I bought my Jonsered 2152 http://www.jonsered.com/int/chainsaws/cs-2152-c/ as my first firewood saw when I started burning 10 years ago. Now that I have 70cc and 90cc saws, I'm thinking its time to trade the 20" bar on it down to something more appropriate for what I use it for now. The website says 13-20 is recommended but I am wondering if 13" is too short?