Somewhat contradicting to my last blog post, where I demonstrated that constructing with concrete is the solution to reduce CO2 emission in urban settings, I would like to, through this blog post, suggest my idea regarding how trees, urban forests to be exact, can also be the solution.
Urban forests benefit cities in many ways, including filtering air, water, sunlight, providing living spaces to animals and recreational area for residents, regulating local climate (Urban heat island effect), smoothing wind and storm water, and shading homes and businesses to conserve energy.
My inspiration came from A-P Hurd and Al Hurd’s work, where it mentions urban trees grow larger and contain four times more carbon that their “wild” counterparts, and three shade trees reduced southern Californian homeowners’ cooling costs by between 10 to 50 percent. I began to imagine what would happen if the scale were to be expanded to city-scale, county-scale, multi-county-scale, or even statewide-scale. My imagination led to my reevaluation of urban forestry.
Currently urban forestry in Seattle is supervised by local organizations such as the Seattle Department of Transportation (SDOT) Urban Forestry section and Urban Forestry Commission, focusing on expanding vegetation covers and increasing health and longevity of urban forest. Yet I believe they have overlooked the potentials in urban forests, a much conservational approach is needed. Whereas urban forests can yield multiple aspects of benefit including recreational, social, psychological, and economic, etc., I would like to suggest an extended inclusion of economic benefits from urban forests, which links this conversation back to constructing with wood.
With advanced construction innovations, wood-structured residential buildings can now achieve new heights. Compared to concrete buildings, the new heights create the density and the economic efficiency (from reducing the costs of construction) that are more applicable in many American cities’ context. Needless to say, wood still holds its value as a construction material and urban forests contain a potential to be a source of woods.
While looking at tree species that are qualified as urban trees, I found that some of them are also qualified as the types of woods for construction and are coincidentally native tree species in Washington State. Now imagine the economic values from selling the woods, the reduction on costs and carbon emission in transport, along with all the benefits in other aspects from close-by urban forests if they were filled with those trees. Undeniably, with only 11% of its land area being green and park land (See here), Seattle alone will obviously face challenges in satisfying the market’s need of wood, even though Seattle is among the 10 best cities for urban forests.
Like I mentioned before, this kind of project could use larger scales. If supervised carefully, the positive impacts can occur in many aspects. For example, urban forests can raise public environmental awareness through inviting citizens to tree replantation events. With an administrative body, the proper harvesting method and higher replantation rates can be guaranteed. Governments can incentivize developers to construct with woods harvested from urban forests to reduce CO2 emission from longer material transport. The proceeds from selling the woods can provide additional operating budgets for the project, local, state, and national parks to ensure their longevity.