i 

United States 

Department of 

Agriculture 

Forest Service 

Southern Forest 

Experiment Station 

New Orleans, 

Louisiana 

General Technical Report SO-45 

August, 1983 

Drive-To-Tree, 

Rubber-Tired Fe 

Buncher Produ 

B. L. tanford and D. L. Sirois 
SUMMARY 

The increasing use of machines to fell trees has created a need for better 

understanding this process and what factors affect production. This report 

provides infomation on feller buncher activities and presents means for 

estimating production rates for rubber-tired drive-to-tree machines. Four 

types of machines were tested and were found to have different production 

rates. Total productive felling and bunching time per tree increased with 

increasing Dl3H and distance between trees and decreased with larger 

aecumaalations, During the .test the average production. per productive 

machine hour ranged from 109 to 214 trees per hour. 
Drive-To-Tree, Rubber-Tired Feller Buncher Production Studies 

ford md D, L, Simis 

INTRODUCTlON STUDY CONDITIONS 

Considerable attention has been given to the advantages of mechanized methods of felling trees. 

Machines that also put the trees in piles offer even 

more advantages. Skidders with hydraulic grapples 

work very efficiently behind these felling and bunching machines. By having the trees in piles, grapple 

skidders generally spend less time accumulating a 

payload than a skidder with chokers whose operator 

must pull cable to singly located trees. At the loading 

deck the grapple skidder operator can drop his load 

very rapidly, often without loss of fomard motion. 

Grapple skidders can be used to pick up individual 

trees, but if the trees are small, the production rate 

is low with high cost per unit of production. Consequently, it is very desirable to have trees in piles 

matched to the capacity of the skidder, such as those 

that can be made by feller bunchers. 

The, alternative to mechanized felling is manual 

felling using a chain saw, While most wood is presently felled with chainsaws, operators willing to 

endure the physical strain are becoming scarce. During the hot summer months, manual fellers must 

take frequent breaks in order to avoid heat exhaustion, Since felling is the first act of tree processing, it influences all subsequent activities such as 

skidding, delirnbing, and loading, so it is the key 

productioa element of the system. Because of these 

problems, logging managers have become keenly 

interested in mechanized feller bunchers. They find 

that these machines fell trees faster than manual 

methods and are capable of maintaining these rates 

day after day, woods workers are also more interested in operating a feller buncher than a chainsaw 

because of the reduced physical effort and protection 

from the weather by the cab. To benefit from the 

advantages of feller bunchers, it is necessary to unIn general, fsur categories of feller-bunchers can 

be identified: rubber-tired dsive-to-bee, crawler 

drive-do-tree, mbber-tired s&ng-to-tree, and crmles 

swing-to-tree, A ""dive-to-tree" or ""tee-to-tree" machine moves to a tree, holds and cuts it, and moves 

to another tree or to a pile while carrying the fir& 

tree. In contrast, the '"wing-to-tree" or ""lmited 

area'haehines have a boom that connects the felling 

head to the carrier and allows the machine to reach 

out to a tree rather than driving to it. Typically, the 

swing-to-tree machine sets up where it can reach 

several trees, proceeds to cut each and puts them in 

a pile. The sab&visions of "crawler" and ""rubbertired79efer to the mode of locomotion inherent to 

the carrier. 

This study focused on fsur drive-to-tree, rubbertired feller-bunchers working in a clearcutting pattern. The machines studied were working on coastal 

plains and lower piedmont sites in the states of 

Georgia, Florida, and Mississippi. 

During a normal day's activity, a feller-buncher 

is involved in one of three categories of time: productive, down, or idle. Productive time is that time 

spent processing trees: i,e. moving, felling, and 

bunching. Down time includes both scheduled and 

unscheduled repair and maintenance on the machine, 

when it is not cutting wood. Service is considered 

part of scheduled maintenance. Idle time is when the 

machine is available for work but is not' doing so. In 

this report only the productive phase will be covered. 

Consequently, the reported rates contain no adjustment for down or idle times. To apply these productive rates to predict daily machine performance, they 

must be reduced by the ratio of productive to scheduled time. This ratio is commonly called the "utilization" mte. 

derstand their production potentials and limitations. 

