Shrinkage of wood in ship construction

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Material Information

Title:
Shrinkage of wood in ship construction
Series Title:
Report ;
Physical Description:
6, e p. : ill. ; 26 cm.
Language:
English
Creator:
Teesdale, L. V
Forest Products Laboratory (U.S.)
University of Wisconsin
Publisher:
Dept. of Agriculture, Forest Service, Forest Products Laboratory
Place of Publication:
Madison, Wis
Publication Date:

Subjects

Subjects / Keywords:
Wood   ( lcsh )

Notes

General Note:
Cover title.
General Note:
"In cooperation with the University of Wisconsin."
General Note:
"December 1942."
Statement of Responsibility:
by L.V. Teesdale.

Record Information

Source Institution:
University of Florida
Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 029301055
oclc - 223415691
System ID:
AA00025971:00001

Full Text




SUINIAGECT Or WOO IN

SUIP CONSTIUCTICN

December 1942


















UN.IV O) F IL IUB
DCUMENT DEPT



U.S. DEPOSITORY


NO. IP1424




UNITED STATES DEPARTMENT OF AGRICULTURE
FOREST SERVICE
FOREST PRODUCTS LABORATORY
Madison, Wisconsin
In Cooperation with the University of Wisconsin







S1F.DTKGDI OF 'TOOfl IN' SHIP C01\STRIJCTIO1'


By


Senior Engineer





Wood, like many other materials, shrinks as it loses moisture an& swells as
it absorbs moisture.

')hile green, freshly cut logs may contain water ranging in quantity from 30 to 300 pDercent, based on the weight of the oven-dry wood, the removal of only the last 25 or 30 percent of this moisture content 1's the effect of shrinking the Wood upon drying-, and since wood in service is never totally dry, the possible shrinkage effect falls within a relatively narrow range of moisture cont ent.

later is held in the wood in two distinct ways -- as imbibed water in the walls of the wood cells, and as free water in the cell cairities. 7.hen wood. begins to dry, the free water leaves first, followed by the imbibed water. The fiber-saturation point is that stage in the drying or wetting of~ wood at which the cell walls are saturated and the cell cavities are free from water. For most woods, this point is between 25 and 30 percent moisture content.

The dimensions of wood change only when the moisture content dro-ps below the fiber-saturation point. Since in seasoning green wood, tlie surface dries more rapidly than the interior and reaches the fiber-saturation point first, shrinkage may start near the surface of a piece while the average moisture content of the board or timber is still considerably above the fiber-saturation point. Wood shrinks most in the direction of the annual growth rings (tangentially), about one-half to two-thirds as much across these rings (radially), and very little, as a rule, along the grain (longitudinally). The combined effects of radial and tangential shrinkage on the shape of various sections in drying -from the green condition are illustrated in figure 1. 11hen a board or portion of a board is cross-grained, the lengthwise shrinkage resulting from a combination of crosswise and longitudinal shrinkage is greater than that in a straight-grained piece. Shrinkage is usually. ex-oressed as a percentage of the green dimensions, which represent the natural size of the piece. Table 1 gives the range in shrinkage in different directions for most of the commercially important native spocies.





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Tabe I.--Range in average shrinkage of a number of native species of wood.

: From green : From green to air-dry con: to oven-dry : dition (12 to 13 percent Direction of shrinkage : condition : moisture content)

----------------------------Percent of : Percent of
green Mize : green size

Tangential .................: 4.3 to 14 : 2.1 to 7
Radial ...................... : 2 to g-5 : 1 to 4.2
Longitudinal ................ : .1 to .2 : .05 to .1
Volumetric .................... : 7 to 21 : 3.5 to 10.5



Shrinkage in drying is proportional to the moisture lost below the fibersaturation point. Approximately one-quarter of the total shrinkage possible has occurred in wood seasoned to a moisture content of 28 to 20 percent, about one-half when the moisture content is 12 to 13 -percent, atid about three-fourths in lumber kilh dried to a moisture content of about 6 to 7 percent. Wood is a hygroscopic substance; that is, it has'the'-broperty of absorbing or giving off moisture according to the conditions of the surrounding atmosphere. When wood is subjected to a constant temperature and relative humidity, it will in time come to a definite moisture content determined by the prevailing humidity, which is called the equilibrium moisture content. This relationship between tie moisture content o' w,!ood and the surrounding atmospheric conditions is shown on figure 2. Atmospheric temperatures are constantly changing, both during a single day and with the seasons. The relative humidity also fluctuates. The rate of exchange of moisture between wood and atmosphere is,however, comparatively slow, and the equilibrium moisture content is based on the average humidity prevailing over an'extended period rather than on changes during veryir short periods, even 'though fluctuations may then be through a wide range. Thickness of the wood is also a factor, the moiscbre content of thin material reacting to atmospheric changes more rapidly than thick material.

