A 55-year-old Roseburg man who crashed a bicycle Tuesday on a park path and suffered extensive head trauma was in critical condition today, Mark Daniel Kitzman was riding downhill on the bike path connecting Riverfront and Stewart parks and was 50 yards east of Stewart Park Drive near the disc golf course when the accident happened at about 8:30 p.m. Roseburg police said Kitzman was halfway down the hill when the front tire of his 21-speed mountain bike came off and lodged between the bicycle frame and the pavement. Kitzman’s bicycle flipped and the front forks jammed into the pavement, …