Urban Ecosyst Fig. 3 a. Distribution of landscape carbon accumulation (per unit area) and b. Relationship between landscape carbon accumulation and number of trees on the property
entire property, total N fertilization was directly related to property size in our calculations. The distribution of N fertilizer application rates was significantly skewed among households, with 28% of the households reporting that they did not apply fertilizer at all (Fissore et al. 2011). On average, household rates of N fertilizer applications were approximately eight times those estimated for wet and dry atmospheric N deposition (Table 1). There was no correlation between the rate of N fertilizer applied and the export fluxes associated with lawn clipping and leaf removal. Nitrogen fertilizer application on average exceeded those exports summed with N accumulation in wood and soil, resulting in a positive inferred N flux that was 82% of total output fluxes and 51% of inputs. Over two-thirds of landscape N accumulation occurred in soil, and the remainder accumulated in wood (Table 1). Landscape N accumulation represented approximately 38% of total N inputs. Given the statewide P fertilizer restriction in Minnesota, we assumed that homeowners were not applying P fertilizer to their lawns. Inputs of P to the household landscape were estimated to be 0.2 kg P household−1 year−1 (Table 2) and were dominated by pet waste, which accounted for 84% of total landscape P input fluxes, with atmospheric P deposition accounting for the rest (Table 1). We assumed that atmospheric deposition was uniformly distributed across the entire property; therefore larger properties had higher total P input