William Felker has studied phenology in أوهايو, USA since 1973 and now publishes "Poor Will's Almanack", a phenological almanac for farmers (not to be confused with a late 18th century almanac by the same name).
William Felker has studied phenology in Ohio, USA since 1973 and now publishes "Poor Will's Almanack", a phenological almanac for farmers (not to be confused with a late 18th century almanac by the same name).