by Fiona Ferbrache
Deep in Californian redwood forests, Mexican gangs are at play. Reshaping our imagined geographies of woods and forests, it has been reported that ‘marijuana gardens’, containing up to 100,000 plants, are growing within familiar woodland spaces of logging, wildlife and leisure. Many of these gardens have been linked to Mexican gangs seeking to avoid smuggling cannabis across the Mexican/US border, and taking advantage of the difficulty to see the plants for the trees. Unfortunately, to ensure protection of their crops, trip-wire explosives and snipers have been used, and have caused concern among local communities of violent crime incidents in the forests (Blakely, 2011).
U2 spyplanes and helicopter-borne teams of armed eradicators are part of Government attempts to combat this growing industry. Having read Zhang et al.’s (2011) Area paper concerning airborne light-detection and ranging (LiDAR) data, I wonder whether this mode of forest classification could be used to help seek out marijuana gardens?
LiDAR is an active remote sensing technique offering benefits over other means of forest classification and forest mapping. Zhang et al. show how LiDAR is highly applicable for penetrating the overstorey and identifying the composition of forest layers making up the mid- and lower-storey. The data produces high-density sampling, in three dimensions, with a high level of accuracy (91.4% in this study). As Zhang et al. illustrate, the practical uses are significant, so is there a possibility that geographers could play a role in helping to combat Mexican drug gangs?
Zhang, Z., Liu, X., Peterson, J. and Wright, W. (2011) Cool temperate rainforest and adjacent forests classification using airborne LiDAR data. Area DOI: 10.1111/j.1475-4762.2011.01035.x