Awards for the 1986
Field
Notes
Articles
Thanks to the efforts of those readers who took the
time to fill out and submit rating sheets we can
that
the
now announce quite unequivocally
following
articles were found to be the top three of 1986
DRUM ROLL
PLEASE
Article
Authors
ASNAP
Administrative
Site Needs Assessment
Process
Lynn Kanno
Civil Engineer
Los Padres National
Forest
5
Region
Decisions... Decisions...
Decisions
Suhr
Civil Engineer
Region 4
Evaluation
Report--ComputerAided Drafting/Design
for
Use by Forest Service
Architects
and
Structural
Engineers
Nelson Hernandez
Structural Engineer
Jim
Region
5
Maurice Hoelting
Architect
Region
8
Robert Sandusky
Architect
Regional
5
Region
Stephen Sichau
Supervisory Electrical
Engineer
6
Region
to the authors of these articles and
Congratulations
special thanks to all the others who made the time
to write and
submit articles to Engineering Field
Notes.
We appreciate your willingness
to share your
ideas and experiences
with others and the extra
effort you put forth to do it.
Remember
every reader is a potential author of an
If
Engineering Field Notes article.
youve had an
or have some information that
interesting experience
may be of interest to Engineering Field Notes
1
readers why
be
to
EFNsREADERS
to
submit
hear from
not
it
for publication
you
Well
And
Really--we do want and need to hear from you.
A
you dont need to be a professional writer either.
1- or 2-page article on some aspect
of your
work that you feel would interest others would
Double spaced/single
really be appreciated.
spaced/
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typos--it
doesnt matter.
Well do our best to help you share
and to share others
experiences
your experiences
with you.
Engineer-ing
EPN
it
A NOTE
waiting
2
Black-Forest Service
Engineer of the Year
Robert
S.
On February 18 Bob Black Forest Engineer on the
Six Rivers National Forest in Region
5 received-the
Forest Service Engineer of the Year award at the
8th Annual NSPE Federal Engineer
of the Year Awards
in
Virginia.
Arlington
Ceremony
Following
is
a
brief statement
of
achievements
ROBERT
S.
BLACK USDA Forest
Bobs
recent
Service.
Forest
Engineer Six
Engineer Supervisor
Rivers National
Forest Eureka California.
B.S. Logging Engineering Oregon State
Civil
Univer-sity.
of
Mr. Black exhibits a rare combination
technical skills and common sense and acts with
a
determination
to innovate and get
things done.
In 1983 after the USGS issued a state-I
alert for Californias Mammoth Lakes area
and
at the
request of the FHWA his engineering
unit on the Six Rivers National
Forest took the
lead in locating and designing the Mammoth
Alternative
Access Route which
could save the
and
tourists
in the event
area
residents
40000
of a cataclysmic
both
eruption.
Using
and an
photogrammetric
techniques
based
road design
graphic
micro-computer
he
initiated
the
successful
6-month
system
of the access
design and construction
$200000 and 11/ months off both FHWA
and Cal Trans estimates for designing and
His leadership in the economic
that
route.
planning and design of rural low-standard roads
is evidenced
by his selection to his Agencys
National
Roads Program Productivity
Improvement
Team--the technical/managerial
recommendations
of which
should save the Agency an estimated
$20 million annually.
vol-canic
unconven-tional
inter-active
route--saving
build-ing
The
Awards
National
Ceremony was
Engineers
February 22
through
3
the
Week
28.
highlight
which was
this years
celebrated
from
of
More than 30 Engineers of the Year represented
their respective
Dr.
Agencies at the ceremony.
with
the
Bureau
of
Mines
Kealy Mining Engineer
named Federal Engineer of the Year.
Dr. Kealy
a
leader
in
mine
as
geotechnical
recognized
C.
D.
was
engineer-ing
is
During Bobs visit to the Washington
Office he
Director
Engineering
Sterling Wilcox
accompanied
to a morning NFS Staff session a Chief-and-Staff
session and a Roads Briefing that was given to
Assistant Secretary Dunlop and Deputy Assistant
Bob also was the guest of
Secretary MacCleery.
honor at the Washington
Office Engineering Staff
Week
Social.
Engineers
Our sincere
prestigious
congratulations to Bob on receiving
award and well-deserved
attention.
this
Figure 1.--NSPE President Joseph
H.
Kuranz P.E. and Forest Service
Office Director of Engineering Sterling J. Wilcox present
Washington
Bob Black
with
Service Engineer
plaque distinguishing him as Forest
of
the
Year.
EFN
4
Yakutat Global Positioning Project
Dave Wood
Land Surveyor
Region 10
INTRODUCTION
1
During the winter of 1985-86 the advance of the
which is located 25 miles
Hubbard Glacier figure
and
its
north of Yakutat Alaska accelerated
off
the
mouth
of
forward movement
to
close
began
Russell Fiord.
Glacier movement was measured at as
On May
much as 40 feet per day during peak periods.
its
advance
across
the
the
29
glacier completed
entrance of Russell Fiord forming a glacial dam at
the
northern end and changing the fiord into a
lake.
The runoff from spring rains
76-square-mile
and snow melt caused a steady water rise of as much
A water
level
of approximately
as 1 foot per day.
185 feet would
cause an overflow at the south end of
the
lake and with a lake water level of 70 feet in
August it appeared possible that an overflow could
occur
by fall
1987.
almost certainly would enter the Situk
the richest fishing streams in Alaska.
River
The-additional water and current likely would scour
the
salmon spawning beds and seriously damage
out
this resource.
This was of great concern
to the
the
Situk
River
of
because
Yakutat
people
Not only
heavily to the economy of the town.
is the
river a source for commercial fishing but
thousands of sport
fishermen visit Yakutat
yearly to
fish this stream.
Guide services motels
air taxis and charter boats all benefit from
It was predicted
that
the river
the
Situk River.
would take several years to recover partially from
An overflow
one
of
contrib-utes
restau-rants
the
flooding and many
existing productivity.
The PLANNING
STAGE-
years
if
ever
to
regain
Russell Fiord and the Situk River both lie within the
Forest so the Forest Service has a
Tongass National
interest
in
controlling or mitigating
strong
In examining
damage.
every known alternative
to save the
Situk River it seemed that a diversion
at
the point of overflow would be the most effective
and
long-lasting solution but existing
environ-mental
100-foot-5
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LEGEND
Existing
A
Primary
Secondary
Figure
1.--Map
b33
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A
a
T
Control
285
T2
Sttu
Control
aa
to
s
p
et
ý
r.i
ý
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ocea
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Cýaan
Ca
Control
of Hubbard
Glacier
area with
control
points.
6
1
interval U.S.
Geological Survey USGS contour maps
were not detailed enough to evaluate overflow routes
and develop mitigation plans for the Situk drainage
or Yakutat
foreland.
New maps were requested
to
The Forest
provide adequate
floodplain analysis.
Service and the U.S.
Geological Survey agreed to
combine efforts in the mapping project
the Forest
for the
Service would be responsible
necessary
control work and USGS would do the mapping.
USGS
immediately sent the Forest Service work maps
aerial photographs
showing all control points
needed for the mapping.
USGS needs coupled with
some Forest Service needs made a total of 26
control points and an additional 57 points
With a total of
needing only vertical data.
83 control points to establish the Forest Service
quickly ruled out any conventional means of acquiring
this information and
decided to consider using a
Global Positioning
System GPS.
hori-zontal
and
the Region had no hands-on experience
with
Although
GPS information received from other users and firms
offering the service was positive enough that-the
Forest Service was convinced
that GPS would
be not
only more accurate but also faster than any other
is in a remote area with
means.
Since this project
few roads nearly 100 percent helicopter
time would
be required
no matter what means of survey was
used.
the most expedient method would
Selecting
therefore result in a savings.
concern with using GPS was the time of
the project would have to be
Since the Block I satellites used for
GPS currently number only seven
they are visible
only at certain times of the day in any one location.
This observation
period known as a window opens
twice a day in Alaska.
Only one window was usable
on our project because the other fell at night when
On September
the working
window
we could not
fly.
5 hours
and
was approximately
long
opened at
800 a.m.
The window moves earlier by
4
minutes per day meaning that by September 15 it
would open around 700 a.m. and by the end of
it would begin at 600 a.m.
While the window is
moving one way daylight is lost at the rate of 4 to
6 minutes per day.
Some observation
time would be
lost as the month of September
wore on.
One
major
year that
done--September.
1
approx-imately
Septem-ber
7
The
SURVEY
con-tracting
The decision
to proceed
with the project was not
made until late August.
The Forest Service
section did an exceptional
job of getting
this unusual contract
in a very short time.
let
With speed mail and the cooperation of potential
contractors
on proposals
working over the weekend
the entire process
The
took less than 10 days.
date
for
contract
was
set
proposed
starting
September
2.
famil-ia
recon-naissanced
Two
Office
people from the Forest Service Regional
unit
in
Juneau
flew
to
Yakutat
on
engineering
August
25 and met with an individual
from the USGS mapping
division in Denver.
This person is thoroughly
with USGS field procedures
and
input requirements
for preparing maps.
The entire project was
aerial
by air using the work map and
Both the map and the photographs were
photographs.
marked with the general location of proposed control
Once this location was found the control
points.
Final location was based on
point was selected.
ability to view satellites from the point to be
occupied and to identify the point on an aerial
had furnished a printout
The-contractor
photograph.
and sketch map showing the paths of the satellites
with azimuths and elevations plotted for every
2.5 minutes.
This made it very easy todetermine
whether and how much brushing was needed.
most control points were located on the
beach in muskeg or in mountain alpine which
required little or no brushing.
Fortu-nately
Steel rods were driven in the ground at each point
and a lath containing
the point identification
number driven nearby.
Fluorescent ribbon was used
generously to outline the area so it could be found
Each
again as quickly as possible from the air.
horizontal control point also was marked with a
30-foot target and photographed
from 2000 feet
above.
This provided easy photo transfer and
ensured the position on the ground.
All preliminary
work was completed before the contract
startup date.
Geo-Hydro
Inc.
received the contract
for the lease
4000S GPS units and the contract
Because
required a positional accuracy of 1 foot.
of the
technical complexity of operating
these
units the contractor sent a field expert with the
His duties included training people in
equipment.
the use of the equipment
trouble shooting and
processing the data so that same-day results were
available.
On this project the field expert was
of
three Trimble
8
invaluable.
His knowledge
of the
operation of the
receivers and computers was such that many problems
were easily and quickly solved with just a few words
of instruction.
The training
that the
operators
received was limited only by the amount of time they
chose to spend.
After I or 2 days of training most
This
operators were ready to go to the field.
training provided good general working knowledge
but in no way prepared the operators for all of the
in the field.
problems they encountered
Without
the
field expert many observation periods referred to
as sessionswould have been lost.
This project was delayed a full week by unexpected
events.
The field expert could not
to Yakutat
get
until September 4.
He came from Edmonton
Alberta
and was traveling with the equipment until the plane
landed at Juneau Alaska.
U.S.
Customs then held
the
With no
equipment while he went on to Yakutat.
one to sign the release Customs continued
to hold
It took
several days and many phone
everything.
calls to get the equipment released.
Once released
the equipment continued
to sit in Juneau
because
Alaska Airlines the only commercial airline serving
Yakutat would not carry the extra freight.
It
seemed that every flight coming into Yakutat was at
capacity with sport fishermen and their baggage and
We finally chartered a plane to bring the
gear.
Operator training took place
equipment to Yakutat.
on September
8
and
9 and
the project started on
September 10.
A control
traverse was run through all points
This was done using a
requiring horizontal data.
translocation
method meaning that one GPS unit
sometimes referred to as the master occupies a
a triangulation station
point with known values
and
one or more additional slave or rover units
Once a session has been
occupy desired points.
the
most
forward
unit holds that point
completed
while the other units leapfrog ahead and repeat
the
same procedure until the original station has
been reoccupied.
When using translocation all
units must interrogate
the
same satellites during
the
same period of time.
During this project
traverse points were occupied for as close to
60 minutes as possible.
Information received before the beginning of the
project indicated that only a 60- to 70-percent
success
rate could be expected when traversing.