Surface coatings retard the rate of exchange of moisture between the wood
and the atmosphere. All wood used in ships above the water line, as well as interior parts not exposed to water, will in time attain a moisture content in equilibrium with the atmospheric conditions surrounding.it. This moisture content may vary more or less according to changes in atmospheric conditions
and exposure to wetting, but will in general remain consistently below the fiber-saturation point. Exterior planking below the water line that is exposed to the vessels interior atmosphere will have a moisture content on the inner face that is below the fiber-saturation point, while its outer face
when in contact with the water will be at or above the fiber-saturation point. Deck boats and other types of small water craft that are kept out of the water most of the time will attain a moisture content consistently below the fiber-saturation point, probably as low as 10 percent at times.

M1imeo. R1424 -2-






Hence, if wood intended for ini at a moisture content in accord ith its sece prospect of satisfactory performance without serious changes in size cr dAtortion of section. On the other hand, if green or partially seasoned material is used under conditions such tiat further drying will take Taoe after installation, some shrinkage may be expected.

In general, the heavier species of wood shrink more across the grain than the lighter ones. Heavier wood of the same species also shrinks in this direction more than lighter wood. When freedom from shrinkage is a more important requirement than hardness or strength, as, for example, in the planking of small boats, a lightweight species should be chosen. When it is important to combine ha-dness or strength with low shrinkage, such as in the dase of treenails, some spe.ies like black locust is to be preferred. Average tangential, radical, and voluumetric shrinkages for individual domestic specibs when dried from the green condition t6 various moisture-content valued are given in table 2. The average tangentiali radial, and volumetric shrinkage for a limited number of tropical s'Tecies when dried from the green to an oven-dry condition is given in table 3. This table is included for comparative purposes only, since very few tropical species are available to United. States boat builders due to wartime conditions,

Theoretically, and for practical purposes, the normal moisture contentshrinkage relation may be considered a direct one, from zero shrinkage at the fiber-saturation point to maximum shrinkage at zero moisture content. Actually, however, the relationship is similar in boards to the curves in figure 3. The curves re-present average values, and the shrinkage of an individual board may, of course, be above or below the average amount indicated.

Changes in moisture content in seasoned rood, such as those cause& by seasonal variations in relative humidity, produce changes in dimension that are proportional to the moisture-content changes. For example, assume that a piece of flat-sawed southern yellow pine sheathing at 12 percent moisture content loses 5 percent of its moisture. The shrinkage curve (marked "tangential") indicates that the shrinkage in width from the green condition to 7 percent moisture content would be 5 percent, and that from the green condition to 12 percent moisture content would be 3-1/2 percent. The difference of 1-1/2 percent Is the shrinkage in the width of the board due to the 5-oercent loss in moisture. These curves re-resent average values, and the shrinkage of an individual board may be somewhat below or above the indicated amount,

Moisture pickup below the fiber-saturation point causes expansion or swelling just as moisture loss causes shrinkage. For instance, reversing the above example, a pickup of 5 percent in moisture content from 7 to 12 percent would cause a flat-sawed board to swell about 1-1/2 percent of the green width.

Where swelling is restrained during a cycle of moisture pickup, such as in the case of tightly fitted planking or decking, the surfaces tend to buckle or become deformed or slightly crushed at the edges. Upon redrying to the

Mimeo. R1424 -3-





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28

26

24 22

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SHfR/NKAGE ,PER CEN T OF GREEN 9//V/E NS/OH


'tgure }.--'typical moisture-shr'inkage ourvee. These cuirves are for
Doug~las-fir adz southern yellow pine and may be used for
estimating the amount of change in dimension that vill take
answus-r place with change in the moisture content of the wood.
-A
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6

4




0-
0 / 2 3 4 5 6 7 8 9 /0
SHRINKA GE (i'PER CENT OF GREEW 01MENSION)


Figure 3. --TypicaJl moistur s-shrinkage curves. These curves are for
Douglas-f ir and. southern yellow pine and may be used for
stimating the amount of change in dimension that wili take ZU-22049-F place with change in the moisture content of the wood.











