On Friday, US senator Ron Wyden (D-Oregon) introduced legislation to legalize marijuana at the federal level—a bill called SR 420, of course. Thirty-three states and the District of Columbia have so far expanded access to weed in some form. But with federal law lagging behind, the states have landed in a tangle of rules that are at times contradictory, self-defeating, and lacking in scientific support.

For the many people affected by the marijuana industry, some of the most pressing questions center on what the industry itself should look like as it morphs from small, underground farms to sprawling industrial outfits. The federal government has historically made it extremely difficult for researchers to explore cannabis, particularly its health effects. And universities haven't exactly been clamoring to fund studies into how and where cannabis is grown.

But late last month, UC Berkeley opened the Cannabis Research Center to start tackling some of these social and environmental unknowns. With its proximity to the legendary growing regions of Northern California, the center can start to quantify this historically secretive industry, measuring its toll on the environment and looking at how existing rules affect the growers themselves. The goal is to create a body of data to inform future policies, making cannabis safer for all.

In California’s Humboldt and Mendocino counties, growers fall generally into three groups. Some growers work on their own land, but without the permits the state now requires to produce cannabis; a second cohort does the same but with permits. The third contingent is the trespass growers, who schlep equipment into federal land and set up ad hoc operations. If you’re a researcher trying to study these different operations, the first hurdle is figuring out how many are out there in the first place. Even if you were able to hike across the entire Northern California countryside and find every last grower, many of them are not going to be happy to see you.

So for the past few years Van Butsic, codirector of the Cannabis Research Center, and his colleagues have been sifting through satellite images to pinpoint those unaccounted-for farms. “We have an army of undergraduates who look at high-resolution imagery and digitize how big the farms are, how many plants we can see,” Butsic says. Because cannabis plants love light, growers usually keep them out in the open. The researchers still miss many trespass growers, however, who tend to hide their plants in the brush to avoid detection.

Still, Butsic is starting to build a better picture of the scale of cannabis farming in Northern California. With this data, researchers can begin to dig deeper into the environmental impacts of cannabis agriculture. How might the distribution of farms, for instance, correlate with the poisoning of wildlife with rodenticides used to keep rats off grow operations? And how might large farms—which are more likely to be permitted—differ in their water use from the much more numerous small farms?

“It's unclear what the environmental impacts of those different types of production methods would look like,” Butsic says.

Pinpointing the distribution of farms will also help identify those that might, for example, overlap with the habitats of endangered species. Water withdrawals from certain streams, for instance, may impact coho and chinook salmon. “It's not that cannabis is clearing the whole forest,” he says. “It's more that cannabis is making these little pockmarks in sensitive areas.”

The satellite work has been going on since 2015, so it both quantifies the scale of cannabis production in Northern California and adds historical context. This allows the Berkeley researchers to observe the changes before and after the legalization of recreational use in January 2018. Anecdotally, old-school cannabis farmers are struggling with legalization. One permitted farmer in Mendocino says he’s sunk $100,000 into consultants and another $20,000 into fees to bring his operation into compliance. Growers are forced to choose between dealing with a galaxy of new regulations meant to protect consumers and the environment, or sticking to the black market.