Posts Tagged: land use
A recent study led by UC Cooperative Extension specialist Van Butsic used high resolution satellite imagery to conduct a systematic survey of cannabis production and to explore its potential ecological consequences.
Published this spring in Environmental Research Letters, the study focused on the “emerald-triangle” in northern California's Humboldt, Mendocino, and Trinity counties, which many believe is the top cannabis-producing region in the United States.
The UC Berkeley-based Butsic and his co-author Jacob Brenner used Google Earth imagery to locate and map grow sites (both greenhouses and outdoor plots) in 60 watersheds. Most cannabis grow sites are very small, and have gone undetected when researchers used automated remote sensing techniques, which are commonly used to detect larger changes such as deforestation.
“We chose to use fine-grained imagery available in Google Earth and to systematically digitize grows by hand, identifying individual plants. Most plants stand out as neat, clear, little circles,” said Brenner, who is on the faculty of the Department of Environmental Studies and Science at Ithaca College. “The method was laborious — it took over 700 hours — but it proved to be highly accurate.”
Butsic and Brenner paired their image analysis with data on the spatial characteristics of the sites (slope, distance to rivers, distance to roads) and information on steelhead trout and Chinook salmon, both of which are listed as threatened species under the federal Endangered Species Act. These and other species are vulnerable to the low water flows, soil erosion, and chemical contamination that can result from nearby agriculture.
Results of the study show 4,428 grow sites, most of which were located on steep slopes far from developed roads. Because these sites will potentially use significant amounts of water and are near the habitat for threatened species, Butsic and Brenner conclude that there is a high risk of negative ecological consequences.
“The overall footprint of the grows is actually quite small [~2 square kiliometers], and the water use is only equivalent to about 100 acres of almonds,” says Butsic, who is in the Department of Environmental Science, Policy, and Management at Berkeley. According to Butsic, California currently has more than one million irrigated acres of almonds.
He stresses that the issue lies in the placement of the sites: “Close to streams, far from roads, and on steep slopes — cannabis may be a case of the right plant being in the wrong place.”
Last year, California legislature passed laws designed to regulate medical marijuana production, and state voters will weigh in on whether to legalize recreational marijuana this coming fall. Given these changes as well as the profitability of cannabis production, Butsic expects that marijuana cultivation will expand into other sites with suitable growing conditions throughout the region. He and Brenner assert that ecological monitoring of these hotspots should be a top priority.
Bills recently signed into law by Governor Jerry Brown have made some advances in this direction — requiring municipalities to develop land use ordinances for cannabis production, forcing growers to obtain permits for water diversions, and requiring a system to track cannabis from when it is first planted until it reaches consumers.
But the researchers say that regulation will likely be a constant challenge because it will rely on monitoring procedures that are just now emerging, as well as voluntary registration from producers and budget allocation from the state for oversight and enforcement.
“Some of the same fundamental challenges that face researchers face regulators as well, primarily that cannabis agriculture remains a semi-clandestine activity,” says Brenner. “It has a legacy of lurking in the shadows. We just don't know — and can't know — where every grow exists or whether every grower is complying with new regulations.”
While the legality of California’s medical marijuana dispensaries is being debated in courtrooms, a UC Cooperative Extension forestry and wildlands ecology advisor says there are a number of issues related to the unregulated land-use practices of illicit cannabis growing that have not been addressed.
Greg Giusti. “And you can’t talk to anybody today on the North Coast without the topic of cannabis growing and cannabis impacts on land coming up.”
In Lake and Mendocino counties, Giusti performs research and shares information with public agencies and private landowners in relation to forest management and freshwater ecology on behalf of UC Cooperative Extension. Marijuana farming is not a topic that Giusti ever intended to address.
Effects on natural resources
Most of the data available about illicit cannabis grows is based on drug enforcement actions, specifically how many sites were busted and how many plants or pounds of plant material were seized. Giusti has gathered photographs and anecdotal evidence of the effects on natural resources of commercial-scale marijuana grows operated illicitly on public and private lands.
