University of California
Western Tree Failure Database/California Tree Failure Report Program
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LinkedInA Twenty Year Look 2000/2010/2020
Data Summary comparisons: 2000,2010,2020
| 2000 | 2010 | 2020 | ||
| Total Reports | 2587 | 4887 | 6284 | |
| Top genera (% of total) | Pinus | 20.6 | 18.3 | 16.9 |
| Quercus | 19.1 | 21.5 | 23.4 | |
| Eucalyptus | 14.6 | 12.4 | 12.5 | |
| Cupressus | 12.9 | 9.8 | 8.6 | |
| Top species (% of total) | Pinus radiata | 13.5 | 10.3 | 8.8 |
| Cupressus macrocarpa | 11.9 | 9.1 | 7.9 | |
| Quercus agrifolia | 9.5 | 10.7 | 11.5 | |
| Eucalyptus globulus | 5.3 | 5.4 | 5.6 | |
| Location of failure (% of total) |
trunk | 28 | 30 | 28.7 |
| branch | 36 | 36 | 36.7 | |
| root | 36 | 34 | 34.6 | |
| Mean age | 63 | 61 | 61.5 | |
| Mean DBH | 30" | 29" | 29 | |
| Mean height | 56' | 55' | 55 | |
| Most frequently reported defects (excluding decay) % of total |
heavy lateral limb | 19 | 18.8 | 18.7 |
| Codominant/multiple trunk | 14 | 15.6 | 15.6 | |
| dense crown | 10 | 10.3 | 10.6 | |
| Site category (% of total) | residential | 28.3 | 34.9 | 33.3 |
| park | 40 | 29 | 28.3 | |
| street | 11 | 14 | 15.9 | |
| Site use (% of total) | high | 46.1 | 48.7 | 54 |
| medium | 26.7 | 24.7 | 22.9 | |
| low | 18 | 18 | 15.7 | |
| undeveloped | 8 | 8.6 | 7.4 | |
| Tree occurring (% of total) | alone | 35.2 | 39.5 | 39.7 |
| in a group | 55.9 | 51.2 | 50.8 | |
| altered stand | 8.6 | 9 | 9.1 | |
| Stand type (% of total) | natural | 21.1 | 24.6 | 23.3 |
| planted | 72.3 | 67.2 | 69.3 | |
| mixed | 6.6 | 8.1 | 7.3 | |
| Hardwood (% of total) | 60.6 | 64.2 | 67.2 | |
| Conifer (% of total) | 39.4 | 35.8 | 32.8 | |
| Origins (county) of reports (% of total) | San Francisco | 33.5 | 21.7 | 18.5 |
| Alameda | 10.7 | 14.3 | 12.7 | |
| San Mateo | 8.6 | 11.6 | 12.2 | |
| Santa Clara | 7.8 | 8.8 | 10.1 | |
| Yolo | 4.2 | 2.5 | 2.1 | |
| Contra Costa | 4.2 | 3.8 | 4.8 | |
| Sonoma | 3.6 | 2.8 | 2.6 | |
| Los Angeles | 3.4 | 2.8 | 4.4 | |
| San Joaquin | 3.4 | 2.6 | 2.1 | |
| Ventura | 2.1 | 1.8 | 2.0 | |
| Napa | 2.4 | 4.3 | 4.1 | |
| Marin | 2.0 | 3.3 | 3.4 | |
| Stanislaus | 1.4 | 2.8 | 0.6 | |
| Santa Cruz | 0.5 | 2.3 | 2.3 | |
| Mariposa | 2.4 | 2.1 | 1.7 | |
| Mean costs of failure (includes property damage and cleanup)* | All (trunk, branch and root) |
$2506.00 | $3477.00 | $3417.40 |
| trunk | $3798.00 | $3562.00 | $3461.20 | |
| branch | $604.00 | $3516.00 | $3373.54 | |
| root | $3198.00 | $3351.00 | $3425.49 |
* Costs are estimates and in about 38% of cases they are not reported.