Don’t use too many fasteners. This gives the tree room to move and grow. Even for smaller, lighter tree houses where the load is spread over three or four attachment points, consider using or lag bolts.
Mounting Anchor - Lag Bolts & Shields For Saris Wave Bike Racks. See product detail information below. 5/16x2". 8 bolts/8 shields per set. Works with all Wave bike racks.
BIKEHAND Bike Bicycle New Designed Wall Mount Hanger Repair Rack Stand. Easily mounted on any solid wall. Mounting flange has 2 holes, allowing use of bolts or lag bolts to mount ( Mounting bolts not included ). Durable powder coated finish.
National Hardware N179-158 V1863 Hex Head Lag Bolt, Black, 1/4" x 1-1/2"