This report provides information on feller buneber Time Study Procedures 

activities and presents means of estimating produc- Data for this report was collected during tho 

Lion rates, summer of 1978. Descriptions of the forms and proB. 8;. Lanford is Ass~ciade Professof;, Alabama AgricuiduraZ Experiment Station, Auburn University, AL, and D. L. Sirois is 

Research Engineer, Southern Forest Experiment Station, Forest Servic+USDA, Auburn, AL. 
eedures are given in the Appendix. The field work ' 

involved three phases, First, after a feller buncher 

operator had been selected, the time study crew 

examined the cutting area for portions which avere 

reasonably uniform in species composition, stand 

density, and slope, No at-tempt was made to bias 

the operation away from the extremes; the only 

restraint on a study plot was that it represented 

only a single set of terrain conditions, However, any 

one plot could differ greatly from another, Plots were 

usually fifty feet wide by one to two hundred feet 

long depending on the hawesting pattern and cutting 

area. The long axis was selected in the direction that 

the machine would normally move during pmcessing. 

On a plot, each tree 2.5 inches and larger was tallied 

by XY coordinates, species, and diameter class at 

breast height (DBH). Each tree was given a number 

which was written in large numerals on a key punch 

card that was stapled to it in a position where the 

number could be read late from a distance. Typically, 

several plots would be set up prior to processing by 

the machine. 

The second phase of the study involved the feller 

buncher cutting trees within the plot. The operator 

was instructed to cut in a normal manner within the 

customary merchantability limits, Most operations 

did not harvest smaller trees measured on the plots, 

The time study crew timed each elemental activity 

of the machine: i.e. the productive tirne elements of 

moving, position and shearing, dropping, and bunch 

maintenance. Moving included any traveling by the 

feller-bunches, either to a tree or to the bunch location. Position and shear was the cutting phase of the 

function and dropping was the tirne to release the 

trees from the shear head onto the pile. Bunch 

maintenance occurred when the machine adjusted 

the stems on the pile. Any other time elements, such 

as delays for machine maintenance or idle time, were 

recorded but will not be discussed in this report. 

During the timing, tree numbers of those felled were 

recorded along with other variables such as accumulation and bunch numbers. 

third phase took place after the test; plot, was 

cut. A sample of felled trees were selected for volume 

determination. Measurements of total height, stump 

diameter, DBH, clear bole and diameter sf largest 

limb were taken on these trees. 

Data Analysis 

After the field data had been recorded and hand 

edited, the irlformaGion was key punched and stored 

on a magnetic disk for computer analysis, Since each 

field record of data islvolved only a single time element, it had to be sr-mnmarized into cycles, A feller 

huncher cycle was defined as the actions necessary 

to create and deposit an acemulation of trees in a 

pile. For example, a cycle would start when the 

machine moved to the first tree to be cut. It would cut 

that tree and perhaps one or two more before moving 

to a bunching location to drop the accumulated trees, 

The next cycle would begin when the machine moved 

to cut the next "first" tree. This would also end the 

first cycle, No time was lost during or between the 

cycles. Typically, the machine would put more than 

one accumulation on the same pile, Cycle summaries 

were expressed in. per tree measurements: moving 

tirne per tree, position and shear time per tree, 

average DBH, ete. Least squares regression analysis 

was the basic statistical tool employed to develop 

production estimates. Dummy variable techniques 

were used to handle noncontinuous variables, Lanford (1975) describes the general analysis procedure 

and the application of dummy variables. 

Since it was possible that time elements might be 

affected differently by the various descriptions of 

the work environment, each was analyzed separately 

before calculating a composite model for the total 

productive cycle time. Tree size, load size, and stand 

density measure were tested for each element of the 

cycle, as was the effect of different machines. DBH 

was used to indicate the tree size while the number, 

basal area, and volume of the accumulation described 

the load being handled by the machine. Stand density measures were taken from the plot being cut 

and included trees, basal area, and volume per acre. 

RESULTS 

Table 1 displays the summarized time, production, 

and stand characteristics experienced during the 

study. F'or one feller buncher type, two machines 

with their operators were observed. On other types 

only one machine with its operator was timed. This 

means that the operator could have a significant 

effect on the production rate, In general, all machine,.' 

operator combinations were found to be different, All 

operators were expenertced crew members, thoroughly familiar with their particular machine. 

