give the certificate of Qualified Arborist. The Qualified Arborist can then be used to offset partial experience towards the Certified Arborist. Tree Risk Assessment Qualified credential (TRAQ) designed by the International Society of Arboriculture was launched in 2013. At that time people holding the TRACE credential were transferred over to the TRAQ credential. In Canada, there are provincially governed apprenticeship programs that allow arborists' to work near power lines upon completion. These apprenticeship program have to meet the provincial regulations (for example in BC WorkSafeBC G19.30), and individuals must ensure they meet the requirements of the owner of the power system. Cultural practices Trees in urban landscape settings are often subject to disturbances, whether human or natural, both above and below ground. They may require care to improve their chances of survival following damage from either biotic or abiotic causes. Arborists can provide appropriate solutions, such as pruning trees for health and good structure, for aesthetic reasons, and to permit people to walk under them (a technique often referred to as "crown raising"), or to keep them away from wires, fences and buildings (a technique referred to as "crown reduction"). Timing and methods of treatment depend on the species of tree and the purpose of the work. To determine the best practices, a thorough knowledge of local species and environments is essential. There can be a vast difference between the techniques and practices of professional arborists and those of inadequately trained tree workers who simply "trim trees". Some commonly offered "services" are considered unacceptable by modern arboricultural standards and may seriously damage, disfigure, weaken, or even kill trees. One such example is tree topping, lopping, or "hat-racking", where entire tops of trees or main stems are removed, generally by cross-cutting the main stem(s) or leaders, leaving large unsightly stubs. Trees that manage to survive such treatment are left prone to a spectrum of detrimental effects, including vigorous but weakly attached regrowth, pest susceptibility, pathogen intrusion, and internal decay. Pruning should only be done with a specific purpose in mind. Every cut is a wound, and every leaf lost is removal of some photosynthetic potential. Proper pruning can be helpful in many ways, but should always be done with the minimum amount of live tissue removed. In recent years, research has proven that wound dressings such as paint, tar or other coverings are unnecessary and may harm trees. The coverings may