(defendant, U.S. Forest Service, seized and sold 354 head of plaintiff's cattle grazing in Apache-Sitgreaves National Forest in Arizona; plaintiff did not get federal grazing permit on basis that his water and forage rights entitled him to grazing use; defendant issued notice of trespass and ultimately seized the cattle; plaintiff waited until seven years after seizure to sue and defendant claimed six-year statute of limitations applied to bar the suit; if seizure constituted taking, then six-year statute of limitations applied, but defendant's lawyers, at oral argument, argued that defendant's actions were not a taking but an exercise of police power; plaintiff brought suit within six years of sale of cattle; court refused to dismiss case because defendant's position that neither seizure nor sale constituted taking but pursuant to regulatory scheme).