Q.Pine Tree Resin
There is an old pine tree in my garden that has recently started to drip resin.
This leaves the paving slabs under it sticky and difficult to remove.
Why has this just started, is it because the tree is old?
Can I do anything to stop it or do I have to cut down the tree?

Certified GKH Gardening Expert
If you are seeing increased sap from the tree, it could be a sign that there are pests on the tree. As a precaution, I would treat the tree with a insecticide to deal with any possible pest infestation.
The increased sap could also be from stress. A very wet or dry spring may have brought it on. The sap should return to normal either when the pests are dealt with or the seasonal stress is gone, which ever was the cause.
This article has suggestions that may help with cleaning it up: https://www.gardeningknowhow.com/ornamental/trees/tgen/how-to-remove-tree-sap.htm