Arborists climb onto a tree s branches using ropes and hanging seats called climbing saddles. They carefully remove branches with chainsaws, shears, and tiny clippers. If a branch is diseased, arborists sometimes dip their tools in disinfectant before cutting another branch to prevent the spread of infection. Jeff, like all arborists, uses mathematics to analyze a tree s structure before he decides which branches to cut. We measure the tree s circumference, and we can figure out a tree s height without climbing it.
Some arborists use computer programs to calculate the forces and weights within a tree.
A tree s structure can be a matter of life and death for the people who live near it. Weak, diseased, or unsupported branches can crack and fall, crushing cars, houses, or people beneath them. Despite all the treatments available, some trees cannot be saved. It s not until a tree is screaming for attention that most people notice there s a problem. We can t always save trees that are already very sick.