Forester Acronyms and Fun Wandering in the Woods

December 18, 2005

Guest article written by Tom Kisliuk, Registered Professional Forester

Most forests have variable stocking which is generally overstocked (too many trees) or understocked (not enough trees). One measurement foresters use is Trees Per Acre (TPA) to aid in assessing timberlands. Natural stand development after a stand replacing fire or event is thousands of trees germinate, per acre, as seedlings. Over a period of decades, the number of trees per acre decline as the dominant trees shade out the overtopped trees.

Many timberland owners try to control the number of TPA to maximize production. The theory is similar to thinning out carrots or other vegetables from seed. In order to grow a nice carrot or large tree it is best to ensure the plant has room to develop without intensive competition.

I enjoy walking through the woods with a pair of loppers or a bow saw and I try to manage stocking of small trees (saplings) to promote better growing conditions for the trees I select to continue growing. I also trim branches and such to facilitate future wandering in the woods.

A radius of 6.8' from a point center is about 1/300 of an acre. A radius of 11.8' is about 1/100 of an acre. Jackson State Demonstration Forest studies indicate maximum productivity in young second growth redwood types is about 150-200 trees per acre. I manage for a mixed species forest and generally thin to promote a variety of species. Industrial timberland owners generally thin to promote the most valuable species, generally redwood and Douglas Fir, in our area.

If your yard has too many trees maybe, you would enjoy reducing your TPA. If it is understocked maybe, you need to plant or grow a few more! Have fun in your forest and grow large trees!

Tom Kisliuk is a Registered Professional Forester based in Westport in Mendocino County, CA USA.