My dad once lived in the woods one winter in a hole under a pine tree covered with limbs and dry leaves he stayed dry and warm i seen this 3/4 in to the winter . i plan to teach my kids how to do this in the fall this year , he did not use one tool to make it . he dug the hole with sticks and rocks and used what the woods gave him to use to build the roof covered in dry leaves with pine needles in the hole . also makes a good hideout ...