AN6LE A97ER SWELLING OQIOIAIA 4 4AIC L E AA16L E A,-=7.R SHPIJVJrA


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PI&W* It.-OhoMes in am-Tod woa mxbw Gazood by abrimiage od vollUg.
(lot drom to scale.)






ri a isture content, such pieces will shrink and assume a dimension eh ls before swelling started, and the joint will open. Repea cycles of swelling and shrinking under pressure in the course of time c e the piece to become narrower. Tight recaulking when the joints are
opened by shrinkage will cayuse mcre rapid loss of dimension than would occur if the caulking is tapped in lightly. Moreover, seam composition should be of a trpe that will remain soft in service so that it can expand and contract as the wood shrinks and swells. Since the swelling and shrinkage are proportional to the width of the piece, it follows that the narrower the piece is the less the joint will open or close. "ith proper caulking, the joint can take up some of the expansion before the forces developed tend to deform the contact surfaces of the wood; hence, on the basis of shrinkage effects, narrow material gives better service than wide material.

EEcxosed decking, particularly if unpainted, is subject to very severe exposure and rapid moisture changes, hence, the width used is generally not more than one-third greater than the thickness, and often less. Planking contributes materially to the strength of the vessel and, within certain limits, the wider the plank is the greater are its strength properties. On the other hand, to prevent trouble from expansion, particularly above the water line, the width must be limited. Since the exposure is less severe than for decking and the material is invariably well protected with paint to minimize moisture changes, such planking can safely be wider than decking, and generally, the width is equal to three or four times its thickness.

Lifeboats, deck boats, utility boats, or similar types that are out of the water the greater part of the time should be constructed of material having
a moisture content that is at or slightly below that which they will attainin service. This means a moisture content generally not less than 10 percent and not more than 19 percent. To prevent rapid moisture changes, such boats should be well painted, inside and out. Aily further protection from sun and rain, such as boat covers, will minimize moisture changes and lengthen the useful life of the boat. When not in service, such boats should be supported at least a foot above the ground and should preferably be stored in open, well ventilated, unheated sheds, or covered to protect them from the sun.


Effects of Change of Moisture Content on Bent wood Members

The checks tIhat develop in bent members, such as ribs, frames, and similar parts, are largely the result of unequal drying but the stresses set up because of tne bending accentuate the checks to some degree. Heat in combiation with moisture tends to plasticize wood, hence stock intended for bending is heated with hot water or steam immediately before bending. The contained heat causes raid evaporation from the surface, thus setting up the first factor favorable for checking. As the drying progresses after the stock has cooled, any checks present maybe extended. Checking may be minimized by using stock having a moisture content of 15 to 20 percent. If the moisture content is 12 percent or less, the breakage during bending is likely to be more frequent than if more moisture were present.


7imeo R1424 -4-







Somne change of' shape of bent me-ibers that are~ not restrie may b x0ce with a change o"f moistu~re co-ntent. !Caetner restrained or not, such -oar develop corn-rlex interior stresses. because of moisture cha nges and resulin shrinkage. For example, assumne the frame to bCe semicircular. 'Then losseo moisture occurs the. radial dimension, being across the grain, tendsI to decrease, which in turn leads to decreases in the length of' the inner or outer arc, or both. The upset fibers in the inner arc also tend to sh'rin-k while there is little or no tendency ior the fibers in the outer arc to shrink. Consequently, if the -piece is not restrained the curvature tend-s to increase or closee the bend." (fg .If' it'is restrained so that no change in curvature can take rlace, a tension stress is develooeO -acrotss the grain (radially~i with comnression-stress in the outer arc and tension stress in the inner arc.

Oon-verselyr, an increase in moisture content results "in ra~dial qiwelln .and swelling of the upaet fibers of thie inner'arc, tend ing to "open" or decrease the curvature. If the -niece is restrained, from movement, thle -stresses develo-ned are the reverse of thioser caused. by shrinkage.

