Timber Estimation

FORS 3000 Note: Because timber estimation is an entire class, it is not considered a module for FORS 3000.

Description

Timber estimation requires the contestant to quantify the timber volume of a 5 to 10 acre stand in 90 minutes or less. Contestants are provided a map and volume tables in advance so that they can decide on their timber cruising methodology and equipment. They are allowed to use any conventional timber cruising equipment, such as calipers, diameter tapes, clinometers, cruiser sticks, compasses, etc. The winner is the contestant that submits a volume closest to the actual volume determined by the judges' representative, who performs a 100% tally of the tract prior to the competition. Timber estimation has been a Conclave event every year since at least 1960.

Timber Estimation Example Photos

Photo Credit: Student using a prism to tally trees in a point while timber cruising. Photo by Jeremy Stovall.

Photo Credit: Student using a diameter tape to measure a tree while timber cruising. Photo by Jeremy Stovall.

Photo Credit: Student using a hypsometer to estimate tree height while timber cruising. Photo by Jeremy Stovall.

Academic Background

Timber estimation, also commonly called timber cruising, describes an array of methodologies whereby foresters sample a stand to determine structural variables, such as the number of trees per acre, their size, and the volume of timber present. Information gained from timber cruising is used by individuals and companies to buy and sell land, buy and sell timber, and make management decisions. Timber estimation is an important practice when a stand is being manged for timber, but similar field techniques and statistical methods are often used for other management objectives such as wildlife or recreation. In order of decreasing importance to the accuracy of their estimates of volume, timber cruisers must correctly tally the number of trees in a sample plot, estimate their diameters (often by eye alone), and then estimate their height (again, often by eye alone). Basic arithmetic and statistical techniques are then used to tabulate the results of numerous samples per stand, and bound those tabulated estimates with metrics that describe the variability. Efficiency and accuracy are key components to timber cruising; proficient cruisers may spend only a couple minutes per plot depending on sampling technique and stand conditions, and may complete dozens of plots per day, all while rarely missing a tree that should be tallied.

Resources

Study Guide: Cruise Design and Layout

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Study Guide: Line Point Sampling

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