My gut reaction is to not bring log loaders or chainsaws. Focus on the planting and pruning. 
Is there a tree on site with a big dead limb it in that you could go up and prune out. Rope it down....let the kids rope it down? 
Have the kids make a list of all the things trees give us. Kids are usually good at that.  Food, shade, medicine, wood, rubber, etc. 
love
nick