The land that became the Jaci Paraná Extractive Reserve had been worked long before anyone drew its boundaries on a map. Rubber concessions in this area — generically called the Jaci Paraná concessions — date back more than a hundred years, to the era when Amazonian rubber fueled the industrial world. The traditional residents who inherited that legacy shifted to gathering native fruits: cupuaçu, tucumã, açaí, and bacuri. They collected Brazil nuts, hunted and fished for subsistence, and maintained small plots of agriculture. The Jaci-Paraná Rubber Tappers Association represented them in managing the reserve. Their economy was modest and sustainable, built on the forest's abundance rather than its destruction. It was also, in the eyes of ranchers and land speculators, an inefficient use of valuable land.

By 2014, roughly 200 illegal cattle ranches had established themselves inside the reserve, running over 44,000 head of cattle on land that was supposed to belong to rubber tappers and Brazil nut gatherers. The invasion had been building for years. Between 2002 and 2007, according to the research institute Imazon, the rate of deforestation inside the reserve hit 3.74 percent — second only to the neighboring Bom Futuro National Forest at 4.34 percent. By July 2007, some 37,500 hectares, a full 20 percent of the reserve's total area, had been stripped of forest. Loggers came first, then squatters and land speculators followed the cleared paths inward. Large volumes of timber were harvested illegally, the chainsaws audible to anyone who cared to listen.

On 16 January 2014, owners of cattle in the reserve were given 40 days to remove their herds. The ranchers' response was swift and political: less than a month later, the state legislature passed decree 506, revoking the 1996 decree that had created the reserve. The same session also revoked protections for the Rio Madeira Environmental Protection Area, the Rio Madeira B State Forest, and the Rio Vermelho State Forest. Traditional populations opposed the move. Loggers, ranchers, and farmers supported it. The vote was not close — only one deputy in attendance dissented. It was a legislative attempt to retroactively legalize what had already been taken by force, granting a veneer of legitimacy to years of illegal occupation.

The Amazon Working Group — a coalition of more than 600 organizations representing farmers, rubber tappers, indigenous communities, quilombolas, environmentalists, and human rights groups — published an open letter denouncing the decree. On 14 April 2014, the state prosecutor obtained an injunction suspending it, citing the Brazilian constitution's mandate that government and society share the duty to protect an ecologically balanced environment. The area was being rapidly degraded, the prosecutor argued, which justified urgent intervention. The case wound through the court of Rondônia for two years. On 2 May 2016, the court upheld the prosecutor's decision, reinstating not only the Jaci Paraná reserve but also the Rio Madeira Environmental Protection Area and the state forests that had been stripped of their protections in the same legislative session.

The reserve's 197,364 hectares span three municipalities — Porto Velho holds nearly two-thirds of the area, with Buritis and Nova Mamoré containing the rest. The Jaci Paraná River traces its western boundary. To the east lies the Rio Pardo Environmental Protection Area; to the northeast, the Bom Futuro National Forest, separated by the Rio Branco. The reserve was intended to join the proposed Western Amazon Ecological Corridor, linking it to neighboring conservation units in a continuous web of protection. But corridors work only when their constituent pieces hold. The court restored the reserve's legal existence. What it could not restore was the 37,500 hectares of forest already cleared, the timber already hauled away, or the trust of the rubber tappers whose home had nearly been voted out from under them.