Wallyhood writer Cathy Tuttle provided the following update on the trees of N. 40th St.:
The City Arborist will talk about plans for the trees on 40th at the next Wallingford Community Council meeting, 
Wednesday Nov. 7 at 7 pm, room 202 Good Shepherd Center.
Wallyhood neighbors love the beautiful old oak trees lining N 40th St., so naturally many people were concerned to see signs go up a few weeks ago on the trees from the Seattle Department of Transportation (SDOT). After many neighbors called SDOT, SDOT wrote an FAQ.
For folks who have trouble reading bureaucratize, here’s a quick translation (note I did talk to the Urban Forester David Body, SDOT’s Urban Forester to get this update).
40th will be repaved in the next year or two. As part of the repaving process, SDOT has to evaluate whether sidewalks are walkable and if people in wheelchairs can use them in a 4-foot clear zone. Some sidewalks along 40th are badly buckled 
because the red and Spanish oak trees planted in the 1970s were put in without enough space for their roots. SDOT loves this established corridor of trees, but their staff must evaluate 23 trees that have caused the biggest sidewalk heaving. SDOT will do heroic things to save these trees including big root pruning, steel plates, and tree pit expansion as they attempt to level the sidewalks — trees really are a priority at SDOT these days. Trees are great for air quality, local climate, CO2 mitigation, neighborhood character, and the presence of mature trees has been shown to increase road safety and reduce speeds of people who drive.
Only after SDOT has tried its best with root pruning and sidewalk realignment, or it there is actual structural integrity and safety problems with a particular tree, will SDOT staff recommend removing a tree. When and if a tree is slated for removal, it will get a YELLOW removal card taped to it. Let’s hope for no yellow cards taped to this beautiful oak corridor next year!