In most urban situations sectional felling is normally the only option, as hazards or obstacles are often within close proximity to the tree. The operation of sectional felling to remove trees can take more time than other work plans but offers much more precision and control. It is often the only way to achieve safe removal of a tree without high risk to life and limb, or damage to surrounding property.
The operation of sectional felling is undertaken as follows: the climber will access the highest / safest point of the tree and install his climbing line, rigging block and bull line (pulley and lowering line). Once these are installed the tree surgeon will then decide where to start dismantling – this is usually the lowest branch. All the cut material is lowered to the ground with a great deal of care and precision, the ground crew run the lowering rope through a friction device to aid in taking the full weight of the branch. This process then gets repeated until all the side branches are removed.
Once all the side growth has been removed, the climber / tree surgeon will then start ‘topping down’ the stem in sections. This is quite difficult to undertake and requires good communication between climber and ground crew because the cut timber is within close proximity to the climber. Once cut, the climber will push the cut section off the top and it will then be under the control of the ground crew, who will lower it to the ground and avoid ‘shock loading’ the tree and lowering equipment. This is very important as shock loading an unsound tree could have dangerous consequences and cause the structure to fail.