Simulation data for: Greater variability in environmental stress favours trees that prioritise storage of carbohydrate reserves over growth: a modelling analysis

This dataset contains simulation output from a forest patch model investigating the competitive outcomes of four tree carbon allocation strategies under varying environmental stress regimes. The model tracks individual trees over 100-year simulation runs within a 100 m² patch, following the plant model framework (https://github.com/traitecoevo/plant, Falster et al. (2016); doi: 10.1111/2041-210X.12525) and extended in a new plant model plantNSC (https://github.com/foxeswithdata/plant). Note results have been processed to remove dead individuals and individuals with diameter below 5cm. Experimental Design Simulations were structured across three nested levels: 1. Environmental treatments (8 total) Two average stress intensities as represented by mean duration of stress (low: 54.75 days or 0.15 year and medium 91.25 days or 0.25 year) were crossed with four levels of stress stochasticity as represented by variance around the mean duration of stress (none: variance 0 days, low: variance 15 days, medium: variance 30 days, high: variance 60 days), yielding 8 environmental treatments. An additional control simulation was included with no stress (duration of stress 0 days), no stochasticity, and no storage-related mortality, giving 9 treatments in total. 2. Environment repetitions (env_rep) For each treatment with stochasticity, five random stress sequences were drawn from the treatment's probability distribution (one sequence for the no-stochasticity treatments). These represent stochastic variation in the environmental stress time series. 3. Run repetitions (run_rep) Each stress sequence was run four times to account for model stochasticity arising from germination and mortality processes. Each simulation run contains all four allocation strategies simultaneously, each receiving an equal seed rain of 0.5 seeds m⁻² yr⁻¹ (derived from the FF16 deterministic model). An adaptive time-step was used, ranging from 10⁻⁶ to 10⁻¹ years. Total simulation count 6 stochastic stress treatments × 5 env_rep × 4 run_rep = 120 runs 2 non-stochastic stress treatments × 1 env_rep × 4 run_rep = 8 runs 1 control treatment × 1 env_rep × 4 run_rep = 4 runs Total: 132 simulation runs File Structure Simulation outputs are organised by environmental treatment, environment repetition, and run repetition: env_{env_mean}_{env_sd}/envrep_{env_rep}/runrep_{run_rep}/ ├── env_data_processed.rds ├── env_stress_processed.rds └── tree_data_processed.rds Each run directory contains three files: env_data_processed.rds Patch-level light environment openness conditions. Column Description Units time Simulation time years height Canopy height distribution m canopy_openness Proportion of light reaching canopy at height height 0-1 env_mean Mean environmental stress intensity for this treatment % year env_sd Standard deviation of environmental stress for this treatment days env_rep Environment repetition index integer run_rep Run repetition index integer env_stress_processed.rds Time series of environmental stress experienced during the simulation. Column Description Units time Simulation year years stress Realised time of stress in year years env_stress Realised time of stress in simulation (env_stress = time + stress) years env_mean Mean environmental stress intensity for this treatment % year env_sd Standard deviation of environmental stress for this treatment days env_rep Environment repetition index integer tree_data_processed.rds Individual tree-level state variables and derived quantities at each time step. Column Description Units time Simulation time years dt Time step duration years tree_id Unique identifier for each individual tree — species_id Allocation strategy identifier (1–4): 1 = Slow-Risky, 2 = Slow-Safe, 3 = Fast-Risky, 4 = Fast-Safe — height Tree height m diameter_stem Stem diameter m area_stem Cross-sectional area of stem m² area_leaf Total leaf area m² area_sapwood Cross-sectional area of sapwood m² area_bark Cross-sectional area of bark m² area_heartwood Cross-sectional area of heartwood m² mass_leaf Leaf mass kg mass_sapwood Sapwood mass kg mass_bark Bark mass kg mass_root Root mass kg mass_heartwood Heartwood mass kg mass_storage Non-structural carbohydrate (storage) mass kg storage_portion Fraction of biomass allocated to carbon storage — is_alive Whether the tree is alive at this time step boolean (0/1) dead_flag Whether the tree is dead at this time step boolean (0/1) mortality Mortality likelihood based on mortality function. yr⁻¹ mortality_new Total Mortality factor used in mortality function. — mortality_growth_dependent Growth-dependent mortality likelihood — mortality_storage_dependent Storage-dependent mortality likelihood — mortality_growth_dependent_dt Growth-dependent mortality factor used in mortality function yr⁻¹ mortality_storage_dependent_dt Storage-dependent mortality factor used in mortality function yr⁻¹ fecundity Fecundity rate seeds yr⁻¹ fecundity_dt_abs Fecundity rate seeds yr⁻¹ net_mass_production_dt Net mass production rate kg yr⁻¹ dbiomass_dt Rate of change in total biomass kg yr⁻¹ respiration_dt Total respiration rate kg yr⁻¹ respiration_leaf_dt Leaf respiration rate kg yr⁻¹ respiration_sapwood_dt Sapwood respiration rate kg yr⁻¹ respiration_root_dt Root respiration rate kg yr⁻¹ respiration_bark_dt Bark respiration rate kg yr⁻¹ productivity_area Net mass production per unit leaf area used in mortality calculation. kg m⁻² competition_effect Effect of competition on light environment. Equivalent to leaf area. m² stress Environmental stress value at this time step. Equivalent to amount of photosynthesis that can occur at this time point (1 - no photosynthesis limitation, 0 - full photosynthesis limitation) — darea_leaf_dt Rate of change in leaf area m² yr⁻¹ darea_leaf_dmass_live Change in leaf area per unit live mass m² kg⁻¹ dmass_leaf_darea_leaf Leaf mass per unit leaf area (LMA) kg m⁻² dmass_sapwood_darea_leaf Sapwood mass per unit leaf area kg m⁻² dmass_bark_darea_leaf Bark mass per unit leaf area kg m⁻² dmass_root_darea_leaf Root mass per unit leaf area kg m⁻² dmass_leaf_dt Rate of change in leaf mass kg yr⁻¹ dmass_sapwood_dt Rate of change in sapwood mass kg yr⁻¹ dmass_bark_dt Rate of change in bark mass kg yr⁻¹ dmass_root_dt Rate of change in root mass kg yr⁻¹ dheight_darea_leaf Height growth per unit increase in leaf area m m⁻² height_difference Calculation for adjusting expected mass to height allometry post stress. m height_adjustment Calculation for adjusting expected mass to height allometry post stress. — mass_sapwood_difference Calculation for adjusting expected mass to height allometry post stress. kg mass_sapwood_adjustment Calculation for adjusting expected mass to height allometry post stress. — env_mean Mean environmental stress intensity for this treatment % year env_sd Standard deviation of environmental stress for this treatment days env_rep Environment repetition index integer run_rep Run repetition index integer