Transcript Document
Cruising Approaches
Area Based Methods
Tree Based Methods
Area Based Methods
Strip Cruise
Fixed Plot
Point Sampling
Remote Sensing
Fixed Count
Fixed Count Measure
Fixed Plot with 3P
subsample
Point Count Measure
Point Sampling with 3P
subsample
3P Point Sampling
Main Types
Varieties for specific
applications
Tree Based Methods
For stands too variable in
density to plot cruise or
where trees are not
suitable for cruising by
other methods
Examples – partial
cutting, small clearcuts,
stratification by species
or size class is desired
Sample Tree Method
Small or irregular shaped
harvest units
Widely scattered trees
Very large stands
Used where a wide volume
range occurs within a
species group
Measure as few trees as
possible
Cut tree marking
Not used in this region
3P
Strip Cruising
Strips could be randomly allocated. Hard to stratify without
bias.
Area Based Methods
Strip Cruising
Disadvantages of strip cruising:
1. Inaccurate estimation of strip width may lead to
errors.
2. Difficult to maintain a straight strip centerline.
3. Brush and windfall are more of a hindrance in this
system.
4. Spot-checking the cruise is difficult: strip
centerline is rarely marked.
Remote Sensing
Best for low value products
Best for even-aged, single canopy and
species stands (tree farms)
Needs recent high resolution photos
Pre-sampling needed to establish
relationships i.e. volume versus canopy
cover estimates
Photos must be geo-referenced
Remote Sensing
Fixed Plot
1.
2.
3.
4.
5.
Locate Plot Center
Temporarily mark plot center
with wire flag or paint for instance
Plot size targets 4 to 8 trees per plot
Use same size plot throughout
Plot radius checked with hipchain
Pacing is less accurate
Determination of “IN” Trees
Plot center to tree center
Horizontal Limiting Distance
HLD = Plot Radius – (0.5 X DBH/12)
Must be corrected for slope if steeper
than 10%
Slope Correction
Slope Limiting Distance
SLD = HLD X SCF or HLD = SLD/SCF
SCF means Slope Correction Factor
Slope Correction
Fixed plot size (acre) = ¼
Plot radius = 58.9 feet
Measured distance to tree face = 59.8 feet
DBH = 12.6 inches or 1.05 feet
DBH/2 = .525 feet
Slope percent = 20
Slope correction factor = 1.02
Limiting Distance =
In or Out =
SLD
= (58.9 - 0.525) X 1.02
= 58.375 X 1.02 = 59.5
Out by 0.3 feet
Problem Trees – Forked Trees
if the boundary
passes through
the center of
the tree at
DBH, count as
IN
Problem Trees – Leaning Trees
if the
boundary
passes
through the
center of
the tree at
DBH, count
as IN
Problem Trees – Broken or Down
Trees
locate breast height at 4 and 1/2 feet above the root collar as the tree lies on
the ground. If this point lies on or inside the plot boundary, the tree is IN
Null Plots
Must be tallied as having no trees for
correct expansion factor to apply to whole
site.
Manual Method
Dot-Dash Tally
Field Aids
Species Codes
Tree Codes
Location Codes
Tree and Log Grading Rules
Percentage Deduction Tables
Standard upper limit Diameter Outside
Bark (DOB) by species
Limiting distance tables for point-sampling
Stratification guides
Recording Equipment
Compass and/or GPS
Clinometer or laser to determine slope
D-Tape
100 foot tape or hipchain
Flagging and/or paint
Prism or angle gauge for point cruising
Hypsometer
Pencil and paper or Data Recorder
Forms
Date = 8/19/2013
Size = 1/10th acre Forest Cover Type =
Stand Size and Condition =
Stand Age =
Stocking or Density Class =
Site Index =
Slope =
Soil Classification =
Understory Vegetation =
Treatments needed =
Plot = 1
Tree Species DBH
Form Class
Height
Grade
Crown Class
1
RO
14
78
1.5
2
2
SP
16
80
2
2
3
YP
18
82
2.5
1
Plot = 2
Etc.
Notes
Electronic Data Recorders
Pocket Dog
FS Cruiser
If your field data recorder has built in
GPS – even better. Can include location
in tally data for periodic rescaling, etc.