Breakage of bent members after the bending o peration --often after they have been installed. in th'-e boat -- is in 'some cases caused byr i'hrinkage s t resse s
ora obination of such- stress-es wIith soine weakness in tne piece, suich as localized etiago-nal -'rain, a concealed defect, ch-eckL or spI:lit, or P. par t i.una.etecte~l brep'k thept occnrree in enOdinj.


Shrinkage of Pln".ood

~~Tor'~~~al ita~t~rie woharetiely hil- strength and Pli -,ht shirinkFce -properties in the direction' of the gtain., Across the grain, however, the shrinkage is relatively 1higjt1 and. the strength nroert.- r is low. In :?l7-rwood with t'he ranof adjacent ,-lie'.-- 6rpenidicular, the lat~ra. slrinka;:-e of ad1acent plies is al-most completely restrainedi, a.,d the length and w-idth of'
TlProdynels, Pre hence only P~lightly affected by moist-Lre content changes. Th~e shrin-':age, in tne, thi7ckness o" the -lehwvr is unopposed, hence the roanel will shAriak in t1-ickness just as does normal wood.The shrinkage off a rlnooO. pnnel in the two 1>-teral directions will be the S=n of the 'ongitucinpl s1ri-;_-mge anOd the longitudinal compression assu~med by the -Plies. T'hios &irink age i-ill vary with the species, the ratio of nly thicknesses, the num'mJr of plies, .the character of the grain, and the combination of s- recieq. The avern47e 8hrinlKage obtained from several hunf;reC tests on a. variety,, of combinations, of spcisand. thicimiesses in bringing 3-p)ly wood. from the soaked. to the oven-dr-y condition was about 0*.45 percent parallel to the face grain anO, 0.67 -percent norpendicular to the face grain. The species incl-mdeO in the tests were basswood, birch, black walnut, chestnut, elm, mahogan7-,, banishh cedar, spruce, sugar male, iweetgmm, tu-pelo, and, yrel lowTjO-,la r.

M~imeo. R1424 -5-







Prom this it is seen that the shrinkage of plylood is only about one-tenth as great as that across the grain of an ordinary board. The total lateral shrinkage of a 1-1/2-inch southern yellow pine board with two 1/12-inch sweetgum face veneers was only 1 percent, or about one-seventh of the normal shrinkage. The values given for shrinkage are based on a moisture content ranging from a green or soaked condition to an oven-dry condition. In service the change in moisture content will be much less, generally not more than enough to cause a dimensional change of one-fourth to one-hlf of that
represented in the tests.











































Mimeo. 142~4 -6-







Table 2.--Shrnkae values for comeroially Important woods grown in the United States.


