1. Planting and Sustaining a Full Row of Trees
Trees along sidewalks need care to grow large and shady. In Washington DC these trees are planted and owned by the city Urban Forestry Administration (d.Trees). Nearby neighbors are supposed to care for them subject to city rules.*
Restore Mass Ave is concerned that willow oaks, a favored District street tree, are threatened by a once-benign pest, oak lecanium scale (Parthenolecanium quercifix). We conducted a model project to fight the infection on the few willow oaks on Embassy Row. See our Oak Lecanium Scale page for more on the pest. See our Second Row of Trees page for our project.
How to boost growth of sidewalk street trees
- Remove piles of dirt and mulch from tree base; these “volcanoes” harm trees.
- Clear tree box of weeds, grass, and deep-rooted plants.
- Remove dirt around tree to expose the flare, so water flows easily to tree roots.
- Uncompact hard soil by soaking and tilling.
- Spread shredded hardwood mulch 3” deep and keep it away from tree base.
- A layer of leaf-mulch before regular mulching is a great one-time treatment.
- Plantings shall be shallow-rooted and no more than 18” high.” DCMR 24 109.11
- Water the tree with 25 gallons of water per week, spring through fall.
- The city will provide a free black tub around street trees you sign up to care for under its Canopy Keeper program .
Good tree mulching
Ricky Fuentes of Professional Gardens LLC demonstrates model mulching techniques in the 2014 video at right.
* City rules for street trees
- Gravel is prohibited around street trees. DCMR 24 109.10.
- No pruning of city or others people’s trees is at 2002 Tree Law ¶ 201 ddot.dc.gov/publication/urban-forest-preservation-act-2002.
Treatment of tree boxes and fences DCMR 24 109
- Sidewalk trees grow best in grassy strips; tree box openings should be 9’ x 4’. If the box is smaller, use the city 311 line to have the box enlarged.
- Contractors must make tree box fences 18” high. Public Realm Design Manual ¶ 3.6.4 dc.gov/DC/DDOT/On+Your+Street/ Urban+Forestry/Tree+Fence.
- Fences should be open along curb to allow for car doors. DCMR 24 109.9.
- Lowest rail of the fences should be above grade, so water flows from sidewalk to the tree.
- Same-design fences for each tree in a line enhances a street’s sense of place.
- Owners who beautify tree spaces are not liable for injuries due to such improvements, so long as the improvements comply with DC code. DCMR 24 109.4.
- An excellent guide is Casey Trees’ Tree Space Design Handbook.
- See also PRDM 2011 3.6.3 (pp. 3-19 to 3-22).
Which tree species for your street? PRDM ¶ 3.6.2
- On Mass Ave we urge the city to plant elm, lindens, ginkgo, red or swamp white oak, london plane trees. See Our Grand Avenue Species.
- The city plans species for each street but you can request a tree you prefer Public Realm Design Manual 2011 (PRDM) ¶ 3.6.1 ddot.dc.gov/page/public-realm-design-manual-0.
- Under overhead wires, the city requires small-type trees. See Partnering with the City.
- City Street Tree Services Schedule includes Street Tree removal Map.