If you are camping you normally bring a tent and other camping gear with you, but what if you are caught without the usual camping supplies? Perhaps you got lost while hiking, or you simply forgot to pack the essential shelter of a tent. Don't panic, there is usually enough forest litter just lying around a wooded area to make a simple emergency bivouac shelter. The purpose of a bivouac shelter is to provide a minimum of protection from the elements for at least one night, it's not the fanciest of shelters but its one side will double as a wall and a roof, helping to keep you warmer and dryer than just lying out in the open.
Since you are building an emergency bivouac shelter against the elements, it is important to determine what you are defending against first. In what direction is the wind generally blowing? Is there a slope that water will run down in case of rain? What are the chances of rain? These effect the placement of your emergency bivouac shelter but for the most part just use your best judgment. For instance, you want the one wall to face the wind and any incoming rain with the wind, you also want some measure of protection from water runoff. For this reason placement of a bivouac shelter is key.
The first thing you will need for your emergency bivouac shelter is some poles. Obviously you probably didn't bring any with you but hopefully you at least have a good knife. Find a couple strong pieces of wood at least four feet in length. Preferably these first two poles should have a "Y" shape on one end from where two branches would have met. Next you’re going to drive these into the ground so that they stand upright on their own and are sturdy, at least eight to twelve inches into the ground. Next find one more "pole" of wood to go across the other two. It should fit into the notches at the top of each of the other two pieces. It may take several tries to get your bivouac shelter to stand, don't give up. Instead, consider using a tree to help support it.
Now that you have the frame of the emergency bivouac shelter complete, start finding smaller twigs and sticks and stack them against the frame, the longest ones first. Next, starting at the bottom, thatch your shelter with sod, bark, twigs, or anything else you can find. Make sure that each layer lays on top of the one before, so that water will run down and over the outside of your shelter, not inside. Finally put heaver sticks on top to prevent the wind from blowing your thatch away.