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You have important decisions to make about your trees and our recommendation is that you do it with the advice of an arboricultural consultant with expertise in hazard assessment. See http://ascaconsultants.org to find one in your area.
There are 82 cases of Cedrus deodara failures in the database. 61 are branch failures. The mean diameter of the branches at point of failure is 11 inches. 45 failed out on the limb and 16 at the attachment. No decay was observed in 48 of the branch failures and the structural defect "heavy lateral limbs" was reported in 31 cases. 41 branches failed under conditions of no precipitation. 26 branches failed in winds less than 5 mph, 25 in winds 5-25 mph and 15 in winds over 25 mph.
There are only 5 reports of E. cladocalyx. Four came from southern California locations. Mean age 44 years, mean Ht 68 ft., mean DBH 34 inches and mean crown spread 49 ft.
One root failure and 4 branch failures. All branch failures occurred away from the point of attachment. Defects listed are heavy lateral limbs, dense crown, and uneven branch distribution. No decay for all five. 3 failed in winds below 5mph. Precipitation: 3 none and 2 rain. One branch failure was thought to be "summer limb drop"
Unfortunately, total population information for any species in any location is hard to come by, so we aren't able to look at the data that way. The best way to look at it is "Report numbers for species do not provide an assessment of the frequency of failure for the species (i.e., how often a species fails relative to its occurrence in a population of trees). Rather, it is likely the data reflect the relative abundance of a species in the areas from which reports are being received" You may notice that the majority of reports originate from the San Francisco Bay Area and that's not because failures occur more often there, but because more cooperators send in reports from there.
If you are interested in comparing species, rather than ask "Are oaks more likely to fail than euks?"you might ask "How do the failure patterns differ between oaks and eucalyptus?" Look at the "Species Profiles" page for examples.
The 50plus list is derived from the current database which includes all the reports received dating back to 1987.
Bark inclusion and decay are commonly associated with limb failure, but I don't know which photo(s) you are talking about.
There are 82 Cedrus deodara failures out of 5415 reports to date. Trunk 6 (7%), Branch 61 (74%), Root 15 (18%). Mean Age: 55 years, Mean DBH: 33 inches, Mean Height: 65 ft. and Mean Crown spread: 44 ft.
Structural defects (not including decay) reported are mainly heavy lateral limbs 42% and dense crown 11%. 15% reported no defects.
No decay was reported on 4 trunk, 48 branch (59%) and 10 root failures.
46% of the failures occurred in the months of November through March.
26 branch failures occurred in winds less than 5mph. All of the other failures reported winds over 5mph.
Precipitation: None:43, Some: 32
Yes, you can. E-mail me at treefail@mac.com.Tell me your name and e-mail address and I will send you the records you have submitted in Excel or FileMaker format.
No, there haven't.
Of 5366 reports in the CTFRP database to date, 24 are silver dollar gum, Eucalyptus polyanthemos. Mean age 20 years, mean height 41 ft. and mean DBH 20 inches. Failure type: Trunk 8, Branch 13 and Root 3. No decay was noted in 18 cases, some in 4 and unknown in 2. Other structural defects associated with the failures were heavy lateral limbs, multiple trunks/codominant stems, embedded bark and multiple branches arising from the same point.
It sounds as though you are doing the best you can to try to keep your tree safe. As the tree ages, it would be wise to have it inspected periodically by an arborist who is expert in structural analysis. See the American Society of Consulting Arborists http://asca-consulstants.org
There is only one report for Abies magnifica in the CTFRP database. This is a species that is seldom seen in urban locations, so perhaps someone from the Forest Service would be willing to share his/her experience with the species.
CTFRP data on redwood trunk failures has not changed since Comment #13 on 02/23/12. The likelihood of failure of any individual tree should be based on a careful examination of the tree by someone who has expertise in structural assessment.
We only have 15 reports on Ailanthus altissima. Trunk 7, Branch 5 and Root 3. Mean age 37 years, mean Height 41 ft. and mean DBH 25 inches. Decay was noted in 8 cases. Other structural defects include included bark (8 cases) and lean (4 cases). All of the reports originated from northern Californa Counties. No pruning at failure location was noted in 10 cases. No precipitation was noted in 10 cases and 9 failed in moderate to high winds
Of 5352 reports in the dabase to date, 42 are Eucalyptus camaldulensis. Mean age: 32 years, Mean DBH: 25 inches, Mean Height: 52 ft.
Trunk (7) Branch (31) Root (4)
The majority of the reports came from northern California counties and one from Riverside and one from Los Angeles county.
76% of the failures happened in the months November-March.
No decay was noted in 81% of the failures. Other commonly reported structural defects include Multiple trunks/co-dominance 32%, Heavy lateral limbs 22% and Dense crown 11%
70% of the failures happened in winds of over 25 mph.
These questions can't be answered by CTFRP data. An on-site evaluation of the tree is needed to determine what the results of root cutting might be. Contact the American society of Consulting Arborists http://asca-consultants.org.
