Evolutions Within the Dunbar/Spring Public Commons

By Brad Lancaster

A bare beginning

When I moved to the Dunbar/Spring neighborhood in 1994 much of it was not a pleasant place to walk.

Most of the public right-of-way (the area between the street curb and property lines/fences) was just hot, bare dirt devoid of shade trees and other life. There were few sidewalks, but thankfully there was plenty of room for earthen footpaths. Yet many people parked atop the footpaths rather than parking on the street. I’m afraid my brother and I were guilty of this too (fig. 1A). This was partly due to a fear that the cars would get broken into if parked on the street. This fear was due in part to there not being many neighbors’ eyes on the street. Which was due in part to having impassible footpaths, and you did not want to hang out or look out into the bleak lifeless street environment. Another problem was the traffic in the streets…

The neighborhood at that time was often rife with speeding cut-through traffic (especially on the east-west streets), which would often collide with slower moving pets or cars parked on the street. Thus I did not consider the hot streets to be a viable alternative to walking in the right of way.


But there was much to love about the community, and a number of neighbors saw great potential for simple transformations of the negatives to positives, with the past and present sometimes informing the future. For example, before she passed away, Dunbar school alumni and activist Willie Fears told me that many decades ago when she was a child, trees lined Main Avenue and its footpath to downtown, enabling kids to walk there barefoot in summer from our neighborhood and back.

Those trees were all gone when I moved here, but an oasis could be (and still can be) found on Perry Avenue between University Blvd and 2nd Street where South American mesquite trees planted by neighbors in the 1980s canopied over most of the street. Steve Leal obtained well over a hundred of these trees, which were planted by volunteers around the neighborhood. But many of these trees were eventually lost as they blew over or were leaning so much they had to be removed. On the northwest corner of Perry and University Blvd a different tree, a huge native desert ironwood tree grew (and still grows)—planted many years ago by Elizabeth Upham who bought it as a seedling in a one-gallon pot from Target.

These and other tree stories and plantings inspired then newcomers such as myself, along with longer-term residents to begin in 1996 what has become an annual neighborhood tree-planting project, which brings neighbors together to plant native, food-bearing trees along our streets, walkways, and property lines. As we planted, we found cars moved to the street (figs. 2A and B). Where we did this the neighborhood immediately felt enhanced and more cared for. Native songbirds, butterflies, and pollinators returned to the growing habitat. More people started walking and bicycling in the neighborhood. Crime dropped.

Since 1996 our neighborhood’s annual tree planting project has resulted in neighbors planting over 1,400 trees! Still more were planted before 1996, or since by individual efforts outside of the neighborhood programs.

And those trees are doing particularly well where individual and/or neighborhood efforts are also passively harvesting rainwater and street runoff (while reducing downstream flooding). Over a million gallons of rain per year falls on a one-mile stretch of a typical Dunbar/Spring street. If that rainwater is directed to street-side basins as opposed to storm drains, there is enough street runoff along our streets to freely irrigate over 400 low-water-use native trees per mile, or one tree every twenty five feet, on both sides of the street.

Beginning in 2004 my brother and I created demonstration pilot sites where we made illegal cuts or core holes in the street curb to enable the street runoff get to the street-side tree basins. Vegetation flourished. We dialogued with the city, and by 2007 the practice of cutting street curbs to harvest street runoff had been legalized, and was later even incentivized. Now legal curb cuts spread as pioneering neighbors such as the Jacobs and Turtle and Ian installed them on their blocks.

Interestingly, our neighborhood’s lack of sidewalks proved to be an asset in pioneering this street runoff harvesting as it enabled the neighborhood more leeway to make larger basins for stormwater and trees along the street than would’ve been possible if sidewalk placement had left a street-side planting area too narrow for effective stormwater harvesting. Additionally, we did not have the expense of cutting through, and then repouring concrete sidewalks. We were also able to pioneer more naturalistic, slightly meandering, tree canopied, earthen footpaths.

In 2009 our neighborhood was awarded a $500,000 Neighborhood Reinvestment Grant for tree planting, rainwater and street runoff harvesting, traffic-calming, and public art—all in the public rights-of-ways—our public Commons. Thanks to that grant, individual efforts, previous small grants, and donations by the year 2012 our neighborhood’s green infrastructure included:
• 10 water-harvesting traffic circles,
• 33 water-harvesting/traffic calming chicanes
• And over 85 street-side basins fed by 50 curb cuts and 35 cores
All of this harvests over 700,000 gallons (2-acre feet) per year of stormwater, which used to flood our streets.

Thanks to these growing and culminating efforts, there is now far more life in the neighborhood than there was in the early 1990s (fig. 1B).

Figure 1A. Cars blocking walkway 1998. There was often high-speed cut-through traffic in the streets at this time.

