Answer: Your fig tree is experiencing some kind of "plumbing problem", such as drought, root loss from extended soggy soil conditions, nematode damage to roots, or fertilizer burn on the roots. The burned edges on the leaves are signs of some kind of stress and usually point to fertilizer burn or root damage.
Dig up some of the smaller surface roots and look for the "knotty", or swollen areas which indicate root knot nematode damage. There is no cure for these pests which are most commonly found in sandy soil. The other causes can be remedied by the obvious: watering, stop overwatering, don't overfertilize, etc.
Thanks for the question and good luck with your figs trees.
Q&A Library Searching Tips