Acronyms are a pretty common occurrence in BLM office here in Roseburg. Just out of curiosity, I tried googling this one and came up with the following possibilities; Pacific Crest Trail, Pennsylvania College of Technology, and Patent Cooperation Treaty. In fact, what PCT stood for in the context of my day was Pre-Commercial Thinning.
I did not actually conduct the thinning, instead I went out with the silviculturists to mark the boundaries of what is to be thinned (Pre-Pre-Commercial Thinning?). The idea behind PCT is that it can both help overall forest health, as well as maximize the production of timber (in our case; Douglas fir). When trees are planted too closely, they compete with one another which can prevent them from growing quickly, in terms of both diameter and crown height. It also can lead to heightened tree morality and dense patches of even-aged trees that can increase the chances of pest outbreaks and contribute to fuel build-up and wildfires. Despite the costs of contracting a PCT, the increases in terms of volume per acreage often make it financially attractive for private timber companies, and the BLM likewise usually thins out the forest it manages to promote forest health and promote the growth of large trees, as well as to meet the timber targets of the Northwest Forest Plan as established by Congress in 1994. Pre-Commercial Thinning, as the name might suggest, doesn’t produce any economically valuable timber as the stand is still too young. However, periodic commercial thinning, which takes places later in the stand’s development, instead of one-time clear cutting events is seen by some as a good compromise in balancing the often competing interests of forest health and maximum timber production.
We flagged the boundaries around the units relying both on a handheld GPS with the ‘official’ boundary lines, but also based on what we were seeing in the forest around us. You can tell, after some practice, where the boundary lines are just based on the distance between trees, the diameter of the trees, and the amount of understory that signal different ages and treatment regimes. These visual clues don’t always match up perfectly to the GPS boundaries. Part of this is because there may be impassable bluffs, rocky areas with poor soil that were managed differently, and because past silviculturists may have created buffers around streams and other sensitive areas. Essentially, there is plenty of variation even within the same unit. At some point in the near future, a crew of people with chainsaws will come through what we marked and cut trees according to a criteria of distance between trunks and size of trunks. You can see the effects of this type of treatment when looking at the tree rings of a cut tree. The tree rings are wider immediately following thinning treatments and for several years afterwards, indicating faster growth when the canopy opens up and competition beneath the ground lessens.
Okay, so I can’t actually complete this post without mentioning the incredible solar eclipse of a few weeks past, and the fact that the entire Pacific Northwest is on fire right now. Enjoy a few pictures of those, because my camera didn’t come with me on the silvicultural escapade!