Figure 1B. Walkway in 2016. Thanks to tree planting, public art, and water-harvesting traffic calming high-speed cut-through traffic in the streets has been dramatically reduced.

Figure 2A. Neighborhood tree planting in 2006, desert ironwood tree just planted

Figure 2B. Neighborhood tree planting in 2006

An old challenge reappears in a new form

However, ironically in some areas of the neighborhood’s public right-of-way there is now so much life, that it is again becoming unpleasant or impossible to walk along the footpaths due to vegetation blocking the route. Simple pruning can remedy this, with the goal of maintaining a minimum standard of a continuous 5-foot wide by 7-foot tall clear walkway area enabling two people to comfortably walk side by side or pass one another (our neighborhood has mostly 20-foot-wide public rights-of-ways).

City standards for sidewalk and walkway clearance
City of Tucson Development Standard 3-01.4.0 (p. 278) states that sidewalks/walkways must have a minimum width of 5 feet and a minimum unobstructed vertical clearance of 84 inches (7 feet) (fig. 3).

Figure 3. Sidewalk/walkway minimum height clearance diagram from page 221 of City of Tucson Development Standards

Best times to prune

According to certified-arborist Aleck MacKinnon we can prune our native trees anytime here in the Sonoran Desert—especially if we need to remove a barrier such as a branch forcing people to duck while walking along a pathway.

But he says the least beneficial time is fall, October/November since that's when fungal spores are flying with the possibility of infecting open wounds, and more over the trees are not as actively growing to seal off and heal the wounds until the following spring.

Aleck says the best time for maintenance pruning of pathways, etc. is late spring, April /May after the flush of spring growth, and to prep for monsoon growth as the best bang for the buck. Since if you prune too early in the growing season you often end up with two sprouts where you tried to get rid of one. 

Another good time to prune is post-monsoon rains as needed August/September.

Additionally, Aleck notes, late winter January/February when leaves are gone, is the best time for structural pruning, young tree and fruit tree pruning, when you can see the branches and help develop good structure before the growing season begins.

How to prune, while enhancing community

See here for a video on how to prune. See here for more.

Though some people don’t know how to prune, they are not physically able to prune, or they are unmotivated.

To try to remedy these living barriers, the neighborhood has organized free pruning workshops taught by certified arborists (such as Aleck MacKinnon, fig. 4), followed by the workshop participants and instructors all helping to prune sections of the neighborhood right-of-way and its footpaths. The results have been wonderful, and the neighborhood has become more walkable (figs. 5 and 6). Though there are still a number of areas with barriers still in place.

Figure 4. First free pruning workshop with Aleck in 2013.

Figure 5A. Path blocked pre-pruning 2013

Figure 5B. Path cleared post-pruning 2013

Figure 6A. Path with obstacles pre-pruning 2016

Figure 6B. Path cleared post-pruning 2016

Turning “waste” prunings into an on-site fertility resource

As an additional incentive we have made a chipping service available to chip up the green prunings into mulch (figs 7A, B, C). This way none of the biomass and fertility leaves the neighborhood. This has been a reaction in part to the twice-per-year Brush and Bulky programv, which just takes everything (fertile prunings included) to the dump. We wanted to play with transforming the Brush and Bulky waste streams into Chipped and Mulchy resource cycles.

There is a free pruning workshop in Dunbar/Spring Saturday October 1, 2016. See here for more info.

And a chipping service to turn the prunings into mulch Sunday, October 2, 2016. See here for info on how to register for the chipping service.

All of this is to also help get ready for our neighborhood tour Sunday, October 16

We, along with University of Arizona researcher Mitch Pavao Zuckerman PhD (fig. 8), have found the mulch helps:

• Dramatically increase the rate of stormwater infiltration into the soil
• Reduce soil moisture evaporative loss
• Reduce weed growth
• Increase soil life
• Naturally filter or bioremediate toxins from street runoff.
(Basins mulched with organic matter were found to bioremediate over 10 times as many pollutants as an unmulched or rock-mulched soil in street-side basins)
• Enhance the growth rate and health of associated perennial vegetation

In the early days, working with local non-profit Watershed Management, we got a grant to pay for a local landscape company to chip up the prunings. Though as of late with grant money spent, neighbor/landscaper Omar Ore-Giron has been renting and operating a chipper after the workshop and charged a nominal fee ($30 donation) to cover the cost of the equipment rental and some of his time. It is then up to those who requested the chipping to promptly distribute their resulting mulch within basins or around vegetation.

And of course one can hand-chip prunings into mulch with hand pruners or loppers (fig. 9). It is best to chip prunings into 6-inch or shorter pieces so the resulting mulch will look better, easily compact down, and beneficially decompose by maximizing soil-mulch contact. Prunings that are not cut up appear and act as brush piles.

Figure 7A. Neighborhood volunteer pruners, and prunings beside curb under trees awaiting the chipper.

