In parts of semi-arid W. USA, 11 spp. of Pinus and 9 spp. of Juniperus dominate 325 000 km (2) of woodland as a result of reduced frequency of fires, and reduced competition from herbaceous plants due to livestock grazing. The historical reasons for this, and recommendations to restore forage spp. and reduce erosion are presented.
Available at: http://works.bepress.com/neil_west/96/