Did you have acorns raining down on your head this year as we did? Mast years are when trees across the country produce a bumper crop of fruit or nuts.

Mast years are thought to be advantageous for the trees as they swamp animals which eat the seeds so that a proportion will germinate to form a new generation of trees. 2013 was the last big mast year. NatureSpot reports on why they occur.