By 1860 时间状语, the settlement of the American West along with timber shortages in the East 主语 converged谓语  with ever-widening impact on the pine forests of the Great Lakes states 结果状语.

到了1860年，美国西部的移民定居以及东部的木材短缺这二个因素叠加，对五大湖区的松树林造成了日益广泛的影响。