## 2 Methods
### Model Description  
The terrestrial ecosystems model version hydro (TEM-Hydro [4; 5; 6] consists of multiple pools for vegetation carbon and nitrogen and a single pool for soil organic carbon and nitrogen, as well as a pool for inorganic nitrogen. The vegetation pools include leaves, active and inactive stem tissues (e.g., sapwood and heartwood), fine roots, and a labile pool for storage. Fluxes into and out of the pools include photosynthesis, nitrogen uptake, respiration, litterfall, allocation, and dissolved organic carbon (DOC). The more recent version of the model (TEM-Hydro2) includes improvements to the modeling of land use and a reduced-form open nitrogen cycle [4], which allows for N deposition, N fixation, denitrification, and leaching of dissolved organic and inorganic nitrogen (DON and DIN). [PERSON] et al. [4; 5] provide a complete description of the model, illustrated in a summary figure (Figure S3), along with how human disturbance is treated (Figure 1 from [PERSON] [4]), which is relevant to this paper. The cohort approach is designed to keep track of land use transitions so that when converting impervious surfaces or lawns to forests, for example, the new forest is tracked separately from the existing forest as it is younger and contains soil nutrients from the original disturbed land, not the existing forest. When a forest is converted to an impervious surface or lawn, new cohorts are created to distinguish the new impervious surface or lawn from the original. A full description of the cohort approach is described in [PERSON] [19] and [PERSON] [10], but its application here is relatively simple as there is only a single year of disturbance in each experiment. Since forest consists of both deciduous and evergreen broadleaf types, adding additional forests or creating new cohorts from the forests creates two new cohorts. In these experiments, there are therefore 7 cohorts prior to 2030 (2 forests, impervious surface, barren land, lawn, crop, and pasture) and 9 cohorts after the disturbance in 2030. Following a disturbance, the area of the original cohort that has been depleted is adjusted accordingly. The output is then area-weighted for each of the cohorts. The initial model runs started with the 7 land cover cohorts, as follows: impervious surface, barren field, deciduous forest, coniferous forest, lawn, cropland, and pasture. The area of each cohort was used in TEM as postprocessing to area-weight the output. To examine land use effects, a change to the land use cohort areas was implemented in 2030. The decision to implement LULCC in a single year is a simplification of a more realistic gradual change, but an advance of the assumption of two different states of LULC, which would not capture the carbon effects of that land use conversion and decomposition of its products. The changes were 10%, 25%, and 50% of the area of the cohort that was being converted. All the experiments involved conversion to or from forests in the year 2030, and the forest cohorts were split into two cohorts to represent coniferous and deciduous forests. When forest area is being converted into either impervious surface or lawn, we assume the equivalent of agricultural clearance in the year 2030. During the year of the disturbance, 60% of the vegetation is burned. The remaining 30% goes into the 10-year pool, and 10% goes into the 100-year pool, where they decay at a rate of 10% and 1% per year, respectively [10]. [PERSON] and [PERSON] [10] tested several assumptions about the distribution between the amount of timber going into the fuelwood and the 10- and 100-year product pools for both agricultural clearance and timber harvesting and concluded that the net effect on cumulative NCE was relatively minor, while there is a redistribution between the pools. Harvested crops go into the 1-year pool, where they are assumed to be consumed within the same grid where they are grown within the year. The seed is harvested, so the seed carbon goes into the 1-year product pool.