Figure 7B. Omar chipping up green prunings

Figure 7C. Mulch spread under trees

Figure 8. Student researchers testing soil in 2009 as part of research by Mitch Pavao Zuckerman PhD on the neighborhood’s water-harvesting green infrastructure

Figure 9. Hand-chipping of prunings into mulch

Different mulches for different places

Note that while the mulch from the chipper is great for water-harvesting basins, it is not appropriate for public footpaths because it is too coarse and can make walking more difficult for those with less sure footing, those pushing baby carriages or those in wheel chairs. My brother and I made the mistake of mulching the footpaths of the public right-of-way adjoining our properties with woody mulch that was too coarse (3-inch and smaller particle size). It worked great for the soil and vegetation, but not accessibility. We mistakenly thought people walking on the coarse mulch would quickly break it up into finer pieces, but the coarse wood chips proved more resilient than we anticipated. So, we will replace the coarse mulch on the path with finer mulch (1/2-inch and smaller particle size) in time for our neighborhood’s home tour.

Good and bad path materials

The following materials on public paths were found to be barriers to public access:

• Loose rock or gravel
• Decomposed granite larger than 3/8-inch in particle size
• Course organic material (woodchip) mulch larger than 1-inch in size
• Broken concrete/sidewalks

Thus we ask that these materials be removed where needed to maintain a continuous 5-foot wide footpath in the public right-of-way.

And slope or grade all pathways so the path sheds water, avoiding puddles on the path. Path runoff can be beneficially directed to lower, adjoining planting basins.

The following path materials maintain public access:

• Compacted native soil.,Free and already on site!
• Screened organic material (woodchip) mulch no larger than 1/2-inch in particle size.

(Do not apply thicker than a 1-inch depth. Thicker depths bog down wheels of carriages and wheelchairs). One supplier is Tank’s Green Stuff.

• Compacted or stabilized ¼ to 3/8-inch minus decomposed granite (DG).
There are natural polymers that can be mixed in with the decomposed granite to better hold it together and stabilize it. DG is available from local landscape material suppliers. (Gary Wittwer, Landscape Architect, City of Tucson Transportation Department told me this can be installed to be American Disabilities Act (ADA)-accessible
• Pavers/brick, which can be installed within the grade/slope tolerances of the ADA
• Maintained concrete sidewalks (ADA-accessible)

A history of neighborhood residents-led efforts

For decades this neighborhood has been striving to enhance our individual health, safety, and make the community more walkable and bikeable with tree plantings, community prunings, traffic calming, public art, enhanced bike/pedestrian crossings of major streets, and festivals such as Porch Fest and the Mesquite Millings. Most recently our neighborhood worked with the Living Streets Alliance to do a Walkability Study for the neighborhood.

Other community planning endevours included:

• the Stone Avenue Corridor: Measures for a Liveable Corridor
• the Building Bridges Project, and
• The Dunbar/Spring Community Development Plan in 1995
• The purchase of the Dunbar School in 1995 to create an African American Cultural Center and Museum.
• (Note that in the 1970s the neighborhood fought a proposal to turn the Dunbar School into a jail for DUI offenders, after the school closed in 1971).
• The creation of the John Spring historic district in 1989.

Which brings us to the present

Looking back 10 and 20 years, it is amazing how much more greenery, birdlife, beauty, food, and shade we now have in the public realm of this neighborhood. Coupled with this is a dramatic increase in people walking, running, and cycling through the Dunbar/Spring community, which very often results in face to face interactions where people slow down and stop to talk. This contributed to the city’s decision to reclassify University Blvd, and parts of 9th Ave and 10th Ave from higher-speed/higher auto-traffic streets to bicycle boulevards.

All this has inspired many other neighborhoods and communities (in Tucson and beyond). I’m grateful for this transformation, and I’m grateful for all the neighbors that helped make it happen. So much of these efforts were generated from the question, “What kind of community do we want to live in, and how can we help make that happen?”

This neighborhood’s evolution is not perfect, nor is it done. Evolution and change are constants. But we can consciously strive to direct the evolution we desire in a caring way that enhances life and health for ourselves, our neighbors, and the larger community. Many of us have been trying to do so for years, and we can aim to get better still.

And the very near future

Saturday, October 29th will be our neighborhood’s 21st-annual tree planting.
Check our neighborhood website for details, and come plant with us!

We plan to have two free pruning workshops per year in the neighborhood, aligned with certified arborists’ recommendations for best pruning times, and when the need for pruning is typically the greatest.
One in late spring (April/May)
And one in late summer (August/September)

Both will be followed the next day by a chipping service to beneficially turn the prunings into mulch.
Please join us! As always the pruning workshop is open to anyone and everyone. Invite friends and family (whatever neighborhood they live in).

Check back to this website’s calendar of events closer to the pruning times for more info.

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