The first thing that you should be aware of when selecting the best survival knife for chopping wood is the length and thickness of the blade. The larger and heavier the blade is on the knife, the less force it will take for you to bite the wood with each chop. You should look for a survival knife with a ¼ inch thick blade and one that has a thick full tang. The thick blade and a thick full tang both add to the heft of the knife and the durability that is needed for the task at hand.
The next thing that you should consider is blade length. While there are great 10 inch knives for chopping like the Becker BK 2 and ESSE RC 5, the bigger the blade the more leverage you will get and the more weight you will have behind each chop. If you are looking the absolute best survival knife for chopping wood, look for a knife that has an overall length of about 14 inches. You will also want a knife with a flat grind and a drop, or bowie point. The flat grind allows the blade to easily glide through the wood without getting caught. The drop point or Bowie point make the tip of the knife more durable and better fit for hard use. You should avoid anything that has a double edge as it will make batoning very difficult. Some great knives in this category are the Becker BK 9 and the Ontario RTAK II. Both of these knives are 14 plus inches in overall length have all the recipes to be an excellent chopper.
Ka- Bar Becker BK 9
The Ka-Bar Becker line of knives are hands down some of the best survival knives on the market for the price. The Becker BK 9 is the best chopper of all of them and in my opinion the best non custom chopper that you can find on the market. The Becker BK 9 is a very hefty survival knife and if you visit blade forums or read Amazon.com reviews you will find that this knife is very highly revered in the outdoor survivalist community. The Becker BK 9 is made of 1095 High Carbon steel which is extremely durable and holds a great edge. This type of steel makes the knife virtually indestructible.
The Becker BK 9 will chop through 4 inch saplings with no problem and then turn around and baton a stack of hardwood. There are only a few non custom knives that I know of that will compare to this survival knife.
Ontario RTAK II
The Ontario RTAK II survival knife is an outstanding knife for chopping and shelter making. The RTAK II is near a ¼ inch thick and has whopping 10.25 inch blade. The wedge shape on the full flat grind of the blade makes it ideal for batoning and splitting wood. The knife is a full 2.2 lbs so it is heavy but it is well worth carrying the weight to have this tool at your campsite for prepping firewood or making a shelter. It is basically a hand axe with a longer edge. The blade steel is 1095 high carbon so it will hold an excellent edge and take an absolute beating. The Ontario RTAK II comes with Micarta handles which is considered an aftermarket upgrade on the BK9 however it is really personal preference.
Overall, the Best Survival knife for chopping wood is made from a good steel such as 1095 high Carbon or better and has a large blade of 8 - 12 inches. While these knives are not ideal for all situations and are heavy to carry, they outperform smaller knives if chopping is your desired use. The Becker BK 9 and Ontario RTAK II are great knives and both are in the $80 -$120 range. I recommend both of these knives and hope this was an informative read.