A sample observation was defined as an aecurnulation of stems held in the shear head that received 

only one drop dime, In, this GOD~~X~ sample sizes 

ranged from 86 to 275 accumulations per machine 

type. Assuming that each observation was independent of the others, these samples developed means 

that varied from plus or minus 3 to II percent with 

95 percent confidenee, Since each observation came 

from a cluster created by each plot and operator, 

machine eombimation, they were not necessarily independenl;. Experknce has shown that this clustering 

may underestimate the true variability by 2 to 3 

times (Lanfosd 1973). If so, the true sampling error 
Table 1.-Summary statistics for four types of feller bunchers time studied in the South 

Feller buncher type1 

R%achines visited 

Accumulation summary 

Number 

Productive minutesldre 

Average 

Range 

Coefficient of variation 

DBH 

Average 

Range 

Trees/accurnulation 

Average 

Range 

Basal area (ft2) /accumulation 

Average 

Range 

Volume (c.f.i.b) 2/accumulation 

Average 

Range 

Stand summary 

Number of plots 

Trees/acre 

Average 

Range 

Basal area (f t2) /acre 

Average 

Range 

Volume (cmnits) /acres 

Average 

Range 

Average trees/lPMH4 

Average cunits/PMH3 

IMachine types: 

1. Franklin 170 XLN with a Morbark 15 inch shear. 

2. John Deere 544 with a Morbark 155 inch shear 

3. John Deere 544 with a Rome 20 inch shear. 

4. Hydro Ax 511 with a Morbark 20 inch shear. 

2c.f.i.b. = cubic feet inside bark. 

Taras and Clark, 1974. 

4P&IH =r productive naachise hour. 

of the productive cycle times per tree could range 

from 9 to 33 percent with a 95 percent confidence 

limit, These statistics are prior to regression analysis. 

Tree sizes ranged from 3 to 14 inches in DBH 

(elasses), Only pines were baweskd, In PPO case did 

the tree size exceed the shear design limits, Up to 

seven trees were accumulated per cycle bud averaged 

from 1-7 to 3.1, Average volume per accumulation 

ranged from 9.4 to 17.8 cubic feet inside bark 

( e,f ib.) ; however, maximum aceumaslatlons ranged 

from 20.4 to 47,8 c.f.i.b, It would not "cake many aecumulations to make a full skidder payload if the 

average size accumulation was similar to the maximums observed, 

Stand summaries given in table 1 include only the 

trees that were of the sizes and species harvested. 

Since these were clearcut operations, only very small 

pines and hardwoods are excluded from the baly. 

Average production sates sbowcd the four feller 

bunchers cutting from 1.8 to 3.6 trees per productive 

minute with volume rates from 3 to 16 cunits per 

productive machine hours (P33H). 

Figure I gives a brea"i.bc%o.n of Lime elements within 

cycles. For feller huncher type 1, 53 percent of its 

cycle was spent moving, where 66 percent was required for type 4. Type 1 spent the most time positioning and shearing, but as a percent of total cycle 

machine type 3 took the most, 44 percent. Drop time 
"'" r BUNCH MAINTENANCE TlME 

DROP TlME 

POSITION AND SWEAR TlME 

MOVE TlME 

TYPE OF FELLER BUNGHER 

I = FRANKLIN I70XLN WMQRBARK 15'' 

2 = JOHN DEERE 544 W/MORBARK 15'' 

3 = JOHN OEERE 544 WIMORBARK 20'' 

4 = HYDRO AX Sll WIMORBARK 20" 

Fiere I.-Cycle times by elemcnts for four types of feller 

brrnchers time studied in the South. 

per tree was very similar for each of the four machine 

types. There was no bunch maintenance time for 

type I, and for the other three machine types it 

averaged less than .01 minutes per tree. 

All statistics given in table 1 and figure 1 are data 

summaries, prior to regression analysis. The next 

step is to examine each of the time elements separately for trends with the descriptor variables. 

factors were tested singly and in combination. Results of regression analyses found that only machine 

type 3 displayed a correlation with any of the factors. 

