The Guardian can, with this property, cause one of the elements Earth, Air, Water, or Plant to appear, or cleanse any existing contaminants and poisons.
The number of successes on a Nature Knowledge check indicates how much of the element is affected, and the level of the property determines the dimension.
With Level 1 you can summon cubic centimeters or a few, with Level 2 cubic decimeters and with Level 3 cubic meters.