Do urban trees die sooner

[ATH]

............ut I see huge old ancient trees in Europe in urban environments. It is true that I don't see many but again is this a sign of past practices or a sign of the potential of trees in the urban environment..........

Besides pollutants, don't forget the treatment of soils. Past practices were ABSOLUTELY less stressful to trees than today's. Scraper pans didn't exist 100 years ago, let alone people dumb enough to buy top soil in a plastic bag at WalMart (not that I would ever do that ), so top soil was left in tact. Around here (heavily agricultural area), in preparation for development they scrape the "top soil", but the real top soil has probably been gone for decades. Then they dig a basement with equipment that is so heavy squeezes all of the pore space out of the soil. That dirt from the hole is spread across the surface because it doesn't pay to bring it off site (there is nobody dumb enough to buy that clay). Now lets plant turf and put a tree in the middle of it. What about that is NOT stressful for a tree?

(Did I mention the time we found burried shingles? The homeowner wondered why he had a wet spot in the yard...)

 

[Corymbia]

Ok so perhaps there are still some really bad practices out there, particularly at the planting stage (although we should be starting to see some changes). Once the tree is growing where does it stannd?

 

[ATH]

Ok so perhaps there are still some really bad practices out there, particularly at the planting stage (although we should be starting to see some changes). Once the tree is growing where does it stannd?

In crappy soil

Soil restoration is a LONG process - probably at least a full generation of trees (not people), maybe 2 tree generations.

If we can manage the soil conditions as close to 'natural' as possible and keep people from abusing the above ground portion, I think the other stresses are quite managable in many circumstances and trees will have the opportunity to thrive...that that is asking for a lot!

 

[Corymbia]

Soil is critical

In crappy soil

Soil restoration is a LONG process - probably at least a full generation of trees (not people), maybe 2 tree generations.

If we can manage the soil conditions as close to 'natural' as possible and keep people from abusing the above ground portion, I think the other stresses are quite manageable in many circumstances and trees will have the opportunity to thrive...that that is asking for a lot!

I am not so sure that soil restoration has to be a long process.

I remember attending a lecture in Hawaii that showed a great tropical resort built on what had been lava flow less than 20 years before. Also had the chance to work in a number of arid regions and man made islands that are turned into tropical delights just by adding organic matter and water and the transformation is rapid.

Cold dry regions now that is another deal but I guess that goes back to plant selection.

I do agree that if we can look after the roots the rest is comparatively easy.

 

[Corymbia]

There is huge difference between urban and rural trees because in rural there is an open air atmosphere where as in urban there is a congested environment.

I'm not sure what "open air" and "congested" mean.

Forrest trees have greater competition and CO2 helps increase growth. We have generally reduced sulfur and lead in our atmospheric pollution and we often have these underground irrigation system called leaking pipes.

 

[Boa07]

I am not certain what Ryanmonster was referring to but I suspect he might have been alluding to the very altered conditions that most (almost all) urban trees find with respects to the heat stress they experience.

The characteristics of the 'enclosed' urban tree are very hard to find mimicked in nature...high albedo pavements, convected heat flows from adjacent built infrastructure, irradiated heat from those same structures, and in many cities dramatically reduced solar access and natural air flows.

All these elements and we have not even started to consider the landscape below ground!

Forrest trees have greater competition

Trees have evolved to grow in communities (inclusive of other tree species as well as shrubs, forbs and grasses) within an evolving ecosystem the relationships are just as often mutually beneficial and symbiotic as that community moves towards climax.

Very frustratingly the species palette I often see installed in our cities is something that will never escape from astronomical demands for resource inputs to prevent decline and entropy never attaining sustainable growth and stability.

As for finding professionals who understands what constitutes viable growing media for trees when and what soil amendments are appropriate..and just how much volume of suitable soil a mature tree requires.....well it seems the work of James Urban and Phillip Craul remain largely undiscovered despite having been forged back in the 1990's.

 

[Urban Forester]

"Ryanmoster" is a spammer. They ACT like they are involved in the conversation, but each post contains links they hope your stupid enough to click on. Those links could have malware, spyware or ad tracking cookies or worse a virus. There are 2 or 3 of them working this site. If he's from Austria, I'm the Pope, most likely he's based in Nigeria. Note the syntax of the post, its bogus...

