Ağaçların Sertlik Dereceleri Nasıl Ölçülür?: Janka Yan Sertlik Testi

Mobilya seçerken kullanılan ağaçlar seçim parametrelerimizden biridir. Uzun ömürlü ve sert ağaç çeşitleri ile yapılmış olan mobilyaları be nedenle tercih ederiz. Çünkü bu tür ağaçlardan yapılmış olan mobilayalar dayanıklı olurlar ve uzun süre kullanılırlar. Mesela sert ağaçlar olan ceviz, meşe veya çam ağacından yapılmış olan mobilyalar tercih edilirler. Eğer hafif ve kolay işlenen ağaçlardan yapılan mobilyaları tercih edeceksek bu durumda akçaağaçtan yapılmış olan olan mobilyaları tercih ederiz.

Ağaçların sert mi yumuşak mı olduğu nasıl ölçlülür? Bunun için kullanılan ölçeklerden biri Jank Yan Sertlik Testi’dir. Aşağıdaki resimde de görüleceği üzere bu testte ağaçlara bir çelik bilyenin ne kadar saplanabildiği belirlenir.

Janka Test
Kaynak:precisebits.com

Janka Yan Sertlik Testi, 11.28 mm’lik (0,444 inç) bir çelik bilyeyi çapının yarısına kadar çapraz damarlı bir tahta bloğa bastırmak için gereken kuvveti ölçer. Bu kuvvet hem pound-kuvvet (lbf) hem de kilo-Newton (kN) olarak kaydedilir. Bu kuvvet Janka Sertliği’dir. [1]

Aşağıda precisebits.com‘dan alınmış olan ağaçların Janka Sertlik değerleri hem pound-kuvvet hem de kilo-Newton cinsinden verilmiştir. Bu listeye göre en sert ağaç Peygamber Ağacı’dır (Janka Sertliği=4.500 kN). Bu ağacı Afrika Karaağaç’ı (Janka Sertliği=3.670 kN) ve Meksika Abanoz u Katalox (Janka Sertliği=3.660 kN) takip etmektedir.

Türkiye’de en çok görülen ağaç türlerinden olan cevizin Janka Sertliği 2.140 kN, meşenin Janka Sertliği 2.680 kN, akçaağaç (kırmızı) Janka Sertliği 950 kN’dur.

