How do I stop my bike tires from puncturing? I recently bought a specialized Stumpjumper 29 and its only been a few weeks but I've punctured the tire four times already. I think im getting the punctures from the trees and bark on the trail but is there any type of tire that is more puncture resistant that the stock one I have right now?
Its unlikely that the problem is your tire quality. Stump jumpers are not cheap bikes and come with pretty decent tires. Although a Kevlar belted tire might help, its likely to be a waste of money. 

First up is what you are riding over. Bark, twigs and trees themselves are not going to puncture a MTB tire. Thorns, particularly dry ones, will. Even relatively small thorns (a couple om millimeter) will puncture a tire.

If you have punctured and have not removed the offending pointy thing, you will puncture again, this might be what has happened. Are the holes in the same place each time? This is the most likely reason for four in quick succession. 

Are your punctures one or two holes? If two, you are getting "snake bites" from too low tire pressure - (well covered already, use search).. 

If you are riding over thorns, then you need to buy thick heavy tires with a Kevlar belt. Light tires puncture easier. Also install thick, heavy tubes. This extra weight wil slow you down, but not as much as fixing punctures does. Consider going tubeless (the sealer also helps seal up puncture holes). You could also ride different trails - I have some locally that I avoid for this reason. 

It could always be you just had a bad run of it......