The split leaders (above) were the result of weak attachments because of acute branch angles and included bark of co‑dominante stems. Fortunately the failure only resultedMulti‑trunks can be attractive but are very weak. in minor property damage and no injuries. The result of this same defect can be seen on the multi-trunk melaleuca to the right. This failure landed on a car. Multi-trunks can be attractive but are very weak.
An evaluation of the live oak (left) determined that there was extensive root decay. The crown had severe dieback and, duringthe winter, the area within the dripline had a large number of honey mushrooms (right). These honey mushrooms are the fruiting body of oak root fungus, Armillaria mellea. The tree was not removed and fell over. Fortunately, there were no injuries.
To the left are the basidiocarps of the white rot, Ganoderma applanatum
The conks of Ganoderma lucidum, a white rot (above) are a sign of decay inside the base of this trunk. This fungus kills the cambium as well as... white rot will lead to complete tree failure.rotting the wood. This will lead to complete tree failure.
Look for a TRAQ (Tree Risk Assessment Qualification) certified person.
There are 3 levels of risk assessment defined by the International of Society of Arboriculture's Tree Risk Assessment:
This is a limited walk by, drive by or fly over, which does not necessarily entail a complete walk around a tree. This usually only includes the specific tree or trees that are being considered for the purpose of a proposal for work or risk assessment. This generally focuses on obvious defects, imminent or probable likelihood of failures and may not even classify as true “risk assessment” if there is no evaluation or analysis of the individual tree(s). There are generally no tools used at this level. This is the fastest and least thorough assessment.
This is the standard or basic assessment in response to a client's request for tree risk assessment. This generally entails more time on the tree to include a walk around inspection. Simple tools such as probes, measuring devices, binoculars, mallet or magnifying glass or scope may be used. This typically does not include an aerial inspection (other than, possibly, a ground level inspection with binoculars) or below ground inspection. A Level 2 assessment is usually necessary for determining the need and scope of a Level 3 assessment.
This is the most detailed and time consuming level of assessment. This level usually requires specialized equipment, data collection and analysis, as well as a higher level of expertise from the assessor. Some examples of specialized equipment are the Air‑Spade or the Resistograph. This may also involve sending samples to labs for analysis. The assessor should determine which methods are appropriate and/or the least invasive and discuss this with the client. As noted above, a Level 2 assessment is usually required to determine the need and scope of a Level 3, which will usually take place at a later time due to time requirements determined during a Level 2.
Above are the channels the feeding larvae create under the bark. This is what is left of the tree's vascular bundle. There are different bark beetles for different genus of trees, but the result is the same and the primary cause is stress. Pictured below are larvae embedded in wood.