Annual stem length, annual number of leaves, annual average leaf length, annual total leaf length and leaf lifespan. All of Cassiope tetragona. These parameters were measured at three sites: Ny-Ålesund and Endalen in Svalbard and for Abisko, Sweden. Same parameters were measured in 17 control and 17 Open Top Chambers plots near Ny-Ålesund. Same parameters were measured in 20 control and 20 ... PAR-reduced plots at Isdammen, near Longyearbyen, Svalbard Same parameters were measured in 10 control and 10 doubled ambient precipitation plots at Isdammen, near Longyearbyen, Svalbard Temperature data at vegetation height was measured in all plots and several sites in and around Longyearbyen and in control and OTC plots in Endalen, Svalbard during the summers of 2008-2011. PAR radiation was measured in control and PAR plots in the summer of 2009. Soil moisture was measured at three sites near Longyearbyen (Huset, Nybyen and Isdammen).