Success rate means that sufficient data are
9
line good.
This
collected to call a particular
this
Of
proved true on
project.
many possible
reasons for failure to obtain sufficient data the
or failure on
two most important reasons for success
and reliable
this project were good communications
transportation.
mentioned earlier all units must be locked onto
data
for the same
the same satellites and collect
Unless
all operators
period of time when traversing.
this
is
can talk with one another
nearly impossible
the best laid plans will fail unless everyone is
There is never a
communicating with one another.
will
come on line at a
guarantee that each operator
One operator
mistake a faulty disc
planned time.
of
or a number of other
a
malfunction
one receiver
an
to
operator
begin data collection
things can cause
either later than planned or not at all during an
When using three units as on
observing session.
this project if the middle unit fails to collect
data two line measurements are lost and the only
measurement achieved is one from the master station
In other words
a point
on
to the second rover unit.
the traverse is skipped.
When this happens
all
three points must be reoccupied
or the middle point
must be tied into the traverse in some other manner.
As
Communications with the field expert will save many
Just a few words of advice over the radio
sessions.
can correct problems that an operator with limited
training would rarely solve alone.
repeat-ers
Good
communications with the helicopter
crew were a
Standard Forest Service
must throughout the project.
handheld radios were used but there were no
in the
area which severely limited the range.
could
communicate
Operators
only in a direct line
which rarely worked so the helicopter
was used as a
the
aloft
during
early part of a
repeater by staying
session or by parking on a high point nearby.
This
the
crew
was not totally effective
as
helicopter
said and some
literally had to repeat everything
technical advice was sometimes lost or had to be
This procedure also adds
repeated several times.
time
A repeater was
to a project.
expensive flight
installed about halfway through the contract
and
to
be
much
more
effective.
proved
was essential that the helicopter
crew had a plan
each
and
knew
about the
enough
survey
morning
and
area
to
be
flexible
to change.
project
project
With proper communications
the helicopter
crew knew
It
of
10
The
which operators to pick up and at what time.
of
the
also
knew
the
location
next
crew
points
without having to search for them.
After dropping
off for a session the helicopter
crew
the operators
the
to
be
used
then would search out
points
during
the next session.
This enabled them to provide
The
operators with a quick flight between points.
the
the
on
more time the operators
spent
ground
more sessions they had and data they collected.
project involves a helicopter not only does
ship and crew need to be reliable but also the
Southeast Alaska never has reliable weather
weather.
is for rain.
While weather
unless the prediction
does not affect satellite observation it severely
The Yakutat
area is plagued with
hampers air travel.
rain and low cloud ceilings for much of the year.
Fortunately the month of September this year
more clear skies and sunshine than had ever
been recorded
in Yakutat which
enabled more flights
The project did
than could be expected ordinarily.
suffer some from the clear weather because at this
time of the
year the air is cooling and early
morning fog is common and often does not burn off
until noon or later.
Several sessions and some
lost
were
to weather.
complete days
When
a
the
pro-vided
nature of GPS surveying at this time and with
limited window is to always be in a hurry.
Operators must get to the point as quickly as
possible set up a tripod and antenna connect power
into the receiver
connect
a
cable from the antenna
to the
connect
a
cable
from the receiver
receiver
and program both the
receiver and
to a computer
before
data
collection
can
begin.
Trying
computer
to make the equipment pay for itself on the ground
is a continual concern.
This leaves the door open
for a great deal of human error.
The equipment is
user friendly but there are still many errors to be
on
made if an operator is not fully concentrating
The
the
work.
not
Forgetting one piece of equipment
hooking up a cable properly touching the wrong key
writing down the wrong station number or date and
failing to have properly formatted discs are among a
long list of errors that can ruin the session or the
day.
Operators need to take the training seriously
and to be as knowledgeable
and comfortable
but not
too
comfortable with the equipment as possible.
the
if trying
problem to be aware of especially
of the
a
is
the
weekend
possibility
during
of
Defense
orbits
or
altering
shutting
Department
Another
to work
11
I
i
With the limited number
down one or more satellites.
satellites in the sky it doesnt take too many
sick or stale satellites to ruin a day.
of
SUMMARY
The project at Yakutat
took a total of 26 working
This
days to complete and ended on October 7.
83 control points plus the
included establishing
ties and a base of bearing between two
necessary
The
stations.
triangulation
observed second-order
S7 points requiring only vertical
data were done
This is a faster method
with a side shot method.
than traversing
in that one receiver remains on a
known point and rovers move at will occupying as
many points as possible for at least 30 minutes
each.
Once again each rover unit must be locked on
the
the course
same satellites as the master.
During
of the day all seven satellites will be used at one
time or another but with each operator familiar with
satellite pattern and with good communications
the
The
everyone will know when to change satellites.
success
rate was much higher during this portion of
the project.
Operators were more familiar with the
of solving earlier
equipment and the experience
to this success.
As with many
problems contributed
uncommon jobs just when one becomes somewhat
proficient
its
over.
12
EFN
Mount Whitney
Solar Toilet
Robert Stanley
Wilderness
Area Manag.er
Forest
Inyo National
James G. McDonald
Civil/Sanitary
Engineer
Inyo National Forest
Dave McCauley
Staff Engineer
Pleasant Hill
Engineering Center
5 Regional
Office
Region
solar toilet is located on the Mount Whitney
in the
within the John Muir Wilderness
Inyo
National
Forest figure 1.
The toilet is receiving
heavy use by hikers at a camp that is more than
10300 feet above sea level 15000 hikers use the
trail every year.
More than 1000 gallons of waste
is equivalent
in waste
are deposited each year which
of
water-borne
domestic
to
120000
gallons
strength
The area has very little soil for disposing
sewage.
human waste.
The
trail
Eureka
-----40
Redding9
29
0
01
9r
o
n
eo
San
Reno
so
Sacramento
Francisco
Inyo
National
o
ý
Forest
PROJECT
5
-
- --
395
79
SITE
35
0
01
Los
Angeles
San
Figure 1.--Map
showing
location
13
10
s
Diego
of solar toilet project
site.
heli-copter
installation of the solar toilet.a
was used to fly out 55-gallon drums of liquid
waste from primitive vault toilets figure 2.
This
and
in
tune
with
the
was
too
not
expensive
operation
wilderness
concept.
Before
test the solar-driven toilet evaporated
human
more rapidly than expected.
The results of
the
test were so good that
the Forest Service
two additional units with minor
and will save $10000 per
figures 3 and
has been
operation
year because the helicopter
eliminated.
con-structed
modifica-tions
In
a
wastes
4
Figure 2.--Helicopter
waste drum.
14
removal
of liquid
Figure 3.--Two solar toilet units tied
together with glazed surfaces displayed.
HOW
IT
WORKS
Figure
4.--Toilet
entrance.
fiber-glass
To the user the
and
liquids fall
unit
into
is
a
vault
toilet.
The
solids
bag inside a
The liquids seep through
tank see figure 5.
the bag and
into tank 1.
When tank I is full it
The
overflows into tank 2.
sun heats air behind the
chambers
covered
with glazing.
When the
two separate
air in the
lower solar chamber is warmed an
The thermosiphon
action pulls
damper opens.
the warmed air through the waste
storage areas as
the
the
show
in
which
arrows
figure 6
evaporates
The
air
flows
first
the
warm
liquids.
through
liquid
tanks and then around and through the solids in the
burlap bag before exiting through the vents at the
Calculations show
of the upper solar chamber.
top
that approximately
25 percent of the
solar energy
liquid.
striking the glazing evaporates
a
burlap
auto-matic
TEST
55-gallon drum of waste that would have been flown
was dumped into one of the empty
by helicopter
test was
toilets.
The weather during the September
calm and sunny with the exception of a few overcast
All free liquid was gone within 30 days and
days.
the overall weight
reduction
of the
sewage was
90 percent
in 35 days.
A
out
15
Tank
Fiberglass
Tank
Tank
1
2
Damper
Figure
5.--Side view diagram
of solar toilet.
semipli-able
test
solids on the outer edge
and
8 were in a
bag see figures
fibrous state while the interior solids were
still moist.
All the
solids were dry enough to be
without
carried out on packstock
danger of leakage.
Toilet performance during the 1986 season under full
use conditions confirms the test results.
At
of
MAINTENANCE
the
the
end
of
the
7
ranger handles whatever
to the Wilderness
According
A wilderness
needed.
the
16
maintenance
is
Area Manager
/
I
JQýj/
//
i
/
/
/
ý
\
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ý
\
e/
I
I
I
Seat
aýrai
1
I
\
/L
/
I
Bag
I
ý-ý
tee/
Fiberglass
Tank
i
Damper
Figure
6.--Diagram of air flow
through
individual can handle
which can be packed out.
one
COSTS
solar toilet.
the processed
installed cost per unit
average
installation was a little more than
The
Fiberglass
toilets
tanks
17
ducting
and
storage
bags
for this 2-unit
$20000.
$13000
Figure
7.--Fiberglass
tank.
Figure 8.--View
cleanout
port.
Design structural
for snow and wind
Toilet
construction
labor other than
of gunny
sack through
modifications
load
materials
$1500
and
above
Helicopter transport of toilets to
site performed by test pilots at
no cost
to the Forest Service
POSSIBLE FUTURE
DIRECTIONS
tank
$27000
$0
sani-tation
Possibilities
the future include
the design of
toilet
with
the above
light-weight
componentized
to
maximum
while
mobility
concepts
give
serving
needs in remote areas and the design of a
toilet with the dehydration/thermosiphon
concepts
for developed
recreation sites where vault pumping
is expensive
or difficult.
for
18
a
FOR MORE
INFORMATION
additional information please feel free to
contact the authors at the following
telephone
For
numbers
James
Robert
Dave
G.
McDonald
Stanley
McCauley
19
619
873-5841
619
876-5542
415
825-9800
two articles were prepared
by Forest
The following
Service employees
enrolled in a 2-year masters
program at Oregon State University
OSU
An Empirical Evaluation of Network
Models Used by the Forest Service
Skyline
Thinning
Cost
Comparison
Analysis
for Three
Engineer-in
Yarding
Systems
and
Office Timber Management
Washington
Staffs have sponsored this graduate-level
The OSU program
years.
training at OSU for several
affords enrollees the option of specializing in
for Resource
or in
either Transportation
Management
Beginning in 1986 we asked
Logging Engineering.
to submit a paper
the Forest Service OSU students
in
from their masters projects for publication
Engineering Field Notes so that others could become
more aware of the benefits the Forest Service derives
from sponsoring the program.
The
20
Empirical Evaluation of Network
Analysis Models Used by the Forest
An
Service
Thomas L. Moore
Engineering
Transportation
Oregon State University
BACKGROUND
Program
Computer programs have been used to solve network
since the
analysis problems in forestry applications
These programs were developed
to
early 1970s.
system to
identify the least costly transportation
objectives.
serve an area guided by land management
uses several computer
The Forest Service frequently
programs to solve for the least cost road development
network in a planning area.
MODEL were the
MINCOST and the TIMBER TRANSPORT
Other
first programs used.
programs such as TRANS
INTEGRATED
RESOURCE
PLANNING
NETWORK and the
later to solve
were developed
MODEL/TRANSHIP
to
determine
the accuracy
Studies
similar problems.
the optimal solution
of these models in obtaining
The
were not initiated until the early 1980s.
in nature and
first evaluations
were experimental
were performed on the MINCOST and TIMBER TRANSPORT
evaluated
several small problems
models.
Wong
to determine how the MINCOST model would perform.
Wong observed that the MINCOST model arrived at the
optimal solution on only three of the eight networks
He recorded
he tested.
errors as much as 48 percent
focused on
solution.
above the optimal
Kirby
TRANSPORT
model.
His example
TIMBER
the
evaluating
in
1
and
also
nature
experimental
figures
inaccuracies
of the model.
The
demonstrates
the
TIMBER TRANSPORT
model provides a solution that is
solution.
620 percent higher than the TRANSHIP
IRPM
1
2
PURPOSE
of
STUDY
2
SCOPE Only limited studies have focused
on assessing the
solutions
for
larger problems typically
quality of
used in field situations.
