Forest Ecology & Silviculture Flashcards

What is the primary purpose of a 'stocking guide' in silviculture?

Answer: Defining target tree density ranges for optimal stand development

A stocking guide presents target ranges of trees per acre or basal area to guide thinning and planting decisions that optimize stand growth and quality.

In riparian forest management, a 'streamside management zone' (SMZ) is established primarily to:

Answer: Protect water quality and aquatic habitat from management activities

SMZs are buffers where harvest activities are restricted or modified to filter sediment, maintain stream temperature, and protect the ecological integrity of aquatic systems.

Which of the following is the BEST indicator of long-term site productivity for timber in a given forest ecosystem?

Answer: Site index (height of dominant trees at a reference age)

Site index—the average height of dominant and codominant trees at a specified base age (commonly 50 or 100 years)—integrates all site factors affecting growth and is the standard productivity measure.

What ecological process is described when a spruce-fir forest gradually replaces a pioneer aspen stand after disturbance?

Answer: Autogenic succession

Autogenic (self-driven) succession occurs when the community modifies its own environment in ways that favor replacement species, as when aspen shade enables spruce-fir establishment.

A forester measures a Reineke Stand Density Index (SDI) that exceeds the maximum SDI for the species. This indicates:

Answer: Overstocking and imminent density-dependent mortality

When SDI approaches or exceeds the species maximum, the stand enters the zone of imminent competition-induced mortality, signaling that thinning is needed to prevent self-thinning losses.

Which of the following best describes 'provenance' in the context of tree seed selection?

Answer: The geographic origin of a seed source

Provenance refers to the native geographic location where seed was collected, which is critical because trees are locally adapted and planting mismatched provenances can reduce survival and growth.

The 'intermediate treatments' in silviculture (release, cleaning, thinning, pruning) are distinguished from regeneration harvests because they:

Answer: Are conducted during the main rotation to improve stand quality without initiating regeneration

Intermediate treatments manipulate stand density and composition during the rotation to improve growth, quality, or species composition without triggering a new regeneration cycle.