Kallio, E.

Lothner, D.C.

Marden, R.M.

English

DigitalCommons@USU

Utah State University DigitalCommons@USU Aspen Bibliography Aspen Research 1974 Weight-volume relationships of Aspen and winter-cut Black Spruce pulpwood in northern Minnesota D.C. Lothner R.M. Marden E. Kallio Follow this and additional works at: https://digitalcommons.usu.edu/aspen_bib  Part of the Forest Sciences Commons Recommended Citation Lothner, David C.; Marden, Richard M.; Kallio, Edwin 1974. Weight-Volume relationships of Aspen and Winter-Cut Black Spruce Pulpwood in Northern Minnesota. Research Note NC-174. St. Paul, MN: U.S. Dept. of Agriculture, Forest Service, North Central Forest Experiment Station This Article is brought to you for free and open access by the Aspen Research at DigitalCommons@USU. It has been accepted for inclusion in Aspen Bibliography by an authorized administrator of DigitalCommons@USU. For more information, please contact digitalcommons@usu.edu. i! - RESEAIRCI-I NOTE NC-174................... __ n•NORTH CENTRAL FOREST EXPERIMENT STATION, FOREST SERVICE--U.S. DEPARTMENT OF AGRICULTURE_ _...- " FolwellAvenue,St.Paul,Minnesota55101 1974": v'WEIGHT-VOLUMERELATIONSHIPSOF ASPEN AND WINTER-CUTBLACK SPRUCE PULPWOODIN NORTHERNMINNESOTA, ' David C. Lothner, Associate Market AnalystRichard M. Marden, Principal Forest Products Technologist... Edwin Kallio, Principal Market AnalystDuluth, Minnesota(Office maintained in cooperation with the University of Minnesota-Duluth)ABSTRACT. seasonal ve_gbt-volu=e reZa_on- _n norcbern M_esota is be_n8 purchased inI sh_ps were determined for rough (bark on) tree-length form, which makes _t _mpractical" aspen and black spruce 100-1nch pulpwood to use conventional volume measurements._hat was del_vered _rlth_n 1 week after cut-t.lng"Innorth n M_nnes ta during 1971-72 For aspen (Populus tremuloides M_chx )• • 5)N For .asPen, _he weight of wood and bark per we developed monthly and seasonal conversioncubic foot of wood averaged 56 pounds in factors for summer (June-October) and forthe w_nter and' 61 pounds in the summer, winter (November-March) of pounds of wood and• This relationship f r winter-cut black bark per cubic foot of w od (table 1). Thesei spruce was approximately 53 pounds, factors are for rough 100-inch wood (bark on)delivered to the mill w_thi 1 eek afteOXFORD:526.1:527:I74.7 Picea mariana (776). cutting. Although we did not cord scale theKEY WORDS: welgh_ scallng, Popu/us tremu- loads, we converted the seasonal conversionL_ides_ Piuea mu_iana, factors into pounds per Unit I for a range of• cubic feet of wood per u_it.Only a seasonal factor for winter(November-March) is given for black spruceP P L I C A T I 0 N (Picea mariana (M_11.)B.S.P.) because most. of the black spruce cut for pulpwood in• .Those involved _n the Minnesota pulp- Minnesota grows in swamps that are bestwood market are confronted with a need for logged only after freeze-up. However, someinformation on welght-volume relationshlps loggers do cut black spruce pulpwood duringof pulpwood specles in northern Minnesota the summer but are unable to transport itbecause weight scaling is fast becoming until the swamps freeze. Pulpwood that has" • been cut for more than a month before de-recogn_ze_ as a more efficient measuringtechnlque Only a few Minnesota firms put- livery is usually stick scaled or purchased• I!chase pulpwood by weight at present, but we on the basis of a speclal "seasoned weight.can expect an ever-lncreaslng amount of woodto be Weight scaled in the future. All gov- As illustrated in figure i, springernmental agencies in Minnesota now have the breakup (April and May) and September andauthority to sell timber stumpage by weightwhere consumers have the facilities forwelghlng, and many pulpwood producers are 1A Unit = _ ft (_ ft) 8._$ ft = ]_$.