Die back
Earlier this year I had the chance to spend a few hours in a forest in England with a forester who is a dear friend of mine. It was the first time Id seen him in his place of work and as he gave a guided tour of 'his wood' I was amazed at his knowledge. Every tree, every plant and insect and birdsong had a story. He just rattled off the information as we wandered around. The best I could do was identify three or four common trees. He was able to identify a woodpecker from its song, spot where it was nesting and discern the species from the briefest of glimpses of the adult bird as it came back to its nest to feed its chick. As we toured the woods he started talking about Ash dieback. Its a disease similar in its effect to Dutch Elm disease. It is tearing though British woodland killing off Ash trees at a rate of knots and there is no way to stop it. He was pointing out trees which had it. They looked perfectly healthy to me....