Build Mountain Bike Jumps

If you don't have a mountain bike jump and you are a mountain biker follow these steps.

Steps

Locate an area where you can build your jumps. Sloping trails with workable soil will give the best results, rocks, or rocky soil will present problems.
Get permission for your effort. You won't be able to build permanent jumps on public land, and you will need the landowner's permission to proceed on private property.
Design the jumps. If you are working on an existing trail, you can simply create mounds of compacted soil to create jumps, but make sure they are on a fairly straight section so you can prepare for the jump and land safely.
Build wooden jumps if you cannot excavate and mound up soil in your location. These can be portable, or fixed jumps, and can utilize treated lumber or simply plywood, depending on how permanent you want them to be.
Check the takeoff and landing zones for obstacles or hazards, then test the jumps slowly before getting too fast with them.

Build varying size and height jumps according to the skill of the rider
Use existing materials where possible to reduce labor and cost
Make sure your jumps drain properly so they do not cause erosion or become mud holes

Landowners will not want liability for accidents on their property. Be prepared to sign a release or obtain insurance for riders
Make sure riders have sufficient skill to use your jumps