Suboptimizing on Trees

By Dom Nozzi

June 14, 2002

“Suboptimizing” occurs when one objective is so single-mindedly and aggressively pursued that other important objectives are neglected.

I observed a stark example of this when I was a town planner for Gainesville, Florida. Gainesville strongly suboptimized trees, to the substantial detriment of walkable urbanism.

For example, few years ago, I was forced by my supervisors to insert in several confusing, silly sentences into a “traditional neighborhood development” (TND) ordinance I had written to promote compact, walkable, human-scaled neighborhood development.

The inserted language needed to describe “engineered soil.”

Not only was the definition inherently confusing and complex. I was told by a number of local landscape architects that (a) they have never heard of such soil and/or (b) that such soil would be quite expensive to install. So the TND ordinance I had drafted — which was already too onerous for a rational developer to use to build a subdivision — became even more difficult to use by developers because Gainesville’s elected officials wanted big trees.

This is yet another reason why it is rare for developers to build walkable places. In this case, this unfortunate state of affairs persists because big trees are quite often incompatible with a modest, walkable, human-scaled building-street-sidewalk design.

All of the above is not to say that street trees are expendable. No, street trees are essential for a great street, but are not sufficient. And it is important that when street trees are selected that they not be too large to undercut the essential, human-scaled needs of the pedestrian.

In another example, I had been directed to amend my “Traditional City” ordinance (also designed to promote compact, walkable, human-scaled design) to make street trees required in the Gainesville town center (landscaping was currently not required in the town center). The rules would require that the City require town center developers to jam street trees into all developments and redevelopments. This would add additional complexity, burden, and confusion to the ordinance, and add another disincentive to build or infill in the town center.

A third example was when I heard there was a very good chance that for a proposed new county courthouse parking garage, the town center would not be getting desperately needed on-street parking (one of the most crucial amenities needed for a quality pedestrian experience) along the courthouse street frontages.

Why?

Well it was not, at least, for the goofy reason that stopped the designer from installing on-street parking in front of the new courthouse itself. In that case, the reason was that there is a childish fear of truck-bombers.

No, on-street parking next to the new garage was not going to be stopped because of a fear of a terrorist boogie monster like Timothy McVeigh.

On-street parking was not going to be possible because Gainesville was requesting big trees. The city could have both on-street parking and trees, but trees such as palm trees were unacceptable…

The end result was predictable and nearly certain: Gainesville would soon amend its walkablility codes (in particular, walkability regulations for TND, Traditional City, University Heights, and College Park) for the all-important suboptimizer of big trees. Doing that would push buildings back from the street, discourage desperately needed in-town, infill, walkable development, and substantially increase the cost of infill development. Thereby creating less-walkable streets.

By suboptimizing on big trees, Gainesville misses an essential design principle: In the town center, the needs of pedestrians come first. Not the needs of live oak trees. By neglecting this principle, Gainesville shows either a lack of awareness of the important needs of a town center. Or has no real interest in creating a healthy town center.

The lush, big-tree landscaping looks wonderful from your windshield as you whiz by in your car in Atlanta and Gainesville. But where are the pedestrians? Why are they not img_0263out walking? Isn’t it enough that we provided a lot of shading live oaks?

Has there been a time over the past 30-40 years when Gainesville has not suboptimized on big trees as the number one priority? Has that done anything to stop Gainesville from taking big steps toward becoming a sprawling, car-happy place? Has that done anything to promote walking on Gainesville’s sidewalks?

Lessons from Other Parts of the World

Which cities and streets are the most popular tourist destinations in the world? Are they the cities with streets that look like a forest due to being lined with oaks? Nope. They are the cities with narrow, treeless streets. Why? If it were true that street trees were the most essential element to a street that the world loves to flock to, we’d find everyone flocking to the streets with the most incredible canopy.

But it is very rare for one of the most popular, famous, loved streets in the world are famed because of their tree canopy.

Again, while street trees are nearly always essential for a quality street, they are not sufficient and are not the top priority for designing a street that the world loves. The top priorities for creating a great street are these:

  1. Higher residential density along the street.
  2. A mix of residences, offices, and shops along the street.
  3. Modest dimensions for street widths and building setbacks.

The “3 Ds” — density, diversity, dimensions — when in place together, are usually sufficient. They are the first things we must require of a street when looking for the ingredients to create a great street. Only then do we worry about installing those important street trees.

A number of great Italian cities demonstrate this — Florence, Venice, Siena, Rome. The 3 Ds are therefore the first things we must require of a street. Only then do we think about installing trees, and maybe more ample sidewalks.

The problem all over America: We always put in way too much space on our streets, we prohibit density, and we separate homes from offices and shops. We then wonder why streetscape tactics such as street furniture, street trees and wide sidewalks don’t “fix” such a street. Unless we install the 3 Ds up front, street trees and wide sidewalks are a trivial band-aid for a terminally ill patient.

The issue is not whether we could fit shade trees within our most narrow streets. That is a given. In a city where it is all about trees, it is a given that we will find a way to retrofit trees on such streets. No, the real issue is what our land development codes require for new development. That is the battle I’m interested in here. It is very difficult for me to live in a city (Gainesville) in which so much auto-oriented slum has been built so consistently for so many decades.

This was somewhat mitigated for me as a town planner for Gainesville, as I was able to find I had a marginal amount of influence in not seeing car-happy design dominate all development in Gainesville. What drove me to persist was that I did everything I could to see that the new stuff that was built without making the same suburban mistakes — at least in zones I mentioned above (such as Traditional City and TND).

And that is the rub. Gainesville was consistently watering down and suburbanizing their codes. Staff, commissioners, and citizens see to it that any time modest, walkable, human-scaled dimensional standards are proposed that we immediately emasculate the regulations by enlarging the dimensions for our fire trucks and live oaks. In other words, the new stuff will continue to march us towards being an Atlanta instead of a Florence.

An enormous problem all over America: We always put in way too much space, we prohibit density, and we separate uses. We then wonder why street trees and wide sidewalks don’t “fix” such a street. Unless we do density/mixed use/modest dimensions up front, street trees and wide sidewalks are a trivial band-aid for a terminally ill patient.

 

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