The position and shearing time per tree for machine 

types 1, 2 and 4 can be estimated with constants for 

each, but type 3 needs a model with DBH and trees 

per acre (TPA) as follows: 

PSI" = TYPE 1 X 0,226 -J- TYPE 2 X 0,076 f 

TYPIC 4 X 0,071. J- TYPE 3 X (-0.120 -C 

0,0138 >( DBH + 3,8522 ,< TPA-%..) (I) 

where PST = Position and shearing time per tree in 

productive minudes, 

TYPE I == 1 if referring to feller buncher type 1, 

= 0 or otherwise, 

TYPE 2 -- 1 if referring to feller buncher type 2, 

= 0 or othemvise, 

TYPE 3 - 1 if referring to feller buncher type 3, 

= O or othemise, 

TYPE 4 .= 1 if referring to feller buncher type 4, 

-- 0 or othemise, 

DBH == Average diameter at breast height of an 

accumulation in inches, and 

?"PA = trees per acre. 

?'PA-" is an interest variable which describes 

stand density very accurately. The inverse of trees 

=pr acre is acres per tree; then the square root of 

this number is one side of a square surrounding this 

tree. In other words, TPA-" is a measure of distance between trees. Even though the range of 

densities was limited, this measure proved to be 

important for position and shearing time and more 

descriptive than other density measures. 

All combinations of DBH and TPA were tried, 

but equation I was the best. The R2 for this model 

was 0.61, uncorrected for the mean. Homogeneity 

of variance was checked and no weighting was 

needed. Size of the accumulation did not significantly 

affect the time. It should be pointed out again that 

the maximum diameters cut did not approach the 

design limits of the shear head. It would be expected 

that diameters at or close to the design limits would 

cause the time per tree to increase for all machine 

types. 

Position and Shearing Time 

As discussed earlier, after a feller buncher approached a tree for cutting, time was required to 

position the shear heact, close the blade, and lift the 

tree from its si-unlp. If other stems were already in 

the head, care bad to IPG taken not to lose them 

during the severing of additional trees. 

The time to position and shear was thought to be 

affected by trc~ size as rel=.rescnted by DBH, stand 

density {trees, basal area, or volume per acnl), accurnulalion size (trces, basal area, or volume per 

acctllnulation) and or machine iype, All of theire 

&loving Time 

AToving is that portion of the cycle spent traveling 

to a tree before cutting or traveling to a hunch before 

dropping. From the study data, moving time could 

be affected by the stand density (primarily trees per 

acre), DBH of the tree being moved to, load size in 

the accumulation, and or the type of machine. After 

examining these factors the 13~st model resulted in 

MT TYPE 1 1' (-0.450 -- 2.0-1030 Y DBH X 

TPA-" -l 2.7283 >*, TfdA-""z BBA) 1- TYPE 2 

(-0.12'7 - 0.65558 \, DBK \I TPA-'G- 0.7503 
>( TPA-%iBA) i- TUPE 3 X (-0.127 4- 

0.65558 X DBH X TPA-% -i- 0,7503 X TII"A-% 

/BA) -t- TUPE 4 X (0.053 t 0.21836 X DBH X 

TPA-% + 0.3015 X TPA-s/BA) (2) 

where MT = move time per tree in productive 

rninutes and 

BA .= basal area per accumulation in square feet. 

The regression coeacients for type 2 and type 3 

are the same because the move times per tree of 

the two machines were not significantly different. 

This is not surprising since the basic shear carriers 

are the same for both types. 

From equation (2) it can be seen that as DBH or 

distance between trees increases, the time to move 

increases per tree. Conversely, as the accumuXation 

size increases, the time per tree decreases, which is 

caused by the decreased move to drop times for more 

trees. The number of trees in the accumulation was 

tested and found to be significant if BA was not included, but BA explained more variation than trees 

per accumulation. 

All cross products of DBH, TPA, and BA for different machine types were tested and reduced to 

those found in equation (2). The R2 was 0.37, corrected for the mean, and weighting was not needed 

to correct for nonhomogeneity. For machine type 1, 

move time gets very close to zero for small sterns in 

high densities. Equation (2) will give slightly negative times (less than 0.01 minute) in this range. This 

inconsistence should be ignored by calling the time 

zero if negatives occur. 

Drop Time 

Time spent dropping an accumulation was analyzed for possible correlation with accumulation size, 

tree size, and/or type of machine. Only the accumulation size and machine type proved to affect dropping time per tree, The best model used the inverse 

of trees per accumulation to represent load size, but 

the inverse of basal area was quite similar in strength. 

The model with basal area was chosen because of its 

compatibility with previous models. Machine types 

1, 2, and 3 were found to have similar drop times; 

only type 4 took significantly less time. The selected 

model had an R2 of 0.06. and is as follows, 

DT =. 0.025 i- 0.00506/BA i- TUPE 4 X 

(-0.007) (3) 

where DT = Drop time per tree in productive minutes. 

