Forest Protection (Insects, Disease, Fire)
What this domain tests
Identification and management of insects, diseases, and fire behavior, plus decision rules for suppression, salvage, and prescribed burning.
Core rules
- Bark beetles (Dendroctonus and Ips) mass-attack; pheromones concentrate attacks, and thinning that raises vigor reduces susceptibility. Defoliators such as spruce budworm and gypsy moth cycle with outbreaks; one defoliation rarely kills, repeated defoliation does.
- Root diseases (Armillaria, Heterobasidion) spread by root contact and stumps; infection centers expand radially, so buffering and stump treatment matter more than burning slash.
- White pine blister rust requires a Ribes alternate host; Dutch elm disease moves with elm bark beetles.
- Fire behavior triangle: fuel, weather, topography. Fine fuel moisture and wind drive rate of spread; live fuel moisture governs crown fire. Low canopy base height and ladder fuels allow a surface fire to torch.
- Hazard is the fuel; risk is the chance of ignition. Prescribed fire needs a written burn plan with weather windows and contingency.
Worked example
Byram intensity I = H times w times r. With heat yield 18,000 kJ/kg, 1.2 kg per square meter consumed, and 0.05 m/s spread: I = 18,000 times 1.2 times 0.05 = 1,080 kW/m. Flame length is roughly 0.0775 times I to the 0.46 power = 0.0775 times 24.9 = 1.9 m. That is a controllable low-intensity fire; doubling the fuel load doubles intensity and roughly doubles flame length.
Traps
Confusing hazard and risk; assuming every beetle-killed tree needs salvage; prescribing low-severity fire when fine fuels are too moist; ignoring root disease centers when planning regeneration.