Units of measurement, symbols, significant digits and rounding off
1.1 Units of measurement and symbols
1.2 Significant digits
1.3 Rounding off
1.4 Bias, accuracy and precision
Individual Trees and Logs
2.1 Bole characteristics
2.1.1 Diameter
2.1.2 Height
2.1.3 Bark thickness
2.1.4 Volume
2.1.5 Stem form and taper
2.2 Log characteristics
2.2.1 Diameter
2.2.2 Length
2.2.3 Volume
2.2.4 Weight
2.2.5 Allowance for defect
2.3 Crown characteristics
2.3.1 Width
2.3.2 Depth
2.3.3 Surface area
2.3.4 Volume
2.3.5 Biomass
2.4 Stem analysis
Groups of Trees (Stands)
3.1 Number of trees
3.2 Diameter
3.3 Basal area
3.3.1 Fixed-area plots
3.3.2 Angle count sampling
3.3.3 Advantages and disadvantages of angle count sampling
3.4 Height
3.4.1 Mean height
3.4.2 Predominant height, top height, dominant height
3.4.3 Stand height curve
3.5 Volume
3.6 Crown closure
3.7 Crown biomass
3.8 Growth and increment
References
Appendix 1: Checklist of equipment and materials

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1.3 ROUNDING-OFF

Normal practice is to round-off field records to the nearest smallest unit feasible from measurement or to a number which ignores the non-significant digits.

An accepted convention for rounding-off to a whole number which avoids bias is illustrated below for a two digit number, n.5, where n indicates the units digit:

  • If the number is < n.5, round off to n.
  • If the number is > n.5, increase the units digit by 1.
  • If the number = n.5, then round-off to n if the units digit is even but increase n by 1 if the units digit is odd.
Thus, 7.3 rounds off to 7; 7.7 to 8; 7.5 to 8; and 8.5 also to 8.

In some situations, it may be desirable to round measurements to some other interval than a whole number, e.g., to the nearest 0.5. Sometimes convention dictates that measurements, e.g., of log length, be rounded down to the lower whole number. 		 

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January, 1999.