This study addresses this
the
first published
question and represents
evaluation
of network models currently used in
Forest applications.
large-scale
solu-tions
purpose of thisstudy was to compare the
generated by three network models using data
in
from five field problems currently evaluated
The
21
1
13
15
1
7
1
11
LEGEND
Origin
Demand
19
I
Node
El
Node6
6
3
4
0
5
8
9
7
2
1
T.
Transport
Haul
$329000
Fixed Cost
$5620000
Cost
$5949000
Total
NOTE
Figure
Cost
Solution
All
1.--Kirbys TIMBER
Sales
TRANSPORT
1000
MODEL
mbf.
example and TIMBER
22
TRANSPORT
MODEL
Solution.
1
3
1
1
Q
19
1
1
LEGEND
1
1
Origin Node
Demand Node
6
3
4
5
8
7
2
1
Transhipment
Haul
Figure
Cost
Solution
$560000
Fixed Cost
$400000
Total
Cost
$960000
NOTE
All
2.--Kirbys TIMBER
Sales
TRANSPORT
1000
MODEL
mbf.
example and
23
TRANSHIP
solution.
9
for
The approach
Forest applications.
developed
of the
this study was to assess the significance
errors provided by the models compared to the
uncertainty of the input data.
evaluated
three network models
NETWORK
The study
TRANSPORT
MODEL.
and
the
TIMBER
MINCOST
time
the
period
problem
limited
to
single
was
solving
with no more than 100 loading nodes and 99 project
We
have
fixed
STUDY AREAS
costs.
The study areas used for this research were selected
with the objective of demonstrating how the models
would perform using various network sizes types
All of the
and
study areas previously
complexities.
in the field using one of the network
were evaluated
and
run
models.
The data then were reformatted
through the other two models.
The
networks
connectivity
few loops to
selected exhibit various degrees of
ranging from basic tree patterns with
grid-type networks with many loops.
The five study areas are located in different areas
around the country and this is partially the
For
for the wide variation in the input data.
Area
near Mt.
the
Off
figure
Planning
example
St. Helens in Washington
logging
incorporates
system analysis which increases variable costs.
in California
The Peavine
Planning Area figure
considers smaller sale units thus providing for
lower volumes.
This network includes several
of
whether the inaccuracies
to
determine
loops
the MINCOST model as identified by Wong also exist
3
reas
three-node
4
applica-tions.
5
problems as well as in experimental
situated
The Silver Planning Area figure
the
networks.
the
of
all
in Idaho
average
represents
The Kosciusko Planning Area figure 6 is a small
This network is unique in
island located in Alaska.
of water transport.
Logs
that it considers the cost
transfer
trucks
terminal
site
hauled
via
to
a
are
and
barged to the mainland loaded back onto trucks
increases
This water haul
hauled to the destination.
variable cost
compared to the other
the average
The Beaverdam Planning Area figure 7 is
networks.
located in Tennessee.
Labor rates for construction
than in the west and therefore
much
less
are
projects
road construction
costs are much less.
in
field
24
Ir
lip
ý
\
10
1
ý
1N
1a
r.
a_
ar
t
i
S
ý
a
1
1
1
Y
is
ý
ý
al
\
\
33
\
\
\
ý
n
LEGEND
rrig
Demand
Node
Node
Fixed Costs
Figure
3.--Off Planning
Area coded
0
A
----
network.
25
al
1
LEGEND
Q
L
Origin Node
Demand
Fixed
Node
Costs
72
----7.
%
Q
71
a
.
Is
a
p
a
a.
7s
.
a
st
17
4
1
7
.
1
37
71
39
O
3
M
43
T
k
3
ssý
It
L
1
Is
P
17
N
f
7
1
71
a.
la
ý71
1
Q
38
ý
1
1
1.
a
j7
Z
4
7
771rý
N
7.-
Y
aIN
ý
i/
a7
1
ý
7a
1.
17
U
1.
1
77
1
It
.7
7
M
7.11
1
ý
y
R
1f
Al
11
ý
.
1
4
Figure
4.--Peavine
Planning
Area
coded
network.
26
a
7
I
1
i
1
1f
1
f
7
ff
ý
1
\
1
\
\
7
f
------hý--ý-ý
ý
Y
ýJt
ý3i _---1fi
1
1
7
1
f
f
1
/
/
/
I
/
f
I
t
f
f
1
f
LEGEND
Origin Node
Demand Node
Fixed
osts.---IM
Figure
5.--Silver
Planning
Area coded
network.
27
------------ N
1
ýý
tIEA
N
ý
PT1
-13
D
48ý
1
1
1
LEGEND
Origin Node
Demand Node
Fixed Costs
n
ý
1
1
1
Jýý
O
A
---Water
Haul
---Log
0
Transfer
/
Figure 6.--Kosciusko
Planning
Area
coded
network.
28
1
T
t
p
Ii
1
1
1
Y
Q
y
a
t
1
1
ý
ý
N
ý
oil
------ýf-77
i
N
7
I
it
LEGEND
or
Origin Node
Demand Node
Fixed Costs
Q
6
.
---Figure
7.--Beaverdam
Planning
Area coded
network.
29
-
n
-fay
PRELIMINARY
ANALYSIS RESULTS
five study areas were analyzed using the three
different network models.
The MINCOST and NETWORK
models ran smoothly and yielded solutions relatively
The TIMBER
TRANSPORT
model presented
quickly.
many
difficulties.
The five networks
were run through
Phase
the route generation phase successfully.
The results from these runs then were loaded into
Phase
the optimization
phase using the
option and resulted in the program aborting on four
of the five planning
The Off Planning Area
areas.
was the only network that ran successfully.
Upon
further investigation
of the
other four it was found
that
the mixed-integer linear program
a
program
used by TIMBER TRANSPORT
was too small to evaluate
these larger network problems.
The program was not
to arrive
completing the branch and bound technique
at the
linear program optimal solution.
The four
areas subsequently
were run using the
option and
an answer.
produced
The
1
0
2
F
analy-sis.
solu-tions
Two
versions of NETWORK were included in this
Version 9 is the most current and provides
better answer for one of the networks.
a
results of running the networks using the three
different models are shown in table 1.
These
were obtained without user intervention
and
without
incorporating manual sensitivity analysis.
The
NETWORK
SENSITIVITY to
INPUT DATA
second half of this project we developed
a procedure
to compare the errors provided by the
network models to uncertainties
of the
input data.
In
the
Planners cannot
estimate every road
consistently
and
timber unit volume exactly
some degree of uncertainty is associated with every
estimate.
Generally if this estimate is within
10 to 20 percent from the
true value the analysis
is deemed satisfactory.
It
is largely unknown
whether the errors in the network model outweigh the
errors from using uncertain
data.
cost
haul
cost
This
project addressed this question by employing a
Each
termed Monte Carlo simulation.
technique
value in the link and sale file was changed to
conform to a certain distribution.
Adjusting every
value exactly 10 to 20 percent from the estimate and
then running the network model is one approach.
However this method would not represent what occurs
in the field.
In reality
some of the values may be
estimated exactly while others could be very far
30
SolutionbSensitivity
Original
with
x
100
100
of
Number
x
100
S
Value
Sc100
with
IdenticalResults
Scenariosallncertainty
2.0
x
100
-1
Cost
etwor
of
Number
Value
cenarios
48.0
100
of
Value
na
g
Or
Value
Scenarios
2.0
1.0
2.63
48.0
0.57
NA
0
2..7
16.7
NA
4.4
0
0
0
Solution
47..0
1.0
1.14
NA
11.0
3.4
0
0
7.4
enarios
76.0
47.0
0.12
NA
NA
1.0
0
0
Silver
Scenarios
Valuec
76.0
0.49
31.2
NA
1.3
0
0
Off
Expected
MINCOST
UncertaintySensitivity
Maxsim
Valueb
Valuea
0-Option
F-Option
9
Ver.
8
Ver.
Areas
Maximum
uncertaintyvalues.
NA
TTM
TTM
Planning
NETWORKNETWORK
NA
and
Table
2.--Sensitivity
NA
2.7
NA
0
0
31.2
NA
3.4
0
4.4
NA
1.0
0
16.7
1.3
0
11.0
0
7.4
Beaverdam
418776
389768
400150
454663
NA
0
Kosciusko
17622233
17622233
17622233
18395092
NA
0
4384842
4384842
4532140
4868373
NA
0
NA
NA
0
Peavine
4738935
NA
1474166
1459524
1459524
Silver
Peavine
0-Option
F-Option
MINCOST
9
Yer.
8
Ver.
0-Option
MINCOST
F-Option
3658155
3612804
3612804
Off
Kosciusko
TTM
NETWORKNETWORK
TTM
TTM
NETWORKNETWORK
TTM
9
Ver.
8
Ver.
Area
Beaverdam
Solution
Best
PercentIncrease
Over
dollars
Cost
Total
Planning
cMaxsim
run
results
initial
l.--Summary
of
Table
detailed study were to monitor
relative to the estimated values
Because a study
a
certain distribution would exist.
of this nature would
require a great deal of
the
normal distribution is assumed for this
off.
if
Indeed
the actual
values
a
infor-mation
analysis.
distribu-tion
Each value in the link and sale file of a network
model was changed to conform to the normal
using the following limits
1
2
Fixed Costs.
Fixed costs road construction
costs were allowed to fluctuate 20 percent
from the estimate for one standard deviation
67 percent
of the occurrences.
or
The Forest Service does not
Variable Costs.
monitor log hauling costs since it is an item
in the
timber sale appraisal and not subject to
a
variation exists
individual bidding.
Although
for every
cost this report does not consider
this variation.
expe-rience
reason-to
fluc-able
simula-tions
3
Timber
Timber volumes generally
It
is
greatest variation.
expect that timber volumes could
30 percent for one standard deviation.
Volumes.
the
tuate
different random normal numbers 100
The results were analyzed to
were generated.
determine how many solutions were identical to the
A large number of solutions that
original.
the original would indicate that the particular
network was not sensitive
to changes in the
input
Using
dupli-cated
data.
important values were generated from the results
The Sensitivity Value
these simulations.
represents the number of times that the original
network solution was encountered
expressed as a
The
percent of the number of simulations run.
Uncertainty Value was determined by fixing the
solution paths generated by each of the 100
tions
injecting the original network data into
The solution cost was
this fixed set of paths.
recalculated
for each of these simulations and the
from these
expected value then was determined
This
value was represented as a
100 simulations.
percent increase above the original network solution
Value.
cost and called the Uncertainty
Value was compared to the errors
Uncertainty
Two
of
simula-and
The
32
in the models and
produced
a
determination
was made
of these errors relative
addressing the significance
to the uncertainty of the data.
RESULTS
DISCUSSION
above procedure was performed onall five
planning areas by running 100 simulations for each
The results are shown in tables 2 and 3.
area.
Table 2 reveals that the Uncertainty
Value is always
less than the errors produced
the
models.
For
by
example the MINCOST model produced an error of
1.3 percent above the
solution provided by NETWORK
for the Off Planning Area.
The increase
resulting
from uncertainty for this study area is 0.49 percent.
This would tend to indicate that the errors produced
by the models outweigh the errors produced
by using
uncertain
data.
Basic statistical theory can be
used to determine the level of significance
of these
Table 3 identifies the confidence
errors.
levels
for each of the planning areas using the various
network models.
This table shows that most of the
errors produced
Two
by the models are significant.
areas using the MIN-COST
model Off and Beaverdam
levels of significance
of
Planning Areas developed
0
percent indicating that the uncertainty of the
data may be more important than the errors developed
by the MINCOST model.
CONCLUSIONS
The NETWORK Version 9 program provided the lowest
cost solutions to all five planning areas.
TIMBER
TRANSPORT
the
cost
answers
and
generated
highest
MINCOST provided solutions that generally were
slightly higher than the optimal.
The
F
The TIMBER TRANSPORT
option consistently
provided
inferior results and should be avoided.
The TIMBER
TRANSPORT
option worked well for smaller problems
with few projects and loading nodes and having less
than 10 paths to the destination per each loading
node.
