KEAM Forestry: Ecology, Silviculture and Measurement
What this domain tests
Forestry in KEAM uses the PCB stream and covers forest ecology, silviculture, dendrology, wildlife, conservation and forest products. Questions connect biology to management: how forests regenerate, how species are identified, how habitats are measured and how yield is estimated.
Core rules and concepts
- Forest ecology: succession, canopy stratification, nutrient cycling and edge effects shape community structure.
- Silviculture: even-aged and uneven-aged systems; clear-felling, shelterwood, selection and coppice differ in regeneration and shade tolerance.
- Measurement: diameter at breast height (dbh) is measured at 1.37 m; basal area = π(dbh/2)²; tree volume uses basal area × height × form factor.
- Conservation: in-situ versus ex-situ methods, core/corridor/buffer zoning and IUCN threat categories.
- Products: timber, fuelwood, bamboo, rattan and non-timber forest products require sustainable harvest rules.
Worked example
A rectangular plot is 20 m × 25 m, so area = 500 m² = 500 ÷ 10,000 = 0.05 ha. Five trees are counted. Trees per hectare = 5 ÷ 0.05 = 100. If the same plot were mistakenly treated as 0.5 ha, density would be wrongly reported as 10 trees/ha. The reasoning is to convert square metres to hectares before dividing; density is individuals per unit area, not a raw count.
Traps that cost marks
Measuring dbh at the wrong height; confusing basal area with canopy cover; forgetting the form factor in volume estimates; and treating a 20 m × 25 m plot as 0.5 ha. For conservation items, distinguish habitat protection from species-level recovery programmes.