TREE RISK ASSESSMENT
South Bay Community Assn.
120 Spinnaker Place
Pt Ludlow WA 98365
08/20/07
Richard R Hefley
Consulting Arborist
ISA #PN-0784A
Purpose of Report:
Examine trees located south of the South Bay Club building, and along the trails running through this area. Determine which trees appear to be most likely to fail in the near future and make recommendations for their removal or maintenance.
Disclaimer:
Any tree can fail at any time.
Trees may possess stress fractures or root rots that are undetectable by visual examinations.
Any tree can fail in high winds, especially winds following soaking rains.
Due to the large number of trees to examine and limits on budget, I visually examined these trees to make my recommendations.
Overview:
The majority of the trees examined were located approx. 50-150 south of the Bay Club building.
This stand consists of approx. one third Red Alder, one third Western Hemlock, and one third Western Red Cedar.
The average height of these trees is 100.
Since our winter storms are primarily comprised of winds from a southerly direction, there is a good likelihood that these trees could cause significant damage to the Bay Club building if they fail.
Tree Characteristics:
Red Alder (Alnus rubra) is a pioneering tree. When lands are cleared, either by natural or man-made means, alder is usually the first tree to re-colonize these areas.
They are very important trees to replenish the ground. Their roots fix nitrogen, the most important element in plant growth, back into the nutrient depleted soils.
They are also very short-lived, seldom lasting much beyond 75 years, and they decompose quickly, adding more nutrients to the ground.
The characteristics that make alder a useful tree to forest ecosystems also make them poor neighbors to live with.
Their limbs tend to break apart easily, especially under snow loads, and they sometimes fall in slight winds as they age and become more brittle.
The alders present in the vicinity of the Bay Club are approx. 50 years and older. They are entering the over-mature stage of their life cycles, and will become increasingly prone to failure.
Western Hemlock (Tsuga heterophylla) is a problematic conifer. It has the highest failure rate for any conifer in our region. It tends to have a shallow root system, and so is susceptible to being blown over by high or even moderate winds that follow a period of soaking rain.
The wood of the tree is very brittle with age. It is very common to see these trees break at almost random points along the trunk.
They are susceptible to many root and heart rots, several of which are apparent on the trees in this stand.
Hemlocks, like alders, are difficult to predict when and which ones will fail. The visually healthy seem as likely to break as the obviously stressed and diseased trees.
While they are beautiful trees when young, I cannot recommend them to remain on the windward side, within striking distance, of people or property.
Western Red Cedar is the best tree to live close to.
The wood is strong and seldom breaks or uproots in high winds.
This tree is also much more tolerant of adverse conditions brought on by development than other conifers in our region.
When cedars do fail in storms, it is usually due to the breaking out of one of multiple leaders in the top.
This condition forms when the top is broken out of the tree at a younger age. It sometimes replaces this loss with two or more branches that grow from points close together on the tree. As they age, the bark grows together to form a wedge of wood between the new leaders. This is a structural flaw; a weak connection in the wood, and is the most likely point of failure in the tree.
Background:
In early August I received a call from Linda Colasurdo, Operations Manager for South Bay Community Association.
She had several trees marked for removal from a Tree Service, and wanted to have a second opinion and a written report before beginning the project.
I agreed to meet and examine the trees on 8/16/07.
Methods:
I visually examined each tree located within striking distance on the south side of the Bay Club.
I first determined the species of the tree.
I examined the crown for the ratio of living branches to the trunk, which is referred to as the Live Crown Ratio (LCR). Conifers with less than 15% LCR (say, a 100 tall tree that only has living branches in the top 15) is considered to be a tree with a high likelihood of failure.
I then assessed the density of the foliage, expressed as a percentage called the Crown Density (CD), (for example, a tree with 50% CD has approx. ½ the thickness of leaves, or needles, of a healthy tree). This is a rough indicator of crown health.
I examined the trunk for structural flaws such as weakly attached wood, cracks, bulges, seams, crooks etc.
I examined the lower trunk and surrounding soil for signs of fungal growths that would indicate the presence of internal or root decay.
I attached an aluminum tag to each tree that was in need of removal.
