FM Forest Ecology & Silviculture 3 ā Questions and Answers
Question 1: Which of the following best describes 'allelopathy' in a forest context?
- Competition for light between canopy layers
- Chemical inhibition of one plant species by another (Correct answer)
- Mycorrhizal nutrient sharing between trees
- Wind pollination across species boundaries
Correct answer: Chemical inhibition of one plant species by another
Allelopathy occurs when a plant releases chemical compounds that inhibit the germination or growth of neighboring plants, as seen with black walnut and many understory species.
Question 2: A silviculturist prescribes a 'crop tree release' treatment. What is the PRIMARY goal?
- Removing all understory vegetation
- Freeing selected high-value trees from competition (Correct answer)
- Establishing a new cohort of seedlings
- Reducing ladder fuels for fire prevention
Correct answer: Freeing selected high-value trees from competition
Crop tree release removes competing trees touching or overtopping selected crop trees, directing site resources to the most valuable individuals.
Question 3: What is the ecological significance of the 'duff' layer in a forest floor?
- It reflects solar radiation, cooling the soil
- It stores water, nutrients, and supports decomposer communities (Correct answer)
- It forms an impermeable barrier preventing deep root growth
- It is the primary source of airborne particulates
Correct answer: It stores water, nutrients, and supports decomposer communities
The duff (partially decomposed organic matter) layer retains moisture, cycles nutrients, moderates soil temperature, and hosts the fungi and invertebrates that drive decomposition.
Question 4: In the context of forest management, what is a 'mast year'?
- Year with maximum timber volume increment
- Year of exceptionally high seed production by trees (Correct answer)
- Year when crown fire risk is highest
- Year when prescribed burns are scheduled
Correct answer: Year of exceptionally high seed production by trees
A mast year is a synchronized, episodic event when tree species (especially oaks and beeches) produce far above-average quantities of seeds, benefiting wildlife that depend on this food source.
Question 5: Which silvicultural system is most appropriate for managing Ponderosa pine, a shade-intolerant species, in the western US?
- Single-tree selection
- Group selection
- Shelterwood or clearcutting variants (Correct answer)
- Uneven-aged high forest
Correct answer: Shelterwood or clearcutting variants
Shade-intolerant species like Ponderosa pine require significant light for regeneration, making shelterwood or clearcut systems (which create large openings) most suitable.
Question 6: The 'leaf area index' (LAI) of a forest stand is defined as:
- Number of leaves per cubic meter of canopy
- Total one-sided leaf area per unit of ground area (Correct answer)
- Ratio of photosynthetic to non-photosynthetic biomass
- Average leaf size across all canopy species
Correct answer: Total one-sided leaf area per unit of ground area
LAI is the total one-sided area of leaf tissue per unit ground surface area and is a key indicator of light interception capacity and stand productivity.
Question 7: Which process describes the conversion of atmospheric nitrogen into plant-available forms by microorganisms?
- Denitrification
- Mineralization
- Biological nitrogen fixation (Correct answer)
- Nitrification
Correct answer: Biological nitrogen fixation
Biological nitrogen fixation is carried out by bacteria (such as Rhizobium and free-living Azotobacter) that convert Nā gas into ammonia, making it available for plant uptake.
FM Forest Ecology & Silviculture 3
Which of the following best describes 'allelopathy' in a forest context?