Larger problems cannot be solved using the
option because of the limitations of the
linear program used by TIMBER TRANSPORT.
0
0
mixed-integer
three-node
demon-strated
The
well
MINCOST
model had difficulty
solving the
loop problems nested in field-sized networks
as in experimental
examples previously
by Wong.
The
as
analysis of the five planning areas evaluated
in
report shows that the errors provided by the
network models generally are more significant
than
the
errors from uncertain
The exceptions
input data.
this
33
Table
3.--Percent
Planning
Areas
confidence
NETWORK
Ver.
levels
of significance
for
NETWORK
8
Ver.
uncertainty.
TTM
9
TTM
MINCOST
F-Option
0-Option
0
NA
99.9
Off
NA
NA
Peavine
NA
NA
92.9
NA
NA
Silver
NA
NA
97.1
99.6
NA
Kosciusko
NA
NA
NA
97.1
NA
Beaverdam
88.8
NA
0
98.7
NA
this statement are the Off and Beaverdam Planning
Areas which provided levels of significance of
0 percent
using the MINCOST model.
to
This
study would tend to indicate that the selection
network model should be based partially on the
a
accuracy of solution sought.
of
REFERENCES
I.
Wong
option
Notes.
1981T.
2.
of the
empirical evaluation
proration
Network
Program.
Engineering Field
USDA Forest Service.
Washington D.C.
April
of
P.
pp.
Kirby
California
Forest
An
MINCOST
15-22.
M.
Range
TIMBER TRANSPORT
Examples.
Berkeley
USDA Forest Service Pacific Southwest
Experiment Station.
EFN
34
Skyline Thinning Cost Comparison for
Three Yarding Systems
Peter H. Hochrein
Logging Engineering Program
Oregon State University
ABSTRACT
rates of prebunching
Yarding costs and production
with a small yarder and swinging with a midsize
yarding with the
yarder are compared to conventional
small and midsize yarders in two different thinning
intensities.
For the average
study conditions
conventional
yarding with the small yarder cost 9 to
12 percent
less than conventional
yarding with the
Conventional
midsize yarder.
yarding with the
and
and
prebunch
midsize yarder
swing yarding had
The
cost
of
conventional
yarding
similar costs.
20
to
22
in
the
was
light thinning
percent higher
This
increase in cost
compared to a heavy thinning.
for
the
small
when
more
would be less
yarder
exist.
Cost
conditions
manual slackpulling
for
and
reductions
are possible
prebunch
swing
yarding on steeper
yarding by using a smaller crew
slopes and using different yarding techniques.
and swing yarding could
With these changes
prebunch
than conventional
become less expensive
yarding with
yarder.
a small or midsize
favor-able
INTRODUCTION
indi-cated
diam-eter
stands require harvesting the
more second-growth
forest industry will need to find ways to reduce the
of harvesting
these stands.
Beuter
cost
1980
that in western Oregon 70 percent by volume of
softwood timber is less than 21 inches in
the
with 37 percent less
at breast height
than 13 inches dbh.
Average stand diameters of 10 to
20 inches will be common as more of these stands are
clearcut or thinned.
These changes require more
efficient ways fo handle the increased
As
dbh
Sweet
1Logging was conducted
Home Oregon.
35
by
More
Logs
Inc.
number
of small pieces such as using smaller
expensive equipment or different techniques
to
increase production.
less
Prebunch
and
swing yarding has been considered
as a
harvesting
to use midsize yarders more
procedure
In this
efficiently in thinnings Kellogg 1980.
a
small
the
technique
yarder brings logs to
skyline
corridor.
After work is completed with the small
yarder a midsize yarder yards prebunched
logs to
the
The advantages
of the procedure
landing.
are
that
the small lower-cost yarder is used for the
more time-consuming
portion of yarding while the
midsize yarder can obtain optimal payloads and work
at faster yarding
speeds.
Thus the capabilities of
each machine are realized more fully.
Past smallwood skyline harvest studies at Oregon
State University have quantified
rates
production
and costs for different yarders and thinning
These studies generally have shown the
of smaller less expensive
advantage
equipment
Kellogg 1983 Kellogg and Olsen 1984.
Kellogg
1976 and Zielinsky 1980 found that prebunch and
swing yarding produced
a
significant
savings compared
to conventional
yarding2 with a midsized yarder
while Keller 1979 observed a significant
increase
in yarding costs for prebunch
and
swing yarding.
opera-tions.
and Butler 1982 used simulation to study
of conventional
and
yarding versus prebunch
swing yarding for a range of diameter classes and
stem removals.
Simulation results showed that for
the entire range of stem removals
and diameter
classes studied prebunch
and swing yarding produced
considerable
savings over conventional
yarding with
a
midsize yarder.
Thinning intensity did not
influence either conventional
yarding or
and swing costs when tree removal was more
prebunch
than 80 stems per acre.
However increased log size
significantly improved productivity and reduced
costs.
LeDoux
the
cost
sig-nificantly
The
purpose of this study was to compare harvesting
and cost between three different yarding
production
2Conventional
yarding
the
to
logs
to
the
logs
yarding in a thinning involves
skyline corridor and then yarding
landing in one complete cycle.
a
36
in two thinning
intensities.
techniques
Regression
was
used
to
relate
stand and harvesting
analysis
variables to the production
and
cost of each yarding
condition.
STUDY
SITE
METHODS
Douglas-fir
The
east
study
of
Forest.
area was
located
Salem Oregon
on
in the
Cascade Mountains
the Willamette
National
main merchantable
species was
Pseudotsuga menziesii Mirb. Franco with
western hemlock Tsuga hetero h la Raf.
sarg..and
noble fir Abies procera
Re d.
for
accounting
The understory was
only 5.5 percent of-thevolume.
mostly vine maple Acer circinatum Pursh and
rhododendron
Rhododendron macrophyllum D. Don.
The
The study area averaged
49.8 cunits 21.5 thousand
board feet
acre
in about 350 trees per
per
acre.
The average
diameter at breast height for the
The heavy thinning
study area was 12.2 inches.
removed 125 trees or 25.2 cunits 10.9 mbf per acre
while the light
thinning removed 80 trees or
12.0 cunits 5.2 mbf per acre.
Volumes do not
include
trees
removed
because
of damage or
crop
yarding requirements.
mbf
1
slack-pulling
The
small yarder was a Koller K-300 figure
equipped with a Koller multispan manual
The Koller K-300 has a tower
carriage.
height of 23 feet external yarding distance
of 1000 feet and a 60-horsepower
rating.
This machine was used for conventional yarding and
A loader was required for all the
prebunching.
conventional
Koller yarding because of steep landing
chutes or deck size.
An experienced
five-person
of
a
consisting
crew
rigging slinger/hooktender
two choker setters a yarder engineer/chaser
and a
loader operator work during the conventional
The loader operator was not
yarding.
needed during
Chokers
were
prebunch
yarding.
preset with an
of three chokers used per turn.
average
capa-bilities
The midsized yarder was a Madill 071
crawler-mounted
mobile skyline yarder equipped with a Danebo MSP
mechanical
The
slackpulling
carriage figure 2.
Madill 071 has a tower height of 50 feet an external
yarding distance of 1800 feet and a 284-horsepower
This machine was used for conventional
rating.
and
yarding and swing yarding.
Decking
loading were
accomplished
using a Bantam C-366 hydraulic heel
boom loader.
An experienced
crew consisting of a
a
hooktender
rigging slinger two choker setters a
37
Figure
1.--Koller K-300
yarder.
chaser
a
yarder engineer a loader operator and
and
company owner were used during conventional
For conventional
swing yarding.
yarding chokers
were preset with an average
of four chokers used per
turn.
Four chokers also were used during swing
yarding but they were not preset because the
prebunched
logs were located under the skyline.
During swing yarding usually two or more logs were
yarded per choker.
the
PRODUCTION
RATES
COSTS
Hourly operating costs for yarding and loading
operations were $284.50 for the Madill yarder
for the Koller yarder and $94.04 for
$123.00
prebunch
yarding Hochrein
1986.
Table I
and cost per cunit.
yarding production
Log
value was $95.04 per cunit and other harvesting
sum-marizes
38
Figure
2.--Madill
071
yarder
for the Koller were respectively 12 percent
percent lower than the Madill in the heavy and
The cost of prebunch
and swing
light thinning.
the
Madill
yarding even
yarding was similar to
had
67
a
though swing yarding
percent increase in
to
conventional
Madill yarding.
production
compared
costs
and
9
39
Table 2 shows delay-free yarding cycle regression
models.
The thinning condition
indicator variable
cut occurred in production regression models but
not
in the cycle time regression models.
No
difference in yarding cycle times occurred
the heavy and
between
light thinning levels for the
conventional
Koller and Madill yarders.
In contrast
rates were influenced
production
by the thinning
condition.
In the production
models a negative
coefficient
occurred
for the heavy thinning for both
the Koller and Madill yarder.
However larger turn
sizes occurred
in the heavy thinning
so the net
result was a higher production
level for both
machines
in the heavy thinning.
sig-nificant
DISCUSSION
Figure 3 shows the range of yarding costs for the
light thinning when varying slope yarding distance
while holding
the other independent
variables
constant.
Yarding with the Koller yarder is the
least expensive for the range of yarding distances
shown.
However with increased slope yarding
distance the savings between the Koller and Madill
becomes smaller.
Production was 20 to 22 percent lower in the light
thinning for both machines compared with the heavy
thinning in part because of the increased landing
and
road changes
required for the light thinning
levels the smaller turn size and some adverse
The effective
hour decreased
yarding conditions.
7 percent
and
11 percent
for the Koller and Madill
in the light thinning.
Turn size
respectively
decreased
17 percent for the Koller and 23 percent
for the Madill in the light thinning.
Flat chord
and
slopes
high ground-to-carriage
clearance
also
contributed
to decreased
in the light
production
thinning for the Koller.
The
chord slope in one portion of the light
average
15 percent compared to 57 percent
was
in
thinning
the
With
increased
heavy thinning.
slope yarding
distance pulling line laterally became harder
because of greater friction between the line and the
In another portion
of the
ground.
light thinning
as the
slope yarding distance increased
the
carriage
height also increased to more than 120 feet.
As the
the
height
amount
of
in
the
carriage
increased
sag
mainline also increased
and
additional yarding time
was required to take this sag out of the mainline.
40
j.-Harvest production
Table
and cost.
Heavy
Koller
Yarder
production
Delay-free
Effective
Actual
Yarding
Total
Profit
$/MBF
Table
2.--Delay-free
production
cost
logging
$/cunit
$/cunit
$/cunit
$/cunit
times
yarding regression
Variable
Intercept
cubic
Production
74
57.88
64.97
64.65
76.70
83.24
87.12
94.21
93.89
18.34
11.80
7.92
0.83
1.15
models.a
Lateral
Distance
feet
feet
Number
of
Logs
yarder
464.7
-0.3380
-1.885
130.5
Prebunch
730.9
-0.3123
-2.008
136.8
Swing
554.5
-0.6681
Indicator
Variablec
R2d
-52.60
0.68
-137.6
0.71
-6.327
140.2
0.62
minute
Koller
yarder
3.587
0.003672
0.01657
0.2337
Madill
yarder
1.838
0.003403
0.02360
0.1903
-1.206
0.002334
0.01057
0.6446
2.936
0.003521
Prebunch
Swing
heavy
dCoefficient
Slope
percent
foot/hour
Madill
cl
71/69
3.64/7.33
54.00
132.2
in
5.06/10.61
66
47.46
-0.8385
variables
6.60
4.38
-0.2485
values
Swing
2.13
197.4
aAll
bAll
68
Prebunch
Yarder
5.27
yarder
cycle
3.12
Madill
2.59
Koller
Time/yarding
Koller
Yarder
Thinning
2.315
Slope
Distanceb
Dependent
7.15
73
cunits/hour
loading
Madill
Yarder
3.57
percent
hour
and
cunits/hour
Light
Thinning
the
are
are regression model
coefficients.
level.
significant at the 0.05
table
and
0
thinning
of determination.
light
thinning.