Shrinkage percentt of dimension when green) f:, s green to -18 or 20 s 12 or 13 6or 7 Oven dried to
percent moisture1 percent uoistureZ percent moisture1 : 0 percent moisture
speule* I (estimated values) (estimated values) (estimated values) 2 (test values)
--------------------------------------------.----...........................................
:Radial : Tan. Volu. :Radial Ta- : Volu- :Radial t Tan- : Volu- :Radial : Tan- ; Volu: gentiallmetrio gential : etric 2 gentilllmetric :gential:metrie
------------------------------------------------------------------------------ ----------- --.------- .Ash&
Blak...........I.........: 1.2 2.0 3.8 2.5: 39 :7.6: 3.8: 5. 8 11.4 :5.o : 7.8 : 15.2
Comeroal white.........: 1.2 : 1.9 3.2 2.3 : .8 : .4 2 :.6 2 9.6 :4.6 2 7.5 12.8
Oregon...................:1.02:2.02 t 2.0 : .0: 6.6 :3.12:6.1259.9 : 5. .12:13.2
Iec ron...............
Basswood.....................: 1.6 2 2 : 39 :0 :. 11.8 : 6.6:
Ie Ameroan............... 1.3 2.2 41 11..8 : 8.2 1.2 12.6 11 : 16*3
abih .......................1.0 2.2 40 4. ': 12.2 :3 s
Butternut ... :8 1.5 2.6 1.6 3.0 5.1 2.5 4.6 7.6: 33 61 10.2
Alaska.yellow- :7 1.5 2:3 1.4 3.0 4.6 21 45 6.9 2. 6.0 9.2
eastern red............... .8 1.2 0 1.6 2.4 3*9 23 3*5 55 3.1 U4,7 7.5
Ineanse ................... .8 1321:1 .6 : 2.6 3 2.5 39 5*7 '37 2 7.6
Northern white. .......... 5 1.2 1. 1.0 : 2.4 3 5 1. 35 52 2. 57 7.6
Port Orford white......... 1.2 1.7 2 5 2.3 : .4 5.2 7.6 4.6 6.9 10.1
Atlantio white........... 7 13 2 1.4 : 2.6 2 .1 3.9 6.3 : 2.8 52 8.4
stern red.................6: 1.2: 1.9 1.2 :2 3*.5' 1*8 3.5 : 5.:2.14:5.0:77
Chary, bas~ek................:.0 2 1.8 : 2.9 1 5.8 : 2.8 5.3 : 3.6:3 .7: .1:11.5
huant.................... .8 :1.7 : 2.9 : 1.7 :3** 5.: 2.6: 5.o:5 .7: 34:6 .7:1.5
cottonwood:
Eastern ................... 1.0: 2.3 .5 : 2.o 4.6:7. 2.9 : 6.9: 10.6 3:9 2 14.1
Northern black............: t .9 2.2 4 : 1.8 2. 2:6.2 2.7 : 6.4 : : .6 5.6 t 12.4
Cypress, southern...........: 1.0 2 1.6 2 .6 : 1.9 : 3.1 2 5.2 : 2.5 4.6 7.9 : 3.8 : 6.2 10.5
Dougla-fir: : .2 2. : : :
coast region............. 1.222.0 :3.0 :2513.9 2 5.9 3. 25.52 3:: 550 : 7.5* 11.
VInland Empire region.- 1.0 1.9: 2. 2.0 3 3.8 5. 3.1 25.7 : 7.6 10.
Rocky Mountain region.....: .9 1.. P1 1 3*1 1 5*3 :2.7:4.6 8.0 :3.6 6.2 10.6
El.: I S 1 I 1 3 381 Ii I
American .................. 1.0 s 2.4 : 3.6 2.1 4 3 32 71 11.0 : 4.2 9.5 '14.6
Rook...................... 1.2 2 2.0 .35 24 40 .0 6 61 10.6 34.5 : 1 8A 14.
Slippery.................. 1.2 2.2 34 2.4 4.4 9 3.7 6.7 10.4 14.9 8.9 13.8
Balsam ......... .1.6 2.7 1.4 3* *A 21 5.0 28.1 2. : 6.6 10.8
Commercial wht ......: .5 : 1.8 2 .4 1.6 : 3 .9 2.4 53 7.4 }*. 71 9.8
