For average tree diameters between 3 to 7 inches, which chart should be used?

For average tree diameters between 3 to 7 inches, which chart should be used?

• A. The chart on the left
• B. The chart on the right
• C. The chart in the middle
• D. No chart is used

Answer: (C)

The key idea is to match the chart to the size range you’re analyzing. Charts are built from data for specific diameter classes, and the relationship between diameter and other attributes (like height or volume) changes with size. A 3–7 inch average falls squarely in the mid-range, so the chart designed for that middle diameter band best reflects the actual growth and yield patterns you’d expect for trees around 5 inches DBH. Using charts intended for much smaller or much larger trees would misrepresent those relationships and yield less accurate estimates. So the middle chart is the appropriate choice for trees in the 3–7 inch diameter range.

The key idea is to match the chart to the size range you’re analyzing. Charts are built from data for specific diameter classes, and the relationship between diameter and other attributes (like height or volume) changes with size. A 3–7 inch average falls squarely in the mid-range, so the chart designed for that middle diameter band best reflects the actual growth and yield patterns you’d expect for trees around 5 inches DBH. Using charts intended for much smaller or much larger trees would misrepresent those relationships and yield less accurate estimates. So the middle chart is the appropriate choice for trees in the 3–7 inch diameter range.