In tree-falling, the term "kerf" refers to the space or hole that the chainsaw created. So when you slice into a tree and make the cut, that open cut is called the kerf. As you continue to work on the tree, the kerf will sometimes move (open up or close) and will let you know if the tree is about to go somewhere. In theory, the sawyer has cut in a manner to fell the tree where it needs to go. But that kerf will indicate if the sawyer needs to readjust or move out of the way (quickly). So the saywer's motto "observe the kerf," means a heckofalot for those working around the tree.
Today I felled my first tree. No, I did not yell "timber!" but I did have to yell "tree falling!" Not only was it my first time cutting down a tree (it was maybe about 10 inches wide and 40 feet tall), but it was the first time I used a chainsaw. ZSZCHRRZSRR! I sat through the classroom training yesterday about how to use/clean/maintain the chainsaw, the proper technique for felling trees, and what nasty wounds from chainsaws look like (yes, pictures on a PowerPoint). I believe they call that "instilling a healthy fear" of a tool that can theoretically take your life (doing a job that can also theoretically take your life). Today I got to go out and put my newly-learned knowledge to work.
I am not going to lie. I enjoy getting certified in stuff like this because I like being a walking contradiction. I will wear heels and pearls one day then [safely] mow down a tree the next. I appreciate the new layers of complexity that this creates in me. But even more than that, I am amazed at the science involved in this type of work. Who knew physics could be fun? From the fairly process of taking down a tree to the understanding of an ecosystem enough to manage it effectively, the knowledge base to work in these fields astounds me. I am grateful for the opportunities I have in my current job to experience these things.
Tomorrow I will fell some more trees and hopefully receive my "A" faller's certification (the first step). No worries, Mom and Dad. I will observe that kerf.