Oh what a wonderful Tree.

Dreadflame recently expanded upon what we know of how the Tree of Life works.

A few notes from the Dark Lord…
A Bane Circle is a physical object, like a monolith, that is easy to notice… and to target.

Top-level nation trees can provide energy to other trees within the nation (the capitol city can aid its provinces). That energy is added to the pool that the lower-level tree gets every second. Thus, a nation can help a fledgling province survive long enough to build a lasting bailey and defensive structure.
It can also aid the province during a siege. This would tend to indicate that you want to have assassins not only in your target city, but in the capitol city as well. Add all this to roleplaying intrigue, alliances, secret traitors, distractions, occupations, outposts, and “police actions,” and you have a complex siege equation. The most successful sieges will have been won before the army ever arrives- by virtue of planning, alliances, and treachery.

Wow. That puts a whole new emphasis on declaring feality. It also means that assasins are going important. Kill that guildleader so he can’t switch Tree of Life management, then start your siege as their Tree of Life is sending part of its power to other cities.