$taking advantage of this opportunity. In ft 3 which is an e_pression of stacked volumeadd_tlon, an increasing amount of pulpwood co_only used in Minnesota.MAINT,&INED IN COOPERATION WITH THE UNIVERS!TY OF MINNESOTA/,,. . -• .,, ,/,.'c- • _ ; " "_ _h __ii_Table l.--Weight of wood and bark per cubic 8 64foot o_ aspen pulpwood by month and _ 63 - •.... o" 8_C(,801'Z*SUMMER _ 62: : Wood and bark per ¢u. _ 61Honth : Loads : ft. of wood _: " m 60: : Average : Range 2 _ 59 BNo. Lbs. Lbs. _ 5sJune 21 56.30 54.20-58.40 _ 57July 16 55.22 51.99-58.45 _ 56 "Aug. 17 55.71 54.01-57.42sept. 17 55 89 54 27-57 50" " " Z 5 5 IOct. 13 57.34 55.05-59.63• o I I I I I I I I I I I IAve. 84 56.09 55.12-57.06 Ju._JuLyAUO SEPTOCT ,OV OEC JA, F_B_,R AP._,V" MONTH, WTNTER Figure l.--Mean value of pounds of wood andbark per cubic foot of wood for lO0-inchNov. 9 62.15 60.21-64.10 aspen pulpwood delivered within 1 weekDec. 17 61.27 58.70-63.83 after cutting.Jan. 25 61.78 60.21-63.35Feb. 18 59.78 58.14-61.42 user's deliveries are considerably greaterMarch 20 58.72 56.51-60.93 during certain months than during others.Ave. " 89 60.74 59.86-61.61We recognized that stick-scaled esti-IAll pulpwood was cut during the mates are affected by judgment and procedureperiod Jamwn_ 19?l-March 1972, except differences among scalers, buyers, and gov-during the spring breakup months of April ernment agencies as well as by differencesMay, within a ?O-mile radius semi- in stick straightness, piling techniques, andCircle south of International Falls, Minn., distribution of stick diameters. Past ex-delivered within _ week after cutting, perience has shown that a volume of a unit2Calculated at a 95percent confi- of aspen pulpwood can range from 74 to 84denceinterval, which indicates that cubic feet and that a unit of black spruceauthors can be 95 percent certain that pulpwood can range from 78 to 88 cubic feet.these ranges include the true means. Because of these differences, we developedconversion factors in pounds per unit forthe range of volumes shown in table 2.October are the transition periods in which Users can select the factor that best fitsthe rate of change in weight per volume is their operations or compromise on angreatest. This was the basis for grouping alternative.months to obtain the summer and winterconversion factors.For aspen, the winter conversion D 0 C U M E N T A T I 0 Nfactor was 60..74 pounds of wood and barkper cubic foot of wood. The summer conver- Weight scaling of pulpwood (and occa-sion.factor was 56.09 pounds of wood and sionally of saw logs and other timber pro-bark per cubic foot of wood. ducts) has gained acceptance in many areas.... of the United States and Europe. SomeFor 'black spruce, the winter conversion advantages of weight scaling have beenfactor was 52.78 pounds of wood and bark per reported: good wood quality is encouragedcubic foot of wood. (Barienbrock 1959); system is more equlta-between buyer and seller (Eggen 1967);In deriving these seasonal conversion helps solve bookkeeping problems (Chamber- ,factors, we assumed that an equal volume of laln 1958); reduces total scaling time andpulpwood is delivered each month of the sea- improves accuracy (Muller 1958); pulpwoodson. However, a different prorating scheme inventories are more easily maintainedcould be used to develop seasonal conversion (Taras 1956); and promotes safety infactors from the monthly averages if a scaling (Guttenberg 1967).Table 2.--seasonal weights per Unit for March 1972. Aspen was sampled each monthalternative number of cubic feet of aspen except during spring breakup (April and May).and black spruce pulpwood I Only the black spruce sample loads delivered- ASPEN during January through March both in 1971 and1972 were used in the analysis because there: Volume of : Wood and bark per unit was not a sufficient number of loads deliv-Seas°n2 wood/unit Average : RangeS ered during the other months to ensure a°e • Istatistically reliable sample.Cu. Ft. Lbs. Lbs.From a presample taken in 1970, we hadS,,_er 76 4,263 4,189-4,337 determined that approximately 16 loads aWinter _ . 