1) tree canopy cover percentage 2) shrub cover percentage 3) identification of dominant and...
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)
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
90 m
N
30 m30
m
Biometry
Measurement
Area
90 m
90 m
GPS
LANDCOVER = ________________
N
Homogeneous Land Cover
Biometry Measurements
30 m
30 m
Biometry Measurement Area – Pacing Semi-Diagonals
N
21.2 m
NE
SESW
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
30 m
Biometry Measurement Area – Pacing Semi-Diagonals
N
NE
SESW
NW
Biometry MeasurementsFrom 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 MeasurementsMeasuring Tree Height
Using right-angle trigonometric relationships
hAngle
Tan(Angle) = h / Distance
DistanceDistance
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 50 -70 degrees Celsius.
DO NOT use a conventional oven.
Bags are weighed ~ daily until no weight change is seen from day-to-day.