Bunch Maintenance Time 

Bunch maintenance is that portion of the cycle 

spent straightening or adjusting the bunch of trees 

being created by the feller buncher. This activity is 

often needed to properly prepare the bunch for subseqwnt skidding. Possible variables tlvhich could influence hunch maintenance time were accumulation 

size, average tree size in the accumulation, or the 

type of machine involved, All these were tested singly 

and in combinations, and none were found significant. 

There were no bunch maintenance times for machine 

type 1, hut this was thought to be a random occurrence, and that each operator would need to perform t his activity oceassionally, The average bunch 

maintenance time per tree for the study was 0.003 

productive minutes. 

Total Productive Time 

Two analytical techniques are available for combining cycle elements into a total productive time per 

tree estimate: One involves adding the estimation 

equations and constants developed from the analysis 

of separate time elements, and the other would be to 

calculate a regression for total productive time per 

tree, combining element times prior to calculating 

the regression. Since the same data goes into both 

approaches, the results should be the same. Differences in coefficients should only be from the precision of the matrix inversion inheritant to the regression calculation program. 

This second apprcach was taken and the following 

was calculated. 

TPT = TYPE I X (-0.185 + 2.10427 X DBH 

(TPAwy2) i- 2.46696 X TPA-%/BA) + TYPE 

2 X (-0.185 + ,05392 X DBH + .04628/BA) 

+ TYPE 3 X (-0.172 -i- 1.20222 X DBH 

(TPA-%) + 1.19569 X TPAm%/BA) + TYPE 

4 X (0.110 i- .29814 'X DBH (TPA-") + 

.38674 X TPA-@/BA) (4) 

where TPT = Total productive time per tree in minutes. R2 for this model was 0.91 uncorrected for the 

mean. All possible combinations of machine types, 

DBH, TPA, and BA were tried, but the most consistent model with the greatest significant variation " 

explanation was equation (4). 

While equation (4) is somewhat simpler than 

summing equations (1) through (3) plus the bunch 

maintenance constant, the summing process was preferred. This is because of the lack of stand density 

information for machine type 2. As can be seen in 

equation (4) there is no TPA variable for machine 

type 2, but from the analysis of moving time it is 

known that the moving time for machine type 2 was 

not different from that of type 3. By using the summing of equations approach, the stand density effect 

can be shown for moving, the time element most 

affected by stand density. Tables 2 to 5 display the 

estimated total productive times calculated by the 

summing of equations method. 
Table 2.-Total predtcctilje felling and bunching time per tree for mrzehr'ner type _I time studied in the South during clearcutting 

DBH Trees per acre - 200 300 400 500 eoo 

.............................................. inches mlnules------------------------------------------------------------ 

4 .T8 .60 .50 .42 3'7 

.58 .44 -35 .30 .25 

.51 .38 -31 .25 .22 

6 1.07 .84 .70 .61 -54 

.87 -67 .56 .48 -42 

-80 .62 .5 1 .44 .38 

8 1.35 1.07 -90 .79 .70 

1.16 -91 .76 .66 .59 

1.09 -86 .71 .62 -55 

10 1.64 1.31 1.11 -97 .87 

1.44 1.14 .97 .84 .75 

1.38 1.09 .92 .80 .72 

12 1.93 1.54 1.31 1.15 1.04 

1.73 . 1.38 1.17 1.03 .92 

1.67 1.33 1.12 .98 .88 

Table 3.-Total productiue felling and bunching per tree for machine type 2 time studied in the South during clearcutting 

DBH Trees per acre 

200 300 400 500 600 

inches .............................................. minutes------------------------------------------------------------ 

4 .28 ,222 .19 .17 .16 

.22 .18 .15 -13 .12 

.20 .16 .14 .12 .ll 

6 .37 .30 .26 .23 .21 

.31 .25 -22 .19 .r7 

-29 -24 .20 .18 .16 

8 .46 .38 .32 .29 .26 

.41 .33 -28 .25 .23 

.39 .31 .27 .24 .22 

10 -56 .45 .39 -35 .32 

.50 -128 -35 .31 .28 

.48 .39 .33 .30 .27 

12 -65 .53 .46 .41 .37 

.59 .48 -41 .37 .33 

.57 .46 -40 .36 .32 
T&fe 4.-Total producdiue felling and bunching time per tree for machine type 3 time studied in the South during clearcutting 

