You know what? Time for some homebrew. Have a spell.
Celestial Circle Spell: Enduring Heartwood Bastion
Cost: 45m
Target: Seed and planter.
Towns and towers grow like trees, taller and wider as they age. To cast this spell, sorcerer first needs a planter sized for a tree made of White Jade, filled with soil enriched by powdered Green Jade. Such an object is a Resources 4 purchase in most large cities.
The planter must be placed in an open, geomantically auspicious point within a group of structures or city, like a courtyard, plaza or central parade ground. The ritual itself starts as moon-rise, were the sorcerer plants a tree seed in the jade-infused soil as the moon rises over the horizon.
From here the sorcerer must sing an old realm verse of strength and endurance until dawn's first light, and water the seed with 3 health levels worth of blood. This is a [Charisma + Performance] roll at Difficulty 3. If successful the tree grows a hundred years old in just a few hours, and its leaves are an impossibly rich, verdant green.
From this point, the essence-infused tree can be connected to any intact structure made of earth, wood or stone within [the Sorcerer's (Essence + Occult) x 100] yards. This connection is created by cutting branches from the tree with a magical blade or tool, and then constructing a shrine to the building's least god. By building the god a grand palace and investing it with power, their domain is proof against ruin. The shrine counts as an arcane link to the tree.
As long as the tree lives or the branch remains enshrined, a protected structure and its components count as a First Age Structure- damage is rolled instead of applied as automatic successes. Further, five minutes after suffering any damage, new stone or unworked earth rises from underground and repairs the structure. Wooden elements and structures grow fresh boughs that merge together creating unbroken spans.
The tree itself is supernaturally strong and ageless, immune to all forms of mundane disease and damage. Only Charms and magical weapons can directly damage it.
The buildings reinforced by this spell are not immune to countermagic, but must be disenchanted individually with Sapphire Countermagic. The tree itself can also be disenchanted in this manner, though one must reach it first. Geomantic upheaval, damage or otherwise souring the local dragon lines can also sicken the tree, but it dies slowly- over five days. If the imbalance can be corrected, the tree regains its strength almost instantly.