I did not attach a tag to the alders in question because they should all be removed if they are in striking distance of property, and there is no difficulty in distinguishing them from the conifers present.
Observations:
The wood examined is located approx. 50-150 south of the Bay Club.
The majority of the conifers reached or exceeded 100 in height.
The wood is roughly comprised of equal parts Western Hemlock, Red Alder and Western Red Cedar.
Following are the tag numbers and descriptions of the tree. I do recommend that all alders and hemlocks within striking distance of the Bay Club be removed because of the inherent characteristics of their species and their location on the windward side of the majority of our severe winter storms.
#465 is a Hemlock (Tsuga heterophylla). It is approx. 30 in diameter and 110 tall. There is a deep fissure from the ground level to 4 high in the trunk. The crown is in good health. Though this is not a particular high risk tree, I recommend that it be removed due to its location and species.
#466 is a Hemlock. It is approx. 16 in diameter and 80 tall. The crown is healthy. This tree is a low priority tree.
#467 is a Hemlock, 24 in diameter and 90 tall. This tree is growing 6 above ground on a nurse cedar stump. At 20 above ground level there are compressions ridges and a crook in the trunk. These are significant defects, and I recommend this tree as a high priority for removal.
***Due to this asthetic qualities of this tree, I recommend that it be topped at approx. 15 above ground level. This way it can serve as a habitat tree, providing food and shelter for wildlife, and its unique above ground roots can be enjoyed.
#468 is a Hemlock, approx. 30 in diameter and 110 tall. There are significant bulges in the lower trunk which indicate internal decay. This tree should be removed.
#469 is a Hemlock, approx. 33 in diameter and 100 tall. This tree has a pronounced lean and deep fissures in the trunk from the ground to approx. 10 above ground level. The canopy is fairly sparse (40%LCR, 50%CD). This tree should be removed.
#470 is a Hemlock, approx. 24 in diameter and 100 tall. The crown is sparse (30%LCR, 30%CD). There are bulges in the trunk at 5 and 15 above ground level. There is a lean towards the building, and fungal growths on the trunk. This tree should be removed immediately.
#471 is a Hemlock, approx. 25 in diameter and 100 tall. It has fungal growths at 2 above ground level, indicating interior decay. This tree should be removed immediately.
#472 is a Hemlock, approx. 20 in diameter and 100 tall. It is grown on a cedar nurse stump 2 above ground level. It also contains a dual leader at approx. 60 above ground level. This tree should be removed, though the stump (up to 15) could be retained as a habitat log.
#473 is a Hemlock, approx. 12 in diameter and 80 tall. The canopy is sparse (50%LCR, 30%CD).
#474 is a Hemlock, approx. 20 in diameter and 100 tall. It has a dual leader beginning at 20 above ground level. This tree should be removed immediately.
#475 is a Hemlock, approx. 30 in diameter and 100 tall. The trunk contains several swellings and crooks. This tree should be removed.
The nest three hemlocks are located in an area commonly known as The Terrace. This is located approx. 100 NE of the Bay Club, and 50 S of residences.
#476 is a Hemlock, approx. 28 in diameter and 100 tall. There are significant swellings in the base located 10 above ground level, and a crook in the trunk located 50 above ground. This tree should be removed due to the threat it poses to the condos location.
#477 is a Hemlock, approx. 18 in diameter and 100 tall. There are two significant crooks located at 40 and 70 above ground level. This tree should be removed.
#478 is a Hemlock, approx. 24 in diameter and 100 tall. It is physically connected to #477, they appear to have grown from the same source. The removal of #477 will inevitably lead to the failure of #478. Both should be removed.
There is a Western Red Cedar located approx. 30 East of Hemlock #477. The trunk is approx. 48 in diameter and it is approx. 80 high. There are triple leaders at 60 above ground level. There is a slight possibility of causing damage to the condos. This tree should be monitored for further signs of included bark in the crown.
Please contact me at the following numbers if there are any questions or comments regarding this report.
Thank you very much,
Richard R Hefley
Consulting Arborist
PO Box 177
Nordland WA 98358
360-385-2921
rkhefley@olypen.com