DBH Trees per acre 

200 300 400 580 600 

inches ---------------------------------------------- minules------------------------------------------------------------ 

4 .41 .31 -24 .20 .17 

.35 -26 .20 .16 .14 

.33 .24 .19 -15 -12 

6 -53 .4 1 -34 .29 .25 

.47 .36 .30 -25 -22 

'45 .35 -28 .24 .20 

8 .65 -51 .43 .38 2-33 

.59 .46 .39 -34 .30 

.57 .45 .38 .32 .29 

10 -77 .62 .52 -46 .42 

.71 .57 .48 '42 .38 

-69 .55 -47 .4 1 .37 

12 .89 -72 -62 .55 .50 

.83 .67 -58 .51 .46 

.81 .fj6 .56 -50 -45 

Table 5.-Total productive felling and bunching time per tree for machine type 4 time studied in the South during elearcutting 

DBH Trees per acre 

200 300 400 500 600 

inches .............................................. minutes------------------------------------------------------------ 

4 .26 .24 .23 .22 .22 

.23 .22 .21 .20 .20 

.22 .2 1 -20 -20 -19 

6 -29 .27 .26 -24 .23 

-26 .24 .23 .22 -22 

.25 .24 .22 ,252 .21 

8 -32 .29 .27 -26 .25 

.30 .27 .25 .24 .23 

-29 .26 .25 .24 -23 

18 -35 .32 .29 .28 -27 

.33 ,229 .27 .26 .25 

.32 -29 .27 .26 .25 

12 .38 .34 .32 -30 -29 

.36 -32 '30 .28 .27 

.35 '31 -29 .28 '26 
SUMMARY AND CONCLUSIONS 

During the summer of 1978, four types of drive-totree rubber-tired feller bunchers were time and production studied of five clearcut hamesting operations 

in the South. A total of 674 accumulation cycles were 

recorded along with the environment in which they 

were working. Individual time elements within cycles 

were analyzed separately. In general, the four machine types, each with different operators, were found 

to have different production rates. Position and 

shearing time per tree was found to be constant for 

each machine and operator combination except for 

type 3 which was significantly influenced by DBH 

and trees per acre. Moving time was significantly affected by DBH, trees per acre, and basal area in the 

accumulation as well as machine types. Machine 

types 2 and 3 had similar move times. Dropping time 

per tree was significantly influenced by accumulation 

size and machine type. After combining all time 

element equations, the total productive felling and 

bunching time per tree increased with increasing 

DBH and distance between trees and decreased with 

larger accumulations. Machine types 2 and 4 processed trees in the shortest time and type 1 was the 

slowest machine/operator combination, 

In conclusion, data taken from the operations observed is represented very accurately by the regression models developed. Since only one machine 

type was duplicated with more than a single operator, 

operator effect may bias the results presented here. 

Additional studies should be made of other operators 

on these same machine types to properly evaluate 

the machine" capabilities. In additional studies, efforts should be made to cut trees up to and above the 

machines' stump diameter limitations to identify the 

effects of these extremes. Species in addition to pine 

should be incorporated, Also, more variety in slopes 

and stand densities should be included in the sample, 

Future studies also should involve the other eategories of feller bunchers such as crawler drive-to-tree 

and swing-to-tree versions. 

LITERATURE CITED 

Cunia, T. Dummy variables and some of its uses in 

regression analysis. Presented at IUFRO subject 

group S4.02 meeting; 1973 June 25-29; Nancy, 

France. 1973. 106 p. 

Lanford, B. L. Projection of forest stand tables based 

on successive measurements of permanent plots. 

Syracuse, NU: College of Environmental Science 

and Forestry; 1975.438 p. Dissertation. 

Lanford, B. L.; Haver, 6. F. Production tables study 

volume 4: Analysis of production study data for 

the South. American Pulpwood Association Harvesting Research Project. Atlanta, GA; 1973. 

123 p. 

Taras, M. A.; Clark, A. 111. Above ground biomass 

of loblolly pine in a natural, uneven-aged sawtimber stand in central Alabama. Tappi, Forest 

Biology Conference; 1974; 107-1 16. 
Appendix 
Study Area Report Instructions 

Purpose: To record tree and slope infomation on a test plot. 

