Mast, and What It Means for Gardeners

Have you heard the expression “a heavy mast year?” Or perhaps you might have heard the whole thing as a sentence,  as in “we are having a heavy mast year.”


This is what a heavy mast year looks like,  the “mast” in this case being the maple seeds from Norway maples. You can barely see the grass in places, they have fallen so heavily.

What is mast? Generally it is defined as seeds or nuts–acorns, pinecones, seeds from various types of trees. It is generally not fruit–in other words, a drupe or a pomegranate, soft bodies which first flower and then produce fruit surrounding areas single or multiple seeds.

Many of what we technically think of as vegetables meet the definition of fruit and only are legally defined as vegetables because the courts and commerce have said so–but that’s a long, complicated topic that takes us away from this one.

When there is a heavy crop of anything–pine cones,  acorns or these nasty maple seeds,  wildlife benefits.  Birds, small mammals, and in the case of acorns,  deer have a much better survival rate as they go into winter torpor (again mammals, for the most part,  go into a dormant state called torpor. They don’t really hibernate.  But that’s a different post too).

White footed mice and voles–2 creatures that are especially problematic for our gardens–have a much better survival and breeding rate in high mast years.

So when you see something like this on the lawn, look out! And expect some damage to the garden next season. (And let’s not even talk about those awful weed seedlings!)

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