 

[jefflovstrom]

"Ryanmoster" is a spammer. They ACT like they are involved in the conversation, but each post contains links they hope your stupid enough to click on. Those links could have malware, spyware or ad tracking cookies or worse a virus. There are 2 or 3 of them working this site. If he's from Austria, I'm the Pope, most likely he's based in Nigeria. Note the syntax of the post, its bogus...

I was told to ignore them or report them. This site is getting hit alot by them spammers.
Jeff

 

[Urban Forester]

I did report it. I'm sure most boards are dealing with this, a shame. Those clowns are always looking for ways to reach more people.

 

[Corymbia]

Persuasive but not convincing.

I am not certain what Ryanmonster was referring to but I suspect he might have been alluding to the very altered conditions that most (almost all) urban trees find with respects to the heat stress they experience.

The characteristics of the 'enclosed' urban tree are very hard to find mimicked in nature...high albedo pavements, convected heat flows from adjacent built infrastructure, irradiated heat from those same structures, and in many cities dramatically reduced solar access and natural air flows.

All these elements and we have not even started to consider the landscape below ground!

Trees have evolved to grow in communities (inclusive of other tree species as well as shrubs, forbs and grasses) within an evolving ecosystem the relationships are just as often mutually beneficial and symbiotic as that community moves towards climax.

That is like saying that a creature, confined in small spaces, regularly exposed to stress, constantly exposed to artificial lighting, fed on highly processed rather than natural foods and stuffed full of chemicals is life shortening. Of course we know that the human race is actually living longer as a result ...!?

Likewise many urban trees (as opposed to city trees) grow faster simply because they have exposure to more sunlight.

As for Urban and Craul's work ... I am not convinced that it is all new or necessarily critical. I agree that reducing the available soil volume reduces growth rates but then so do rocky crags and they are the source of the worlds oldest bonsai.

Of course it is not uncommon for scientific work to go largely ignored particularly in an industry where the majority of practitioners are not scientists. I am sure that I have a number of texts that are more than a hundred years old that have great stuff that is ignored ... try A British Winter Garden by William Barron for a starter ... Unfortunately the bulk of science goes unnoticed by most

I really think the answer to the thread question is "yes and no" Wish it was more black and white but I suspect that it isn't.

 

[Boa07]

Mark, your analogy of humans life span and tree life span is (as I suspect you know) weak at best, longevity in humans has a great deal more to do with improvements in sanitation than anything else.

Urban's and Craul's work is NOT all new and that is sort of my my point....much has been improved since they published their repsective texts, all to no avail when I view the ridiculous landscapes installed in our urban centres.

Likewise many urban trees (as opposed to city trees) grow faster simply because they have exposure to more sunlight.

Hmmm something of a gross simplification that is I know intended to make a point but simply undermines your arguement for me, sorry.

All plants (trees included) require a great deal more than just increased sunlight, you know that Mark. The urban environment consistently provides evidence of planners and architects failure to either understand or take into consideration the requirements that trees have for long term sustainable growth.....huge pot plants with the huge resources they demand is not what I consider to be sustainable nor desirable.

I would whole heartedly agree it is shades of grey everything is.

Bad news for the professionals I have met in vegetation management who are selling an image that is only black and white without those shades...and consequently a reality they ignore and deny.

 

[Corymbia]

I would whole heartedly agree it is shades of grey everything is.

Bad news for the professionals I have met in vegetation management who are selling an image that is only black and white without those shades...and consequently a reality they ignore and deny.

Sean we agree completely

Again I accept that using people is not a perfect example but it is interesting to note that exactly the same argument is used by animal liberationists against caged hens. The truth is we really don't know much.

I am sometimes concerned that we oversimplify things. Containers have solid sides and a bottom. I agree they are not always physical but I do constantly see nature breaking the rules and escaping the container even the physical ones. I also see nature adapting itself to the container and trees are a perfect example. Growth limited by container size is not necessarily unhealthy growth .. in fact with an appropriate species it is often healthy growth.

If a nursery full of pot bound pots is any indicator the greatest limit may in fact be water ... the stuff we catch of hard surfaces and in sub surface drains and divert into our rivers less the soil be replenished of its water.
I do see a time when that does not happen.