Any number of objects, such as shrubs, rocks or fence posts can obstruct the wind force causing sand to pile up in drifts and ultimately large dunes.
(Any number of objects, such as shrubs, rocks or fence posts; can obstruct; the wind force causing sand to pile up in drifts and ultimately large dunes) (the wind force; causing; sand to pile up in drifts and ultimately large dunes) Context(the wind force causing,List([73, 95))):(sand; to pile up; L:in drifts and ultimately large dunes)
the wind force causing,List([73, 95))
Any number of objects, such as shrubs, rocks or fence posts the wind force sand
can obstruct causing to pile up
the wind force causing sand to pile up in drifts and ultimately large dunes
sand to pile up in drifts and ultimately large dunes
L:in drifts and ultimately large dunes