Context. I plan to grow a tall tree on the front yard to achieve a natural look. The surrounding area is limited by walls and powerlines in the ground. So this tall tree better not have its roots expand horizontally too aggressively as it will damage the walls and powerlines. Horizontal expansion of roots must be roughly limited within 2 by 2 meters.
Question. Which trees can grow up to 5 meters tall (at least) such that their roots expand vertically mainly, and not much horizontally?
Typically, deciduous North American and European trees grow roots 50% beyond their canopy, so a 5 meter tree with a 5 meter wide canopy will require a root run of 7.5 meters, regardless of whether it has deeper roots (like an oak) or not. Conifers are a littler more compact, but any tall conifers will still require much, much more room than a 2 meter wide "flower pot". Even if you were to plant a tall tree in the area you want, the lack of root run will dwarf the tree, as if it were a bonsai, which will stress it and most likely lead to an early death.
It seems to me that you either have to vastly downscale your tree or think 'large, tall, shrub'. For a tree, you could, perhaps, try a fastigiate (columnar) serviceberry (Amelanchier sp.) at 3m x 2m would work. For tall shrubs (technically, small trees but usually sold as shrubs), there are fastigiate arbor vitaes (Thuja occidentalis 'Emerald Green' at just under 3m x 1.5m. for example) or junipers like 'Skyrocket' that could work, but the tallest of those would be no more than 3 meters.
Tree roots grow where they want regardless of what a book says, although there may be preferences. Southern pines, oaks and sweet gum grow roots randomly based on trees cleared from my lot: the dirt man pushed over many with a bulldozer so the roots were visible. I have dug hundreds of smaller trees to transplant and never noticed a particular growth habit. I notice my fig tree has many surface roots. I live in an E. TX rain forest and have not noticed utilities ( buried electric, gas, water, sewer) having problems with tree roots damaging facilities. Southern pines are generally 100 feet tall here.
