Forest Vegetation Analysis Flashcards
the Philippines is one of these countries in the world wherein we are enriched in all biodiversity levels in terms of genetic, species, and ecosystem levels
megadiverse
Two ways to assess the biodiversity of the ecosystem:
plotless
plot
for a forest, this plotless method is the most appropriate sampling method to be used
point center quarter method (pcqm)
often related to the size and shape of the plots used and this method is considered time-consuming
quadrat sampling
relies upon random distribution of the organisms in the area to be sampled
pcqm
Uniform or clumped distributions will yield erroneous results
pcqm
This method is one of the most favored for sampling in several habitats including forest ecosystems
pcqm
In this method, a number of randomly determined points are selected in the area to be sampled. These may be taken using a random number chart and distance along a transect tape, as random numbers corresponding to grid positions in the area, or as
random numbers used to select previously arbitrarily determined points in the area. Each point will represent the center of the measurement area. From the center, a compass will be used to define four quadrants. In each of these quadrants, you will determine, and measure the distance to, the closest plant from the center point. The center of the stem, or clump of the stem, should be used. Be sure to measure all relatively close plants to make sure you have the single closest individual.
pcqm
study the quadrant numbering
+1
is the standard for measuring trees
diameter at breast height
Refers to the three diameter measured at 4.5 feet above the ground
DBH
DBH can be measured by
calibrated diameter tape
displays the diameter measurement when wrapped around the circumference of a tree
d-tape
Can also use a string, measuring tape, thumb tack, and a calculator
DBH
Will be used to estimate the area covered by the plant
DBH
formula for getting DBH from circumference
d = π/C
procedure of measuring DBH
1.With a measuring tape, measure 4.5 feet up the trunk of the tree from the ground. Use a thumb tack to mark the height of the tree
2.measure the circumference of the tree trunk at 4.5 feet
3.convert the circumference measurement to diameter by dividing the circumference by Ο (3.14)
number of tress per unit area (hectare)
absolute density of trees
expressed as a number of trees per hectare, where a hectare is 10,000 sqm
absolute density
to get this, a mean distance between trees in the region should be computed:
absolute density
mean distance between trees formula
x = total distance of trees / total number of quarters
compute the mean distance of trees if there are 40.9m total distances of trees, and 20 trees
20.5m far apart
absolute density formula
= (10,000m^2)/ha / (xm^2)/tree
get the absolute density with the ff info:
2.05m^2 mean distance
2,380 trees/ha
absolute density of trees per species formula
number of quarters in which the trees can be found * absolute density
calcualte the absolute density of trees per species with the ff info
Acacia = 8/20
Eucalyptus = 4/20
Causarina = 5/20
Callitris 3/20
AD = 2380 trees/ha
A = 952
E = 476
Cau = 595
Callitris = 357
obtained by taking the number of trees of the species divided by the number of trees of all species multiplied by 100
relative density
comparative value of density in relation with other density of other trees
relative density
relative density formula
(number of trees per species / total number of species)* 100
compute for the RD of eucalyptus with the ff details
absolute density = 476
total number of trees = 2380
20.0%
measured by its basal area or cross-sectional area
absolute cover or dominance
area covered by the tree
absolute cover or dominance
computed using the diameter and derived from the basal area
absolute cover/dominance
formula for (A)
π (d^2/4)
formula for AC
= Mean BA x no.of trees/ha x 1m^2/10,000 cm^2
get the AC of Acacia given that
Mean BA = 31.7
no of trees = 952/ha
3.0m^2
units for cover are sqm/ha (not sq cm/ha) so a conversion factor is required
absolute cover
cover of each species divided by the total covertimes 100 to express the result as
percentage
relative cover
comparable value of cover in relation to other cover of other trees
relative cover
relative cover formula
RC = cover per species/total cover of species *100
solve for the relative cover of a tree species with the ff details
cover per species = 79.9m^2
total cover = 99.0m^2/ha
80.7
percentage of sample points at which a species occurs
frequency
indicates a more uniform distribution of a species
high or law AF?
higher
indicate clustering or clumping
high or low AF?
lower AF
based on number of sample points, not the number of quarters
absolute frequency
normalize the fact that the absolute frequency is more than 100%
relative frequency (RF)
comparative value of frequency in relation to other frequency of other trees
relative frequency
RF formula
(Absolute Frequency of Acacia / Total Frequency of Species)*100
Solve for RF of Acacia when
AF of Acacia 80
Total AF 240
33.3
calculated as the sum of the relative density, relative frequency, and relative cover
importance value
IV formula
π ππππ‘ππ£π π·πππ ππ‘π¦+π ππππ‘ππ£π πΉππππ’ππππ¦+π ππππ‘ππ£π πΆππ£ππ
Gives equal weight to three factors of relative density, frequency, and cover
Importance value
can be dominant if there are enough of them to be widely distributed across the transect
small trees
Can range from 0 to 300 and species will be ranked based on highest to lowest importance value
importance value
used depending on the area and organisms being studied
sampling method
consist of rectangular, circular, or square enclosure
plot method
no definite enclosure in getting the samples
plotless method
method that is plotless and useful in areas of different sizes and shape
PCQM
β’Relies upon a random distribution of the organisms in the area to be sampled
β’Uniform or clumped distributions
β’A number of randomly determined points are selected in the area to be sampled
β’Each point will represent the center of the measurement area. From the center, a compass will be used to define four quadrants
β’In each of these quadrants, you will determine and measure the distance to the closest plant from the center
point
PCQM