Noble ..................... 1.1 2 2.1 3*1 2*2 41 62 334 6*2 t 9.4 4.5 13 12.5
Gum* I
Black ..................... 1.1 : 1.9 35 2.2 3.8 7.0 33 5 10.4 4.4 7.7 13.9
Swes- **********...****. 13 : 2*5 38 2.6 5:0 39 74 11.2 5.2 9.9 15.0
Tupelo .................... 1.0 1.9 3.1 2.1 3 32 57 19.4 4.2 :76 12.5
Hackberry .................... 1.2 2.2 3.4 234 :4.4 6.9 36 67 10.4 : 4. : 9 13.5
Hemlock.
Eastern...................... :1.7 234 15 3.4 4. 2.2 51 7.3: 3.0 6.s9.7
Western.................... 1.1 2.0 3.0 2.2 40: 6.o 3.2 5*9 .9 3 4. 79 11.9
Hickory:
Peog ..................... 1.2 : 2.2: 3.42 2.4 ,4.4 :6.8 :7 6.7 10.2 4.9 : : 13.6
True .................... 1.8 :2. :4. 3.6 :5.7: 9.o : 5 :1 34 15* N
Honey locust ................. 1.0 1.6 :2 : 2.1 1 3.3 2 .4 32 : 6.6 :10.5
Larch, western............... 1.0 : 2.0 3: 2.1 4.0 : 5.6 : 3.2 : 6.1 : 9 4.2 2 5.1 :13.2
Locust, black ................ 1.1 .7 2 2 .2 2 .34 4.9 :3.3 : 52 7 :4.4 :6.9 9.8
obertre.............. 1. :c. : 3 c : 4.4 6.5: .9 : 6.6 :10.2 :5.2 8 13.6
Southern........... 1 1 .*.*6 : 3*1 2*72 3* : 6.2 .0 :5.0 : 9.2: 5.4 6.6 12.3
Mahogany, West-lndies.......... .9 12 2 1.9 2 1*7 : 2* 2 3.8 : 2.6 : 3.6 : 5 8 3.5 48 7*7
Maple : 5 :
BIgleaf ................... .9 :1.5 2.9 1.8 3.6 5 : 2.8 5.3 8.7 3.7 7.1 :11.6
lack ..................... 2 2 2.3 3.5 2.4 : 4.6 : 3:6 70 10.5 : 4. : 93 :14.0
e. .. 1.02 :2.0 : 33 2.0 :4.1 3. 6. 9. : 4.0:52:131
ailver.................... .8 1. 30 : 3.6 60 22 : 9.0 :23.o : 7.2 :12.0
Sugar..................... 1.2 : 2.4 37 :2 71 11.2 4.9 9.5: 14.9
Oak:
Rest...................... 1.1 : 2.2 :37 2.2: 4. 734 :32 6.8 11.1: 4.3: 9.o : 14.8
White1 ...................: 1.4 2 2.: 40 2.7 : 4.6 : 0 40 7.0 12.0 2 5.4 : 9*3 :16.0
Pine:
Loblolly .................. 1.2 : 1. : 31 2.4 :3.7 6.2 :6 :6 :9.2:4. 7.4 : 123
Lodgepole ................. 1.1 : 1.7: 29 2.2 3.4 55 334 5.0 : .6 : 4*5 2 6.7 11.5
Longleaf ............ 1. : 1.9 3.0 2.6:3 : 61 : .6 22 5.1 *5: 1.2
Kaftern white-....... 5'20:*.223.1 :4l '8.
1. 215 290 722 1 10 4 *C
Ponderoa. 1.: 16 24 : .o:3.6 2.9 -72 7 3 63 93
02 3.2 1 .7 7 : .
Shortleaf................. 1.1 1 21 2 3 8 6.2 3.3 2 4 7 : 12.
wht .0 3.o1 2.24 o 2.20.2 5.9:29 5 .
Weser 21.5 0 1.0 2.5 5- 31 5.6 25.:34.1 .4 11.5
Poplar, yellow............... 1.0 1.8 .1 2.0 3. 30 :53 9.2 4.0 12.3
Redwood ............. : 6:1.1 :17 1.3 2.2 3. 20 3. 5.1 2.6 6.
Spruce:
EasternU................. 1.1 :1.9 32 2.2 3.5 6-3 3*8 5 9.4 4.3 77 12.6
Engelmann ............ : 1.6: 26 1.7 .3 5.2 2.6: .0 7.5:3.4 6.6 10.4
Sitka ..... 1.1 : 1.9 2.9 2.2:3*5 5 32 5.6 8.624*3 75 11.5
Sycamore, ~ ~ ~ ~ ~ ~ 1L Amrcn......1 3 l 9 3 6 2 6 3 5 1 37 210.62 51 276 :134.2
Walnut, black ................: 1.3 : 1. 2. 2.6 : 3. 5.6 : 3.9 : 5*3 85 5*2 7*1 11.3

