Tree Based Survival Shelters

If someone is going to get lost, it's likely to be in the woods. Not too surprising really since forests are big attractions to hikers and campers. The trees also make it easy to get lost since they restrict visibility and make it difficult to maintain one's bearings. The good news is that forests provide ample materials and opportunities for building shelters.

Lean-To Shelter
A lean-to is the most common shelter you see on TV and in the movies. It's fairly easy to construct, but may not provide as much protection from rain as other forms of shelters. To begin the construction of one, first start with two trees that are about 7 feet apart with forked branches 4 to 5 feed high on the trunk.

1. Remove any other branches that pose a safety threat or that will interfere with the construction of your shelter.
2. Place a ridge pole (a fallen tree that is approximately 10 feet long and the diameter of your wrist) into the forked branches. If you can't find two trees with forked branches, you'll need to resort to lashing the ridge pole to the trees instead.
3. Lay several support poles across the ridge pole, at 45 to 60 degree angle to the ground. Support poles need to be about 10 feet long and placed 1 to 2 feet apart.
4. Crisscross small branches into the support poles.
5. Cover the framework with 8 to 12 inches of grass, moss, boughs, and so forth. The material should be placed in a layered fashion, starting at the bottom so that rain will roll off the roof rather than in to your shelter.

To improve the protection of a lean-to, you can build a second one on the opposite side of the first lean-to you constructed.

A-Frame Shelter
The A-frame provides more shelter from rain than a single lean-to. It's also fairly easy to construct, but it does require many pieces of wood.

1. Start by finding a tree with a forked branch that is 3 to 4 feet above the base of the trunk and break away any other branches that may injure you or might hamper the construction of your shelter.
2. You'll need to find a fallen tree that is about 12 to 15 feet long to act as a ridge pole. Place this tree in to the fork of the support tree so that you form a 30-degree angle between the pole and the ground. In a pinch, you can use a fallen tree that happens to be at a 30 degree angle to the ground or lay a strong ridge pole against a 3 to 4 foot high stump.
3. As with the lean-to, lay support poles across the ridge pole. This time, you'll be laying them on both sides and at a 60 degree angle to the ground. Support poles need to be long enough to extend above the ridge pole and should be placed about 1 to 1 1/2 feet apart.
4. Crisscross small branches into the support poles.
5. Cover the framework with grass, moss, and leaves. Start covering the roof from the bottom and layer the materials. Doing so will prevent rain from coming in to the shelter.

Note that you could make the high part of the shelter higher up off the ground, but you will then need a longer ridge pole to maintain the 30 degree angle. A steeper angle will result in added exposure to rain and wind.

Platform Bed
The platform bed is intended to elevate you from the ground to keep you out of reach of insects and small animals. In and of itself it doesn't provide shelter without adding some form of roof.

1. Start by finding three trees that form a triangle. If you can't find such an arrangement, cut three poles and push them firmly into the ground so that they form a triangle. Make sure that the long sides of the triangle are at least 7 feet long.
2. Cut two poles 1 foot longer than the triangle's sides and then lash them to the trees or poles several feet above the ground. Make sure they are strong enough to support your weight since you'll be lying or sitting on them.
3. Fill in the gaps of the platform by laying additional poles on top of and perpendicular to the side poles. These too should be strong enough to support your weight.
4. For additional comfort and insulation, cover the top of the platform with 12 to 18 inches of dry moss, leaves, and grass. As an added precaution, shake these materials first to get rid of as many insects as possible.

To add a roof to this structure, use a tarp or poncho to construct a tent-like cover above the bed.

References:
Wilderness Survival by Gregory J. Davenport