B.F. Bachelor of Forestry Bachelor of Forestry Forest Ecosystem 2 — Questions and Answers
Question 1: Which biogeochemical cycle is most directly disrupted when forest soils are compacted by heavy machinery?
- Carbon cycle
- Nitrogen cycle
- Water cycle (Correct answer)
- Phosphorus cycle
Correct answer: Water cycle
Soil compaction reduces pore space, impairing infiltration and disrupting the water cycle most immediately.
Question 2: A forest stand shows declining mycorrhizal diversity after repeated prescribed burns. What is the most likely ecological consequence?
- Increased canopy closure
- Reduced nutrient uptake by trees (Correct answer)
- Higher soil organic matter accumulation
- Greater herbaceous understory diversity
Correct answer: Reduced nutrient uptake by trees
Mycorrhizal fungi facilitate phosphorus and nitrogen uptake in tree roots, so their decline impairs nutrient absorption.
Question 3: In a northern hardwood forest, which trophic level contains the greatest total biomass?
- Primary consumers
- Secondary consumers
- Producers (Correct answer)
- Decomposers
Correct answer: Producers
Producers (trees and plants) hold the largest biomass at the base of the trophic pyramid.
Question 4: What is the term for the process by which fallen logs gradually release stored carbon back into the atmosphere through microbial decomposition?
- Mineralization (Correct answer)
- Volatilization
- Humification
- Nitrification
Correct answer: Mineralization
Mineralization converts organic carbon in woody debris into inorganic CO2 via microbial respiration.
Question 5: A forester observes that a riparian buffer strip significantly reduces nitrate concentrations in stream water. Which process is primarily responsible?
- Volatilization
- Denitrification (Correct answer)
- Ammonification
- Fixation
Correct answer: Denitrification
Denitrifying bacteria in saturated riparian soils convert nitrate to nitrogen gas, removing it from water.
Question 6: Which forest ecosystem type typically has the highest net primary productivity (NPP) per unit area?
- Boreal forest (taiga)
- Temperate deciduous forest
- Tropical rainforest (Correct answer)
- Mediterranean shrubland
Correct answer: Tropical rainforest
Tropical rainforests have year-round warmth and moisture, driving the highest NPP of any forest biome.
Question 7: In forest gap dynamics, what is the primary factor that determines which species colonizes a canopy gap first?
- Seed size
- Dispersal mechanism and seed bank proximity (Correct answer)
- Leaf area index of adjacent trees
- Soil pH
Correct answer: Dispersal mechanism and seed bank proximity
Species with effective dispersal and nearby seed sources gain first access to newly opened gaps.
B.F. Bachelor of Forestry Bachelor of Forestry Forest Ecosystem 2
Which biogeochemical cycle is most directly disrupted when forest soils are compacted by heavy machinery?