what about the temperature of the blacktop on a 100 degree day ....

hot roots too ...

salt dumpage in my zone ...

and.. in my zone.. a couple sunny 60 degrees day in the dead of winter.. and i bet the blacktop heats the roots to 80 degrees or so ... roots coming out of dormancy while the top of the tree is frozen solid ... is .... IMHO ... a sure recipe for death ... [the kids can run around on the black driveway without shoes on a 30 degree january day ... in z5 .... because the driveway gets so warm ....]

i am sure theories are a dime a dozen

ken

It's too bad that more communities don't have good tree ordinances. Or perhaps I should say that most cities don't follow up on compliance. I lived in one city which really put some 'teeth' into their tree and landscaping ordinances (as in 'do overs' and fines) and the results were very successful.

Ooh boy, do I have some stories about improper planting techniques!

I don't think I noticed until recently how AWFUL most trees in urban areas look. I don't mean lawn trees or those in parks, those usually look good, but the street trees and parking lot trees generally look bad. The worst ones are those that can't have been planted that long ago - often you see either only one lower scaffold leafed out and the rest bare and dead, or, perhaps just a few scattered leaves near the trunk and that's it.

I read somewhere that in Baltimore, 6% of the city's trees die annually.

"I read somewhere that in Baltimore, 6% of the city's trees die annually."

Baltimore is a dump of a city full of endless rows of soulless rowhouses without any living trees, grass, or anything else green in sight. Just crumbling buildings and pot-hole filled streets, along with crime, gang "tags" on the buildings, etc. I would believe the 6% death rate easily.

As for why this happens, it's because ignorance is commonplace these days and the people who sell the trees have no interest in long-lived trees. They make more money selling trees over and over to the same mall every few years than they would make selling good trees (with proper care) once. Same idea with the caretakers of the trees (if there are any) and so on. The throw-away culture applies to trees as well these days: you make more money selling crud 3 times to the same sucker than selling him quality once. That, and taking care of trees requires a bit of work and knowledge, both of which are out of fashion these days.

Successful bidders on some of these commercial projects are either low-bidders or minority contractors. That's definitely not a guarantee of knowledge or quality. Baltimore's former mayor had Bradford Pear declared the Official City Tree and planted one in memory of his girlfriend. B'more is notorious for purposely planting "Ghetto Palm" (Ailanthus) and promoting it. There used to be a good ole boys network of officials in the city's Forrestry Division with no knowledge or training whatsoever about trees.
I stopped in at Lowes/Sam's Club in Timonium in February. Koelreuteria was planted in the islands. I couldn't believe the hack job they had gotten. I asked the manager at Lowes and he told me that the boss ordered them hacked back to reduce liability. I told him that it looked like a chimpanzee with a chainsaw cut them back, the discussion ended abruptly.
5-6" CAL Zelkovas in Greenspring Station lot have considerable dieback on them. When snow is cleared in winter it is dumped on the islands. Seems like the salt concentration would be harmful.
If that's not bad enough, the trend is leaning toward no trees at all, ie the trendy Hunt Valley Mall in Balto County. Even without trees it can be hard to find a place to park there. June/July/August/September its like parking your car in a frying pan.

Just out of curiosity (a morbid curiosity, in this case), I looked up to see if Baltimore is a Tree City USA city. It is. :-O

Owings Mills Mall has some awful looking trees. I'd say 75% of the trees on that property are dying.

Columbia Mall, OTOH, looks decent for the most part near the building itself, although some of the lot trees are touchy.

Even here in our much softer climate there are a lot of unhappy trees in parking lots and on streets - although we may also have a much higher success rate than in the harsh conditions that prevail through most of the rest of the country, where the climate is always hotter or colder than here - and often both.

Our main limitations are probably the marked falling off of precipitation in July - right in the middle of the growing season - and the compacted glacial till subsoils that are frequently what is left for plantings to grow in after development.

Otherwise we have the same regulations and behavior patterns as elsewhere, with municipalities promoting trees and requiring landscaping of new developments - and property owners not picking up on the merits of this and maintaining momentum. Shrubs become subject to "maintenance shearing" regardless of style of planting or type of shrub and trees are topped or removed.

