Inside the Emerald Triangle: Modeling the Placement and Size of Cannabis Production in Humboldt County, CA USA

•Cannabis cultivation sites are most likely to exist near other cultivation sites.•The size of a cultivation site is not influenced by neighborhood cultivation.•Typical biophysical drivers of agricultural siting do not influence cannabis siting.•Changing legal status of cannabis may influence future cultivation site choices.

Cannabis agriculture is a multi-billion dollar industry, yet the factors driving the spatial location of cannabis production are not well understood. That knowledge gap is troubling, as there is evidence that outdoor production takes place in ecologically sensitive areas. Policy aimed at mitigating the impacts of current and future cultivation should be based on an understanding of what drives cultivation siting. Using parcel level data and a Heckman sample selection model, we estimate where cannabis cultivation is likely to take place and the number of plants in each site using biophysical, historical, and network variables. We use this model to estimate drivers of greenhouse and outdoor cultivation siting. We find strong implied network effects - parcels are far more likely to have cultivation sites if there are cannabis plants nearby. However, the proximity of other cannabis sites does not impact the size of a parcel's own cultivation. Similarly, a history of timber harvest increases the likelihood of outdoor cultivation, but is linked to cultivation sites with fewer plants. Biophysical properties such as slope, aspect, and distance to water did not statistically impact the likelihood of a parcel to be cultivated. Our results are a first step toward understanding the emergence of an agricultural activity likely to grow in other locales in the future.