Re-engaging the sidewalk parkway

Soon the Los Angeles City Council will consider a measure that will make sidewalk repairs the financial responsibility of homeowners, and not the city, which has been taking care of such repairs since l974.

People ask: What does it matter? Well, it matters a lot.

Past history tells us that, even with a permit process in place, in order to avoid having to repair the sidewalk homeowners will too often butcher trees or even take them out entirely, replacing them with something that might be called a tree, but is actually a glorified shrub. Shrubs cannot provide anywhere near the same benefits as trees.

Sidewalk parkways, where street trees are planted, are public rights of way. They are a space for the public good, traditionally controlled by city agencies. City leaders had the prescience to understand they needed to maintain authority over these strips of land to manage them for maximum public benefit. Trees were traditionally put in these parkways not just for beauty, but for shade and other dividends. These purposes have been forgotten by many, and now trees are too often seen just as decorations and nuisances.

Public parkway trees need protecting now more than ever.

At a time when Los Angeles'economic, environmental, and physical health is increasingly compromised, the public parkway is the interface where city actions can make a big impact. We need our trees , and we need to enable them to do what they are designed to do. That little crack in the concrete is a result of trees trying to spread their root systems to get access to water, as they do in nature. Trees are designed to take the rain and water run-off, clean it in the spongy, porous soil in their root zone, and store it for further use. Healthy trees also filter the air, and by shading, cooling, and lowering urban temperatures, they reduce air pollution and save energy.

Mismanaging the public parkway commons generates problems that are costing our government and us. To manage it properly means re-engaging the space as active "functioning urban forest watershed." It's an opportunity to stop the hemorrhage of money, and to gain the benefits that the watershed can be providing us.

The City of Santa Monica, ahead of the curve on many issues of sustainability, is doing just that. Below are three photos I took that show how the Santa Monica is removing impervious concrete curbs and gutters and replacing them with permeable paving so rain can get into the tree roots and soil, instead of becoming polluted run off.

Here's a shot after impervious concrete was removed:

And here’s what the street looks like with new permeable pavement installed so that water can flow to the root zone:

Finally, here's a short video that takes it to a whole system level. It shows Santa Monica's new "green street" with the parkway re-engineered to be fully functioning. It shows a rain event, and water soaking into the ground, where it can be stored, reused, and saved for a thousand useful purposes, instead of being rushed off to the ocean.

LA's proposal comes at a time when the city is dedicated to planting a million trees, and is working on implementing green infrastructure through green streets and a low impact development ordinance. This proposal sets the stage for setting us backward. Certainly we need safe sidewalks. We also need healthy street trees, which represent a set of ecosystem services that we've spent millions of dollars and decades building. The risk of this measure is that it could mean a short-term budget fix that could cost us far into the future.