I used the API climbing sticks. In Ohio no tree steps (spikes, nails, etc.) are allowed at all on public land; and only on private land with the land owners permission. They came in three pieces that were like 3 feet long. They recommended spacing them about 18", but you could fix it to fit your stature. They hold really tight too. They slipped just a little when I put them up, but after they got "set" on the tree I was bouncing up and down on them and they didn't move at all. Strap on ladders and steps are much friendlier to the tree also. God bless

Brandan