Procedures: Test plots will be selected based on consistency of harvesting conditions and desired results for 

the test. The width wil be determined by the natuml swath of the cutting machine plus approximately 10 

feet on the sides of the rectangular plot. The length of the plot will be determinzd by the logging conditions 

in question but it is usually 100 to 200 feet plus the 10 feet of buffer at the beginning and end. The swath 

boundary will be flagged and all trecs in the plot 3 incbtss DBW (2.6 inches) and greater for both pine and 

hardwood will be tagged with a number on a keypunch card. 

NOTE: Care must be taken 2-0 measure all trees tngged and that all trees are tugged. The base or Y Line 

should be along the left side of the plot making most X measurements positive, The down tree measurements 

of stump diameter, elear bole, height, and diameter of largest limbs will be taken after the plot has been cut. At 

least 20 sets of down tree readings should be taken on each plot. 

Form Entries: 

Data: Month, day, and year the plot was installed. 

Study No: A unique number assigned to each study. 

Location: County and State where study is taking place. 

IS Crew: Initials of time study crews; the first being the crew leader. 

Contractor: Name of the contractor (or Company Crew) being studied. 

Bearing: The 360" reading from magnetic north along the Y and X directions. 

Plot No: A unique number assigned to each plot of a study. Numbers reset to one for each new study. 

Tree Na: A unique number for each tree in a given study; reset the trce count to one at the start of a new 

study. 

DBH: Diameter at breast height (4.5 feet). 

SP: A code indicating the tree species. 

Y Dist: The slope distance in feet along the base line from the start to a point perpendicular to the tree in 

question; use a penta prism to locate this point. 

X Dist: The perpendicular slope distance in feet from the base line to the center of the tree. 

Slope % : Slope readings will be taken at the start of every 50 feet along the base line; one along the Y direction and one along the X direction. Unless a tree falls exactly on this point no tree information will be recorded. 

Stump Dia: The outside bark diameter of the butt of the tree. 

Clear Bole: The distance from the stump to the first limb that must be severed. 

Height: Generally the total height of the tree, 

Llia. Largest Limb: The cross section diameter of the largest limb. 
FOREST HARVESTING ANALSSIS RECORD 

STUDY AREA REPORT 

PdGE OF - 

DATE PLOT NO. STUDY NO LOCATION 

M0 DGI YR COUNTY STATE. 

TS CREW lNIIlALS CONTRACTOR PLOT BEARINGS 

Y X 

--L * .-L.+ - ,i 23 3 1 4 2 4 3 

STUMP CLEnR 

orn BOLE 

Utri 

HEIGHT CARGFST 

LIMB 

Y DIST. X DIST, 
Feller Buncher Cycle Report Instructions 

Purpwe: To record time and production information on feller bunchers. 

Procedures: After a test plot has been laid out, the feller buncher operator is instructed to work within the 

flagged swath, The machine is timed in the smallest elements possible. Tree numbers are recorded along with 

the accumulation and bunch numbers. Slope, felling quality, brush, obstacles, and bagginess should be estimated for each bunch. If a tree does not have a number, DBM should be estimated, 

Form Entries : 

Date: Month, day, and year the recording took place, 

Time of Day: The 24-hour clock time at the beginning and end of the test. 

Study No.: A unique number assigned to each study. 

Location: County and State where study is taking place. 

TS Crew: Initials of time study crew; the first being the crew leader. 

Contractor: Name of the contractor (or company crew) being studied. 

Function: A six digit code describing the beginning and ending points of the operation being studied. Reference APA-HRP System Flow Diagram. 

Mach. No.: A unique number assigned to each machine studied. 

Plot No.: A unique number assigned to each plot of a study. Numbers reset to one for each new study. 

Time: The time in minutes and seconds necessary to carry out some action. 

Code: The number referring to the action timed. 

NOTE : The space between Time and Code is for describing the action literally. 

Tree No. : The number ptaced on the trees in the plot; it should be recorded on the same line as the severing 

action. If more than one tree is cut during an action each should be recorded on separate lines without any 

other data, i.e. no time or code information. 

Accum. No.: A count of the accumulations a machine puts in. a bunch and it resets to one for each new 

bunch. Record it on the firsl; line referring to that accumulation. An accumulation may be one or more 

trees. 

