Early 19th century North American foresters went to Germany to study forestry. Forest supervisors are line officers and report to regional foresters. Industrial foresters plan forest regeneration starting with careful harvesting. Most are owned and used by foresters and game wardens. Deforestation is a threat to forests according to foresters. Special officials known as foresters were in charge of overseeing forest law. But its natural resources attracted expeditions of English and French foresters, who began harvesting timber. Complaints from foresters and farmers led in 1979 to the 1955 law's repeal. The forest law was very strictly enforced, by a hierarchy of foresters, parkers and woodwards. Poachers would resist arrest, sometimes resorting to assaulting and shooting foresters to escape. Urban foresters manage trees in urban green spaces. Pheromone traps can detect the arrival of pests or alert foresters to outbreaks. Among the units of the division were battalions of the Sherwood Foresters regiment. The lineage of the Sherwood Foresters is now continued by The Mercian Regiment. The Irish National Foresters are a nationalist fraternal organisation.