In a previous blog (see here), I wrote about the dangers of pine processionary caterpillars. Late winter and early spring is an ideal time to spot nests. The one in the photograph below is about 40 foot up in an old Scots pine in the One Acre Wood, and now we have spotted it, we have time to paint the trunk of the tree with gloop in order to stop the blasted things reaching the forest floor, setting up camp and then pupating and flying away.
That is really all you can do with the nests that are very high up. If you have low level nests, you can very carefully cut them off the tree, put them in a metal bucket, pour in some petrol and very very carefully set them alight. It has to be a very hot fire in order to destroy the spines, which are the things that are so dangerous to animals and humans.
In case you feel inclined to let nature take its course, know that the spines are exceptionally irritating. On humans they cause a rash that itches worse than anything else I have experienced and that itching will last for over a week. On dogs and cats, the effects are even worse, causing blindness, necessitating tongues to be amputated, and can kill. Tree owners are legally obliged to deal with nests if they are in gardens.
Nature can be a bit yukky at times!