Iteae shrinkage values have been taken as one-fourth the shrinkage to the oven-dry condition as given in the
last 3 columns of this table.
2These shrinkage values have been taken as one-half the shrinkage to the oven-dry condition os given in the
last 3 columns of this table.
these shrinkage values have been taken as three-fourthe the shrinkage to the oven-dry condition as given in the last 3 columns of this table.
Average of Biltmore white ash, blue ash, green ash, and white ash.
Average of sweet birch and yellow birch.
4Average of lowland white fir and white fir.
Average of bitternut hickory, nutmeg hickory, water hickory, and pecan.
Average of bigleaf shagbark hickory, mockernut hIckory, pignut hickory, and shagbark hickory.
2Average of black oak, laurel oak, pin oak, red oak, scarlet oak, southern red oak, swamp red oak, water oak,
and willow oak.
10
Average of bur oak, chestnut oak, post oak, swamp chestnut oak, svamp white oak, and white oak. 11
Average of black spruce, red spruce, and white spruce.

Z m 44732 F





Tbe3,--Tropical woods pretdireetional and. 'volume shrinkage from
green to oven-dry condition.

(Excerpt from 'Y1ropical 'Toods,"' Volume 71, September 1, 19142, "by
Ellwood S. Harrar, Duke University.)


S-oecie s :Rad ial: Tang ent ial: Vo lume


Aboudiklro (Ivoryr Coast)
Entanclrophrag~la cylin~ricum ....................: 5-63 : 9-1~i5 :15.69

Allacede (Phil. IS.)
'Ipllaceodendror. celobicum ................: i4.65 6.97 :12.14g

Amn(Phil. Is.)
Slorea eximia ................................. 6.99 t 7.69 : 1K54

Amaranth (Tro-r.. Aner.)
Peltogyne ranicu1pta ......................... 3.79 5'8 10.17

Amarello (Brazil)
Plath4ymenia reticilata .........................: 6.07 : 6.131 :12.94

Axidiroba (T2ror,. A-.ier.)
Cara-pa Fuiazensis............. %.................: 5.144 8.23 1)4.57

Araca' (Brazil)
Terminalia aff. januarensiz. ................... 3.01 : 4.sp 10.64

Avodire' (11T. Africa)
Turraeanthus africana ..........................: 4.03 : -19 : o.64

AYous (N4. Africa)
Triploch-iton scieroxylon ........................2.149 : 5.11 7 .s14

Blackbean, Australian
Castanos-oermum australe ............. 2.70 7-04 :10.07

Bosse" (Vest Africa)
Guarea cedrata .................................. 3.50 : 5.96 :9.83

73o~mrod, Indian
3uxus semnervirens ...............................5.05 10-7~6 1 6.14g

Bubingp.P ('1. Africa)
Coroaifera aff. Tessmanii .........................4.13 9.56 :15-38

Caomo (Trop. Amer.)
Brosimum Alicastrum ..............................5.12 9 .14o :15.36


iie.R14.24 -a-





-lab 1e 3.-ropical woos -- -ecn ietoa n ouesrnaefo



Sp-ecies :Radial:Taxnge na1:Volum


Ch~err'y, 7f. African
M'imusops Heakelil ......... ....... 5.30 : 7.90 13.72

Coccobolo (Cent. Amer.)
flalbergia, retusa ...............................: 2.105 : 4.26 7.~20

Ebbony, Macassar (Dutch Z. I.) Diosvpyros macassar .............................: 5.20 : 9.1)4 :4g

rrarnerie Of. AfricA,)
Nermnalia ivorensis............................ 4.63 6.ig 4i

Gaboon (Y. Af rica),
Aucoumea Klaineana .............................: 5.63 6.1o :12.62

Garap~a (Brazil)
Apuleia praecox ................................a 4-53 : -11 13.95

Goncalo Alves (Tron. Amer.) Aztronium fra2Einifolium .................................... 5.63 : 9 833 :1)4.70

Greenheart (3r. Guianaa)
Ocotea Rocliaei ................... 3.41 : 4.22' 9 .00

Guapino1 (Trop. Amer.)
gymenaea courbaril.............................. 3.00 : 5.22 g .65

Iroko Of.Y Africa)
Chlorophora excelsa ......................................... .44 4-77s.4

IKoa (Hawaii)
Acacia koa,..................................... 5.47 : 6.19 1 J2-39

Koko (Andaman Is.)
Albizzia I~ebbeck ................. 2.78 6.62 :9.74

Lacewood (Australia)
Cardwellia sublimis ....................... 3,79 : 7.20 :11.47

Lauaan, Red..(Phil. Is.)
Shoreanegrosensis .............................................. 3.27 : .04 119

Laurel, East Indian
Terminalia tomentosa ......................................... 5,97 : 9899 15.43


I'timeo. R1424 -b -





Tabe 3 Troica wodo-- neren directional and- volume shrinkage from
green to oven-J&ry condition. (continue.)


