Resumen de Projecting future winegrape yields using a combination of Vitis vinifera L. growth rings and soil moisture simulations, northern California, USA

J.T. Maxwell, Darren L. Ficklin, G.L. Harley, Gregory V. Jones

• Background and Aim We examined the feasibility of projecting future winegrape productivity by using Vitis vinifera L. growth rings as a proxy to winegrape yields.

  Methods and Results We compared the climate response of V. vinifera radial growth rings and winegrape yields using DENDROCLIM2002. We used the soil moisture model HYDRUS to determine if V. vinifera radial growth rings and winegrape yield can be modelled by soil moisture. Changes in V. vinifera radial growth were projected for 2020/99 Common Era using downscaled general climate models. Climate influences V. vinifera radial growth and winegrape yield similarly (r = 0.53, P = 0.001), indicating that V. vinifera can be used as a proxy for winegrape yield. Additionally, HYDRUS provided a robust model for vine growth and winegrape yield. Projected yields are forecasted to decrease significantly through time.

  Conclusions Based on future climate, winegrape yield showed a consistent and significant decreasing trend resulting in a 12.4% decrease by 2099.

  Significance of the Study Future climate conditions could create a decreasing trend in future winegrape yields, indicating that developing new irrigation systems or increasing irrigation volume will possibly be required for continued winegrape production in California.