A very interesting Japanese technique to try!! Called Shou Sugi Ban 焼杉板 (or Yakisugi), this technique is used for exterior or interior wood surfaces. Being a woodworker before, I had never heard of this technique. The only preservation technique that I knew of was stain and varnish. Please comment below!!
http://www.offgridquest.com/fload/diy/japanese-technique
Here is a video, as well:
R.B.Bailey Jr International Media 