Why are palms such popular street plants?

...Although the greenery is much appreciated and long overdue, the City chose to plant, yet again, non indigenous palm trees. Why do smaller city’s continue to plant this tree! Not only does it reinforce the mythical history of Los Angeles but it provides such little tree and sidewalk shading and absorbs very little CO2. I was very, very disappointed. -email discussion

I've wondered this myself and I was able to puzzle out the following when the City put in palm trees along Rosecrans a couple years ago. I was pleased to see the upgrade (in fact I volunteered with the planting), but I didn't feel they were the best choice.

Cities like palms because:

1. The maintenance is low. Tree pruning is a huge city cost of ownership for standard mature trees - particularly if they are fast growing non-natives like ficus. Our native Washingtonia filifera fan palm (native to S. California desert areas) accumulates a fringe of dead fronds that is perceived as a haven for rats and a fire hazard even though it provides bird nesting habitat as well, so other palms that shed their fronds like the Canary Island palm are chosen over Washingtonia or Mexican fan palms. So street palms tend to be exotic, but other than the frond cleanup (a safe, ground level activity), they don't require pruning.

2. The root balls fit typical too-small sidewalk cutouts and if planted with poor soil their growth is slowed so that they are even less maintenance. The palms we put along Rosecrans were planted in sand amended with a very small amount of organic matter, yet they are doing fine.

3. Minimal leaf litter means minimal required upkeep.

4. The vertical growth habit doesn't obscure merchant signs.

5. The roots won't heave the sidewalk.

6. Difficult to climb with no horizontal limbs limits city liability

7. Difficult to vandalize, even when young. A sycamore across the street from me, two years in the ground, was recently vandalized. It will probably have to be replaced. What a waste.

8. Fits S. California iconography.


What are the cons of palm trees?

1. Limited habitat or food source for birds or insects. Probably less true of fan palms.

2. Limited shade doesn't dramatically affect urban heat islands compared to a tree with a more spreading growth habit.

3. Little CO2 recycling (I'll take this as an article of faith, based perhaps on the leaf area difference between a palm and a standard tree.)

The challenge is to find a tree that offers equivalent benefit but is a better fit for S. California. From the standpoint of City planners it's hard to beat the appeal of the palm for isolated urban plantings.

The LA Times has an article on the palms of LA (Palms in Twilight By Emily Green, Times Staff Writer July 8, 2004).

Like us, palm trees are imports, and seem to come from everywhere but here. Spanish Franciscan and Jesuit missionaries brought the first date palms to California in 1769. A fruit industry built on seedlings from Algeria, Egypt and Iraq followed in the Coachella Valley in the early 1900s.

The story of the earliest street palms is a fronded version of the Johnny Appleseed legend. Characters who passed through the Californian and Sonoran deserts began planting fan palms along orange groves and farm drives. At the beaches, Mexican palms fared better in the damp of coastal night fogs.
...
Soon there were palms and palms. Between 1910 and 1930, the hoi polloi of the Adams district, Santa Monica, Hancock Park and Beverly Hills increasingly upgraded from Mexican fan palms to make the mighty, diamond-trunked, thickly crowned Canary Island date palm the symbol of affluence. Later, modern postwar suburban subdivisions took to lacier, bright green king and queen palms.

Throughout the euphoria, nobody predicted the palmy irrepressibility of the city's 21st century skyline. In the wild, California and Mexican fan palms grow from 40 to 60 feet tall, says Don Hodel, horticulture advisor for the University of California system and author of "Exceptional Trees of Los Angeles" (California Arboretum Foundation). By contrast, their city cousins have spired to between 100 and 150 feet tall.

The varying height was often accidental. Early city planners used seedlings of Mexican and California fan palms interchangeably. They couldn't tell the difference. A century later, this has become clear. A planting scheme intended to bring order and symmetry to the heart of Los Angeles has achieved a bobbing lyricism instead — allées in which rows of runaway tall and skinny thin-stemmed Mexican palms suddenly give way to stockier, shorter California ones.
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Early plantings of Los Angeles street trees were done with nursery seedlings. However, modern developers soon began to require more mature specimens. The single quality that kept the palm vogue alive decade after decade was the ease with which mature palms could be transplanted, giving newly minted developments instant landscaping. When date palms were chosen for Santa Anita Park and the Vegas strip, transplants were moved by the truckload out of old Coachella orchards.

Tadd Russikoff, vice president of the 55-year-old Calabasas-based tree movers Valley Crest, reckons his company moves thousands of palms a year. Distances vary — from the back to the front of a house or, once, a vast procession of Canary Island date palms sent north to San Francisco for the Embarcadero project.

Here's some alternative street tree ideas:

1. Orange or other citrus. Certainly historical in some areas. Leaf litter (evergreen).

2. Redbud. Native. Not too tall in stature. Leaf litter in fall (deciduous). El Segundo has planted some of these on their main street and they are beautiful.

3. Sycamore. Native. Tolerates a wide variety of conditions that other natives might balk at, such as being planted in a lawn. Leaf litter in fall (deciduous). Hawthorne has a number of these. I think they are perceived as a liability because of the ultimate height that they can get to. A fungal infection, anthracnose, is generally not a problem for these trees, but can cause premature loss of leaves in bad years.

4. Santa Cruz Island Ironwood