S-oecies !Radia : Tangential:!Volume
- - - - - - - - - - - - - - - - - - - - - - - - - - -

timba ('I. Afrsica)
< ei'inaia sumerba ..............t 5,13 8.06 :14.37

M9cacau'ba (Brazil)
~ltri6u~poly.staolhyum .................. 4.K63 : 6. L2 :11.51

Mahogany,, Af rican,
IKhayva ivorensis ............... 4.96 8.36 16.88

'Mahogany, Co lumbian
Svwietenia macrophylla ........................................ 2.146 3.80 6.53

7M!ah-ogacr Cuban
Swietenia ahao n i.............................. 2.143 14.147 7.114

Mahogany, _St. Jago
Swietenia mahogoni .............................: 3.19 : 4.13 :7.99

Hahogany (Peru)


'-aloj (Sam Duomingo)
Swietenia mahogoni .........................; 2.06 : 2.91 5.22

Manoonia (" Africa)
Mansonia altissima ..................... 4.63 6.142 ll1151

I14aple, Australian
Flinder-ia Brayleyana ........................... 3.74+ 9 .36 :15.147

Mvingui (OT. Africda)
Distemonanthus Benthamianus ....................: 3.08 5.18 l o.66


Pterocairpus inldicus ...................... 2.54 : 3.63 :6.81

orientalwood (Australia)
Endiandra Palmerstoni ..........................: 14514 9 .55 :13.74

Thadoi~d, African
Pterocarnus Soyauxii .........................: 3.81 4.141 9 .52

Paloiuk, Andaman
PtQLoarpus dalbergioides .................. 3.50 4.o6 7.94


Mimeo. RP14






green to ovenaycniin.(otne.


S-pecies :Radiai 'a-ngent jal Voltuna


P-aldao (Phil. Is.)
flraccnto.1elum &ao ............... 4.15 9-55 :13,3

Palosa-ois (Phil. Is.)
knisoptera thurifera ............... 4.65 7 .6i1 13.37

Pearwood. (Europe)
Eyrus, commumis .................. 4.30 : 14,65 ;19.79

Peroba, White (Brazil)
Faratecoma peroba ............................... 341 : 6.20 :9.$2

Primavera (Cent. Amer.)
Gybaistax Donnell-Smithii ................. 4.23 : 50"05 :9. 2

Rosewood, :3razilian 4A
flalbergia, nigra.... ......................... ..0: 3.141 : 7.70 :12-31

Rosewood, Viast Ind~ian
Dalbergia latifolia .....................2.10 : 5.71 :7.19

Rlos euo oc, French (Madagascar) flalbergia Greveana .. .................... 3.25 : 5.39 9.17

Sapele Ofn. AfPrica)
Entandrophragma cyrclindricum ............... 5.91: 7.142 13.99

Satinwood, Ceylon
Chlorophora Swietenia........................... 5.71 : S51 :14.914

Satinwood, If. Indian
Zanthoxylum flavum ......................: 6.12: 9-19 15-19

Satiny, Red (Australia)
-Sycarpia Hillii................................:,7.06: 7.96 :10.93

Tabasara (Trop. Amer.)
Prioria Cooaifera ...............................2.21 7.31 9.97

Taku (Trop. Amer.) fliplotropip guianensis .......................... 1.21 : 2.63 :3-S6

Tanguile (Phil. Is.):
Shorea polysnerma ...................... 4.47 7 -s4 12.53


14imeo. R114214






Tble 3,-Trpical -wooas -- percent directional and. v7oliume shrinkage from
green to oven-dry condition. (continued)


S'necies R adial: Tangent ial: Volume
---- -------------- ---------------------------- ------ ------Teak (JTava)
Tectonagrandis................................. 6.36 : 9.55 16.34

Tigerwood 04. Africa)
ILovoa Klaineana, ......................... 5.32 : -7 : 13.64

Tulipwooa (Brazil)
2)albergia aff. variabilis ................................: 4.53 :13.03 19l-32

Zebrawood (If. Africa)
Macrolobium sp .......................... ....... .......... : 14.g7 10.214 15,90




































Mimueo. R114214-







UNIVERSITY OF FLORIDA 3 1262 08924 5533