I have not yet grafted any pecan scions, but plan to do so on more than one mature tree growing here that only produce small pecans. Instead of clipping off the lower new sprouts that come out each year, I will graft on some of them. I observe that when large branches are pruned that afterwards new shoots can emerge from near the end that was whacked off. Several months ago one particular trunk with a 14" diameter was cut off and it proceeded to send out several new shoots near the cut end. With this in mind, I just cut it again a little closer to the ground, expecting that it may again send out more new shoots at the newly clipped end for me to graft on while perched on a ladder......Expanding that plan, I am thinking about whacking off the top 40 feet of a 12" diameter tree down to about 5 foot high and later on graft on shoots that it presumably will send up near the cut end......Any experience out there with this kind of project?