
Very briefly, here is one way to measure tree height with a suunto and distance tape.
 On the sample tree, accurately locate 1.3 m above ground on the high side. This is breast height (bh).
 Attach the logger's chain at the centre of the tree at bh or have a crew member hold the end of the distance tape at this point.
 Walk back from the tree to a location where you can see both the top of the tree and bh It is often best to go uphill of the tree. Pull the tape tight and straight between the tree and your eye. With the suunto, read the % to tree top. If the reading exceeds 100%, move further away from the tree and repeat. If the tree has a droopy leader, shoot to the top of the droop.
 Then, from the same location, read the % to bh with the suunto.
 Record, top shot (% to top), bh shot (% to breast height), slope distance, and bh correction (1.3 m).
 Calculate horizontal distance using Table 1 or other slope tables. To use Table 1, multiply slope distance by the appropriate factor to get horizontal distance.
 Combine top and bh shots. If the bh shot is negative, treat both numbers as positive and add top and bottom percents (i.e., +88% top shot, 10% bh shot, combined percentage is 98%). If the bh shot is positive, subtract bottom from top (i.e., +88% top shot, +10% bh shot, combined percentage is 78%).
 Multiply the combined percent by the horizontal distance. This produces tree height above bh. Add the bh correction (1.3 m) to produce total tree height.
 For the growth intercept method, if the tree has a droopy leader, add to the calculated height the amount required to obtain total tree height with the tip straightened up.
Table 1. To get horizontal distance, multiply slope distance by this factor.
Percent to bh (%) 
Factor 
Percent to bh (%) 
Factor 
Percent to bh (%) 
Factor 
Percent to bh (%) 
Factor 
1 
1 
26 
0.968 
51 
0.891 
76 
0.796 
2 
1 
27 
0.965 
52 
0.887 
77 
0.792 
3 
1 
28 
0.963 
53 
0.884 
78 
0.789 
4 
0.999 
29 
0.960 
54 
0.880 
79 
0.785 
5 
0.999 
30 
0.958 
55 
0.876 
80 
0.781 
6 
0.998 
31 
0.955 
56 
0.873 
81 
0.777 
7 
0.998 
32 
0.952 
57 
0.869 
82 
0.773 
8 
0.997 
33 
0.950 
58 
0.865 
83 
0.769 
9 
0.996 
34 
0.947 
59 
0.861 
84 
0.766 
10 
0.995 
35 
0.944 
60 
0.857 
85 
0.762 
11 
0.994 
36 
0.941 
61 
0.854 
86 
0.758 
12 
0.993 
37 
0.938 
62 
0.850 
87 
0.754 
13 
0.992 
38 
0.935 
63 
0.846 
88 
0.751 
14 
0.99 
39 
0.932 
64 
0.842 
89 
0.747 
15 
0.989 
40 
0.928 
65 
0.838 
90 
0.743 
16 
0.987 
41 
0.925 
66 
0.835 
91 
0.740 
17 
0.986 
42 
0.922 
67 
0.831 
92 
0.736 
18 
0.984 
43 
0.919 
68 
0.827 
93 
0.732 
19 
0.982 
44 
0.915 
69 
0.823 
94 
0.729 
20 
0.981 
45 
0.912 
70 
0.819 
95 
0.725 
21 
0.979 
46 
0.908 
71 
0.815 
96 
0.721 
22 
0.977 
47 
0.905 
72 
0.812 
97 
0.718 
23 
0.975 
48 
0.902 
73 
0.808 
98 
0.714 
24 
0.972 
49 
0.898 
74 
0.804 
99 
0.711 
25 
0.97 
50 
0.894 
75 
0.800 
100 
0.707 
Example:
Percent to top: 
+75% 
Percent to breast height (bh) 
15% 
Slope distance 
20 m 
Breast height correction 
1.3 m 
Horizontal distance
= slope distance x factor
= 20 x 0.989
= 19.78 m 

Combined percent
= top shot + bh shot
= 75 + 15
= 90% 

Height above bh
= horiz. distance x combined percent
= 19.78 x 0.9
= 17.80 m 

Total height
bh correction+height above bh
= 1.3 m + 17.80 m
= 19.1 m 

