Using geolocated proxy sensor systems to assess spatiotemporal stability of seasonal wood biomass in northern California vineyards

Previous research has investigated the temporal stability of spatial variation of vineyard wood biomass (pruning weight) as a tool to optimize crop management practices. These studies have used hands-on and time-consuming measurement methods to obtain data over blocks of a single cultivar in relatively small geographic areas. Recent advances in proximal sensor systems have facilitated the collection of vine biomass data across large areas covering hundreds of hectares in northern California. This project seeks to build on previous research efforts to better understand spatial variation in vine size throughout vineyards of northern California and determine to what extent this variation is stable over multiple years. Data collected via the Physiocap wood biomass mapping system was used to analyze the spatial and temporal stability or variance in annual wood biomass in the context of block-specific variables of northern California vineyards. Desktop GIS software was used to process raw data points into raster layers of wood biomass for all vineyards with available data over the last five growing seasons. Wood biomass raster layers were analyzed to assess the spatial and temporal variation between and within vineyard blocks. Temporal stability of spatial patterns and variance was also examined within each block. Lastly, these values were examined in a block-specific context to better understand if temporal or spatial variation levels are linked with parameters like grape cultivar, rootstock, management style, or landscape characteristics. Analysis of this Physiocap database showed that overall, results reflect those of previous studies: spatial patterns of wood biomass are generally preserved over the years while individual vine values can vary significantly both spatially within the field and temporally between vintages. It was also demonstrated that wood index characteristics such as mean biomass value, spatial variation, and spatiotemporal stability all show significant differentiation among blocks of differing rootstock or vineyard age.