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Writer's pictureLiam Bassler

What is a Timber Harvest Plan and What Does It Look Like?

Liam Bassler


A timber harvest plan is a useful method for managing forests for wildlife habitats, plant biodiversity, and wildfire resilience. Trinity County is 2.1 million acres, 75% of which are federal land. The terrain is hard and undeveloped, with only 15 unincorporated communities. Due to its rough terrain and difficult accessibility, wildfire has run rampant. Since the 1900s, nearly 60% of the county has burned at some point. Communities have to constantly worry about fires and evacuations. 


Since much of the forest is inaccessible, prioritizing the areas around communities, also known as the Wildland-Urban Interface (WUI), is how agencies protect those towns. Preventing a wildfire from burning down a hillside into town is a manageable tactic that agencies such as the Trinity County Resource Conservation District and others use. Clear cuts and thinning are two common timber harvest plans. Clear cuts take every tree out in a stand while thinnings reduce stand density and leave larger and healthier trees behind. The Oregon Mountain Timber Harvest is a thinning, which reduces wildfire risk by reducing the potential for fire to carry from crown to crown, reducing ladder fuels, and reducing tree mortality of the trees left behind. 


Oregon Mountain extends from town upwards to the west, making it a high priority for managing the forest from wildfire. From the BLM Environmental Assessment “The purpose of the proposed Oregon Mountain Project is to improve fire resistance and stand resiliency within the WCF by thinning overstocked conifer stands, reducing hazardous fuel loads, and restoring BLM/WCF lands which include coniferous forest, oak woodlands and outer riparian zones, to make them more resilient to drought, disease, and insect infestation.” 


How does a Timber Harvest look?

After all of the environmental impacts have been taken into consideration and the plan is approved, it’s time to start the field fun. Firstly, we need to know the unit boundary and exclusion zones. We have maps of the project with our current location, so technicians go into the field and, following the map as closely as they can, flag and mark the boundary. In this project, there are two oak woodland exclusions and many riparian areas to be flagged and marked as well. 


Oregon Mountain map


The machine that cuts the trees is a feller-buncher, and due to the operator sitting high up, flagging and marks need to be high enough for them to see. When flagging boundaries, it is important that the knot faces into the project area, so operators know if they are inbound or not. An incorrectly marked tree that causes an operator to cut a tree outside of the boundary, which could be private property, can have many legal consequences. 


After the boundary is marked appropriately, it is time to mark some trees. When marking a cut tree, we use special paint provided by a federal agency. This paint is able to be tracked to prevent timber theft. To mark a tree, spray a dot at the bottom of the tree on the downslope side (called a butt mark) and a full ring around the tree high enough to be seen by the operator. 


Photo of a marked tree


Different timber harvest plans have different requirements for what trees can be cut. Below is the Oregon Mountain Project prescription and how it works. 


Oregon Mt. Prescription
  • Goal: 80-180 ft Basal Area (BA just means tree density of a stand)

  • Cut trees ≥8” Diameter at Breast Height (DBH)

  • Can use different Basal Area Factor (BAF is a term that describes the factor of the instrument used) (40, 60, 80, etc)


How to calculate Basal Area
  1. Choose plot center and put the prism at eye level and out to arm’s length

  2. Moving in a circle - count how many tees are in the plot

    1. Ex: 7 trees in

  3. Do calculation to determine BA

    1. 7 trees x 60 (BAF) = 420 BA

  4. We want the BA to be between 80-180

    1. 420-180 = 240 /60 = 4 trees

  5. Mark 4 trees in the area according to tree cut preference list


Cut tree preference: 
  1. White Fir

  2. Lodgepole

  3. Blister Rust Sugar Pine

  4. Diseased DF (most common, leave large complex trees)

  5. Dying Ponderosa (leave ones for wildlife)

  6. Incense – Cedar(uncommon)

  7. Douglas Fir

  8. Ponderosa Pine

  9. Non-Blister Rust Sugar Pine


How to pick trees from preference list:
  • Dead tops

  • Trees that will be dead soon

  • Crown is not full

  • Big pitch streams / beetle holes

  • Blister Rust

  • If you see white fir/lodgepole then mark it

  • DON’T MARK DEAD TREES


Conifers will grow well in the shade under oaks until they eventually outgrow the oaks. Oaks cannot survive in shade so as more conifers grew, oak woodlands quickly died off. Prioritizing encroaching conifers protects the few oak woodlands we have left. Usually, trees that get marked to be cut are diseased or injured causing them to die in a few years. Cutting diseased trees is important to prevent the spread of said disease. 


Once all necessary trees within the project have been marked, operations begin. Since logging operations take place in forests, establishing a road for the machinery is the first step, usually with a bulldozer and/or excavator. Road operations take drainages into account, so adding non-permanent culverts is necessary. Logging trucks, log loaders, and piles of logs take lots of space, so a landing zone is created. After the roads and landing zone is established, the harvest will begin.


Feller-Bunchers are machines with an operator cab on wheels or tracks with a tree-grabbing hydraulic arm furnished with a chain-saw, circular saw or a shear. Their purpose is to cut all marked trees.


Photo of Feller-buncher from NNRG


Once trees are cut and, on the ground, a processor delimbs and bucks a single stem into multiple logs (commonly referred to as a “cut to length” system). First it either grabs and cuts a tree at the base, or lifts a cut stem, then feeds the stem through the cutting head using feed rollers. Delimbing knives shear branches from the stem as it moves through the head. A bar saw cuts the stem to specified lengths.

  

Processor


Skidders are used to move logs from wooded areas to the landing zone. They grab logs with their arm and drag them to the landing zone. Once at the landing zone, log loaders pile logs and eventually load them onto log trucks. Log trucks transport logs to mills where the logs are processed for lumber and plywood. Usually timber harvests take place far from mills so truck drivers usually have to be on the road for a while, but the Trinity River Lumber Company has a mill right in town, so truck drivers get a nice and short drive to and from. 


 Photo of log loader and log truck


Put all of this together and the timber harvest is complete. What’s left is a healthy forest resilient to wildfire. Below is a before and after photo. Notice how nicely spaced all the trees are. The thinning project also focused on opening the crowns to allow more sunlight to the forest floor. This will hopefully lead to a healthy understory in the future!


Before/After

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