Presentation on theme: "1) Tree Canopy Cover Percentage 2) Shrub Cover Percentage 3) Identification of Dominant and Co-Dominant Species 4) Tree Heights of Dominant Species and."— Presentation transcript:
1) Tree Canopy Cover Percentage 2) Shrub Cover Percentage 3) Identification of Dominant and Co-Dominant Species 4) Tree Heights of Dominant Species and Co-Dominant Species 5) Tree Circumferences of Dominant Species and Co- Dominant Species 6) Grass Cover 7) Grass Biomass Biometry Measurements pace semi-diagonals (using densiometer) (trees are 5 m or more in height) (shrubs are under 5m in height) pace semi-diagonals (using densiometer and plant guide(s)) trigonometric relationships (using clinometer and tape measure) measure at 1.35 m (using tape measure)
When to make Biometry measurements Each year, make your biometry measurements –once near the peak of the growing season when maximum green leaves or grass are present –once during the least active season if you have one (i.e. when broad leaf trees have lost their leaves in temperate regions).
Determining Pace ‘Pace’ is a very convenient measurement of distance that everyone can use - no need to take along a meter tape A pace is 2 steps To find you pace –stretch out a 50 m tape flat on the ground –start with heel or toe on 0 m, then walk 10 normal paces –note where heel or toe lands on 10th pace [say 15.7 m] –divide by 10 to get average pace [gives 1.57 m] –repeat twice more; average all 3 results Alternatively can measure how many paces it takes to walk 21.2 m (take three replicates and average)
Biometry Measurements Land Cover Sample Site (homogenous land cover) 90 m N 30 m Biometry Measurement Area
Biometry Measurements 30 m Biometry Measurement Area – Pacing Semi-Diagonals N 21.2 m NE SE SW NW canopy cover ground cover
66 Density of Vegetation Cover Homemade Tube Densiometer –Two diagonal transects –Measurements of green vegetation ‘hits’ intersecting tube’s ‘crosshair’ at each ‘pace’ along transect –% Tree Cover = 100 X ‘Trees’/total number of measurements ‘+’ = tree or shrub Sky
Biometry Measurements 30 m Biometry Measurement Area – Pacing Semi-Diagonals N NE SE SW NW
Biometry Measurements From pacing semi-diagonals can determine: 1) Tree Canopy Cover Percentage 2) Shrub Cover Percentage 3) Identity of Dominant and Co-Dominant Species Still need: 4) Tree Heights of Dominant Species and Co-Dominant Species 5) Tree Circumferences of Dominant Species and Co-Dominant Species
Biometry Measurements Measuring Tree Height Using right-angle trigonometric relationships h Angle Tan(Angle) = h / Distance Distance h = Distance * Tan(Angle) Height Height = h + eye height eye height Height = Distance * Tan(Angle) + eye height
Tree Height Clinometer: Alternative techniques: - Advanced trigonometric methods for non-level ground - Simplified version involving 45 degree angle
What you need in the field: –GPS –Compass(es) –MUC, and local vegetation student field guides –Camera –Tubular densiometer(s) –Clinometer(s) –50m tape measure(s) –Flags –Knowledge of your pace length –Land Cover Sample Site and Biometry Data Sheets Biometry Measurements
Grassland Measurements a. Three or more locations are chosen at random. b. A one-meter square is marked at each location.
Grassland Measurements All grasses within the one meter square are clipped as close to the soil as possible.
Grassland Measurements a. Use grass clippers or strong scissors. b. Collect all grasses. c. Discard leaves, twigs, other non-grass materials.
Grassland Measurements At School: Samples are divided into green (living) and brown (senescent). Samples are placed in brown bags (NOT PLASTIC) for drying.
Grassland Measurements Samples are dried at degrees Celsius. DO NOT use a conventional oven. Bags are weighed ~ daily until no weight change is seen from day-to-day.