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Lab 16 Harvest Strategy . Crystal, Tom, and Jay. Finding the “best” Rotation Time.
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Lab 16 Harvest Strategy Crystal, Tom, and Jay
Finding the “best” Rotation Time. • Figure 1. Relationship between rotation time (in years) and the average annual harvest value (in thousands of dollars) using the Bachmap sparrow population dynamics model for the Tornado Alley 1991 landscape. The model was run with a simulation time of 40 years.
Population Size and Average Annual Harvest Value • Figure 2. Comparison of how rotation time effects both the sparrow population size and the average harvest value (in thousands of dollars) using Bachmap sparrow population dynamics model for the Tornado Alley 1991 landscape. This model was run with a simulation time of 20 years to get a more accurate representation of long term effects
Populations for the Replicates. • Figure 3. Sparrow population sizes over 10 replicates using a simulation time of 20 years and a rotation time of 50 years using Bachmap sparrow population dynamics model for the Tornado Alley 1991 landscape.
Descriptive Statistics of Population Replicates. • Table 1. Descriptive statistics for the replicates of the Bachmap sparrow population dynamics model for the Tornado Alley 1991 landscape with a simulation time of 20 years
Validity of Decision • Table 1: Representative yield function data for southern pine in the U.S.
Validity of Decision • The first column represents the age of the stand, and the second represents the yield in board feet for trees of that age. The third column represents the growth in board feet annually, and the fourth column represents the average annual growth.
Validity of Decision • There are three options: • 1. Harvest when yield is maximized (80 years). • 2. Harvest when annual growth is maximized (30 years). • 3. Harvest when average annual growth is maximized (50 years).
Option 1 (80 years) • If this option is chosen average yearly revenue from timber sales (assuming $100/ mbf) would be $69, or $5,544 when the stand is cut.
Option 2 (30 years) • If this option is chosen, average yearly revenue from timber sales (assuming $100/ mbf) would be $66, or $1,983 when the stand is cut.
Option 3 (50 years) • If this option is chosen, average yearly revenue from timber sales (assuming $100/ mbf) would be $77 or $3,829 when the stand is cut.
Best Option? • The best option is obviously 3, not only from the example provided, but from the simulations that were run in lab. A rotation time of 50 years not only maximizes the average harvest, but also maximizes the sparrow population.
Special Thanks: • Louisiana State University Ag economics and Agribusiness • Available at: • http://www.agecon.lsu.edu/WebClasses/AGEC3503/modules/module2/m2les2.htm#Part5