Spontaneous epigenetic variation in the Arabidopsis thaliana methylome

This is really cool. The authors studied epigenetic inheritance in a species of plant. The authors conclude that, while many epigenetic changes to last a few generations, over the long-term most are not stable and are reversed.

The Science Daily piece stresses the limited duration of these 'epimutations': "Epigenetic Changes Often Don’t Last, Probably Have Limited Effects On Long-Term Evolution, Research Finds." I tend to feel like they might be missing a bigger point: methylation is a response to short-term (a few generations) information about the environment. Would we expect that a plant would make epigenetic modifications based on current environmental conditions that would affect relatives 10 generations from now? If the environment were stable enough to warrant that duration of change, why wouldn't we expect that to be in the realm of DNA mutation?