blog posts and current news.
- Urban Heat Islands – Looking at our region with thermal imagery in the summer, Seattle looks like an island of heat surrounded by greener suburbs, cooler Puget Sound and rural areas. The forested parks, greenbelts and tree-lined Right-of-Ways do some of the heavy lifting to regulate land surface temperatures. When Seattle heats up, its forests stay cool. Spread out across the city, our parks can help us ease through periods of hot weather. Sadly, neighborhoods without tree cover are inequitably impacted by the stress caused by rising temperatures and pollution. Trees for Neighborhoods provides free trees to help assuage the legacy of landscape change and tree removal in certain parts of the city.
- Enduring Drought – Our mature native forests do endure the regular summer droughts. But, do you remember the drought of 2015? Well, we do. It was a rough time to be a treehugger. Even established mature plants, long weaned off water, perished in that broiling summer. Warmer months without rain can be stressful on our younger forests, so we plant early in the season (remember Green Seattle Day on November 4th), mulch heavily, and water newly-installed restoration plantings where we can.
- Hard Rains A-gonna Fall – In addition to hot summers, increased precipitation during winter months is likely, which makes managing stormwater more challenging in the city. Many of our Greenbelts are composed of even-aged native hardwood alder and bigleaf maple stands. The canopy is either closed, branches of trees are touching each other, or gaps are forming as these shorter-lived tree species reach the end of their lifespan. By protecting and replanting longer-lived trees, we endeavor to add complexity and diversity to the forest so that it can better absorb, transpire and mitigate potentially torrential rainfall in years ahead. Most of us are probably ready for some heat after this winter that grew moss on our backs – I will remind you that more than a year’s worth of rain fell on us between October 2016 and early spring 2017. That great amount of rain over such a fleeting period was record-breaking. GSP staff at Seattle Parks have also worked diligently to design our restoration plans with more comprehensive stormwater and erosion control measures. We constantly align and adopt best practices with City and State standards and guidelines. Examples from the restoration activities include leaving less bare ground, causing less soil disturbance and planting more densely.
- Hooglewhat? – Native PNW forests can store carbon not only in aboveground biomass, but they can also escond large amounts of carbon belowground in the matrix of living soil. Some of my favorite plants like western hemlock and red huckleberry seem to thrive on dank, organic soils and elevated substrates like nurse logs. The lack of dead wood on the forest floor will continue to be a limiting factor to our forests sustaining themselves as they traditionally have for centuries. In the meantime, we grow our own future coarse woody debris. We can also cultivate or hack a surrogate in the form of Hügelkultur – a soil building technique to construct a sort of raised planting bed from decaying woody debris and other organic materials. I love that we are encouraging and co-opting this traditional, local knowledge for our restorations!
Adapted and Appropriate – We know many of our native plants could be very resilient to future climate regimes because they are genetically and locally adapted to life in the Puget Trough. 80,000 of native plants installed per year is a pace that requires a lot of resources. It will always be important to educate ourselves about and promote the skills required to carry out local seed collection and backyard propagation every year. Every plant we grow ourselves is a plant we don’t have to import from outside the city. We are also beginning to think about exploring options for choosing genetically-appropriate plant material that is adapted to a warmer future.
- Garbage Has a Footprint – That means we need to get creative. Virtually none of our weed waste leaves the restoration sites. While some cities see the piles of dead ivy and blackberry as waste product to take to the transfer station, we pile or windrow that vegetative debris to form habitat piles that are used by woodland birds like bush tits, juncos and wrens. This saves us bundles in gas and tipping fees every year, in addition to reducing potential landfill mass and preserving valuable nutrients on-site. Another shining example: We also drink a lot of coffee, Seattle. Coffee is made from beans. Those beans arrive in our city from around the world in burlap bags, and are roasted in the Green River Valley. Some of these bags end their lifecycle in Seattle’s forests. We accept donations of thousands of those bags a year for use in sheet mulching and soil building that would otherwise go to waste.
- Parks Won’t Escape Rising Seas – Proudly, GSP has started working on a few forested parks that touch the Puget Sound shoreline, namely Arroyos Natural Area, Discovery Park and Herring’s House Park (Tualtwx). With an expected 2 feet to 5 feet of sea level rise, a Climate Preparedness Inventory from the City of Seattle report estimates that 16 to 50 acres of Seattle Parks land will be affected respectively. Other West Coast cities are dealing with similar issues. Revegetating our shorelines will decrease their vulnerability to higher tidal and wave action while also providing nourishment to the nearshore habitat. You can see the City Sea-Level Rise Map here.
- Carbon Loop Feedback – Years ago, a certain band now in the Rock n Roll Hall of Fame wished to plant trees to offset their output of carbon dioxide as they toured. Locally, those trees from the early days of Forterra’s Evergreen Carbon Capture Program continue to thrive in Discovery Park’s “Pearl Jam” site (one of the best zone name’s in our history BTW). A similar scheme lets people test-drive or purchase a Carter Subaru while also enabling us to plant trees in the Mountains to Sound Greenway. You may have planted some of these seedlings if you have volunteered at Discovery, Golden Gardens, Dr. Jose Rizal or Me-Kwa-Mooks Parks.
Along with these examples of activities we are doing right, read on about some challenges to the current way we do business that we could improve upon.
Operating Citywide – Fortunately, the forested parkland is distributed all around the city. We are now active and making positive impacts in over 100 parks. On just about any given day, one can find the Green Seattle Partnership active somewhere in the city. Our actions have many benefits; however, Seattle is a fast-growing city with lots of traffic. Over 50 project partners, Seattle Park staff, thousands of individual volunteers and numerous contracted crews are constantly in motion to make the magic happen for healthy forests.
Thus, minimizing our greenhouse gas impact from transportation weighs heavy on our minds. Many of our volunteer forest stewards can walk out their door, cross the street into the park and get to work. Long ago GSP started providing on-site tool boxes with enough gear to support a normal sized volunteer event. This saves countless staff hours of tool delivery. Also, thanks to the Seattle Park District funding, GSP staff at Seattle Parks has been able to upgrade its fleet to include some hybrid vehicles. Program participants also use popular car-sharing services, public transportation, and bikes to get to work, meetings, site visits and workparties. Further opportunities could also include greater partnership with the Neighborhood Greenways to increase foot and bike trail access. This would benefit both our health and wellness while also cutting down on the need for driving. Ultimately, we need to explore more alternatives for decreasing our transportation-related carbon impacts.
Educating and Encouraging Others – In restoring our piece of the urban forest, we not only protect and enhance our Park Natural Areas, we are also encouraging healthy lifestyles, engagement with nearby nature and education about the importance of our City’s natural assets. This is good insurance for dealing with some of the pain associated with the changes of a warming climate. Meeting new and old friends alike at a local restoration work party goes a long way to building strong communities. Working side-by-side with each other, Green Seattle Partnership events can provide a forum for people to discuss how we are going to experience the inevitabilities of climate change.
Believe that we can make positive change in our own backyard and the rest of the urban forest. All the trees form a complex system, adapting through years of change as the city has expanded, contracted, and now changes again. Programs like ours both scale down and up to complement other efforts in green cities. Our simple acts of restoration will eventually add up to decades of investment that will also lead to climate resiliency dividends for future generations of Seattleites.
Great detailed article and well thought out. Go GSP.
Great article! Very informative. I’d never really thought about the benefits of leaving piles of invasive material on site.
Michael, this is brilliant! We need to write a similar explanation of strategies we use in our developed parks that help mitigate climate change, and explore how we can adapt our parks to be more resilient in a warming climate. I think we could use your help.