This brave chap is doing what is known in the tree surgery trade as delimbing. Using ropes he climbs the tree and with a chainsaw cuts it piece by piece until he leaves 10 or so metres of trunk known as standing timber, ideal for wildlife. This particular tree was suffering from a fatal disease and would have collapsed, potentially damaging near by properties. This method allows the best of both worlds being safe and creating great habitat. All relevant bird and bat surveys were carried out before any work started.