Do good fences make good business? Strapped for cash, Brazil is experimenting with private management for some of its national parks. The government says these partnerships, which ensure the parks get adequately cared for but sometimes leave would-be visitors staring at fences, are a necessity. The private-sector parks game is gaining steam elsewhere too — even Yosemite recently partnered with a commercial concessionaire. But it’s riling some Brazilians who consider mixing conservation and profit “taboo,” and who simply want access to their country’s greenest spaces.