41
0.09862
-0.1009
0.37
0.45
0.05662
0.63
0.26
65
07l
60
ý0ý
44ýýýyG4ý
55
50
45
800
700
600
500
400
300
200
FEET
DISTANCE
YARDING
SLOPE
is
varied.
70
and
loading
cost
for
light
thinning
when
slope
yarding
distance
75
U
Figure
3.--Yarding
80
x
N
in portions of the
conditions also occurred
light thinning with the Madill yarder but they did
because of
not significantly influence production
For the Koller
the
mechanical slackpulling
carriage.
in the light thinning yarding
time increased as the
slope yarding distance increased because hand
Without
is required for lateral yarding.
conventional
Koller yarding in the
these conditions
and
light thinning would have had higher production
lower costs.
These
slack-pulling
conven-tional
signifi-cant
these yarding conditions affected
Although
Koller yarding they were much more
during prebunch
yarding.
Slope yarding
than Koller
distances were greater for prebunching
Also the carriage
yarding in the light thinning.
because of headspar
was higher during prebunching
and
tailhold locations.
During prebunching
heavy
slash present in some of the corridors contributed
to greater line friction and
increased the cycle
time.
POTENTIAL
IMPROVEMENTS
in selecting areas to
Important considerations
with a small yarder where slack is pulled
prebunch
manually include the chord slope and the carriage
Areas with flat chord slopes and much
height.
should be avoided.
For areas
understory
vegetation
than
50
feet
between
the
with more
ground and
the
close
to the ground to
skyline keep
skyline
the
avoid excessive
mainline possibly by
sag in
block anchor at the base of a
a pull-down
placing
tree to keep the
skyline lower.
of manual slackpulling
areas where the difficulty
influenced
by slope yarding distance and the
carriage is kept close to the ground the slope
yarding term in the prebunch
regression model should
The
slope yarding distance term was
drop out.
excluded from the prebunch
regression model to
ideal
conditions.
Additional
savings
yarding
could result with a smaller crew size than used in
this study and with reduced
delays through better
use of personnel
Hochrein 1986.
Figure 4 shows
when
the yarding
and
loading costs
using these
during prebunch
optimal conditions and techniques
and swing yarding compared with conventional
yarding.
and
For the
swing
average
study conditions prebunch
yarding with the Madill yarder was 15 percent cheaper
than conventional
Also at slope distances
yarding.
and swing yarding
greater than 325 feet prebunch
At
cost less than yarding with the Koller yarder.
than
325
the
increased
distances greater
feet
In
is
not
sim-ulate
43
4ýG
50
45
40
800
700
600
500
400
300
200
FEET
DISTANCE
YARDING
SLOPE
techniquescompared
60
conditions
ýp71
65
and
optimal
with
swing
and
and
loading
cost
for
prebunch
70
4--55
Figure
yarding.
with
conventional
75
U
4.--Yarding
80
Z
outhaul and inhaul speed plus larger turn sizes of
for the additional
the Madill yarder compensate
At
and swing yarding.
handling involved in prebunch
closer distances it seems better to yard
with the Koller yarder and avoid the extra
handling associated with prebunching.
conven-tionally
CONCLUSIONS
Commercial thinning of stands on steep slopes with
diameter at breast height of 12 inches
an average
and
external slope yarding distances of less than
1000 feet appear most economical to yard with a
The small yarder
small yarder and
small
crew.
in both the
maintained a cost advantage
light and
is
that
cost
levels.
While
there
heavy thinning
difference managers also should consider other
variables such as log size yarding distance and
yarder availability when selecting a yarder.
the yarding conditions studied the volume per
effect on cost.
acre removed had a significant
of
the
trees removed from
Reducing
average number
125 to 80 increased the yarding and loading cost
is not
20 to 22 percent.
If manual
slackpulling
adversely affected by slope yarding distance the
Koller yarding would
of conventional
increased cost
20
less
than
the
be somewhat
percent observed.
For
Conventional
yarding with a midsize yarder increased
was
12
cost
Swing yarding production
by
percent.
with
the
midsize
than
production
significantly higher
below
conventional
did
not
lower
costs
yarder but
midsize yarding for the operating conditions and
studied.
Using a smaller crew size
techniques
in
and swing yarding and operating
during prebunch
is
not
adversely
areas where manual slackpulling
distance
influenced
by increased slope yarding
and
swinging less
appear to make prebunching
expensive than conventional yarding with either a
small or midsize yarder.
REFERENCES
Beuter
J.H.
of
Zielinsky
Hochrein
yarding
Paper.
63 pp.
Personal communication with Cary
data.
January 1980.
unpublished
Prebunching versus full-cycle
M.
For.
in different thinning
intensities.
State
University.
Corvallis Oregon
Oregon
P.H.
1986.
45
Keller
skyline
Corvallis
138
Prebunching with a low investment
thesis.
in thinnings.
M.S.
Oregon State University.
Oregon
R.R.
yarder
1979.
pp.
Kellogg
L.D.
swinging
a
M.For.
and
study of prebunching
system for young forests.
Corvallis Oregon Oregon State
A case
thinning
paper.
88 pp.
University.
Kellogg
Corvallis
1980.
pp.
Kellogg
cable
1983.
Thinning young timber stands in
Bulletin 34.
terrain.
Research
Oregon State University.
Oregon
L.D.
mountainous
19
1976.
the small tree resource with
Handling
Journal 33425-32.
Forest Products
L.D.
systems.
Kellogg L.D.
and
44
a
E.D.
small
Olsen.
Increasing the
productivity
yarder crew size skidder
hot
Research Bulletin
46.
swinging
thinning.
State
Corvallis Oregon
Oregon
University.
of
1984.
pp.
LeDoux C.B.
Results
and D.A.
Butler.
Prebunching
from simulation.
Journal of Forestry
80279-82.
1982.
Olsen E.D.
and L.D.
Kellogg.
Comparison of
for evaluating
time-study techniques
logging
Transactions of the American Society of
production.
American Society
Agricultural Engineers.
Michigan
of Agricultural
1665-1668.
1983.
Engineers.
pp.
a
Zielinsky C.R.
Operational
prebunching
reduce
to
loggers application
skyline thinning
costs.
M.For. paper.
Corvallis Oregon Oregon
State
University.
97
pp.
1980.
EFN
46
Errata Notice
following editorial corrections to the HP-41C Estimate of
article in
Uncertainty for Conventional Ground Method Closed Survey Traverses
your copy of Engineering Field Notes Vol. 19 May-June 1987
Please make
If
Page
51
Page
54
not
program
the
4th line from the bottom
1-minute
default should read
In
the
XY
figure
corrected
3
the
output.
------------------Editor
EFN
6-9-87
continued
with
XýY
On
error in figure
line
3
numbers
page
54
1-foot transit
transit default.
316 323
and
345
replace
could lead to erroneous
HP-41
C
Estimate of Uncertainty for
Conventional Ground Method Closed
Survey Traverses
Kayser
Land Surveyor
Region 1
Al
INTRODUCTION
This program is based on a simplified approximate
method of analyzing propagated random errors in
closed survey traverses to determine compliance with
The analysis
specifications.
positional tolerance
and
also will help to detect poor survey technique
The
traverse.
the presence of blunders in the
program computes potential errors for each leg an
estimate of uncertainty of each station and a
closure based on the methods used to perform the
A sample analysis is included at the end
traverse.
of this documentation.
ANALYSIS CRITERIA
The
random
analysis depends on four basic criteria
distance measuring
error inherent in electronic
equipment deviations of angle-measuring instruments
resulting from reading and pointing error foresight
and backsight
target miscentering and distances
traversed.
Other random errors may exist but should
when correct instrument adjustment
be negligible
and proper calibration
have been
procedures
per-formed.
Poor statistical expected
closures indicate
Problems to consider in such
imprecise methods.
case include backsight too short relative to
foresight poor methods of plumbing target poor
instrumentation and too few angle repetitions.
a
Actual field closures poorer than expected are
undesirable
and
should be examined for input errors
Problems to
in the
traverse.
or possible blunders
consider in these cases include poorer technique
than presumed in the tables too large target size
too high horizontal and/or vertical
angular
limit improperly adjusted instruments.
rejec-tion
Field closures better than expected are of course
than presumed in
desirable and show better technique
the
program or a more favorable propagation of random
errors.
47
PROGRAM
ANALYSIS
the estimate
of uncertainty
of position of
station relative to the point of beginning.
The square root of the difference
between Eu 2
for any given corner or point and Eu 2 of its
controlling corners should be less than the
tolerance
specified for the given corner.
Eu
is
each
posi-tiona
Compute linear and angular closures before executing
this program.
Closing Eu will be compared to
linear closure after proper angular adjustments have
been made.
If angular closure
is significantly
greater than expected
comparing Eu to linear
closure will be misleading.
This is a stand-alone program.
it can
Although
handle extremely long traverses such cases might be
analyzed better with a program integrated with
traverse and least squares adjustment routines.
See figure I for the steps the program takes.
Angle
measuring and target plumbing errors are optional
for each leg of each traverse.
Initial values inpu
from tables 1 and 2 in figure 1 in steps 3 and 4
become default values
and remain the default values
regardless of optional values input for individual
legs of the traverse.
Distance
measuring instrument
coefficients are not optional.
Dont
be discouraged
by the
speed of the program at
first station things will speed up after the
For each station
program has completed one run.
the program will take between
15 and 40 seconds
to
input values calculate results figure
and
print the analysis.
the
2
Table
based on statistical data for instruments
The data
European manufacture.
are for one D-R
pair of angles two repetitions.
The program is
set up to handle data in this form.
Tests have shown
that some instruments have a standard deviation
If the
greater than their least count.
standard
deviation of the instrument being used is available
use
rather than the value from table 1.
If
the
standard deviation is not available determine it.
The best value to use is a value measured under the
actual conditions in which the instrument is used
not
the value measured under laboratory
conditions.
Use table 1 values in the interim.
I
is
of
s
3s
Table 2 contains typical
measured centering errors
leapfrogging
tribrachs
48
3s
values based on
forced centering
independent
tripod setups
of
printer
If
Step
is
attached
Labela
A
SIZE
Instructions
In
1
set to MAN
user
mode
Initializes
Input
the
Prompts permanent
value from table
4
LABEL
program.
Prompts permanent
value from table
3
label
12
char.
R/S
ESTIMATE
OF
UNCERTAINTY
DEFAULTS
default
3s
1.
default
2.
3s
value
Prompts correction
manufacturer
typically
5
Display
load program.
Prompts for printout
if printer attached.
2
Key
SS.s
Ft
3S
TABLE
1
3S
TABLE
2
R/S
R/S
EDM/MM/COR
from
5.
mn
R/S
ppm
R/S
EDM/PPM/COR
value
Prompts correction
manufacturer
typically
6
7
from
5.
DIST.
number
Prompts for default
times distance is measured.
of
Prompts for default
of
REPS.
R/S
REPS.
8
single
angle
number
R/S
repetitions.
CLOSING
9
a
Closing distance from
calculation.
DIST
prior
Ft.
R/S
CLSRE
10
Angular error from prior
calculations.
D.MMSS
R/S
BS
11
Initial
BS
distance
Ft.
DIST.
R/S
approximate.
12
Displays station
STA
EU
number.
Displays estimate of uncertainty
of position
of station.
HOR.
Prompts horizontal distance
to FS at each station.
DIST.
Ft.
0
end
R/S
Y
DEFAULT
13
To
Default
will
to
skip
Enter
values
steps
14
optional
for station
to 18 or
D
values.
E
DIST.
14
15
16
17
of distance
repetitions if different than
default.
REPS.
Enter number
Enter value from table 2 if
different than default.
R/S
R/S
Enter value from table 2 if
different than default.
R/S
Enter value from table 1 if
different than default.
3S
TARGET
BS
3S
TARGET
FS
3S
Table
R/S
REPS.
Figure
N
i.--Program steps.
49
1
024
Labela
Step
Instructions
18
Enter number
repetitions
default.
of
if
Input
Key
Display
single angle
different than
R/S
Displays potential error at
each station.
ERROR
ERROR
ERROR
Angular error.
Position error from angle.