Some of the effects he has documented:
- illegal water controls (including dams, stream diversion and water storage)
- water pollution from petroleum, pesticide and fertilizer products
- pesticides applied without permits
- pesticides, fertilizers and other chemicals left behind
- indiscriminate fish and wildlife killing (including poisoning, trapping and poaching for food)
- human trash and waste left after camping
“It’s not this green industry that people talk about,” Giusti says. “They’re diverting water, they’re polluting streams, and there’s a portion who are poaching. We’re also seeing all of the negative effects of unregulated road building, unregulated construction and unregulated human inhabitation for months and months out in the woods.”
Giusti explained that some cannabis growers divert water from streams to store in large water bladders, prematurely lowering stream levels during critical times in the year.
“It's illegal to do, but at the same time you can drive up and down Highway 101 and easily buy these huge bladders,” he said.
He notes that local businesses are selling compost by the ton, rodenticide by the pallet, thousands of pairs of clippers and turkey bags in lots of 100.
“Mainstream businesses are supporting this underground industry,” Giusti said. “You don’t have to be growing cannabis to be making money off of it.”
In 2010, Giusti organized two community workshops in Lake County to address the impacts of illicit cannabis land-use on forest resources, for a combined attendance of nearly 400 community members. Giusti has shared his results with the board of supervisors for Lake and Mendocino counties, local news media, local foresters and the staff of the North Coast Regional Water Quality Control Board.
“My intention was to initiate a communitywide discussion to ask, ‘Is this what you want to happen to your forests?’” Giusti said. “Up until now it's been talked about in hushed tones, and I wanted to initiate a dialogue out loud. Everybody has been whispering about it.”
The presentation he developed for those meetings continues to generate discussion. Most recently, he has presented to the North Coast Water Quality Control Board staff and other agencies. He has shared photos collected for his presentation with Congressman Mike Thompson’s office as well.
“With the water quality control board, I had the opportunity to engage people whose job it is to protect the beneficial uses of water — and hopefully stimulate an internal dialogue so that they can continue the discussion after I leave their office,” he said. “There are other resource agencies that need to be involved, and county planning departments too. This is an unregulated land-use practice.”
This month, the Lake County Record-Bee ran an article by reporter Linda Williams with the headline “Thirsty marijuana grows suck Eel River dry,” which included some information presented at Giusti’s meetings.
“My efforts seem to be improving people's awareness,” he says. “The very thing I wanted to accomplish — creating broader dialogues — is happening.”
View Giusti's presentation: Illicit Cannabis Production on Forest and Wildland Resources
Geographic information system (GIS) models developed at UC Davis are being used to pinpoint the best farmland for conservation in the Central Valley. A new landscape-scale method, described in a recent issue of California Agriculture journal, was applied in Fresno County, and the approach is being extended regionally in the San Joaquin Valley.
“Policy programs and local planning agencies must assess farmland before implementing policies and programs aimed at farmland conservation,” lead author Evan Schmidt wrote in California Agriculture. “The application of GIS to existing land-assessment practices can update and reinvigorate [currently used] techniques.”
The method involves integrating environmental and human factors into a GIS to develop maps of strategic farmlands to be targeted for conservation. These five factors are:
- Soil productivity, based on maps developed by the California Department of Conservation’s Farmland Mapping and Monitoring Program (FMMP).
- Water cost and reliability, based on maps developed by California agricultural commissioner’s offices.
- Microclimate, to identify areas with optimal growing conditions.
- Environmental sensitivity, to incorporate state and federal designations of vernal pools and wetlands.
- Urban growth pressure, to identify areas within and adjacent to existing cities that are expected to be developed in coming years.
With extensive input from the public, agency officials and land-use professionals, the method expands upon farmland assessment frameworks developed by the U.S. Department of Agriculture and FMMP soil classification maps.
The Fresno County GIS-based assessment identified 343,321 acres of “very-high-value” farmland, mostly in the eastern and southern county and located in areas without existing or projected urban development. “High-value” farmland, totaling 491,613 acres, was similarly situated but included more acreage in the western county.
“In Fresno County, we found that the majority of growth to 2050 could fit into existing spheres of influence,” Schmidt and co-authors wrote. “This important information challenges decision-makers to set and maintain policies that encourage compact growth and infill development in order to preserve Fresno County’s highest-value farmland.”