The data consists of plant structural plant community measurements from fifteen sites located in the Conwy catchment (North Wales) and from two sites in North West England. Annual aboveground net primary productivity (NPP), canopy height (cht), bryophyte cover (Bcov), leaf dry matter content (LDMC), leaf mass area (LMA) and specific leaf area (SLA) were measured on the dominant plant species. Data were collected in 2013 and 2014. The sites were chosen to represent habitat types and the terrestrial productivity gradient in Britain from intensive agriculturally managed lowland grasslands through to montane heath. Plots within the sites were located using a stratified random sampling design. Plant trait values were taken from existing published databases or were directly measured in each plot for the two species contributing the highest percentage cover. NPP (grams of dry mass per square metre per year) was measured using a variety of methods according to the plant functional types present. SLA and LDMC was measured on site focussing on the dominant vascular plant species in each plot defined as the two species contributing maximum standing biomass in the year of sampling. Leaf area was calculated based on scanned photographs analysed using Image J software v1.46r. Plant parameters were tested across a land use intensification gradient to detect parameters that can predict aboveground biomass production across different land management types. Data were used to enhance the predictions of biomass production in the Joint UK Land Environment Simulator model (JULES). Measurements informed the improvement of the nitrogen cycle component in the model. Measurements were undertaken by trained members of staff from Bangor University, the Centre for Ecology & Hydrology and Exeter University. This data was collected for the NERC project - The Multi-Scale Response of Water quality, Biodiversity and Carbon Sequestration to Coupled Macronutrient Cycling from Source to Sea (NE/J011991/1). The project is also referred to as Turf2Surf.