Position error from distance.
-
POTENTIAL
DEG
D.MMSS
FT.
Ft.
ERROR
DIST.
Ft.
R/S
C
Cycles
to
12
step
until
end.
Displays distance traversed.
Displays closure based
methods of survey.
Closing distance.
Angular closure.
on
End
aLabel
a
C
B
EU
program
May
be
used
to
restart at
be
used
to
back
be
used
to
review
may
be
set
01
up
on
ER LNR
ER
NOW
9.
station to correct
or reprint closures.
one
for automatic
Table
3s
TYPICAL
Instrument Class
7.0
3s
RANDOM ANGULAR
Least
7.4
3s
0.0015 feet
0.005 feet
0.020 feet
feet
feet
feet
feet
Figure
3s
OF
INSTRUMENTS
Scale
or Vernier
20
30
1
10.5
13.0
15.0
2
CENTERING
Method
of
Forced
centering
ERROR
Plumbing Target
leapfrog
tripods
tripod setups
no
wind
Waist-high plumb-bob
of 4-foot plumbed range pole
Top
Head-high plumb-bob no wind
Top of 3-foot lath over point
Independent
Top
1.
stations.
VARIOUS
of Micrometer
7.5
TARGET
of
input.
1
10
Table
TYPICAL
default
ERROR FOR
Division
6
in
0.053
CLOSURE
Value
1
R/S
step
of
8-foot-high
cont.--Program
Ft.
FIELD
queue.
May
May
CLOSURE
D.MMSS
ER
definitions
Flag
0.026
0.030
0.040
STATISTICAL
Value
closure.
of
M
1
R/S
Displays closure based
data returned.
survey
Closing distance.
Angular
DISTANCE
plumbed range pole
steps.
50
WHAT
Ft.
D.MMSS
and 4- and 8-foot-high plumbed range poles.
The
values for plumb-bob and lath targets have no
statistical backing and are presented
as a guide
until better values are determined.
PROGRAM LISTING
STORAGE
REGISTERS
Figure 3 contains
following are the
program
00
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
SAMPLE ANALYSIS
the actual program listing.
The
storage registers used by the
Pointer leg number
instrument default
target default
EDM/MM/COR
EDM/PPM/COR
Closing distance
Angular closure
Horizontal distance FS
Angular error of leg2 As2
target FS
Sum error radii2 Eu2
Sum horizontal distances
Sum angular error2
2
Horizontal distance BS
Pointer FS BS distance
Error radius of leg2
Number of distance repetitions default
Single angle repetitions default
Number of distance repetitions of leg
Angle pairs of leg
Pointer FS/BS target type
target BS
Error linear of leg
instruments of leg
3s
3s
Ec
3s
E
Er2
3s
3s
Ed
A 1-minute transit and an EDM were used to perform
the
Station I and 6
sample traverse in figure 4.
are section
3
station
is
a
corners
temporary point
for the
lost quarter corner between
them and the
other stations are random traverse points.
Station
10 is common
to and
closes on station 1.
A lath
3 feet
approximately
long was used as a target for
all fore- and backsights.
Two distances
and
one
direct and reverse pair of horizontal angles two
single angle repetitions were measured at each
station.
Upon execution of the program SAMPLE
label
was keyed in for the
From table
prompt.
15 was keyed for the
1-foot transit default.
From
table 2 0.04 was keyed for the 3-foot lath used as
The EDM millimeter and parts per million
targets.
corrections
each were S.
1
51
d
Di stance
s
Standard
IE
Instrument
deviation
and
pointing
centering
error linear
TE
Target
BTE
Angular error
FTE
Angular error from
As
Angular error per
Ed
Position error from distance
Ea
Position error from angle /
Er
Greater
Ep
Propagated
Eu
Estimated uncertainty
of
starting
from backsight
the
error angular
reading
target miscentering
foresight
miscentering
target
station
station
station
errors
position
angular
/
Ed
or
Ea
/
station
error
of
position
of
any
point
in
relation to
point
4
IE
Value
from
table
1
TE
Value
from table
2
BTE
ARCSIN
FTE
ARCSIN
/
I
d
Foresight TE
BTE2
IE2
Ed
3
Ea
SIN
d
FTE2
dppm2
EDM constant2
As
Foresight
TE/32
d
2
2
..
EP
JAs1
Eu
JEr12Er22...
Figure
pairs
TEE
Bac
Backsiht
sight
Foresight
As
Angle
2.--Formulas
As2
used
in
Asn
2
Ern2
estimate
52
of
uncertainty.
Al
LBL
EU
02
LBL
A
68
69
SF
55
70
ADV
LBL
135
a
03
FC
04
CF
21
05
06
SF
00
0.50000
72 STO 00
01
73
07
08
FIX
74
CLOSING
9999
CF
09
75
09
CF
08
10
CLRG
CF
71
4
32
LBL
LBL
76
77
STO 05
CLSRE
142
SF
143
GTO
01
214
144
LBL
D
216 DIST.
145
CF
LBL
211
00
78
PROMPT
79
13
SF
80
STO
ADV
14
ADV
81
82
PROMPT
146
147 DIST.
148 RCL 16
149 FS 00
BS
LABEL
16
AON
83
17
PROMPT
84
85
XEQ 22
STO 07
GTO 31
86
LBL
ESTIMATE
OF
XEQ 24
23 UNCERTAINTY
22
XEQ
24
87
FC
88
GTO
89
ADV
90
CF
01
153
XEQ
17
154
XEQ
19
CF
91
BACK
ADV
92
AVIEW
27
ADV
93
PSE
94
GTO
12
28
LBL
29
DEFAULTS
95
30
AVIEW
96
15
01
2
LBL
FS
01
04
232
LBL
233
SF
08
234
235
CF
21
X42
98
RCL
15
164
10
165
RCL
08
166
3
/
03
X2
101
ST-
12
167
102
RCL
07
168
37
ADV
103
ST-11
104
RCL
13
170
SQRT
105
STO
07
171
3
43
SF
44
/
109
LBL
45
1000
110
ADV
46
/
111
ADV
08
31
47
48 STO 03
49 EDM/PPM/COR
50
PROMPT
51
XEQ
52
ADV
1
54
/
55
ST0
LBL
113
SF
116
117
118
REPS.
67
CF
SF
0
12
252 RCL 10
253 SQRT
254 /
16
186 STO
19
187 RCL
188 RCL
23
19
4
191
08
XEQ
18
127 SF 08
195
129 STO
131
XY
X0
GTO
estimate
258 FIX
259 XEQ
/
194
RCL
1
00
192 X42
193 STO
130
to
17
REP
XEQ 21
125 HOR DIST.
126
PROMPT
128
used
RCL
251
189 SQRT
190
SQRT
23
12
133 XEQ
134 STO
3.--Program
AVIEW
FIX 0
23
/
120
132
Figure
I-CLOSURE
250
1
00
124
12
249
178 HR
179 STO
181
STATISTICAL
FC 55
STAT
257 AVIEW
123 FIX
24
247
248
255
256 ARCL
16
66 XEQ
246
RCL
2
CF
17
01
175 XEQ 15
176
10000
177 /
185
XEQ
XEQ 16
63 STO 17
64 -----------65 SF 12
174
184
122
62
23
XEQ
245 ADV
INT
121
61 RCL
11
244
XEQ
16
REPS.
21
243 DISTANCE
FS
16
60
SF
242 RCL
183
XEQ
59 STO
58
55
182
RCL
57
241
173 STO 22
180
STA
119 FIX
04
56 DIST.
01
21
114
115 RCL
22
E6
53
112
X2
172
108
FC
C
237 SF 12
238 XEQ 24
239 CF 12
240
ADV
169
12
31
236 -----------09
02
42 ENTER
12
159
162 RCL
1
00
08
163
ST- 00
ISG
GTO
161
107
08
ST
231
01
106
11
RCL
07
22
XEQ
39.37
228
07
ST
09
STO
41
226
227
10
RCL
CF
XEQ
22
225
ST
CF
36
38 EOM/MM/COR
39 PROMPT
223
224
230
08
RCL
XY
220 X$2
STO 15
222 SF 09
229
GTO
100
XY
19
97
99 ST-
ERROR
23
18
RCL
07
196
XEQ
XEQ
13
197
XEQ
20
198
21
261
RCL
262
263
SQRT
12
WS
ER
23
267 9999
268 RCL 05
269
XY
ERROR
f-POTENTIAL
C
199
200
22
201
07
202
XEQ
RCL
53
21
SF
265 XEQ
266 ADV
17
24
08
203 SQRT
204
ERROR
X
4
260
264
20
uncertainty.
FT.
22
XEQ
158 RCL
XEQ
35
40
FS
3S TARGET
157
a
BS
160
TABLE
PROMPT
34
ERROR
01
3S
33
UP
155
156
-
23
221
09
25
XEQ
32 STO
REPS.
XEQ 16
STO 18
152 3S TARGET
26
31
219
01
151
08
ERROR
217 XEQ
150
21
24
00
218
B
07
XEQ
215 RCL
DIST.
15
RCL
212
213
01
06
21
210 SIN
E
55
ADV
208 CLD
209 SF
23
141
GTO
20
XEQ
HR
PROMPT
FC
AVIEW
19 AOFF
207
PROMPT
GTO 32
12
18
Y N
HMS
140
139
DIST
11
12
205
206
136 FS 01
137 GTO D
138 DEFAULT
09
-
DEG
270
GTO
01
271
GTO
02
272 LBL
273 FIX
274
01
333
0
334
FIELD
275
FC
276
277
E- CLOSURE
336
FLD
1
337 STO
20
338
RTN
LBL
19
RCL
02
RCL
11
339
340
05
341 ENTER
282
283
342
343
/
ARCL
X
286
RCL
287
SF
288
289
XEQ
290
ER
346 XEQ
347 RTN
22
LNR
348
20
23
349 RCL
350 RCL
21
291 RCL
00
XY
05
ER
FS
PROMPT
344 STO IND
345
AVIEW
285 FIX 4
284
06
351
LBL
XEQ 23
352 ASIN
293
ADV
294
LBL
353
354
295
FC 55
355 RTN
296
CF
356
357
LBL
358
RCL
02
21
299
SF
CF
12
302
CF
21
303
NOW
14
SF
08
21
21
10
EU
24
301
20
IND
359 SQRT
360
12
300 XEQ
02
ST
361 XEQ 23
362 FC 55
363 CF 21
WHAT
304 AVIEW
364
RTN
21
365
LBL
22
STOP
308 GTO A
366
367
FC
55
305
FS
306
SF
55
307
368
309
LBL
15
310
RCL
01
FS
00
311
312
3S
TABLE
369 ACA
ACX
1
XO
XY
318
XEQ 22
RTN
319
LBL
317
323
RTN
327
LBL
328
13
329
STO
330
21
331
STO
373
LBL
381
382
22
LBL
FC
383 RTN
4
384
ACA
385
ADV
386 RTN
387 END
17
14
20
used
FS
23
X
379 AVIEW
380 RTN
TN
332 RTN
cont.--Program
RTN
h-_
XY
326
ADV
377
378 ARCL
16
PROMPT
324 XEQ
315 FIX
371
372
55
374
375 GTO 22
376 SF 21
320 ENTER$
321 FIX 0
322
RTN
370
313 PROMPT
314
315
GTO 15
316
F-
to
estimate
uncertainty.
54
20
IND
/
292
297 ADV
298 ------------
3.
14
9
281 RCL
280
Figure
18
7
335 STO
55
278 AVIEW
279
LBL
24
55
STA
DEFAULTS
3S TABLE
3S TABLE
0.0400
2
EU
HOR
EDM/MM/COR
EDM/PPM/COR
DIST.
STA
5.
10.
15.0000
1
POTENTIAL
DEG
0.0020
0.0809
ERROR - FT.
DIST. ERROR
0.0647
ERROR
5.0000
2.
REPS.
2.
0.2475
842.0000
EU
-
DISTANCE
STA
13415.0000
STATISTICAL
EU
6.
ER
EU
551.0000
DIST.
STA
1.
0.0000
HOR DIST.
