Very often fallen trees are in wet areas, so the ground under the fallen tree is very likely wet. Therefore it may be hard to find fallen trees which have a nice flat root system sticking up into the air that can be used as part of a shelter wall.
Make sure the fallen tree isn't going to fall further to the ground, ie, onto you.

The value in this type of fallen tree, where the roots are sticking 'way up in the air, is that this flat base of the fallen tree can function as one wall of a shelter.

In order to complete the shelter, you could build a debris hut with the roots as one side of the shelter.

Alternatively, you could simply use the fallen tree as a reflector for fire.

As well, it could be roofed over with smaller fallen trees, with branches and evergreen boughs on top to help keep you dry.

Use your imagination!

Here's another good example of a useful fallen tree. Of course, you're not going to use this particular one as a base for shelter building as it is in a park right by a walking trail, but you get the idea.

Another type of fallen tree that may be used as a shelter. In this case, the fallen tree consists of more lightweight branches with leave still attached. All you need to do is add to the framework, perhaps only building up one side to serve as a windbreak.

It is very tempting to utilize this large fallen ash as a roof-pole for some sort of shelter. If you do, you'd better be sure that it isn't going anywhere - ie, that it is still very firmly attached to the stump and won't slip or fall further towards the ground while you're under it!

Survival Shelter Trees Cordage Furniture

READ THE DISCLAIMER