Forest Ecology and Silviculture Flashcards

What is 'crown fire' behavior in forest fire ecology, and which stand structure is most susceptible?

Answer: Fire spreading through tree crowns; most susceptible in dense conifer stands with ladder fuels

Crown fires spread through tree canopies and are most common in dense conifer stands where ladder fuels connect surface and crown fuels.

In forest ecology, what does 'site index' measure?

Answer: The potential productivity of a site based on dominant tree height at a reference age

Site index measures site productivity by comparing dominant tree height at a standard base age (typically 50 or 100 years) to reference curves.

Which of the following best describes 'advanced regeneration' in silviculture?

Answer: Young trees established beneath an existing canopy prior to harvest

Advanced regeneration consists of young trees or seedlings that established under the existing forest canopy before the overstory was harvested.

What is the primary ecological impact of invasive earthworms (e.g., Lumbricus terrestris) in North American hardwood forests?

Answer: Rapidly consume the forest floor duff layer, disrupting native plant communities

Invasive earthworms rapidly consume the forest duff layer, depleting nutrients that native understory plants depend on and altering forest floor ecology.

What is the difference between 'high thinning' and 'low thinning' in silviculture?

Answer: High thinning targets trees in the upper canopy for removal; low thinning removes trees from lower crown classes

High thinning (crown thinning) removes trees from the dominant and codominant crown classes, while low thinning (German thinning) removes suppressed and intermediate trees.

Which forest ecosystem process is defined as the total amount of carbon fixed by plants minus the carbon they release through respiration?

Answer: Net Primary Production (NPP)

Net Primary Production (NPP) equals gross photosynthesis minus autotrophic (plant) respiration, representing actual biomass available to consumers.

In the context of prescribed fire ecology, what is the term for accumulated dead organic material on the forest floor that burns slowly?

Answer: Duff

Duff is the partially decomposed organic layer beneath fresh litter that smolders slowly during fire and can burn for days after a prescribed burn.