A pilot study for climate risk assessment in agriculture: a climate-based index for cherry trees

Cherry trees are one of Chile's most important specialty crop activities. Its commercial orchards have an extensive spatial distribution between the 31 degrees S and 48 degrees S, spreading from semiarid to tundra climates, but the trees appear primarily in the Mediterranean climate. Different extreme weather events, such as frosts, precipitation, and high temperatures, affect this crop at different phenological stages, especially in bloom, ripening, and floral differentiation. Based on a high-resolution climatic-gridded dataset of daily temperature and precipitation data, we defined an integrated risk index (RI) representing the frequency of occurrence of the events throughout the plant development period and considering each type of risk affecting each concrete phenological stage. High RI values indicate high climatic risk. The RI follows a meridional pattern influenced by elevation, with higher values in the highest elevations between 36 degrees S and 40 degrees S, sensitive to the simultaneous occurrence of frosts and precipitation events. The northern coast exhibited the lowest risk values, while a general gradient from low values in coastal areas to higher ones in inland elevated zones revealed an altitudinal pattern. Low-risk areas have a sparse distribution of crops, which can be explained by several factors restricting cherry cultivation such as soil limitations, high slopes, lack of productive support infrastructure, and competition with other profitable forestry and agricultural activities in the north and forest production in the south. These results will help to improve climate impact assessments for production systems, which can be conducted by following an easy-to-understand tool.