"Is the American Holly compatible with septic tanks and leach beds?" It depends a lot on the specifics of your system. Most new septic systems are not prone to damage from smaller trees. Planting any type of tree directly over or very near a septic tank is not a good idea because of the need for access. "How deep would one have to go..." Here is a rough/generic rootball size guide for transplanting trees and shrubs. Soil type, tree species, and other factors are not taken into account, but it will give you an idea: For trunk diameter below 1/2", multiply the diameter by 20 to get approximate rootball diameter. For trunk diameter between 1/2" and 1", multiply the diameter by 18 to get approximate rootball diameter. For trunk diameter between 1" and 1-1/2", multiply the diameter by 16 to get approximate rootball diameter. For trunk diameter between 1-1/2" and 2-1/2", multiply the diameter by 14 to get approximate rootball diameter. For trunk diameter between 2-1/2" and 4", multiply the diameter by 12 to get approximate rootball diameter. Here are guidelines for rootball depth: For a rootball with a diameter of 1', depth should be approximately 8". For a rootball with a diameter of 2', depth should be approximately 1'. For a rootball with a diameter of 3', depth should be approximately 15". For a rootball with a diameter of 4', depth should be approximately 18". Here is a link that might be useful: Generic Rootball Size Guide

It has been shown that norway spruces regularly exposed to strong winds develop a different cross-section of their major roots. The roots on unstressed trees have oval/circular cross-section while those of stressed trees have a T-shaped cross-section that improves their resistance to wind-throw. Biological systems (and most complex systems, also inanimate ones) develop in different ways in response to consistent stresses. Just as a plant develops a deeper root systems in response to droughts, or grows taller to reach canopy, I don't see what is so unbelievable in imagining how a plant will direct its resources to improve its structure, when repeatedly stressed by wind. What Tom mentioned is, I believe, also responsible for the phenomenon of the Fir Waves... Now, coming to the topic of the conversation, I believe these adaptations will take time to set in, and I think staking would make sense in that light. Also, staking means everything and nothing. I can stake a tree so that its trunk will not move by one inch. Or I can stake widely enough just so it won't topple. These two ways of staking must have completely different effects on how the plant will adapt to wind.

I think you came up with the answer on your own. Not all root systems have that healthy, vibrant look to them. I've repotted other species that had the same characteristics. Plant sounds like it is a good one.

We want to build a stone seating wall around our 25 year old jacaranda tree with a diameter of 16 feet (8 ft from the center trunk in all directions). The tree needs a major haircut and the roots 8 feet from the tree all around will have to be cut. My concern is that I don't want to spend $5000 on a seating wall that encloses the tree and then lose the tree due to root damage. And, if I did lose the tree, how in the heck would they remove it after the wall is in place.? Is 8 feet a reasonable distance from the trunk? Advice welcome.