Field Survey & Data Collection Flashcards
7 cards from real SAF practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Field Survey & Data Collection flashcards as text
In the context of forest data collection, a 'tally' sheet that includes a running average check column is designed to:
Answer: Allow real-time detection of outlier measurements before leaving the plot
A running average check column lets the cruiser identify anomalous readings immediately while still on the plot, before moving on and losing the opportunity to remeasure.
Which type of sampling error is introduced when a cruiser consistently underestimates diameter by reading the tape too loosely?
Answer: Systematic bias
Consistent underestimation due to technique is systematic bias, shifting all measurements in the same direction rather than randomly.
A forester needs to establish a baseline and run a perpendicular offset to locate a plot center. The correct field technique uses:
Answer: A 3-4-5 right triangle (or multiples) laid out with a measuring tape
The 3-4-5 right triangle method uses a measuring tape to create a perfect 90° angle in the field without specialized survey equipment.
When cruising timber on steep terrain (slopes >30%), plot shape should be adjusted because:
Answer: Horizontal circular plots become elliptical on the slope surface, oversampling the area
On steep slopes, a horizontal circular plot projects onto the slope surface as an ellipse, sampling more area than intended if slope distance is used uncorrected.
What is the recommended protocol when a tree's center falls exactly on the plot boundary (borderline tree)?
Answer: Use a consistent alternating include/exclude rule (e.g., include north/east, exclude south/west)
A consistent borderline tree rule (such as the half-in/half-out or north/east rule) removes bias that would result from always including or excluding boundary trees.
In an aerial photo interpretation supporting a field cruise, 'photo plots' and 'ground plots' are used in double sampling. The efficiency of this design improves when:
Answer: The correlation between photo and ground estimates is high
Double sampling efficiency improves as the correlation between inexpensive auxiliary (photo) measurements and expensive ground measurements increases.
A forester records crown class for each tree during a stand examination. Which crown class describes trees with crowns extending above the general canopy level?
Answer: Dominant
Dominant trees have large crowns extending above the general canopy level, receiving full overhead light and some light from the sides.