Methane is combustible and highly explosive when it builds to high concentrations. However, because methane is less dense than the air on Pandora, the pods will detach and float off when they enlarge to a certain size. Explosions usually occur after the pods have detached and drifted off, making them relatively harmless to life on Pandora.
The vein pod is related to the puffball tree and puff daddy, all of which are considered keystone species on Pandora for their important role in maintaining stability of the environment. The globular balls produced at the tops of the vein pod trees and ends of the branches act as sponges, absorbing methane from the atmosphere. This function is similar to that of the plant vacuole at the cellular level, which sequesters plant waste products and other molecules such as pigments and minerals. Because of their ability to sequester methane, these plants emit a strong foul odor and are usually avoided. (Read more)