Tree Measurement
Seniors will measure 4 standing trees and fill out the table on their scoresheet. For each tree, seniors will identify the species and estimate the diameter and merchantable height. Diameter should be measured and recorded in even 2-inch diameter classes. Height should be measured in 16-foot logs to the nearest full half-log. Merchantable height should be measured from stump height to either an 8-inch top diameter, a major fork, or a serious defect that affects more than half the tree's diameter at that point.
In addition, Seniors will determine the total volume in the plot and the volume per acre. Ten points will be allowed for the correct volume per acre. The plot acreage and tree volumes can be found in the table below. Remember, the total volume in the plot must be multiplied by a factor (20 for a 1/20-acre plot, 10 for a 1/10- acre plot, 5 for a 1/5-acre plot and 4 for a 1/4-acre plot) to determine the volume per acre. Point allocation will be 10 points for ±5% of the official volume, 8 points for ±10%, 6 points for ±15%, and no points over ±15%.
Tree volumes can be found on the table below, which will be provided on the contest scoresheet.
Volume Table
International ¼ inch Log Rule -- Form Class 78
VOLUME (board feet) BY NUMBER OF 16-FOOT LOGS
|
|
Height (number of 16-foot logs) |
||||||||
|
DBH |
1 |
1½ |
2 |
2½ |
3 |
3½ |
4 |
4½ |
5 |
|
10 |
36 |
48 |
59 |
66 |
73 |
----- |
----- |
----- |
----- |
|
12 |
56 |
74 |
92 |
106 |
120 |
128 |
137 |
----- |
----- |
|
14 |
78 |
105 |
132 |
153 |
174 |
187 |
200 |
----- |
----- |
|
16 |
106 |
143 |
180 |
210 |
241 |
263 |
285 |
----- |
----- |
|
18 |
136 |
184 |
233 |
274 |
314 |
344 |
374 |
----- |
----- |
|
20 |
171 |
234 |
296 |
348 |
401 |
440 |
480 |
511 |
542 |
|
22 |
211 |
290 |
368 |
434 |
500 |
552 |
603 |
647 |
691 |
|
24 |
251 |
346 |
441 |
523 |
605 |
664 |
723 |
782 |
840 |
|
26 |
299 |
414 |
528 |
626 |
725 |
801 |
877 |
949 |
1,021 |
|
28 |
347 |
482 |
616 |
733 |
850 |
938 |
1,027 |
1,114 |
1,201 |
|
30 |
403 |
560 |
718 |
854 |
991 |
1,094 |
1,198 |
1,306 |
1,415 |
|
32 |
462 |
644 |
826 |
988 |
1,149 |
1,274 |
1,400 |
1,518 |
1,637 |
|
34 |
521 |
728 |
934 |
1,119 |
1,304 |
1,447 |
1,590 |
1,727 |
1,864 |
|
36 |
589 |
826 |
1,063 |
1,274 |
1,485 |
1,650 |
1,814 |
1,974 |
2,135 |
|
38 |
656 |
921 |
1,186 |
1,428 |
1,670 |
1,854 |
2,038 |
2,224 |
2,410 |
|
40 |
731 |
1,030 |
1,329 |
1,598 |
1,868 |
2,081 |
2,294 |
2,494 |
2,693 |
Scoring
A total of 30 points are available for this station:
- 20 total points for tree scores:
- One point for each correct tree identification
- Two points for each correct DBH
- Two points for each correct tree height
- 10 points possible for volume per acre: Point allocation will be 10 points for ±5% of the official volume, 8 points for ±10%, 6 points for ±15%, and no points over ±15%.
You will need a Biltmore stick that fits your arm length. You can make your own Biltmore stick by purchasing a yard stick or a blank stick or strip of wood, and taping a scale to your stick.
Resources
- 2023 Tree Measurement Scoresheet
- Tree Measurement (PDF, pages 14-18 of the 2014 Invitational Handbook)
- Tree Measurements Using a Biltmore Stick (PDF, University of Kentucky)
- Biltmore Stick Instruction Video (Video by Paul Decker, University of Florida)
- Directions for Scale Stick Measurement (on the 4-H Forestry Invitational site)
- Scale Stick Directions (on the 4-H Forestry Invitational site)