Lecture 8 Forestry 3218 Forest Mensuration II Lecture 8: Inventories with Sample Strips or Plots Avery and Burkhart, Chapter 10

Lecture 8 Forestry 3218 Strip cruisingPlot cruising Sample area X Fixed-area sampling Selecting sample trees with probability proportional to frequency

Lecture 8 Forestry 3218 Strip System of Cruising  Sampling intensity  Orientation of strips

Lecture 8 Forestry 3218 Strip System of Cruising   Nominal cruise intensity (I)   Actual cruise intensity   Expansion factor (EF) Strip width Distance between strips

Lecture 8 Forestry 3218 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

Lecture 8 Forestry 3218 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

Lecture 8 Forestry 3218 Line-Plot System Cruising As with the strip method, line-plot inventories are often planned on a percent cruise basis

Lecture 8 Forestry 3218 Line-Plot System Cruising planning  Problem –Develop a plan of line-plot cruising with a given sampling intensity, plot size, and line distance  Example: –A stand of 10 ha (A) –Sampling intensity = 10% (P) –Plot size = 0.04 ha (a) –Line distance = 100 m (L)  What we need to know –How many plots (n) –How to space the plots (B)

Lecture 8 Forestry 3218 Line-Plot System Cruising planning Area of all plots = A p

Lecture 8 Forestry 3218 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.

Lecture 8 Forestry 3218 Permanent Sample Plots   Purpose: To measure changes in forest conditions   Standard procedures for measurements   Remeasured at periodic intervals   Can determine causes of change

Lecture 8 Forestry 3218 Ontario Permanent Sample Plots Networks   Provincial growth and yield PSPs   Provincial wildlife sample plot network   National Forest Plot Network   Forest company PSPs

Lecture 8 Forestry 3218 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

Lecture 8 Forestry 3218 Regeneration Survey with Sample Plots   Methods – –Stocked-quadrat method (proportion of land utilized) – –Plot-count method (number of trees per acre) – –Staked-point method (like permanent plots)