Data Analysis & Reporting Flashcards

Which remote sensing technology is most effective for mapping individual tree crowns and estimating stand-level basal area in dense conifer forests?

Answer: Airborne LiDAR

Airborne LiDAR penetrates canopy gaps to measure 3D structure, enabling individual tree delineation and structural attribute estimation in dense forests.

In forest inventory, 'periodic annual increment' (PAI) is calculated as:

Answer: Volume growth over a period divided by the number of years in that period

PAI = (V₂ - V₁) / number of years, representing average annual growth over a specific measurement period.

A residual plot from a linear regression of tree height on DBH shows a fan-shaped pattern (variance increasing with fitted values). This indicates:

Answer: Heteroscedasticity — non-constant variance of residuals

A fan-shaped residual plot is a classic sign of heteroscedasticity, where the variance of residuals is not constant across fitted values, violating a key OLS assumption.

The Forest Inventory and Analysis (FIA) program uses which primary sampling design across the contiguous United States?

Answer: Systematic hexagonal grid with clustered fixed-radius plots

FIA uses a systematic grid of hexagons (~2,400 ha each), with one plot cluster per hexagon, each cluster containing four fixed-radius subplots.

When a forester calculates 'trees per acre' from a prism walk and tally, she divides each tallied tree's contribution by its basal area. This approach is called:

Answer: Point sampling (horizontal point sampling)

Horizontal point sampling (angle gauge or prism cruise) uses a sweep from a fixed point, where each 'in' tree represents a stand-level estimate inversely proportional to its basal area.

In a chain-of-custody (CoC) timber report, the term 'controlled wood' most closely refers to:

Answer: Wood from sources that are not certified but meet minimum standards excluding the most controversial origins

Under FSC standards, controlled wood comes from non-certified but screened sources that avoid the five categories of unacceptable forest management.

A forester observes that the Moran's I statistic for a mapped distribution of a forest pest is close to +1. This indicates:

Answer: The pest is clustered — nearby areas tend to have similar infestation levels

Moran's I near +1 indicates strong positive spatial autocorrelation — infested areas tend to be adjacent to other infested areas, indicating clustering.