Tree Mesaurements Reference Material
Prepared by William H. Livingston
School of Forest Resources
University of Maine
May 2010
1
Diameter Measurement
Avery, T.E., and H.E. Burkhart. Forest
Measurements, 5th ed. McGraw Hill, NY.
Pg 144-153
The most frequent tree measurement
made by foresters is diameter at brest
height. In the United States, diameter at
breast height (dbh) is defined as the
average stem diameter, outside of the
bark, at a point 4.5 ft above ground as
measured from the uphill side of the stem.
In countries that use the metric system,
dbh is usually taken 1.3 m above ground.
Direct measurements are usually made
with a diameter tape, tree caliper, or
Biltmore stick. Collectively, instruments
employed in determining tree diameters
are referred to as dendrometers.
With a diameter tape, tree circumference
is the variable actually measured. The
tape graduations, based on the
relationship between the diameter and
circumference of a circle, permit direct
readings of tree diameter, usually to the
nearest 0.1 in. If a steel diameter tape is
level and pulled taut, it is the most
consistent method of measuring dbh.
However, as tree cross sections are rarely
circular, taped readings of irregular trees
are likely to be positively biased.
Wooden or steel tree calipers provide a quick and simple method of directly measuring dbh. For ordinary
cruising work, a single caliper measurement will usually suffice. Directional bias can be minimized by
measuring all diameters from the tree face closest to a cruise plot center. If stem cross sections are
decidedly elliptical, two caliper readings at right angels should be made and the average diameter
recorded. When caliper arms are truly parallel and in correct adjustment, the instrument gives reliable
measures of dbh to the nearest 0.1 in. Calipers are ideal for trees up to about 18 in. in diameter. The
diameter tape is often preferred for bigger stems because large calipers are bulky and awkward to handle
in thick underbrush.
-----------------Major points to remember:
Keep instrument/tape perpendicular to the sides of the tree (see diagrams).
Measure 4.5 ft up from the uphill side of the tree
-----------------
2
Total Tree Height Measurement
Avery, T.E., and H.E. Burkhart. Forest Measurements, 5th ed. McGraw Hill, NY. Pg 154-155
National Core Field Guide, Version 3.1
October, 2006
Northern Edition
U.S. Forest Service
http://www.fs.fed.us/ne/fia/datacollection/manualver3_1/index.html
TOTAL LENGTH

Record the TOTAL LENGTH of the tree, to the nearest 1.0 foot from ground level to the top of the
tree. For trees growing on a slope, measure length on the uphill side of the tree.

If the tree has a missing top (top is broken and completely detached from the tree), estimate what
the total length would be if there were no missing top.

Forked trees should be treated the same as unforked trees.
3
Honer’s Volume Equations
An Excel spreadsheet that will calculate the volumns is available for
download at:
http://www.forest.umaine.edu/k-12-education/
click on “Unifying Themes” and then “2009-10 Links/documents”
More information on the volume equations is at:
http://ifmlab.for.unb.ca/People/Kershaw/Courses/For1001/Honer.html
Honer’s (1967) total volume equation has been widely used throughout eastern North
America. In a study conducted in 1998 (Shailer, et al. 1998) in New Brunswick, Honer’s volume
equations were shown to best predict total volume from a set of almost 20 different published
volume equations for nine important commercial species.
The original form of Honer’s total volume equation (Honer 1967) was:
where,
VTot = Total volume in ft3
D = diameter outside bark (inches) measured at breast height (4.5 ft)
H = total height (ft)
b0 and b1 are species specific regression coefficients.
For metric values, the volume equation then becomes:
where,
VTot(M) =total volume in m3
4
d1.3 = diameter at 1.3 m in centimeters (metric dbh)
Hm = total height (m)
a0, a1, and a2 are species specific regression coefficients.
5
Table 1. Original coefficients for estimating total volume (ft3) based on Honer’s (1967) volume
equation, the taper coefficient for conversion of dbh1.3 to DBH1.37(Honer et al. 1983), and the
metric derived coefficents for estimating total volume (m3) by species.
Species
White Pine
Red Pine
Jack Pine
Black Spruce
Red Spruce
White Spruce
Balsam Fir
Cedar
Hemlock
TremblingAspen
Balsam Poplar
White Birch
Yellow Birch
Maple
Basswood
Beech
Black Cherry
White Elm
Ironwood
Red Oak
Honer's (1967) coefficients
b1
b2
0.691
0.710
0.897
1.588
1.226
1.440
2.139
4.167
1.112
-0.312
0.420
2.222
1.449
1.046
0.948
0.959
0.033
0.634
1.877
1.512
363.676
355.623
348.530
333.364
315.832
342.175
301.634
244.906
350.092
436.683
394.644
300.373
344.754
383.972
401.456
334.829
393.336
440.496
332.585
336.509
Taper
Coefficient
0.184
0.151
0.151
0.164
0.169
0.176
0.152
0.155
0.155
0.127
0.127
0.176
0.181
0.145
0.145
0.145
0.145
0.145
0.145
0.145
metric derived coefficients
a0
0.691
0.710
0.897
1.588
1.226
1.440
2.139
4.167
1.112
-0.312
0.420
2.222
1.449
1.046
0.948
0.959
0.033
0.634
1.877
1.512
a1
110.848
108.394
106.232
101.609
96.266
104.295
91.938
74.647
106.708
133.101
120.287
91.554
105.081
117.035
122.364
102.056
119.889
134.263
101.372
102.568
a2
0.004319
0.004331
0.004331
0.004327
0.004325
0.004322
0.004331
0.004330
0.004330
0.004341
0.004341
0.004322
0.004320
0.004334
0.004334
0.004334
0.004334
0.004334
0.004334
0.004334
References
Honer, T.G. 1967. Standard volume tables and merchantable conversion factors for the
commercial tree species of central and eastern Canada. Can. Dept. Forestry
Rural Devel., For. Mgmt. Res. and Serv. Inst. Info. Rep. FMR-X-5.
Honer, T.G., Ker, M.F. and Alemdag, I.S. 1983. Metric timber tables for the commercial tree
species of central and eastern Canada. Maritimes For. Res. Centre. Info. Rep. M-X-140.
Shailer, S., Kershaw, J.A., and Zundel, P. 1998. Comparison of total volume equations for use in
southwestern New Brunswick. Research Report perpared for Georgia Pacific (The Timber
Company), St. Croix district.
6