What equipment would I need to keep my child safe whilst tree climbing?
You don’t need all the proper indoor climbing equipment such as ropes, harnesses, belays as you would need somewhere stable to put the rope and in a tree its unlikely that you will find that ! Climbing trees is safe as long as you’re watching them to see if they are falling; if you really want to be over-safe then you could buy a boulder mat that is basically a mattress but for outdoor climbers. They range in price depending on which one you want but personally i wouldn’t bother! Maybe you should take them indoor climbing to boulders climbing centre?