Just south of California’s Joshua Tree National Monument, beyond the tightly managed domain of the US National Park Service is BLM land – an area loosely administered by the US Bureau of Land Management and occupied by itinerant RVers, boy-racers on ATVs and gun enthusiasts seeking an open range. Across the freeway, where the road sign points to Mecca, California, is a roadside turnout where truckers take rest breaks on the hundred-mile trip between Indio and Blythe. The turnout is littered with dumped cargo, broken TV sets, an old water heater, underwear, socks and baby diapers. Through it all runs a desert wash – a basin that very occasionally transforms into a raging river as it carries runoff from the mountain ranges on either side of the valley. I arrived at the wash just after one such flood, and went back three times, for three days at a time, camping in the BLM and photographing the heaps of detritus that had bundled up around the trunks of the trees – gnarled by parasitic mistletoe – that subsist in this utterly marginal land.