Reindeer lichens resemble dead litter more than live tissue in their susceptibility to fire. Continuous mats of reindeer lichen present an uninterrupted surface along which a fire spreads. Lichen mats also accumulate tree and shrub litter which adds to the flammability. Wind most important dispersal agent. Grow vegetatively by producing new growth annual at the top of the podetium, which lengthens the internode formed in previous years.
Podetium passes through three growth stages.
During this stage no part of the podetium dies off. This stage often exceeds 100 years. Podetium degeneration period, the podetium dies off at a greater rate than it grows. This stage may also exceed 100 years.