This dataset contains total green biomass, palatable green biomass, sheep stocking rate, Pinus contorta tree density, P. contorta basal area and percentage canopy cover in sites across northwest Patagonia, during the summer of 2020. We measured total green biomass in the peak production (kg /hectare/year), as a metric for aboveground annual productivity, in five different sites and for a wide range of P. contorta abundance. We also measured palatable green biomass (kg/hectare/year), considering only those plant species foraged by sheep. We calculated the sheep stocking rate that can sustainably support the grasslands of our study based on the feeding requirement of an Ovine Livestock Unit (OLU). The OLU represents a Merino wether (castrated male sheep) with an average live weight of 40 kg that consume 365 kg of dry forage in a year in Patagonia grasslands. We counted the number of P. contorta individuals to calculate density (trees/ha) and recorded their diameter at ground level to calculate basal area (m2/ha) (an alternative measure of P. contorta abundance). Additionally, on each subplot we took a hemispheric picture to estimate the canopy cover (%) of P. contorta (a third measure of P. contorta abundance). Full details about this dataset can be found at https://doi.org/10.5285/066b0d36-d28a-422e-b29a-298c98b8a536