Sampling Techniques THE SEQUEL Warning Material included on

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) – 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)

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

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

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

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

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

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

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% • How get rel. density, rel. frequency, rel. cover values?

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

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

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

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

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 m 2/hectare (ha) – D in meters (m) • Correction factor?

Plotless (distance) methods • Steps: • Correction factor? – 2 nearest individual method – 1. 67 nearest neighbor method – 1 point centered quarter method

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%

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

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

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)

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

How place sample units? • Random not always representative sample • Ex: X X X

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

How place sample units? • Techniques: • Systematic

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

Ch. 4: Soils, Nutrition etc.

• Definition: Soil – Natural body: layers (horizons)

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

Weathering Factors • Mineral component: generated by weathering rock

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

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

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

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

Soil Horizons

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

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

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

• • • 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

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

Soil Horizons • Layers subdivided (numbers) Fig. 4. 5

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)

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

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

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

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

Parent Material • Extreme cases, serpentine “barrens”

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

Time • General trends (as time increases): – – p. H decreases organic matter increases clay increases depth increases

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

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

Soil Fertility • Humus negative charge: clay & humus hold cations

Soil Fertility • Cation Exchange Capacity: amount negative charge/unit soil • Units: centimoles charge/kg dry soil (cmolc/kg) • Represents “potential fertility”

Soil Fertility • Exs: • US prairie: 30 cmolc/kg • NE US conifer forest: 2 cmolc/kg

Soil Fertility • H+ (& Al+++) also attracted negative charge. – Not useful. • Base saturation (BS): % sites “good” cations (bases: Ca++, Mg++, K+) plus Na+

Soil Fertility • BS, p. H & CEC determine “actual fertility” – 1) High CEC + high BS = more fertile – 2) If BS low: p. H low (lots H+) Actual fertility: Multiply BS by CEC

Soil p. H • Most AL: 4. 5 -5. 1 (strongly acid) • Black Belt: 7. 9 -8. 4 (alkaline)

Soil p. H • p. H effects: • 1) H+ damages roots (@ extreme p. H values) • 2) soil microflora – Acid favors fungi (incl. mycorrhizae) – Alkaline favors bacteria • 3) soil structure (sometimes)

Soil p. H • 4) nutrient availability. Major influence! • Nutrient deficiency: • Acid: N, P, Ca, Mg, K, S

Soil p. H • 4) nutrient availability. Major influence! • Nutrient deficiency: • Acid: N, P, Ca, Mg, K, S • Alkaline: Fe, Mn, Zn, Cu, Co, B

• 4) nutrient availability. Major influence! • Nutrient toxicity: • Acid: Fe, Mn, Zn, Cu, Co • Alkaline: Mo Soil p. H

• Plant sensitivity & nutrient needs • Black Belt lab (#2): – Black Belt soil: Soil p. H