Personally I dont like the idea of massive amounts of weight being supported by wires and rotting out more and more year after year as people are gardening under it etc.
With experience you will learn to accept cabling. It's understandable for inexperienced arborists to call for the removal of every challenging tree, but it is not necessary for liability or any other reason. See November TCI mag. When clients ask me for a guarantee I give them this:
11. “The materials and workmanship involved in the cabling system are guaranteed to be free of substantial defects. The Extra High Strength (EHS) cable shall comply with ASTM A475, Standard Specification for Zinc-Coated Steel Wire Strand, so it resists corrosion and can last 30 years or more. The fasteners shall be manufactured of stainless steel to resist corrosion. The design and installation of the system is guaranteed to comply with the ANSI A300 (Part 3) -2006 Standard Practices for Supplemental Support Systems and the 2007 edition of the ISA Best Management Practices for Tree Support. The tree and the support system should be inspected every year.” (For most trees, calling for inspection every three or five years may be more appropriate. )
Many cities and many arborists are concerned about the specter of liability associated with installing support systems in trees. Their fear is that, by admitting that a defect exists, owners and workers can be blamed for anything that happens to a tree. However, according to the USDA’s Urban Tree Risk Management Guide, “Choosing not to install a cabling and bracing system because of a fear of liability is not a good decision.”1 Also, pruning alone can be interpreted by insurance companies as admitting a defect exists. We can’t hide from liability, so there is no use running from it. This article will describe two cases that show that municipal tree risk can be abated by cabling, but first consider the recent experience of Pete Morris, City Arborist for Laurinburg, NC:
“In every previous case, after the adjusters look over my notes and the incident, they find that the City provided reasonable care for the tree and thus were not liable. This past summer, a large limb fell from an older oak, damaging a house and a vehicle. The owner watched from his wheelchair as I assessed the situation. There was no decay, so it seemed to be a case of summer limb drop. The insurance company decided that the need for previous pruning alone should have put us on alert the tree was hazardous and should have been removed or at least given special attention. I guess what has us concerned is most of our older trees have been pruned and cut on for all kinds of reasons...storm damage, disease, decay, etc. We'll have to see how things go from here.” So in this adjuster’s opinion, pruning admits liability, and every urban tree is hazardous!
A disclaimer is a useful tool because it limits liability by describing the limitations faced by consultants and other contractors. Item 10 below is adapted from the disclaimer in the Guide for Plant Appraisal:
“10. Unless expressed otherwise: 1) information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection; and 2) the inspection is limited to visual examination of accessible items without climbing, dissection, excavation, probing, or coring. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the plants or property in question may not arise in the future.”
When cabling was proposed for a cracked sweetgum tree in another municipality, the Public Works Director asked if the contractor would provide a guarantee. While it is common sense that trees cannot be guaranteed against failure, it seemed reasonable to guarantee what could be controlled. Item 11 is that contractor’s guarantee, which was also attached to the disclaimer with the Thoburn Oak report: