Lecture 8 Lecture 8 Forestry 3218 Forestry 3218 Forest Mensuration II Forest Mensuration II Lecture 8: Inventories with Sample Lecture 8: Inventories with Sample Strips or Plots Strips or Plots Avery and Burkhart, Avery and Burkhart, Chapter 10 Chapter 10
Forest Mensuration II. Lecture 8: Inventories with Sample Strips or Plots Avery and Burkhart, Chapter 10. Fixed-area sampling. Strip cruising Plot cruising. Sample area. Sample area. X. Selecting sample trees with probability proportional to frequency. Strip System of Cruising. - PowerPoint PPT Presentation
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Lecture 8Lecture 8Forestry 3218Forestry 3218
Forest Mensuration IIForest Mensuration II
Lecture 8: Inventories with Sample Strips or PlotsLecture 8: Inventories with Sample Strips or Plots
Avery and Burkhart,Avery and Burkhart,Chapter 10Chapter 10
Lecture 8Lecture 8Forestry 3218Forestry 3218
Strip cruising Plot cruising
Sample areaSample area
X
Fixed-area sampling
Selecting sample trees with probability proportional to frequency
Lecture 8Lecture 8Forestry 3218Forestry 3218
Strip System of Cruising
Sampling Sampling intensity intensity
Orientation of Orientation of stripsstrips
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Strip System of Cruising
Nominal cruise intensity (I)
Actual cruise intensity
Expansion factor (EF)
100DW
I
Strip width
Distance between strips
100areatracttotal
sampleinareaa
I
I
100EF
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Strip System of Cruising
Advantages– Less time wasted in traveling between
strips than for a plot cruise of equal intensity.
– Fewer borderline trees, because the total perimeter of the sample area is smaller
– Less risk to personnel in remote areas: two people generally work together
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Strip System of Cruising
Disadvantages– Errors are easily incurred through
inaccurate estimation of strip width– Brush and windfall are more of a
hindrance in this system– Spot-checking the cruise is difficult
because strip centerline is rarely marked
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Line-Plot System Cruising
100drepresente area
plots of number *size plot
As with the strip method, line-plot inventories are often planned on a percent cruise basis
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Line-Plot System Cruisingplanning
ProblemProblem– Develop a plan of Develop a plan of
line-plot cruising with line-plot cruising with a given sampling a given sampling intensity, plot size, intensity, plot size, and line distanceand line distance
Example:Example:– A stand of 10 ha (A stand of 10 ha (AA))– Sampling intensity = Sampling intensity =
10% (10% (PP))– Plot size = 0.04 ha (Plot size = 0.04 ha (aa))– Line distance = 100 m Line distance = 100 m
((LL)) What we need to knowWhat we need to know
– How many plots (How many plots (nn))– How to space the plots How to space the plots
((BB))
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Line-Plot System Cruisingplanning
2504.0
1.010
aAPn
1.0100400
LPaB
Area of all plots = Ap
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Line-Plot System Cruising Advantages
– Suitable for one-person cruising– Cruisers do not have to tally trees while
following a compass line– Cruisers pause at plot centers, allowing
more time to check measurements– Tree tally is separated by plots, permitting
quick summary of timber types, species composition, etc.
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Permanent Sample Plots
Purpose: To measure changes in forest conditions
Standard procedures for measurements
Remeasured at periodic intervals
Can determine causes of change
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Ontario Permanent Sample Plots Networks
Provincial growth and yield PSPs Provincial wildlife sample plot
network National Forest Plot Network Forest company PSPs
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Regeneration survey with Sample Plots
Purposes – To evaluate regeneration status– To determine effectiveness of regeneration
treatment– To identify additional treatments needed– To collect data to predict growth and yield– To demonstrate compliance with laws
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Regeneration Survey with Sample Plots
Methods– Stocked-quadrat method (proportion of
land utilized)– Plot-count method (number of trees per