Point intercept and biomass data for vascular plants in a manipulative experiment of rear-round, winter-only, summer-only grazing, mowing and full exclosure at Molslab, Denmark

Data from two sets of sample quadrats included, both from nine experimental blocks, each replicating the treatments: rear-round grazing, winter-only grazing (summer exclosure), summer-only grazing (winter exclosure), mowing (one annual event in autumn) and full exclosure (no cattle or horse grazing, no mowing, but grazing by wild roe deer and hare). 1) Each of the 24 sample plots (six blocks times four treatments, mowing excluded) was first sampled non-destructively with the point intercept method, then above-ground biomass was cut at the soil surface, sorted into species fractions, dried and weighed. Data recording September 1–16, 2020. 2) Each of the 45 sample plots (nine blocks times five treatments) was sampled non-destructively with the point intercept method. Data recording August 2–20, 2021.The point-intercept method was used to assess plant species' abundance. A gridded quadratic aluminum frame was used to systematize the distribution of points within the 25 × 25 cm sampling area with 5 × 5 cm spacing. The frame had two parallel grid layers, made of nylon fishing cord, in order to provide a fixed trajectory for the vertical stick, which was a 0.8 cm thick wooden stick. The frame was placed on four aluminum legs, with a height of 50 cm. Above-ground biomass was assessed by cutting plant biomass as close to the soil surface as possible, immediately sorting it into fractions by plant species (with standing litter as a separate fraction) and drying it at 55 ˚C until constant weight. The 2020 data were used to make calibration models for above-ground plant biomass estimated by point intercept methodology