610.0000
ERROR POTENTIAL
ERROR - DEG
0.0025
EU
0.4658
0.0059
0.2604
FIELD CLOSURE
3647.0000
ERROR POTENTIAL
- DEG
0.0018
ERROR
0.3193
ERROR - FT.
0.0838
DIST. ERROR
HOR
CLOSURE
28798.
1
-----------------------BS
0.4658
ERROR
5.0000
REPS.
DIST.
DIST.
1
13152.
ER
LNR
1.0200
0.0050
ER
-----------------ERROR
-
DIST.
ERROR
FT.
STA
EU
0.0641
ERROR
-
ERROR
-
FT.
0.1531
HOR
DIST.
ERROR
ERROR
0.0702
ERROR
0.0744
2013.0000
POTENTIAL
-
DEG
0.0021
ERROR
-
FT.
0.2011
DIST.
ERROR
DIST.
STA
0.0702
3.
EU
HOR
DIST.
ERROR
POTENTIAL
DEG
0.0018
FT.
0.0844
ERROR
-
ERROR
-
DIST.
ERROR
STA
0.0651
4.
EU
HOR
0.2144
986.0000
DIST.
0.2305
973.0000
ERROR
-
POTENTIAL
DEG
0.0019
ERROR
-
FT.
0.0904
DIST.
ERROR
0.0651
ERROR
Figure
4.--Sample estimate
DISTANCE
28798.
EU
ER
0.4396
1783.0000
ERROR POTENTIAL
ERROR
- DEG
0.0016
ERROR
FT.
0.1403
0.0688
DIST. ERROR
DIST.
STA
9.
EU
0.4614
551.0000
HOR DIST.
POTENTIAL
ERROR
- DEG
0.0022
ERROR
ERROR
-
DIST.
ERROR
FT.
of uncertainty.
55
CLOSURE
0.4658
0.0059
FIELD CLOSURE
8.
EU
13415.0000
STATISTICAL
1
1
HOR
STA
DIST.
ERROR
2.
EU
0.4120
2010.0000
POTENTIAL
DEG
0.0016
HOR
STA
7.
0.0744
0.0580
0.0640
34397.
ER
LNR
ER
0.3900
0.0000
The closure initially input was the closure before
The
angle adjustment 1.02 feet and 50 seconds.
in this case was known
because
backsight distance
it was
the same as the last leg of the
traverse 551
feet.
After all the distances were input
was
keyed to calculate the statistical closure.
C
The
program then made a comparison of expected
angular closure and actual angular closure computed
from field data.
The program indicated that
the
maximum random angular error expected to
its
59 seconds.
Actual angular closure was
50 seconds.
This shows that the 50 seconds of error
is in the
realm of random accumulation
and can be
distributed by the rules of random error
By looking at the potential error at STA - I
of 25 seconds
and
the 16 seconds at STA - 8 it
becomes rather obvious the 50 seconds of error should
not be equally divided
between the stations.
STA I
should get 2.4 times the correction of STA
accumu-at
adjust-ments.
8
252
STA
2
/
162
should
212
/
get
162
2.44
1.7
1.
times the
72
and so
correction
of
STA
8
on.
point the angles were adjusted and a new
closure computed
and
rather than 1.02 feet there
were 0.39 feet of unaccountable
error. The
expected maximum closure was 0.47 feet.
The field
closure is
the
realm of random accumulation
and
the
distance error can be distributed by the rules
of random error adjustments.
At
this
iin
we assume a positional
tolerance of 2 feet between
section
quarter corner and each of its controlling
we need to
corners we can calculate how accurately
measure between the section corners to ensure that
the standard is met
If
a
V22
22
2.8
The difference between Eu of one section
corner
and the other must be less than 2.8 feet.
In
this
sample the difference between Et1 of STA 1 and STA
6 is
0.26 feet.
This
shows that our methods of
traverse can easily meet the standard.
Our field
closure was less than the expected closure therefore
our measurement
between section
corners will meet
the
standard.
56
temporary point for the 1/4 corner STA 3 had
of 0.21 feet from STA I and 0.15 from
an uncertainty
STA 6.
This meant our methods to get from the
temporary point to the true point must ensure no
more than 1.99 feet of random error.
The
0.212
-
o2
VO.262
-
.21
122
-
0.21
0.212
0.15
1.9.9
Had the field closure been 1.02 feet after proper
angular adjustment we would have assumed that our
error was not random in nature that a blunder had
occurred and that the blunder could be 1.02 feet in
for setting the
The tolerance
quarter
any leg.
corner
feet would not be exceeded by this one
foot bust.
However if a 1/16 corner were to be set
within a 1-foot tolerance the 1.02 foot bust would
become significant.
2
EFN
57
A Primer on
Satellite
Sensors
Jerry D. Greer
Project Leader
National
Forestry Applications
EDITORS
NOTE
Program
article is the first of a series we
following
hope of short articles designed to help you know
and understand specialized terms from new fields.
We hope the articles will keep you thinking--that
they ultimately will result in the increased use of
to
advanced technology.
We want high technology
become low technology we want it to become a common
of the public
part of our lives in the management
The
lands.
when
plan to publish these primers occasionally
Notes
readers.
Field
they appear to meet a need of
Please let us know if there are topics that you would
to
All readers are encouraged
want to see covered.
submit similar articles.
We
INTRODUCTION
Space
the
final
frontier.
Everyone who has watched Star Trek will recognize
the program.
Captain Kirks words as he introduces
is no longer a realm occupied by writers of
Space
fiction.
We are there now looking back and
data about the spaceship Earth.
collect-ing
from space will have an increasing
Sensors operated
the
literature of remote sensing.
in
importance
Reading about digital data from the sensors will
will be called
take more of our time.
Specialists
what
the
data mean and
upon more and more to explain
that
data
in
resource
to find ways to use
management.
a
This article is designed to help you understand
that
used
in
this
field.
few of the basic terms
are
TERMS
In describing
Apogee.
point on an elliptical
59
an
orbit
orbit that
the apogee is the
is the farthest
It
away from the body being orbited.
usually may be
interpreted as the point farthest from the bodys
surface such as the Earths sea level.
In
is the
Perogee.
describing an orbit the perogee
on
orbit
that
is
the
closest
to
an elliptical
point
It
the center of gravity of the body being orbited.
be
read
as
the
of
the
orbit
that
point
usually may
is closest to the
bodys surface such as the Earths
sea
level.
Orbit.
The circular or elliptical
a
satellite as it revolves around
other satellite.
The altitude
Absolute Altitude.
above the actual surface either
planet
or
path
a
described
planet moon
of a
land
by
or
spacecraft
or
water
of
a
moon.
time limits that
Launch Window.
The exact date and
must be met if a satellite is to be successfully
if
inserted into a prescribed
orbit.
For example
a
satellite is to be placed into a sun-synchronous
orbit so that it will pass over all latitudes at
1000 a.m. local sun time there are very strict
requirements about where and when the satellite must
be launched.
satel-lite.
The path of a satellite over land or
Ground Track.
falls
water that
directly below the passing
It normally is shown
as a line on a map that
Observers standing
illustrates the satellites path.
the
on that line could look vertically up and
satellite.
see
ERTS Earth Resources
The
Satellite.
Technology
name of the first Earth resource satellites launched
States.
by the United
They carried electro-optic
scanning sensors.
They were later renamed Landsat.
Renamed
from ERTS the Landsat satellites
Landsat.
sensors that
are sun-synchronous electro-optic
collect information about light reflected
from the
Earths surface.
Several different wavelengths
colors of light are detected and their intensities
are recorded.
The data are reassembled into usable
images or into computer-compatible
processing facility.
tapes
at
a
ground
satel-lites
Seasat.
is
Similar
designed
to Landsat
to monitor
60
this series of
the conditions
and
movements of the Earths oceans.
of
determine many characteristics
surface elevation
and currents.
They use radar to
ocean waves
e
satellite as
The French launched the Spot
the
Earth
resources
r entry into
monitoring
the U.S.
business.
It has better resolution than
is
of
Landsat and
collecting overlapping
capable
images that provide for the first time stereo
of Earth scenes from space.
coverage
Spot.
equa-torial
A satellite in Earth
Satellite.
Synchronous
orbit at an altitude of 35900 kilometers.
the
satellite makes one revolution
At
this altitude
of the Earth in 24 hours synchronous with the Earths
rotation.
To an observer on Earth the satellite
Satellites
to
be stationary in the sky.
appears
transmissions
are
of
this kind.
television
relaying
Sun Synchronous.
An Earth polar orbit with an
altitude such that the satellite passes over all
twice
places on Earth having the same latitude
time.
at
the
same
local
sun
day
a
alti-tude
A chemical
oxidized nitrogen that
Hydrazine.
used as a fuel to supply energy for satellite
control.
The act of placing
orbit.
This is done
prescribed
on an expendable launch vehicle
from a manned craft such as the
Insertion.
a
is
satellite into a
either by launching
ELV or by deploying
Space Shuttle.
A ground facility that tracks a
Data
satellites passing with radio antennas.
stored
collected by the satellite sensors are
on
to data
board the satellite and dumped on command
The tracking stations also
recorders on Earth.
upload commands and updated data that are essential
of the satellite and
the
to the proper functioning
sensors.
Tracking
Station.
mathemati-cally
A general description
of
Nominal Orbit Altitude.
Orbits are
the altitude
of a satellite.
complex and cannot be described in simple
terms.
This description of altitude gives the
of the
satellites place
reader a general knowledge
in space in relation
to the Earth.
STS
Space Transportation
component
comprises
is
Space
support
the
many
61
System.
Shuttle but
activities.
The
best
the
known
system
GOES Geostationary Operational
Environmental
A satellite deployed
Satellite.
to receive data
transmissions from remote and unmanned Earth-based
sensors and to relay the data to central collection
and processing stations.
Satellites of this type
have been used to collect data from automatic stream
flow monitoring stations and from snow pack sensors.
Polar Orbit. An Earth orbit in which the
passes over the north and south poles.
satellite
An Earth orbit in which the
Equatorial Orbit.
satellite follows the Earths equator in its West
East
ADDITIONAL
INFORMATION
to
flight.
more information readers may want to refer to
recent encyclopedias
or to textbooks
on the physics
of orbital dynamics.
The Manual of Remote Sensin
edited by Robert N. Colwell
2nd a
Falls Church
American Society of Photogrammetry contains some
excellent reviews of many of these terms.
Some of
the definitions
in this article are paraphrased
from
this manual.
For
EFN
62
Central Tire Inflation Program-Boise
National Forest Field Evaluation
Deborah J. Taylor
Civil Engineer
San Dimas Equipment
INTRODUCTION
Development
Center
Forest Service maintains more than
roads to transport forest products
from National
Forests.
Approximately 95 percent of
The cost of transporting
these roads are unpaved.
of
forest products includes not only the actual cost
of
constructing
transportation but also the cost
the
roads.
Efforts to save dollars
and maintaining
to
mean a need to develop better road technology
reduce costs incurred in all phases of road
and use.
Much of the direction for doing this
Program
is set by the Road Technology
Improvement
Currently
the
342000 miles
of
construc-tion
RTIP.
Devel-opment
Under
RTIP direction
SDEDC
the
San Dimas
Equipment
the effects
is investigating
of transporting
forest
of tire pressure on the
cost
An initial
products over Forest Service haul roads.
can be found in the
report on this investigation
Center
Engineering Field Notes article Using Central Tire
Inflation Systems to Decrease Vehicular
Damage to
Vol.
15
Forest Roads L.B. Della-Moretta
To begin to quantify the
1983 pp. 17-19.
relationship between logging truck tire pressure and
road and haul costs and to familiarize the logging
the
industry with the low tire pressure concept
a
Forest Service is conducting
two-part test program.
January-March
Part one
consists of structured tests to quantify
between tires the road and
the
interrelationship
and
the associated
benefits of low tire
the vehicle
of
series of field
two
consists
a
Part
pressures.
to the
tests that should demonstrate
logging
of low tire pressure and
the concept
of central tire
evaluate the effectiveness
indus-try
qualita-tively
inflation
conditions.
