There are three ways of erecting the front framework.
Outdoor shelters.
The first is to find two trees standing about seven feet apart with convenient branches down low enough to support the horizontal top cross pole when laid in the crotches. Lacking the proper trees, the second method is to get two strong, straight, forked poles of green wood and drive them down into the ground deep enough to make them stand firm and upright by themselves the required distance apart. The third way is to reinforce the uprights by shorter forked stakes driven firmly into the ground and braced against the uprights, but this is not often necessary.
Having your uprights in place, extending above ground five feet or more, lay a top pole across, fitting its ends into the forked tops of the uprights. Against this top pole rest five or six slender poles at regular distances apart, one end of each against the top pole and the other end on the ground slanting outward and backward sufficiently to give a good slope and allow sleeping space beneath. At right angles to the slanting poles, lay across them other poles, using the natural pegs or stumps left on the slanting poles by lopped-off branches, as braces to hold the cross poles in place ([Fig. 18]).
When building the frame be sure to place the slanting poles so that the little stumps left on them will turn up and not down, that they may hold the cross poles. Try to have spaces between cross poles as regular as possible. A log may be rolled up against the ground ends of the slanting poles to prevent their slipping, though this is rarely necessary, for they stand firm as a rule.
You can cover the frame with bark and then thatch it, which will render the shelter better able to withstand a storm, or you may omit the bark, using only the thatch as a covering. Put on very thick, this should make the lean-to rain-proof.
With small tips of branches from trees, preferably balsam, hemlock, or other evergreens, begin thatching your shelter. Commence at the bottom of the lean-to, and hook on the thatch branches close together all the way across the lowest cross pole, using the stumps of these thatch branches as hooks to hold the thatch in place on the cross pole ([Fig. 19]). Overlap the lower thatches as you work along the next higher cross pole, like shingles on a house, and continue in this way, overlapping each succeeding cross pole with an upper row of thatch until the top is reached. Fill in the sides thick with branches, boughs, or even small, thick trees.
The lean-to frame can be covered with your poncho in case of necessity, but boughs are much better.