AğaçBilimsel AdılbfkN
afrormosiaPericopsis elata6.91,560
albarcoCariniana spp.4.51,020
alder, EuropeanAlnus glutinosa2.9650
alder, NepaleseAlnus nepalensis 7.41,690
alder, redAlnus rubra2.6590
alder, whiteAlnus rhombifolia5.91,320
andirobaCarapa guianensis51,130
angelinAndira inermis7.81,750
angeliqueDicorynia guianensis5.71,290
animeProtium spp.4.1920
appleMalus sylvestris7.71,730
ash, blackFraxinus nigra3.8850
ash, blueFraxinus quadrangulata92,030
ash, greenFraxinus pennsylvanica5.31,200
ash, oregonFraxinus latifolia5.21,160
ash, pumpkinFraxinus profunda4.4990
ash, whiteFraxinus americana5.91,320
aspen, bigtoothPopulus grandidentata1.9420
aspen, quakingPopulus tremuloides1.6350
avodireTurraeanthus africanus4.81,080
azobeLophira alata14.93,350
baldcypressTaxcodium distichum2.3570
balsaOchroma pyramidale0.490
banakVirola spp.2.3510
basswood, AmericanTilia americana1.8410
basswood, CarolinaTilia caroliniana1.8410
basswood, whiteTilia heterophylla  
beech, AmericanFagus grandifolia5.81,300
bengeGuibourtia arnoldiana7.81,750
birch, Alaska paperBetula neoalaskana3.7830
birch, Alder-leafBetula alnoides3.7830
birch, downyBetula pubescens4.1930
birch, grayBetula populifolia3.4760
birch, grayBetula populifolia3.4760
birch, paperBetula papyrifera4910
birch, riverBetula nigra5.61,260
birch, silverBetula pendula5.41,210
birch, sweetBetula lenta6.51,470
birch, yellowBetula alleghaniensis5.61,260
blackwood, AfricanDalbergia melanoxylon16.33,670
blackwood, AustralianAcacia melanoxylon5.21,160
blackwood, BurmeseDalbergia cultrata14.93,350
blackwood, MalaysianDiospyros ebonasea14.13,180
bloodwood, conduru, cardinal woodBrosimum rubescens142,900
boxelderAcer negundo3.2720
bubingaGuibourtia spp.122,690
buckeye, OhioAesculus glabra  
buckeye, yellowAesculus octandra1.6350
buckthorn, cascaraRhamnus purshiana4.61,040
bulletwoodManilkara bidentata14.23,190
butternutJuglans cinerea2.2490
buttonwoodConocarpus erectus  
catalpa, northernCatalpa speciosa2.4550
catalpa, southernCatalpa bignonioides2.4550
cativoPrioria copaifera2.8630
cedar, AlaskaChamaecyparis nootkatensis2.6580
cedar, atlantic whiteChamaecyparis thyoides1.6350
cedar, Port OrfordChamaecyparis lawsoniana3.2720
cedar, yellowCupressus nootkatensis2.6580
ceibaCeiba pentandra1.1240
chalviandeVirola spp.2.1481
cherry, black, AmericanPrunus serotina4.2950
cherry, BrazilianCastenea dentata10.42,350
cherry, wild, EuropeanPrunus avium5.11,150
chestnut, AmericanCastenea dentata2.4540
chinkapin, giantCastanopsis chrysophylla3.2730
Cocobolo, Cocabolo, CocobolaDalbergia retusa14.12,960
coffeetree, KentuckyGymnocladus dioicus6.21,390
cottonwood – balsam poplarPopulus balsamifera1.3300
cottonwood, blackPopulus trichocarpa1.6350
cottonwood, easternPopulus deltoides1.9430
courbarilHymenaea courbaril10.52,350
cuangareDialyanthera spp.1.7380
cypress, AustralianCallitris glaucophylla61,375
cypress, MexicanCupressus lustianica2460
degameCalycophyllum candidissimum8.61,940
determaOcotea rubra2.9660
dogwood, floweringCornus florida9.62,150
Douglas-fir, coastPseudotsuga menziesii3.2710
Douglas-fir, interior northPseudotsuga menziesii2.7600
Douglas-fir, interior southPseudotsuga menziesii2.3510
Douglas-fir, interior westPseudotsuga menziesii2.9660
ebony, African, Gaboon, NigerianDiospyros crassiflora14.13,220
ebony, black and white, pale moonDiospyros malabarica7.91,790
ebony, Ceylon, East IndianDiospyros cebenum10.82,430
ebony, Macassar, stripedDiospyros celebica14.13,220
ebony, munDiospyros mun13.43,000
ebony, persimmon, whiteDiospyros virginiana10.22,300
ekki, azobeLophira alata14.33,220
ekopTetraberlinia tubmaniana4.1910
elder, blueSambucus cerulea3.7840
elm, americanUlmus americana3.7830
elm, cedarUlmus crassifolia5.91,320
elm, rockUlmus thomasii5.91,320
elm, slipperyUlmus rubra3.8860
elm, wingedUlmus alata6.81,540
fir, balsamAbies balsamea1.8400
fir, California redAbies magnifica2.2500
fir, grandAbies grandis2.2490
fir, nobleAbies procera1.8410
fir, pacific silverAbies amabilis1.9430
fir, subalpineAbies lasiocarpa1.6350
fir, whiteAbies concolor2.1480
goncalo alvesAstronium graveolens9.62,160
granadilloPlatymiscium yucatanum10.92,450
greenheartChlorocardium rodiei10.52,350
hackberryCeltis occidentalis3.9880
hackberry, netleafCeltis reticulata  
hemlock, easternTsuga canadensis2.2500
hemlock, mountainTsuga mertensiana3680
hemlock, westernTsuga heterophylla2.4540
hickory, bitternutCarya cordiformis6.71,500
