Simulates a mortality event (fire, drought, insects, disease) by assigning mortality status to trees based on size-dependent probabilities. Achieves a target proportion of dead trees by preferentially killing trees with higher mortality risk.
Arguments
- trees
Data.table. Tree data with all attributes
- target_mortality_prop
Numeric. Proportion of trees to kill (0-1). Default 0.15 (15 - 0.05-0.15: Low intensity disturbance - 0.15-0.30: Moderate intensity disturbance - 0.30-0.60: High intensity disturbance - 0.60-0.90: Stand-replacing disturbance
- mort_params
List. Species-specific mortality parameters passed to
calc_mortality_probability. NULL uses defaults.
Value
Data.table. Input trees with added columns:
- MortalityProbability
Numeric. Calculated probability (0-1)
- Status
Character. "live" or "dead"
Details
Process: 1. Calculate mortality probability for each tree using size-dependent model 2. Sort trees by probability (highest risk first) 3. Mark top N trees as dead where N = target_mortality_prop * total_trees 4. Mark remaining trees as live
This approach ensures: - Exact target mortality proportion is achieved - Smaller trees preferentially killed (realistic) - Deterministic given the same input (reproducible)
Examples
if (FALSE) { # \dontrun{
# Simulate 20% mortality
trees_with_mortality <- simulate_mortality(result$trees, target_mortality_prop = 0.20)
table(trees_with_mortality$Status) # Count live vs dead
# Analyze size distribution of mortality
dead_trees <- trees_with_mortality[Status == "dead"]
mean(dead_trees$DBH) # Smaller trees preferentially killed
} # }