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Sampling Techniques THE SEQUEL

Sampling Techniques THE SEQUEL. Warning!. Material included on Lecture Exam #1!. Importance. Which plants “ important? ” Measures importance (sp. A) Density of A = No. inds. per unit area (reflects abundance A)

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Sampling Techniques THE SEQUEL

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  1. Sampling TechniquesTHE SEQUEL

  2. Warning! • Material included on Lecture Exam #1!

  3. Importance • Which plants “important?” • Measures importance (sp. A) • Density of A = No. inds. per unit area (reflects abundance A) • Frequency of A = No. times sp. A in samples divided by total samples taken (reflects pattern A) • Cover of A = Area occupied by A (reflects biomass A)

  4. Methods • 1) Quadrat • 2) Belt transect • 3) Line intercept • 4) Plotless (distance) methods

  5. Plotless (distance) methods • Based on points (0 dimensional method) • Often trees along transect

  6. Plotless (distance) methods • Collect: • 1) tree ID • 2) tree size (reflects biomass/cover) • 3) distance measurement (from something to something)

  7. Plotless (distance) methods • Method 1: Nearest individual method

  8. Plotless (distance) methods • Method 2: Nearest neighbor method

  9. Plotless (distance) methods • Method 3: Point centered quarter method

  10. Plotless (distance) methods • Information Collected: • 1) tree ID • 2) tree size (reflects biomass/cover) • 3) distance measurement (from something to something) • IV= Rel. density + Rel. frequency + Rel. cover • <300%= <100% + < 100% + < 100% • How get rel. density, rel. frequency, rel. cover values?

  11. Plotless (distance) methods • Cover: have DBH • Convert DBH to area trunk each species

  12. Plotless (distance) methods • Cover: have DBH • Convert DBH to area trunk each species • % rel. cover species Y: • Cover Y/Cover all species X 100% • IV= Rel. density + Rel. frequency + Rel. cover

  13. Plotless (distance) methods • Frequency: tree identities each point • % frequency species Y: • No. pts. with species Y/Total number pts. X 100% • % rel. freq. sp. Y: • Freq. Y/Freq. all species X 100% • IV= Rel. density + Rel. frequency + Rel. cover

  14. Plotless (distance) methods • Density: ?? No areas measured?? • Geometric principle: as density increases distances measured decrease • Note importance random placement points!

  15. Plotless (distance) methods • Steps: • 1) Calc. mean distance (D) for all trees sampled • 2) Use formula: • Density (all species) = A/(correction factor)(D)2 • For metric units: • A=10,000 m2/hectare (ha) • D in meters (m) • Correction factor?

  16. Plotless (distance) methods • Steps: • Correction factor? • 2 nearest individual method • 1.67 nearest neighbor method • 1 point centered quarter method

  17. Plotless (distance) methods • Steps: • Correction factor? • 2 for nearest individual method • 1.67 for nearest neighbor method • 1 for point centered quarter method • 3) Calc. density species Y: • No. Y/No. all species X Density (all species) • 4) % rel. density Y: • Density Y/Density all species X 100%

  18. Plotless (distance) methods • IV species Y • IV= Rel. density + Rel. frequency + Rel. cover • <300%= <100% + < 100% + < 100% • Repeat calcs. other species

  19. Plotless (distance) methods • Point Centered Quarter method: • 1) More data/point • 2) Relatively simple • 3) No correction factor in density formula (correction factor = 1)

  20. How place sample units? • Generally, random best • Define? • All potential samples have equal chance inclusion • Why best? • Eliminate bias • May be required: statistics/equations (e.g., density formula for plotless methods)

  21. How place sample units? • Random not same as: • Arbitrary: Attempt eliminate conscious bias • Systematic: Use numeric pattern (ex, every 5th tree) • Deliberate: Choose with criteria (ex, all trees > 30 cm dbh)

  22. How place sample units? • Random not alwaysrepresentative sample • Ex: X X X X X X X X X X X

  23. How place sample units? • Techniques: • Random • vs. • Stratified random (subdivide area & sample randomly in each division)

  24. How place sample units? • Techniques: • Systematic

  25. How place sample units? • Techniques: • Random-Systematic (start random, place points systematically: or vice versa) systematic random systematic random OR

  26. Ch. 4: Soils, Nutrition etc.

  27. Soil • Definition: • Natural body: layers (horizons)

  28. Soil • Definition: • Natural body: layers (horizons) • Mineral + organic matter (OM) • Differs from parent material: substance from which soil derived

  29. Weathering Factors • Mineral component: generated by weathering rock

  30. Soil Texture A: Sand & silt know these • Major particle sizes (know these) B: clays

  31. Textural triangle • Distribution particles by size class: texture • Loam: mix sand, silt, clay • Texture important: fertility, water availability

  32. Soil Structure • Particles form peds • Affect water + root penetration How important??

  33. Organic matter (OM) • Humus: partly decomposed OM • Negatively charged: • carboxyl groups (-COOH) • phenols

  34. Soil Horizons

  35. Soil Horizons • Vertical gradients • Leaching: wash material upper to lower layers • Weathering: great at surface • Biotic effects: great at surface

  36. Soil Horizons • Major horizons: • O: organic matter (surface) • A: surface soil. High organic matter • E: leaching strong

  37. Soil Horizons • Major horizons: • B: subsurface soil. • Deposition • Chemical changes (secondary minerals/clays)

  38. Soil Horizons • Major horizons: • B: subsurface soil. • Hardpan: cemented soil grains • Claypan: dense clay • Both: interfere water penetration, roots • Humic layer: organic matter from E

  39. Soil Horizons • Major horizons: • C: weathered parent material • R: unweathered parent material

  40. Soil Horizons • Layers subdivided (numbers) Fig. 4.5

  41. Organisms • Plants influence soil & vice versa • How? • 1) Roots • Depth: record 394 ft: fig tree (Echo Caves, South Africa) • Amount (biomass/unit volume/yr) • Size: woody (shrub/tree) vs. fibrous (grasses)

  42. Organisms • How plants influence soil? • 2) Base cycling • Nutrients “in play”

  43. Organisms • Fertile island effect: under desert shrubs soil fertile • Ex, creosote bush: under shrubs--more nutrients

  44. Organisms • How plants influence soil? • 3) Litter acidity • Ex: soils under spruce (conifer) vs hardwood

  45. Parent Material • Within climate, parent material major influence • Ex, serpentine soil • High Mg, low Ca • Lots Ni, Cr

  46. Parent Material • Extreme cases, serpentine “barrens”

  47. Parent Material Forest on granite in Australia • Within climate, parent material major influence • Ex, granite outcrop soil • Lots sand (coarse texture) • Soil dry (water drains)

  48. Time • General trends (as time increases): • pH decreases • organic matter increases • clay increases • depth increases

  49. Soil Fertility • Defn.: Ability soil hold & deliver nutrients • Determined by texture, organic matter, pH Holding soil….

  50. Soil Fertility • Texture: clays • Negative charge: hold useful cations (Ca++, K+, Mg++, Zn++) • Huge surface

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