I also have at a guess a 20 year old pecan tree. And I go on the record as saying it is CAN as in trash CAN. Not CAN but sounds like con as in CONgress. There are many ways to say it and I"m ok with however anyone says it (as long as they know they are saying it wrong ( if they are.) Any advice on caring for this tree? I know to give it 4 pound of fertilizer for ever 1 inch in diameter measured 3-4 feet above the ground. I know it need ZnS03or4. And that is the extent of my pecan knowledge.