57 TREE MANAGEMENT AND PROTECTION
Table 18.57.060A Existing Trees to Remain. | |||
|---|---|---|---|
(Conversion from diameter (d.b.h.) in inches to tree units for trees protected on-site.) | |||
d.b.h. | Tree Units | d.b.h. | Tree Units |
1 – 5 | 1.0 | 30 | 8.2 |
6 – 10 | 1.2 | 31 | 8.6 |
11 | 1.4 | 32 | 9.0 |
12 | 1.8 | 33 | 9.5 |
13 | 2.0 | 34 | 10.0 |
14 | 2.3 | 35 | 10.5 |
15 | 2.6 | 36 | 11.0 |
16 | 2.9 | 37 | 11.5 |
17 | 3.2 | 38 | 12.0 |
18 | 3.5 | 39 | 12.5 |
19 | 3.8 | 40 | 13.0 |
20 | 4.2 | 41 | 13.5 |
21 | 4.6 | 42 | 14.0 |
22 | 5.0 | 43 | 14.5 |
23 | 5.4 | 44 | 15.0 |
24 | 5.8 | 45 | 15.5 |
25 | 6.2 | 46 | 16.0 |
26 | 6.6 | 47 | 17.0 |
27 | 7.0 | 48 | 18.0 |
28 | 7.4 | 49 | 19.0 |
29 | 7.8 | 50 | 20.0 |
For every one inch greater than 50 d.b.h., add an additional 2 tree units (i.e., 62 d.b.h. = 44 tree units). | |||
Table 18.57.060B Replacement Trees. | ||||
|---|---|---|---|---|
(Conversion from caliper inches to tree units for replacement trees.) | ||||
Deciduous Tree Caliper in Inches | Tree Units for Deciduous Trees | Coniferous Tree Height in Feet | Tree Units for Conifers | Tree Units for Native Conifers |
1.5" | 0.4 | 4' – 6' | 0.5 | 0.8 |
2" | 0.5 | 6' – 8' | 0.7 | 1.0 |
3" | 0.6 | 8' – 10' | 1.0 | 1.5 |
4" | 0.7 | 11' – 12' | 1.5 | 2.0 |
5" | 0.8 | |||
6" | 1.0 | |||
7" | 1.2 | |||
8" + | 1.5 | |||
Table 18.57.060C Sample Tree Density Calculation. | |||||
|---|---|---|---|---|---|
The required density factor is calculated below as follows for five acres: five acres x 30 units = 150 tree units required. Existing density (ED): | |||||
Size | Quantity | Total Units | Size | Quantity | Total Units |
24" | 3 | 17.4 | 12" | 5 | 9.0 |
18" | 3 | 10.5 | 8" | 6 | 7.2 |
10" | 4 | 4.8 | 15" | 8 | 20.8 |
30" | 7 | 57.4 | 4" | 10 | 10.0 |
Total ED | 137.1 | ||||
Replacement density (RD): | |||
|---|---|---|---|
Size | Units | Quantity | Total Units |
2" Deciduous | 0.5 | 12 | 6.0 |
4" Deciduous | 0.7 | 6 | 4.2 |
4' – 6' Native Conifer | 0.8 | 5 | 4.0 |
Total RD | 14.2 | ||
ED + RD = | Site Total Tree Density | > | or | = | Minimum Density Required | |
|---|---|---|---|---|---|---|
137.1 + 14.2 = | 151.3 | > | 150 | Density Satisfied | ||
Figure 18.57.090A Critical Root Zone. ![]() |