4_616 4,549-4_682 month should be measured to allow for no moreS,,_er 78 4,375 4,299-4,451 than a 2 percent error in the average season-Winter " 4,738 4,669-4,806 al weights of wood and bark per cubic foot ofSummer 80 4,487 4,410-4,565 wood at the 95 percent confidence level.Winter 4_859 40_789-4_929 J Sampling was spread through each month asS,mer 82 4,599 4,520-4,679 much as practicable.Winter 4,981 4,909-5,052 JSummer 84 4,712 4,630-4,793 Load weights were obtained by weighingWinter 5,102 5,028-5,175 the loaded truck and unloaded truck on a• BLACK SPRUCE 50-ton platform scale at the Boise-Cascadewoodyard in International Falls, Minn. Afterthe initial weighting (loaded), the truck wasWinter 78 4,117 4,044-4,19080 4,222 4,148-4,298 positioned fox photographing.82 4,328 4,252-4,405 Three sticks were randomly selected and• 84 4,434 4,355-5,512 removed from the top of each load after it86 4,539 4,459-4,620 was photographed. The sticks were identified88 • 4,645 4,563-4,727 (load and stick number) and their lengthsIAll pulpwood was cut during the period were measured to i/I0 foot to provide a checkJanuary 1971-March 1972, except during the on adherence to the 100-inch length specifi-spring breakup months of April and May, cation. A disk (i inch thick) was cut fromwithin a ?O-mile radius semicircle south of the middle of each stick on which measure-International Falls, Minn., and delivered ments were taken--outs/de bark (d.o.b.) andwithin 1 week after cutting, inside bark (d.i.b.)--and averaged (to I/I02Summer: June-October. Winter: For inch) to use in calculating the proportionaspen, November-March; for black spruce, of volume in wood and in bark. These disksJan_.March. were cut into half sections from which theSCalculated at a 95 percent confidence bark was peeled so that the wood and barkinterval, which indicates that authors can could be weighed separately (to i/i0 gram).be 95 percent certain that these ranges The wood and bark from each section were theninclude the true means, bagged together for later use in determiningHowever, Hall and Rudolph (1957) did seasonal variations in moisture content.indidate that weight scaling works to thedisadvantage of sellers who delay selling Photographic slides of each section ofJack pine pulpwood after it is cut. This, the pulpwood loads were projected on a rear-of course, is attributed to the loss of projection screen. 2 We measured the pulp-moisture from the wood that occurs soon woo_ sticks on the projected image andafter timber is felled. Moisture content applied the following volume formula:of standing trees can also vary by seasonsand geOgraphlc locations, as well as cli- _D_2mat£c conditions and soils. _ _ i00V = = 0.04545 D2Study Methods 144(12)We weighed and measured 2 173 truckloads where V = volume in cubic feet, and D -of aspen pulpwood and 47 truckloads of black diameter outside bark to the nearest i/i0spruce pulpwood from January 1971 through inch.All aspen sticks 12 inches or greater2Details of procedure are described in d.o.b, were measured but only every fifthKallioet al. (1973). aspen stick among those less than 12 inches3¢ 4d.o.b, were measured. 3 By measuring only Discussionone out o'f flve of the smaller d.o.b, sticks,we obtained a higher degree of statistical Our research results show a significantaccuracy than we would have obtained by difference in weight per unit volume betweenmeasuring all of these sticks because of summer and winter months for aspen pulpwoodthe larger number of aspen loads. However, delivered to the woodyard within I weekwe had to measure all of the sticks in the after cutting. Because our black sprucesmaller number of black spruce loads to data were confined to the January throughavoid theaddltional variation associated March period, a comparison between a summerwlth subsampling, and winter season was not possible. How-ever, our conversion factors for bothMonthly