Llyri is one of vanishingly few places in Erj in which the air quality is clear enough that trees and other plants can grow outdoors, under open sky, without being consumed by fatal volumes of ash. Though enabled primarily by a confluence of tireless sylph cleaning crews and ingenious engineering, the achievement is also circular; sylph horticulture has bred many species—particularly leafy vegetable plants—which can not only survive in climates with larger concentrations of airborne ash, but can in fact have a detectable positive impact on the volume of ash in the surrounding air.

However, most Llyran flora is not so readily equipped to defend itself against ash, and struggles even in Llyri’s air to remain healthy—a fact readily apparent in Llyran trees, which exhibit a perpetual yellow or red colouration. In recent years, these trees are becoming ever-redder.