USE A 16 INCH DOWL BIT, AND DRILL A HOLE THROUGH THE TREES. USE ALL-THREAD TO HOLD THE MAIN BEAMS TO THE TREES. A 6 FOOT ROD, SOME NUTS AND WASHERS IS USUALLY GOOD FOR ALL FOUR TREES. BUILD THE LADDER AND BUILD IT UP FROM THERE. THE TREES USE USE FOR THE LADDER, IF YOU USE HARD WOOD LIKE OAK OR MAPLE, THE LADDER AND STAND WILL LAST. POPLARS AND OTHER MID HARD TREES BREAK AFTER ABOUT FIVE YEARS. I BUILD ABOUT 2 STANDS PER YEAR. AFTER 15 YEARS, EVERY PLATFORM IS STILL SAFE. BOLTED WITH ALL-THREAD RATHER THAN NAILS IS THE ONLY WAY I TRUSTA STAND YEARS LATER.