Declining trees growth and vegetation productivity resulting from decreasing soil water contents induced by tunnels excavation in karst mountain areas

•The excavation of the ZMRL6 tunnel accounts for the depletion of soil water storage in the tunnel center area.•Tunnel excavation reduces the BAIs of trees within 1500 m of the ZMRL6 tunnel center.•Tunnel excavation decreases the NDVI and NPP within 1500 m of the tunnel center in karst mountain areas.•The closer proximity to the tunnel center corresponds to lower SMC, BAI growth rates, NDVI, and NPP.•Ecological management and conservation strategies in karst tunneling regions are necessary for the future.