Presentation is loading. Please wait.

Presentation is loading. Please wait.

Source: J. Hollenbeck Fixed Area Sampling Avery and Burkhart, Chapter 10 FOR 220 Aerial Photo Interpretation and Forest Measurements.

Similar presentations


Presentation on theme: "Source: J. Hollenbeck Fixed Area Sampling Avery and Burkhart, Chapter 10 FOR 220 Aerial Photo Interpretation and Forest Measurements."— Presentation transcript:

1 Source: J. Hollenbeck Fixed Area Sampling Avery and Burkhart, Chapter 10 FOR 220 Aerial Photo Interpretation and Forest Measurements

2 Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements

3 Nominal cruise intensity How much of the land was sampled? Examples: 1/10 acre plot on a 2 x 5 chain spacing: (remember 10sq. ch. = 1 ac.) Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements

4 Plot cruise planning: 120 acre tract 10% cruise (sample) 1/10 acre plots Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements 1. Area to be sampled: Given

5 Plot cruise planning: 120 acre tract 10% cruise (sample) 1/10 acre plots area sampled = 12.0 ac. Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements 2. No. of plots needed:.

6 Plot cruise planning: 120 acre tract 10% cruise (sample) 1/10 acre plots Area sampled = 12.0 ac. 120 plots needed Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements 3. Samples represent how much area?

7 Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements 4. Plot spacing? Distance between plots Plot cruise planning: 120 acre tract 10% cruise (sample) 1/10 acre plots Area sampled = 12.0 ac. 120 plots needed Each represents 1 acre (43,560 ft 2 )

8 Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements 5. Plot spacing? Distance between lines

9 Some advantages of plot cruising: 1. Suitable for one-person cruising. 2. Cruisers do not have to tally trees while following a compass line. 3.Cruisers pause at plot centers, allowing more time to check measurements. 4. Tree tally is separated by plots: can separate the plots into sets to calculate volumes for different timber types, etc. Plot Cruising Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements

10 Purposes: To evaluate regeneration status To demonstrate compliance with laws To determine effectiveness of regeneration treatments To identify additional treatments needed To collect data to predict growth and yield Regeneration Plots Fixed Area Plot Sampling - Different plots for different purposes FOR 220 Aerial Photo Interpretation and Forest Measurements Plot-count method (number of trees per acre) Stocked-quadrat method (proportion of land utilized) Staked-point method (like permanent plots)

11 Nested Circular Plots Smaller Trees Measured on Smaller Plots Fixed Area Plot Sampling Area (ac) Radius(ft) 1/ / / /10 acre plot 1/100 acre plot 1/500 acre plot Trees > 5 inch dbh Trees 2 to 5 inch dbh Trees < 2 inch dbh

12 Plot Sampling with Fixed Area Plot Sampling Plots and Product Groups 1/10 acre for sawtimber, poletimber, invasive ( ≥ 5 in) 1/100 acre for small trees 1/500 acre for advance reproduction TwoDog Product Groups CodeProduct Group 1 Sawtimber ( ≥ 12 inches dbh) 2Poletimber (5 in ≤ dbh < 12 in) 3Small Trees (2 in ≤ dbh < 5 in) 4Advance Reproduction ( < 2 in dbh) 5Invasive Species

13 Source: J. Hollenbeck Point Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements Avery and Burkhart (2002) Chapter 11

14 A method of sampling based on a tree’s size, rather than its frequency of occurrence. Tools: prisms, angle gauge, Relaskop The probability of tallying a tree depends on its cross- sectional area and the sighting angle used. The smaller the sighting angle, the more trees included in the sample. Point Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements

15 Point Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements Point Sampling (Overhead view) Each tree has a given plot size in relation to it’s size. How many of these plots does our point fall into?

16 Point Sampling (Side view) FOR 220 Aerial Photo Interpretation and Forest Measurements ? Offset tree bole in prism has no overlap with actual tree bole Offset tree bole in prism does overlap actual tree bole Borderline tree - must measure distance from point center Using a prism:

17 Fixed plot samplingPoint sampling Expansion factor Same for all trees Varies by tree Sampling is based on..Frequency of occurrence Tree size Point Sampling Comparing Point Sampling and Fixed Area Plot Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements PPF PPS

18 Point Sampling Important Ideas about Point Sampling 1. Basal Area Factor (BAF) How much BA does each sampled tree represent? 2. Plot Radius Factor How far away can a tree be and still be sampled?

19 Basal area factor (BAF) Related to the sighting angle size of the prism used in point sampling. Chosen to provide a tally of trees per point (8-10) Eastern U.S.: 5, 10, 20 Western U.S.: 20, 40, 60 Point Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements

20 Calculating basal area from a point cruise: Example: BAF 10 prism 202 trees tallied 25 points Point Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements It really is that easy!!

21 Plot radius factor (PRF) The value to use in determining the maximum distance a tree of a given diameter can be from the point to still be tallied. For example, when using a BAF 10 prism, the plot radius factor is Point Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements Which means: For each inch of dbh, a tree can be 2.75 feet from the point to still be included in the point’s tally. Thus a 12 inch tree can be up to 33 feet (12 x 2.75) from the point and still be included in the point’s tally.

22 Nested Plots Point Sampling FOR 220 Aerial Photo Interpretation and Forest Measurements 10 BAF Prism Sample 1/100 acre plot 1/500 acre plot Trees > 5 inch dbh Trees 2 to 5 inch dbh Trees < 2 inch dbh

23 What about TwoDog? Plots and TwoDog Product Groups Prism or 1/10 acre plot for sawtimber, poletimber, and invasive ( ≥ 5 in) 1/100 acre for small trees 1/500 acre for advance reproduction TwoDog Product Groups CodeProduct Group 1 Sawtimber ( ≥ 12 inches dbh) 2Poletimber (5 in ≤ dbh < 12 in) 3Small Trees (2 in ≤ dbh < 5 in) 4Advance Reproduction ( < 2 in dbh) 5Invasive Species

24 TwoDog Product Groups and Products TwoDog Product Groups CodeProduct Group 1 Sawtimber ( ≥ 12 inches dbh) 2Poletimber (5 in ≤ dbh < 12 in) 3Small Trees (2 in ≤ dbh < 5 in) 4Advance Reproduction ( < 2 in dbh) 5Invasive Species Two Dog Products CodeProduct PSPine Sawtimber (≥ 12 inches dbh) 01Grade 1 Sawtimber (≥ 12 inches dbh) 02Grade 3 Sawtimber (≥ 12 inches dbh) 03Grade 2 Sawtimber (≥ 12 inches dbh) TTTie and Timber Grade (≥ 12 inches dbh) CCull (≥ 12 inches dbh) PTPole Timber (5 in ≤ dbh < 12 in) SMSmall Trees (2 in ≤ dbh < 5 in) R0Reproduction < 1 ft tall R1Reproduction 1 to 2 ft tall R2Reproduction 2 to 3 ft tall R3Reproduction 3 to 4 ft tall R4Reproduction > 4 ft tall, < 2 in dbh ITInvasive Trees (≥ 5 inches dbh) ISInvasive Small Tree (2 in ≤ dbh < 5 in) IRInvasive Reproduction (< 2 in dbh)

25 What about snags?

26


Download ppt "Source: J. Hollenbeck Fixed Area Sampling Avery and Burkhart, Chapter 10 FOR 220 Aerial Photo Interpretation and Forest Measurements."

Similar presentations


Ads by Google