How to avoid buckle wheel? So I have been commuting to work on my bike for about 12 months. The route takes me over a mixture of asphalt and some rocky forest trails. Just last week, I managed to get my rear wheel buckle. It got continuously worst over the last few days.

My bike is a Raleigh trekker bike. Similar to this one

http://www.raleigh-bikes.de/en/modelle/2014/trekking-sport/rushhour-10.html

What are some techniques that I can use to minimise buckling my rear wheel?

update: Thanks for the info. I had a closer look and found that the spoke was not able to extend itself enough to accommodate the bending of the rim. This must have occurred when I side hit a rock in the forest.
Start by checking the tension on the spokes of your wheel. To do this you'll need a spoke wrench that fits your spokes. There are lots of fancy tools for the job, but all you have to have is the spoke wrench.

Within reason, the tighter the better. Ideally what you will have is even tension on all of the spokes on one side of the wheel. There are fancy tensiometers to show you what you've got (and very effective and inexpensive apps for smart phones like Spoke Tension Gauge), or if you've got a good ear you can pluck the spokes like a guitar string and get an idea of how even the spoke tensions are by the pitch you hear.

This is especially important on the rear wheel where the gear cluster means that the hub isn't symmetrical and more tension is required on the drive side (right) spokes to keep the rim centered and true. If the drive side isn't tight enough, then the non-drive side will be too loose to support the rim adequately. One way you'll notice that the spokes are too loose is that you'll hear "pinging" noises from the wheel as you ride.

With disc brakes you can get away with a lot of wobble in the wheel, so I'd really encourage you to try it yourself before having a "pro" work on your wheel. It is fun and kind of meditative – just remember that everything affects everything else, and once the wheel is getting up to tension it makes sense to make balanced changes – tighten one spoke and loosen the spokes it pulls against.

If you want to know more about building and working on wheels, see if your library has The Bicycle Wheel by Jobst Brandt, Sheldon Brown also has posts on wheel building and truing and other repairs.