This may not be news to most on this forum, but I'll relate this for those who don't know. Some family members had some trees cut down and left the logs in a pile thinking they would split them when they were needed. Well they sat there for a couple years and we finally got around to splitting them with intention to burn them this winter. Despite the couple years they sat there, the wood was still too "green" or moist to burn. Lesson learned, firewood must be split before drying out for a year or so.