On December 7, 2021, about 0757 eastern standard time, a Beech BE-35, N80YD, was substantially damaged when it was involved in an accident near Tallahassee, Florida. The pilot received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, during his preflight inspection he noted that the oil quantity on the dipstick indicated 11.5 quarts and that the oil filler cap was tight. The pilot also described that he did not observe any abnormalities during the engine runup. The pilot then departed for Columbus Airport (CSG), Columbus Georgia, on an instrument flight rules flight plan. During cruise flight, at 6,000 ft, the pilot reported a faint smell of smoke and observed that the engine instruments were nominal. He was concerned and contacted air traffic control to inquire about the weather conditions at nearby airports and reported that there was dense fog all around. The smoke smell then became more prominent, with the pilot describing it as having a distinct smell of oil burning but without visible smoke. The engine oil pressure then began to decrease, after which the pilot declared an emergency with air traffic control. The engine continued to run smoothly for another two minutes before the oil pressure decreased to zero. Shortly thereafter the engine began to run roughly, and smoke began to enter the cabin. Air traffic control subsequently provided the pilot with radar vectors for an instrument approach to Tallahassee International Airport (TLH), Tallahassee, Florida. The engine eventually lost power completely and the pilot knew that he would not be able to reach TLH. The pilot began to look through breaks in the fog to locate where he could perform a forced landing. The pilot eventually saw a dirt road and as he broke through a final layer of fog, he realized he would not be able to clear a tree line. As the airplane approached the trees, the pilot pulled the control yoke back in attempt to rapidly slow the airplane before it struck the trees with its underside. Following the impact with the trees, the pilot egressed the airplane. The airplane’s fuselage, both wings, and the left ruddervator were substantially damaged during the accident. Postaccident examination of the engine (about 1 month after the accident) revealed that the cylinder Nos. 5 and 6 connecting rods had fractured and breached the engine case. The engine was bearing races were corroded from being exposed to the elements following the accident. The connecting rods were heat damaged consistent with a lack of lubrication. A lighted borescope was used to examine the remaining connecting rods. The No. 4 connecting rod was fractured. The Nos. 1, 2 and 3 connecting rods were intact. All of the rocker covers were removed and no anomalies noted with the rocker arms, springs, or push rods. The oil drain plug was fractured off and no oil remained in the engine. The oil pump was fractured off the engine, impact damaged, and the pressure adjustment screw was missing. The oil pump rotated smoothly. The spark plugs were removed and displayed a worn out-severe appearance. According to the maintenance logbooks, the airplane had an annual inspection completed on June 8, 2021. At that time, the engine had accumulated 4,363 hours of total time and 942 hours since major overhaul. No anomalies were noted.