If you wish to remove a tree within certain municipalities you may need to apply for a permit. Some tree removal permit applications require an arborist report to accompany them. An arborist report for a tree removal permit application would describe the condition of the tree and reasons for removal. The report would typically also include a replanting plan.
In some municipalities, if a construction project is happening, part of the planning process would be the creation of a tree protection plan. An arborist report for a development is a little more complex the report has to describe the current condition of the trees on the site as well as the potential impact the project will have on them. The report will also include detailed specifications on how the tree will be protected during the construction.