ratio estimates _ were used for species represent a given period of timeestlmating pounds of wood and bark per cubic and one location (an approximate 70-milefoot of wood and bark. (See Chap. 6, Cochran semicircle around International Falls).1963 _) Weather conditions do vary from year tO• year. In addition, we have no evidenceThe d.o.b, and d.i.b, measurements from that our seasonal weight-volume factorsthe disks were used to calculate the wood would not vary from one location to another.proportion to total (wood plus bark) cubic Therefore, checks should be made on year-foot volume as follows: to-year variations as well as locationn differences.7 d.i.b. 2 LITERATURE CITEDi=lProportion wood =. n Barlenbrock, R."R. 1959. Buying pulpwoodr d.o.b. 2 by the pound (Mead Corp.). Paper pre-• i=l sented at a technical committee meetingof the Amer. Pulpwood Assoc., Sept. 1959,The average wood proportlon (all truckloads Duluth, Minn.combined) was applied to obtain the conver- Cochran, Wi11iam G. 1963. Sampling Tech-slon factor as follows: niques. Ed. 2, Chap. 6. New York: JohnWiley and Sons, Inc.PoUnds of wood and Chamberlain, C. R. 1958. Purchasing pulp-bark per cubic foot wood by weight Paper presented at aof wood and bark Pounds of wood• technical committee meeting of the Amer.= and bark per Pulpwood Assoc. Jan. 7-8 1958 PortlandProportion wood cubic foot of • ' ' ' 'Maine.wood Eggen, Roy W. 1967. Weight measurement ofThe average wood proportion obtained pulpwood. Wood Meas. Conf. Proc. Tech.from disk measurements from all of the Rep. 7, Univ. Toronto.asPen loads was 88.2 percent. This figure Guttenberg, Sam. 1967. Economic implica-Was used in the 1971-72 data analysis to tions of weight scaling. South. Lumber-develop monthly and two seasonal conversion man 214 (2663) : 33-34, 36.factors of PoUnds of wood and bark per cubic Hall, O. F., and T. D. Rudolph. 1957.foot Of wood (table i). Weight loss of stored jack pine pulpwood.' Minn. For. Notes 57. Sch. For., Univ.For black spruce, the average propor- Minn.tion of wood by volume obtained from the Kallio, Edwin, David C. Lothner, and Richarddisk measurements was 92.8 percent. This M. Marden. 1973. A test of a photographicfigure was used to develop the winter con- method for determining cubic-foot volume ofversion factor, pulpwood. USDA For. Serv. Res. Note NC-155,3 p., illus. North Cent. For. Exp..Stn.,3The 'first stick measured was chosen St. Paul, Minn.r_omly among the first five sticks with a Muller, George. 1958. Weight scaling ofd.o.b, less than 12 inches, hardwood pulpwood. Paper presented at ajoint meeting of the Northeast Technicaln . Committee of the Amer. Pulpwood Assoc., ,• Z load weights Jan. 7-8, 1958, Portland, Maine._R_tio estimate = i=1 . Taras, Michael A. 1956. Buying pulpwoodn by weight as compared with volume measure.r load volumes Stn. Pap. 74. Southeast For. Exp. Stn.,/=1 Asheville, N.C.4_, U.S. GOVERNMENT PRINTING OFFICE: ]974-667-046/5 Region 6/• ,J_NORTH CENTRAL FOREST EXPERIMENT STATION _:_FOREST SERVICE--U.S. Department of AgricultureCORRECTION NOTICE ........,_ ._RECT ION.... BI_or_hner, David C., Richard M. Marden, and Edwin Kalllo.1974. Weight-volume relationships of aspen and winter-cutblack spruce pulpwood in northern Minnesota. USDA For. _Serv. Res. Note NC-174, 4 p., illus.Please make the following corrections in Research Note NC-174"The second sentence of the Abstract should read:•"For aspen, the weight of wood and bark per cubic foot averaged• 61 pounds In the winter and 56 pounds In the summer."•i _ u -,, , T-_- _ i , ,- _ r _ u _l r: "__ ..... : _, 0 "--• , i_;: i_ai;II_ ""..... :_i_;;_@- " " ':i__:_ ':..... ,

Weight-volume relationships of Aspen and winter-cut Black Spruce pulpwood in northern Minnesota

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Weight-volume relationships of Aspen and winter-cut Black Spruce pulpwood in northern Minnesota

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