The landscaping of a supermarket near here that promotes its outdoor plant department with a large banner on the front of the building has a faulty irrigation system, unmulched bed areas and glaring signs of a need for fertilizer. But the maintenance contractor is right on top of maintenance shearing.

When was I was hired as a foreman on a new commercial pruning crew the first subordinate I was given became perplexed when I tried to show him how to do a nice job with the arborvitaes at a condo, exclaiming "I'm used to attacking the landscape!"

I get very infuriated at places like Lowe's and HD that don't care for their stock. I was in Lowe's last month and every plant in the "Greenhouse" area (not under an open roof where rain would get in) was dried up and dead, as if they never once watered a thing there.

Also - as far as the overplanted stuff, just once I want to hear a garden center employee say:

"You don't want a Crimson King maple. Don't you want something different and unique to plant?"

I agree I can't understand why malls etc pay for trees, and then ignore them. Many moons ago, when young, my hubby did landscaping for GE and Samsonite, and his estimate included care (to get them going well) and if they died, replacement, so he took a lot of care getting them going. But then, maybe thats good ol American pride in a job, which seems to be sorely lacking these days. In all fields. I have to say that at least, there is an attempt to have trees and plantings, which is a step in the right direction. We all talk about "going green" and all the possibilities. I've talked til I am blue in the face about one plan. That if there was a "law" that every acre of land MUST have "X" number of live trees on it, one way or another, groupings, fence lines whatever, maybe we can make a difference. I think it would make a HUGE impact. The forest service already gives away free trees. So no one can say they "can't afford one." But as a landowner, you are responsible for its care. You can "own" the plot of earth, but apparently care of it needs to be legislated...
Oh yeah... I forgot... Legislating the pollution of a plot of earth didn't work, why would just caring for a tree??? Sigh.
Maybe the trees WOULD be cared for, if they hid where the dumping was going on! :0
I don't know why these companies haven't thought of going underground? Wouldn't that be cheaper for climate control? When you are in a mall, you don't know whats outside. Then they could build a gorgeous park on top... Draw people who then might decide to go in and buy something. And now I am shutting up before I write an epistle. Poor trees. Wish I could water them all....
A forest lover...

I'm kind of surprised at how many of those trees make it. Around here, the soil is red clay, so the parking lot trees are growing on soil that was heavy to start with, compacted by construction equipment, then paved over. I suppose pavement makes one heck of a mulch as far as conserving moisture goes, but it doesn't seem much rain could make it down there.

The local Home Depot has a lot of zelkovas in their lot, and they seem to be doing quite well. No big dead branches, the leaves look good all summer, and put on a good color display in the fall. They could have a better scaffold branch arrangement, but every zelkova I've seen looks like it should split in the next storm, with all the primary branches smushed together by the trunk.

There's a poor oak at a nearby mall parking lot....it's been severely topped, I don;t know how long it can hang on. Yeesh.

Alex

Our brand new Lowes has the usual large parking lot with a number of small green islands.

The islands are mostly planted with live oaks which are so far healthy. My gripe is that each island is about 30 feet by seven feet and the landscaper planted TWO live oaks in each island.

I suspect that thirty years down the road the trees will go into decline. I can't see how that little green space can support two large trees.

Never pay a landscaper by the plant.

1. Wrong tree type for that environment
2. Not properly watering the trees (more like NEVER) during establishment period
3. Mulch volcanos and/or improper planting techniques

Around here, #1 and #2 apply, but not #3 - no mulch volcanos, no mulch at all (other than occasional emptyings from peoples' dogs). Just hard trampled mud in a 50cm x 50cm square hole in the tarmac, edged with a 2cm raised concrete sill. And NOTHING to protect the tree from being hit by vehicles. So they don't usually have very much bark left at bumper height.

Actually, most parking lots here don't have any trees put in at all.

Resin

Gosh! I guess I've been taking the beautiful trees in Michigan cities for granted! I work in Lansing and must say even our parking lot trees look pretty darn happy and healthy. I see a wide variety of trees planted around here and there are alot of flowering types right now that are gorgeous!