CTI
systems under
63
actual
field
j
FIELD
DEMONSTRATION
TEST PLAN
Moores Creek timber sale on the Boise National
Forest near Cascade Idaho was to be the first
field test to use low tire pressure on an actual
timber haul.
This operation
was selected to
and
associated benefits of
safely the concept
hauling logs with lowered tire pressures and to
determine the effects on haul
costs driver comfort
and fatigue
road maintenance
requirements and
length of haul season.
The
demon-strate
The entire 11-mile haul
route was over unpaved
roads--5 miles of aggregate-surfaced
county road and
6 miles
of native-surfaced
Forest Service road with
tight curves and grades up to 12 percent.
An
the
first day of the
closure effective
test program was placed on the
Forest Service
segment of the haul route restricting the test area
to just the
logging traffic.
admin-istrative
To
test the low tire pressures the Forest Service
the
Boise Cascade Corporation and Hanson Logging of
Horseshoe
Bend Idaho agreed to change the operating
plan for the Moores Creek timber sale for the 1986
fall operating
From September to November
season.
approxi-mately
1986 four 18-wheel
western logging trucks were
with
low
tire
operated
pressures to haul
1.7 million board feet of timber from the
sale area.
This is just one of many projects to be
conducted
throughout the United States to involve
a
wide variety of regional conditions
the comments and
observations
that
result from this test plan depend
upon the conditions peculiar to this sale area.
TEST PROCEDURE
Immediately before testing all four trucks were
equipped with radial tires.
Unlike traditional bias
ply tires newer radial tires perform more
when they are run at pressures more
for a particular operational load and speed.
Since CTI systems were not yet fully developed
and
available for this test tire pressure adjustments
were made manually.
Ordinarily logging trucks
operate with air in their tires set at from 90 to
110 pounds per square inch psi.
For the Moores
Creek sale the driving axle tires were set at
41
loaded condition.
psi for the
Trailer axle tires
were set at 38 psi for the entire low-pressure
test
since they were carried or piggy-backed on the
return trip.
effec-tively
appropri-ate
As an experimental
precaution steering axle tires
were set at 54 psi for the entire low tire pressure
When
the trucks were unloaded
phase.
at the Boise
64
Cascade mill the truck drivers deflated the driving
tires to 25 psi by using automatic deflation
valves
that
had been plugged onto the
tire valve
stems.
By using various pressures tire footprint
were kept constant for
length and deflection
different loads during the low pressure phase
Tire deflection
is the
amount of
figure 1.
axle
Figure 1--Increased deflection of radial
works great.
pressure looks
bad
65
tires
with
lowered
air
i
flatness of a tire for example tires inflated to
100 psi typically are deflected
by 10 percent of
their section height.
Constant deflection
and
were
to
ensure
consistent
footprint length
important
results during low-pressure testing.
demon-stration
Limited field measurements
were taken during the
test program because
the test was to be a
having mostly subjective evaluations.
Truck drivers were responsible
for keeping
a
daily
record of fuel consumption
round trip times and
total loads hauled.
Records were made of any tire
or rim damage--including
conditions causing the
damage the type of damage tire mileage tire
pressure and position of the tire on the vehicle.
A radar gun was used to determine the speed of each
vehicle
through the test segments and other
segments of the haul route.
desig-nated
segments were selected along the haul
record the effects
of changing
tire
pressures under a wide variety of road conditions
curves grades surface soil types and moisture
At
the beginning and
end of each phase of
changes.
readings to be
testing nuclear moisture/density
verified with an oven-dry sample and documentation
photographs
were taken at each test segment.
Five
test
route to
Measurements
of road rutting and
related strain were
taken at a designated
location by Dan Salm from the
Forest Service Graduate Program Oregon State
Once truck drivers or test personnel observed
washboard corrugation
or road rutting depth
were recorded
and photographs
taken to document
the
A rain gauge was installed to
progression.
record daily precipitation.
Univer-sity
measure-ment
TEST RESULTS
Since an objective of the tests on the Boise National
Forest Cascade Ranger District was to provide a
evaluation
of the
low tire pressure
qualitative
t
is discussion
of test results is based
concept
made during
primarily upon comments and observations
the
test program.
Of the approximately
1.7 million
board feet of timber hauled during the test program
1.0 million board feet was transported
on trucks
with low tire pressures-and the remaining 0.7
million board feet with high tire pressures.
After
the first 4 days of haul
with low tire pressure
weather conditions changed
and the road surface
became so wet that the haul was temporarily shut
66
alter-nating
hauls were accomplished
Subsequent
by
high and low tire pressures as road and
weather conditions changed.
down.
Reduced Haul Costs
Condition surveys of the vehicles before and at the
conclusion
of the test program indicated that no
additional maintenance
or repair was required on the
vehicles
after hauling the 1.7 million board feet.
This
is important because costs associated
with
truck maintenance
and
repair are a significant
costs.
The truck drivers
portion of the overall haul
agreed that over an extended time period overall
truck maintenance
repair would be decreased
by the
use of low tire pressures.
believed
that
over
They
a
and degree of
period of time both the frequency
truck repair would decrease.
One of the largest haul
cost
factors to be improved
is tire replacement.
Bruises breaks and cuts
cause of premature
currently are the predominant
tire failure on logging trucks.
With a longer tire
footprint the low-pressure tires actually rolled
over large sharp rocks that protruded above the
road surface on low-speed weak roads without
the
tire damage commonly seen.
The increased bulge
in
the tire sidewalls eliminates the
tendency for rocks
to get
caught between the duals and cause a blowout.
In fact
during
resulting from
occurred during
a
this test program the only blowout
rock caught between the duals
a
high-pressure
phase.
Upon completion of the test program the trademark
design molded within the tire tread area by the tire
manufacturer
was still evident indicating limited
tire wear.
Following an examination of some of the
tires by Bandag Inc. of Muscatine
Iowa for
possible tire damage and retreading additional
miles will be run using the tires from this test
program.
Increased Driver
Comfort
increased
By lowering tire pressures tire deflection
and
the
tire footprint lengthened.
Hence the tire
is in contact with the road surface for a longer
The drivers noticed
period of time.
less bouncing
and
and less discomfort on
rattling of their trucks
their backs.
opera-tion
Because
of the short
duration of low-pressure
the
drivers did not get used to the feel of
handling and stability associated with low pressure.
Power steering would have helped with the handling
67
since the longer footprint requires more power to
turn the steering tires.
The drivers felt some
in curves.
handling difference
However subsequent
tests and inspection found this to be because of the
bunk pads on the trailer rather than the tire
Drivers agreed that overall stability was
pressure.
improved and felt that a truck rollover was avoided
because of the lowered tire pressure.
Reduced Road
Maintenance
main-tenance
both
logging truck drivers and the Forest
changing tire pressures improved the road
surface conditions and decreased
overall road
to Al Noyes of the
requirements.
According
Cascade Ranger District road deterioration did not
occur for either the low- or the high-pressure
This was dramatically
different than the
phases.
previous haul year when the road had required
continual maintenance.
For this test the first
test
phase set the road surface up so
low-pressure
hard and smooth that only in areas of excessive
subsurface
water did the road surface break down
under high pressure.
To
the
Service
The
repairing effect of low pressure became apparent
early on in the test program.
During the first
low-pressure phase when the roads became saturated
and
haul
so slick that the
operation was temporarily
shut down logging traffic other than the logging
trucks had rutted and damaged the road surface with
After the road surface had
high pressure tires.
dried out enough to resume haul the first high tire
pressure phase was planned to begin.
However based
the
of
the
suggestion
logging contractor and
upon
truck drivers 2 days of haul were run using low
tire pressure in lieu of grading the road surface.
The low tire pressures smoothed the road surface
figure 2 and grader maintenance
was not required.
For the remainder of the test program the road
surface remained dry.
The opportunity did not
arise
to haul on wet roads using high tire pressures.
road conditions of
However photographs documenting
this same haul
road when it had been used a year
earlier using normal tire pressures showed ruts as
Road maintenance
had been
deep as 16 inches.
This same haul
road never needed maintenance
throughout the course of this test program.
to the
Cascade Ranger District staff it was
almost too much to believe
that 1.7 million board
of timber was hauled with no maintenance
feet
to the
con-tinual.
Accord-ing
road.
68
Figure
2--Radial
Extended
Season
Haul
tires with
lowered
air pressure
produce
less stress on
the
road surface.
Because of its road-healing
characteristics the use
could
extend the actual haul
tire
of low
pressures
road
for
wet
or snow-covered
season particularly
conditions.
On steep grades truck traction was
In the
improved by the use of low tire pressure.
road
the use
haul
a
wet
of
adverse
over
surface
case
the haul
and delayed
of low tire pressure prolonged
a
temporary shutdown.
The
truck
the possible advantage
drivers recognized
tire
under
of using low
snowy conditions.
pressure
the
road
when
the
first heavy snowfall
During
but
still
warm
was
surface became slick and icy
trucks
all
four
enough to melt the snow tires on
chains
that
were inflated to normal pressures so
However the drivers asked to have
could be used.
their tires deflated back down to lower
pressures--69
claiming that the road surface was not yet slick
that high
enough for chains but recognizing
would
not
provide enough traction.
pressure tires
resumed
with
all
drivers using lower tire
Hauling
pressures.
demon-strated
testing on the Moores Creek timber sale
that CTI technology
can be beneficial in
Tests
are
now needed to quantify
timber operations.
and
net
cost
benefits
identify any operational
Based upon the
problems that must be overcome.
observations
and
comments made by both the Moores
the
Creek logging crew and the Forest Service
timber
sale
conclusion for this particular
was that
of
low
tire
could
reduce
overall
the
use
pressures
driver
reduce
road
haul
comfort
costs improve
maintenance
requirements and extend the overall
haul
season.
The
This test was only one of a series of tests designed
to determine the
feasibility of using CTI systems to
allow high tire pressures on high-speed very strong
roads and low pressures on low-speed weaker unpaved
roads.
of these systems is underway.
Development
This
and other tests are required to determine the
feasibility of equipping logging trucks with CTI
tests indicate that
The results of these
systems.
the potential for future cost savings is tremendous.
This may be the beginning of a whole new era of
forest product transportation.
EFN
it
CONCLUSIONS
70
us
Engineering Field Notes
naru
Administrative
The Series
Distribution
THE ENGINEERING
as a
periodically
FIELD NOTES SERIES is published
of exchanging engineering-related
on activities problems encountered and
or other data that
may be of value to
means
ideas and information
developed
solutions
Engineers
Submittals
Service-wide.
personnel should send material through their Regional
Coordinator for review by the Regional Office to
Information
ensure inclusion of information that is accurate
timely and of
Field
interest Service-wide.
Regional
R-1
Jim Hogan
R-4
Ted Wood
R-9
Fred Hintsala
Information
R-2
Ray
Ollila
R-5
Larry Gruver
R-10
Bill
Coordinators
R-3
Art Marty
R-6
Bill
R-8
Jim Gilpin
Inquiries
Information
Perry
Coordinators
WO
should
Al
send
Niles
Colley
recommen-dations
Regional
and direct any questions
publication
to the following
address
articles
comments or
for
FOREST SERVICE-USDA
Engineering Staff-Washington
Attn D.J. Carroll Editor
P.O.
Office
M. J. Baggett Assistant Editor
Box 96090-Washington DC 20013-6090
703
Telephone
235-8198
Service-U.S.
This
publication is an administrative document that
for the guidance of employees of the Forest
was
developed
of Agriculture
its contractors and
its
Department
cooperating Federal and State Government Agencies. The text
the personal opinions of the
in the publication represents
authors.
This
information
has not been approved
for
respective
distribution
instructions
must not be construed as
procedures
or mandatory
except by Forest Service Manual references.
the
to
recommended
public and
or approved
policy
The Forest Service-U.S.
Department of Agriculture assumes no
for the interpretation
or application of this
responsibility
information
other
than
its
own
The use of trade
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may be
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This
information
unlimited
by private
is
the sole
rights in the
parties.
usage
of the Government with
and cannot be copyrighted
property
thereof
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SERyq
U
S
EWOF
Volume 19
May-June
1987
Engineering
Field
Notes