Lesson 1 - Basic Mensurational Measurement Flashcards
(19 cards)
Forest Mensuration
measurement of tree characteristics and the products cut from them
What does Forest Mensuration deal with?
- identifying the variables that are important for decision making in forest management
- designing a sampling scheme to efficiently collect the information required at an appropriate level
- measuring or estimating variables
- analysing the data to provide the information desired
Describe precision
spread of observations around the long run mean of the observations
- individual measurement = standard deviation
- statistics = standard error
Describe bias
difference between the long run average of the observations and the true value
Describe accuracy
how close and observation, or a series of observations, are to being correct
- combines elements of both bias and precision into a single measure of “goodness” and is often measured by the mean square error
What is a source of error? List them
Source of error: errors of measurement or estimation
- instrumental error
- rounding error
- relationship error
- sampling error
- human error
Give an example of a tree variable
dbh, total tree height, upper stem diamater
What is the collective name for instruments that measure dbh
dendrometer
What is basal area
cross sectional area of the tree at breast height
pi x dbh squared divided by 4
Convert cm to m
divide by 100
At what height do you meausre dbh?
What height is diameter at stump height?
1.3m and 0.3m
Ways to measure dbh
d- tape, calipers, biltmore stick
What is total tree height
distance between the ground and the tip of the tree
How can you indirectly measure tree height
measurement of horizontal distances and slope distances
Suunto clinometer
geometric approach (no angle measuring device)
- staff or merritt hypsometer
trigonometric approach
What is the formula for measuring leaning trees
HT = HT / sin(90-angle)
describe upper stem diameters
diameters which occur far enough up the stem of the tree as to be out of reach of an individual on the ground
What is a relascope and how is it used to measure diameter
an instrument used to measure tree heights, and upper stem diameters. can also be used as a range finder (find out how far you are away from an object)
diameter (cm) = #bands x 0.2 x HD x 100
How do you measure bark thickness?
bark guages or increment borers
What needs to be included for an accurate count of a tree’s age?
pith and bark
