Forest Ecology & Silviculture Flashcards

In the context of forest disturbance ecology, which of the following is classified as a 'chronic' rather than 'acute' disturbance?

Answer: Chronic browsing by ungulates

Chronic disturbances, like sustained ungulate browsing or acid deposition, operate continuously at low to moderate intensity over long periods, in contrast to acute disturbances that are discrete, high-intensity events.

A forester applying the 'two-aged silviculture' system retains a dispersed layer of large, old trees after regeneration harvest primarily to:

Answer: Supply structural legacy elements and habitat for old-growth-dependent species

Two-aged management intentionally retains legacy trees from the previous stand across regeneration harvest to provide structural complexity, wildlife snags, and habitat continuity for species dependent on old-growth attributes.

What is the ecological term for the zone of transition between two distinct plant communities, such as a forest and a meadow?

Answer: Ecotone

An ecotone is a transition zone between two adjacent ecological communities, often characterized by high species diversity due to the 'edge effect' from both adjacent communities.

Which silvicultural approach best describes managing a forest to maintain structural and compositional diversity across the landscape, rather than treating each stand in isolation?

Answer: Landscape-level or ecosystem management

Landscape-level or ecosystem management considers stands within their broader landscape context, coordinating treatments across multiple stands to maintain biodiversity, habitat connectivity, and ecological function at the landscape scale.

The 'R/D ratio' (reproduction-to-density ratio) concept in forest ecology is most directly related to which forest management concern?

Answer: Assessing regeneration adequacy relative to stand density after disturbance

The R/D ratio assesses whether sufficient regeneration is present relative to residual stand density, helping foresters determine if natural regeneration following harvest or disturbance will be adequate to meet stocking objectives.

A silviculturist is working in a mixed conifer stand in the Sierra Nevada and notices that fire exclusion has led to high densities of white fir under a ponderosa pine canopy. This best illustrates which ecological concept?

Answer: Autogenic succession driven by altered disturbance regime

Fire suppression altered the natural disturbance regime that historically maintained ponderosa pine dominance by killing shade-tolerant white fir understory, allowing autogenic succession toward greater white fir dominance.

Which of the following terms describes the technique of cutting branches or small stems to the main trunk to produce knot-free lumber in the lower bole of standing trees?

Answer: Pruning

Pruning removes lower branches from standing crop trees to produce clear, knot-free wood in the commercially valuable lower butt log, improving timber quality over the remainder of the rotation.