On January 22, 2011, about 1230 Pacific standard time, a Bice Air Creation GTE weight-shift-control aircraft, N4668L, sustained substantial damage during a forced landing following a loss of engine power near Hayfork, California. The private pilot and his passenger received minor injuries. The pilot/owner was operating the aircraft under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the personal cross-country flight, which had originated from Fortuna, California, at 1100. No flight plan had been filed. The pilot reported that he departed Rohnerville Airport in Fortuna and climbed to 7,500 feet mean sea level on an eastbound course. As he approached his destination, the engine's exhaust gas temperature and cylinder head temperature began to drop. The pilot believed this was due to carburetor icing. The aircraft was not equipped with carburetor heat, therefore, no corrective action could be taken. The engine subsequently lost power, and he performed a forced landing to heavily forested mountainous terrain, striking several trees before the aircraft came to rest. The wing structure was substantially damaged, and both main landing gear separated from the fuselage. The pilot reported no mechanical failures or malfunctions with the aircraft. At 1155, the weather conditions at Hayfork, located 9 nautical miles east of the accident site, were as follows: wind calm; visibility unrestricted; clear of clouds; temperature 41 degrees Fahrenheit; dew point 39 degrees Fahrenheit; altimeter setting 30.19 inches of Mercury. A review of a carburetor icing chart shows that these conditions are conducive to the formation of serious icing at cruise power.