[blocktuw]

I don't seen how your experience with growing trees is any different than the original author's experience. Both of you may be professional arborists, yet you fail at growing trees. Therefore your conclusion is trees are hard to grow. Maybe you both are bad at growing trees.

[corresation]

The simple fact that "professional arborist" exists as a profession might be hint enough to you that saying "trees exist in nature, therefore you can have them anywhere you'd like" might be a poor bit of logic.

[VLM]

"Maybe you both are bad at growing trees"

Trees are pretty easy to grow, and the posters might be good at growing trees. The problem is there are so many kinds of tree. More likely growing the wrong tree for the local climate and microclimate. Being able to buy a sapling from someone who profits from people having to buy saplings doesn't necessarily prove anything about either the sapling or the environment other than you can definitely make money selling saplings.

If you go into the design process with a selected species before you design its environment, and then ignore its biological requirements in the environment design, its going to fail. Ignoring the environment while planting a tree anyway, is the opposite of being truly ecological or truly green. Looking a couple levels up at the guy with the two dead trees... just grow a different species, it'll take off like a weed unless you're in a desert or worse (grow a cactus?)

The existence of professional arborists proves nothing. There's nothing wrong with trying to stretch both your own abilities and your local/micro climate abilities. An arborist is an expensive way to get someone who knows what they're doing to have your back when you get a little too ambitious. Growing two oak trees in front of my childhood home was a little overambitious once they got up to 100 feet or so, and an arborist (for quite a fee) trimmed the dead branches every couple years for my parents. If you insist and have way too much money, an arborist can probably find a way to grow a palm tree in Alaska or a conifer in Dubai. But you won't like the bill...

Analogy: I want to grow and eat some edible plants. I like bananas (whats not to love?). I plant some bananas outside in Wisconsin. They die in January when it never goes above freezing for three weeks. Therefore no edible plants can or should be grown in Wisconsin, and no one else should even try, and growing edible plants in Wisconsin is just a wasteful fad that should go away. Or maybe not, since I know personally you can eat pretty well off fresh farmers market produce... however, no bananas.

[corresation]

Ignoring the environment while planting a tree anyway, is the opposite of being truly ecological or truly green.

He is doing exactly the opposite of ignoring the environment. Again, your haughtiness is transparent and doesn't make you sound like an expert, but more an armchair expert (which is not an admirable thing).

How many trees in nature grow on spires that are 100s of times higher than their base (hint: trees that grow on mountains do not apply. Mountains are wide enough with a shallow enough grade that they carry their own ground effect. A skyscraper does not), raising hundreds of meters above ground level?

Zero. None. Nada.

This discussion has nothing to do with enclosing tropical plants in polar areas. It has to do with trees environmentally exposed 100s of feet in air. Completely exposed to an incredibly hostile environment. It is enormously impractical.