CTFRP data is insufficient to accurately compare failure potential among species. As data accumulates, it is hoped that failure patterns for individual species will emerge. When a question arises about the hazard potential for an an individual tree, it is always best to have an expert analysis done. You can find an expert by consulting the American Society of Consulting Arborists website at http://asca-consultants.org
Eucalyptus globulus data summary:
287 reports of 5322
Mean age: 64 years, mean DBH: 43", mean Height: 81',
Failures at: Trunk: 14%, Branch: 42%, Root: 43%
Major structural defects associated with failures: Heavy lateral limbs 26%, multiple trunks/codominance 10%, dense crown 11%.
Decay was present in 55% of cases.
Precipitation: some 56%
Wind:<5mph 26%, 5-25mph 26%, >25mph 48%
For an expert opinion, you can find a consulting arbortist in your location at http://asca-consultants.org
There are too few reports on Sequoia sempervirens trunk failures to be predictive, but so far we have reports on 110 redwood failures and 54 of those are trunk failures. The mean height at the point of failure is 30 ft. The mean diameter at the point of failure is 16 inches. Multiple trunks/codominant stems was mentioned as a defect in 25 cases and included bark in 14 cases. No decay in 30 cases, some in 20 cases and in 4 cases decay was not reported. 39 failed in high winds.
There are 154 reports of P. pinea failures in the database. 57 of those are root failures and only five are from Alameda and San Francisco counties. None of the five report root cutting or root pruning, but kinked/girdling roots are listed as defects twice.
For all 57 of the root failures, two mention root pruning, two root cutting and kinked/girdling roots are listed as defects 12 times.
London plane is the most widely planted street in the San Francisco Bay area, yet out of 5253 reports to date, only 17 failure reports have been filed for the species. Trunk: 6, Branch: 9 and Root:2
Mean Age: 32 years, Mean DBH: 20 inches, Mean Height: 36 Ft. Mean Crown spread: 22 Ft.
Decay: present at point of failure: none: 9, some: 4, unknown: 4
Other structural defects: failed portion dead: 2, multiple trunks/codominance: 2, dense crown: 1, uneven distribution: 2, kinked, girdling roots: 2 none: 3, data missing: 3
Months of failure: November-April: 8, May-October: 8, data missing: 3
Site use: High: 13
Wind: Some: 9, data missing: 8
Precipitation: none: 6, some: 3, data missing: 8
This phenomenon has occurred in several locations in the Bay Area and a fungus disease may have been involved in some cases. There is no information about it in CTFRP data, however. Your question will be referred to someone who may have better information. Stay tuned.
There are only 22 reports for E. polyanthemos. 8 trunk, 11 branch and 3 root. Mean Ht. 41ft., mean DBH 18 inches and mean age 20 years. 17 failed between November and March. 19 reports originated from northern California counties and 3 from southern California.
For the branch failures, 7 failed at the point of attachment. There was no decay noted in all but one of the branch failures. Most commonly reported defects were included bark and heavy lateral limbs.
For the trunk failures, 2 failed at ground level and the remainder from 6-30 ft. above ground. No decay noted in five trunk failures and multiple trunks and codominance were the most commonly reported structural defects.
Two of the 3 root failures reported no decay.
Weather factors: 19 failed in moderate to high wind. 3 did not report wind speed. 14 failed in the rain.
There are 550 reports on Quercus agrifolia (coast live oak) failures. 208 (38%) are root failures. 72% of root failures occurred when the trees were between 26 and 100 years old. 83% of the root failures had a DBH of between 13 and 42 inches. Mean crown diameter is 45 ft. 82% of the root failures occurred in the months of November through March.
Root decay was a factor in 73% of cases. Other commonly reported structural defects include: lean (18%), failed portion dead (16%), uneven/one sided (14%), multiple trunks (12%), and dense crown (12%).
Other factors commonly reported include: root cutting (18%) and grade change/fill (17%)
Soil conditions were reported as: saturated (56.2%), good (29.9%), compacted (11.9%), dry (5.7%), shallow (1.0%) and other (3.3%).
Irrigation: none (55%), up to 3x/month (45%)
Ground covers include: bare soil (21%), mulch (8%), turf (12%), other plants (56%) and paving (3%).
Weather conditions include: rain (68%) and wind speed (< 5mph 34%), (5-25mph 33%), (>25mph 33%).
CTFRP data shows that of 18 redwood branch failures reported, 15 (83%) failed at the point of attachment. Cultural practices such as watering and fertilizing are not reported for branch failures.
This is not a question the CTFRP data can answer. You'll need to consult experts in "large tree removal" to evaluate your situation.
CTFRP data on valley oaks is insufficient to answer your question. However, it is not unusual for large old oaks to have decay and other structural defects that can lead to failure. Check the American Association of Consulting Arborists website http://www.ASCA-consultants.org for someone in your locality who can do a structural assessment of your tree.
Posted by Ted Safford on May 3, 2013
There are only five reports on Pinus torreyana in the database. Four from the SF Bay Area and one (branch failure) from San Diego. We need more reports from southern CA!!
One trunk, two branch and two root (whole tree).
Mean Age: 66 years, mean DBH 38 inches and mean Height 74 ft.
One of the whole tree failures had a severe lean and the other one was on a slope and had root decay on the uphill side. Both failed in winds of 5mph or less. There was no precipitation at the time of any of the failures.