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How we measure forests

How we measure forests. David W. MacFarlane Dept. of Forestry MSU. Why measure the forest?. We want to know the current status of the forest. Size of trees, density and area covered by forests Species Composition = Biodiversity Value of forest products (wood and non-wood)

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How we measure forests

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  1. How we measure forests David W. MacFarlane Dept. of Forestry MSU

  2. Why measure the forest? • We want to know the current status of the forest. • Size of trees, density and area covered by forests • Species Composition = Biodiversity • Value of forest products (wood and non-wood) • Age, health and vigor of trees • Etc.. • How is the forest changing over time?

  3. Basic tree measurements • dbh = stem diameter at breast height ? 4.5 ft. (1.3 m) Digital caliper slope

  4. Measuring dbh Logger’s tape C = π d d 4.5 ft.

  5. Measuring height of standing trees(Trigonometry is useful) Height = H1 + H2 H1 θU = Angle from eye to tree top H1 = D*TAN θU θU D= Distance from tree Use a hypsometer H2 θL θL = Angle from eye to tree bottom

  6. Lidar: Measuring canopy height remotely Aircraft mounted laser

  7. How many trees in Michigan? Michigan = 36.4 million acres *19.4 million acres of forested land Census? We usually express number of trees as: Tree Density = # trees / unit area (e.g., 400 trees per acre)

  8. Sampling Select smaller areas to sample = 13.5 billion trees on forest lands (+ or - ?) Count # of trees to per sample unit area (= density) Project to larger area

  9. Year = 2000 From US Forest Service, Forest Inventory & Analysis (FIA) Program

  10. On Michigan Forest Lands in 2000 dbh = 2” 7.6 billion trees dbh = 6” 1.4 billion trees

  11. What kind of tree is it? • Problem 1: How can we identify tree species? Take: FOR 204 Forest Vegetation! Reproduced from National Arbor Day Foundation

  12. Measuring Biodiversity • Richness = # spp. in an area • Relative Density = (density of spp.) / (density of all species) = % abundance • Relative Dominance = (area covered spp.) / (total area.) = % area covered C Contains spp. A, B and C Richness = 3 A A A A A A C B B A B A A A A A A A A C A C B C C A Richness Relative Density Relative Dominance

  13. Dominance vs. Density = spp. A = spp. B Density A = 2 per area Density B = 20 per area Area defined Area dominated

  14. Merchantable Volume ($$$)(Wood products are important!) Volume of a cylinder = V = Area*Length Scaling Cylinder d L = log Length r How many Boards per unit volume? Area = π r2 r = d/2

  15. 78 Billion Board feet on forested lands in MI, in 2000

  16. Michigan forest statistics for 2000 *13.5 Billion trees / 19.4 million acres = 696 trees per acre on forested land in Michigan *78 Billion Board feet / 19.4 million acres of forest land = 4,020 Bd. ft. per acre on forested land in Michigan ~$0.10 to $3.00 per Bd. ft. *78 Billion board feet / 132 million feet around the Earth = Make a 590 feet wide ring around the Earth!

  17. Measuring change over time CFI = Continuous Forest Inventory *USDA Forest Service (Forest Inventory and Analysis (FIA) *USDA Forest Service (Forest Health Monitoring (FHM) *State Forest Inventories / Health Monitoring Programs *University Researchers / Scientific Foundations *Private Forestland Inventories (e.g., Mead-WestVaco) Year 1 Year 2 Year 3

  18. Remote Sensing of Forest Dynamics Landsat Satellite Images in Area of Traverse City, MI October 19, 2000 April 13, 2001 July 2, 2001

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