Bunch No.: A unique count within a study referring to a separate pile of trees. Each bunch is to be tagged 

with its number when completed. The counter resets to one for each new study. 

DBH: To be recorded after the test is over from the Study Area Report. 

Slope % : Direction of travel; sectors defined in 45" intervals I-Up, 2-Upside, 3-Side, 4-Downside, 5-Down. 

Felling Quality: Orientation of the wood in reference to subsequent skidding. 1-Directional, 2-Non-Directional. 

Brush: Distance of unobstructed vision. 

1-Can see as far as terrain allows or greater than class 2. 

2-Can see less than 2 chains but greater than class 3. 

3-Can see less than 1 chain but greater than class 4. 

4-Can see less than $5 chain. 

Obstacles: The number of obstacles other than tagged trees avoided while cutting a bunch. 

Bagginess: A measure of tractive capability. 

1-Dry or wet but firm; excellent traction, sinkage 0-1". 

2-Dry or wet with loose or soft soil; good traction, sinkage 2-6". 

3-Slippery conditions causing poor traction, sinkage 7-1 1". 

4-Boggy conditions with very poor traction, sinkage 12" 4- . 
FOREST HARVESTING ANALYqIS RECORD 

FELLER BUNGHER CYCLE REPORT 

PAGE- OF - 

DATE TIME OF DAY STUDY NO. LOCATION 

MO DAI YR BEGIN EM0 COUNTY STATE 

TS CREW INtT1ALS CONTRACTOR FUNCTION MACH. NO, 

BUNCH 

WIDTH LENGTH 

_1 

L 

I._ 

1 

L 

SLOPE 

X 

ijL 

1 

1 

L 

I 

-L 

79 

A I 

OBSTd- BOGGI- DIR BRUSH CCE NESS 

---- 6 4 

---- 
Equipment Specifications 

Brand and Model of Carrier 

Horsepower 

Wheelbase 

Overall length 

Width 

Ground clearance 

Weigllt (fbs. ) 

Tire Size 

Hydraulic capacity 

Brand and Model of Shear 

Tree capacity at stump 

Accumulator arm 

Weight (lbs.) 

Shear cylinders 

Number 

Size 

Flow capacity 

Pressure 

Franklin 170 XL N 

117 

10' 0" 

18' 3" 

8' 7" 

1' 7" 

21,310 

23.1 x 263 Logger 

Tandem pumps 

Steering 25 GE"M 

@I750 psi 

LiftlTilt 45 GPkf 

@2500 psi 

Morbark 15" 

15" softwood & 13" 

hardwood 

Yes 

2300 

2 

5 ?hP' 

35-40 GPM 

2100-2600 psi 

John Deere 544 

94 (net flywheel) 

7' 10yzw 

21q6"' 

7"4" 

2y2fe 

1'9,530 

23.1 x 26 Logger 

Tandem pumps 

Steering 28.6 EPM 

@2250 psi 

Lifti'Tilt 45.5 GPM 

@2250 psi 

Morbask 15" 

15" softwood & 13" 

hardwood 

Yes 

2300 

2 

5%" 

35-40 GPM 

2 100-2600 psi 

John Beere 544 

94 (net flywheel) 

7'l1054" 

21' Ci*' 

7' 4" 

1' ,y&?, 

11,530 

23.1 x 26 Logger 

Tandem pumps 

Steering 28.6 CPM 

@2250 psi 

LifLiTiIt 45.5 CPM 

@2250 psi 

Rome 20" 

20'" 

2 

6" 

Unknown 

Unknown 

Hydro Ax 511 

117 

9. 0" 

19"" 

80"" 

1" 5" 

17,530 

23.1 x 26 Logger 

Tandem pumps 

Steering 196 GP&f 

@I800 psi 

tift/Tilt 24 GP-M 

a2250 psi 

Morbark 20" 

2OfP 

4 

5XtP 

40-50 GPhl 

2500-3800 psi 
Lanford, 53. L.; Sirois, D. L, Drive-to-tree, rubber-tired feller 

buneher production studies. Gen. Tech. Rep. SO-45, New 

Orleans, LA: U,S, Department of Agriculture, Forest Service, Southern Forest Experiment Station; 198%. 14 pe 

Presents time study methods rand equations for estimating 

production of rubber-tired feller bunehers during final 

hamrest of southern pine stands. 

Additional keywords: Time study, feller buncher, harmvesting.