hickory, nutmegCarya myristicaeformis5.741,290
hickory, pecanCarya illinoensis8.11,820
hickory, pignutCarya glabra9.52,140
hickory, sandCarya pallida  
hickory, shagbarkCarya ovata8.41,880
hickory, shellbarkCarya lacinosa8.11,810
hickory, waterCarya aquatica6.91,550
hickory. mockernutCarya tomentosa8.81,970
holly, AmericanIlex opaca4.51,020
honeylocustGleditsia triacanthos71,580
hophornbeam, easternOstrya virginiana8.31,860
hornbeam, AmericanCarpinus caroliniana7.91,780
huraHura crepitans2.4550
ilombaPycnanthus angolensis Exell2.7610
incense-cedarLibocedrus decurrens2.1470
ipeHandroanthus spp. (lapacho group), Brazilian walnut15.63,510
irokoChlorophora spp.5.61,260
jarrahEucalyptus marginata8.51,910
jelutongDyera costulata1.7390
juniper, alligatorJuniperus deppeana5.21,160
juniper, westernJuniperus occidentalis  
kaneelhartLicaria spp.12.92,900
kapurDryobalanops spp.5.51,230
karriEucalyptus diversicolor9.12,040
katalox, Mexican Royal EbonySwartzia spp. (S. cubensis)16.33,660
kempasKoompassia malaccensis7.61,710
keruingDipterocarpus spp.5.61,270
koa, Hawaiian koaAcacia koa5.21,170
Lacewood, Brazilian lacewoodPanopsis spp. (P. rubescens and P. sessilifolia)3.7840
larch, westernLarix occidentalis3.7830
laurel, CaliforniaUmbellularia californica5.61,270
laurel, mountainKalmia latifolia81,790
lignum vitaeGuaiacum spp.204,500
limbaTerminalia superba2.2490
locust, blackRobinia pseudoacacia7.61,700
macawoodPlatymiscium spp.143,150
Madrone, Pacific MadroneDalbergia retusa6.51,460
magnolia, cucumber treeMagnolia acuminata3.1700
magnolia, southernMagnolia grandiflora4.51,020
magnolia, sweetbayMagnolia virginiana3.6810
mahogany, AfricanKhaya spp.3.7830
mahogany, Santos, CabreuvaMyroxylon balsamum9.82,200
mahogany, trueSwietenia macrophylla3.6800
manbarklakEschweilera spp.15.53,480
manniSymphonia globulifera51,120
maple, bigleafAcer macrophyllum3.8850
maple, birdseyeAcer saccharum6.41,450
maple, blackAcer nigrum5.21,180
maple, redAcer rubrum4.2950
maple, silverAcer saccharimum3.1700
maple, sugar (hard)Acer saccharum6.41,450
marishballiLincania spp.15.93,570
merbauIntsia spp.6.71,500
mersawaAnisoptera spp.5.71,290
mesquiteProsopis spp.10.42,345
moraMora spp.10.22,300
myrtlewoodUmbellularia californica5.651,270
oak, blackQuercus velutina5.41,210
oak, burQuercus macrocarpa6.11,370
oak, cherrybarkQuercus falcata var pagodifolia6.61,480
oak, chestnutQuercus prinus51,130
oak, laurelQuercus laurifolia5.41,210
oak, liveQuercus virginiana12.92,680
oak, northern redQuercus rubra5.71,290
oak, overcupQuercus lyrata5.31,190
oak, pinQuercus palustris6.71,510
oak, postQuercus stellata61,360
oak, scarletQuercus coccinea6.21,400
oak, shumardQuercus shumardii5.81,290
oak, southern redQuercus falcata4.71,060
oak, swamp chestnutQuercus michauxii5.51,240
oak, swamp whiteQuercus bicolor7.21,620
oak, waterQuercus nigra5.31,190
oak, whiteQuercus alba61,360
oak, willowQuercus phellos6.51,460
obecheTriplochiton scleroxylon1.9430
okoumeAucoumea klaineana1.7380
opepeNauclea diderrichii7.31,630
osage orange, horse appleMaclura pomifera12.32,760
ovangkolGuibourtia ehie5.91,330
para-angelimHymenolobium excelsum7.71,720
parana-pineAraucaria augustifolia3.5780
pau marfim, Patagonian mapleBalfourodendron riedelianum6.71,500
paulownia, royal paulowniaPaulownia tomentosa1.33300
pedauk – AfricanPterocarpus soyauxii8.61,970
peroba de camposParatecoma peroba7.11,600
peroba rosaAspidosperma spp., peroba group7.71,730
persimmon, commonDiospyros virginiana10.22,300
pilonHyeronima spp.7.61,700
pine, CaribbeanPinus caribaea5.51,240
pine, eastern whitePinus strobus1.7380
pine, heartPinus resinosa5.51,225
pine, jackPinus banksiana2.5570
pine, JeffreyPinus jeffreyi2.2500
pine, limberPinus flexilis1.9430
pine, loblollyPinus taeda3.1690
pine, lodgepolePinus contorta2.1480
pine, longleafPinus palustris3.9870
pine, MontereyPinus radiata3.3750
pine, ocotePinus oocarpa4910
pine, pinyonPinus edulis3.8860
pine, pitchPinus rigida2.8620
pine, pondPinus serotina3.3740
pine, ponderosaPinus ponderosa2460
pine, sandPinus clausa3.3730
pine, shortleafPinus echinata3.1690
pine, slashPinus elliotti3.4760
pine, sprucePinus glabra2.9660
pine, sugarPinus lambertiana1.7380
pine, Table MountainPinus pungens2.9660
pine, virginiaPinus virginiana3.3740
pine, western whitePinus monticola1.9420
pine. redPinus resinosa2.5560
piquiaCaryocar spp.7.71,720
poplarLiriodendron tulipifera2.4540
primaveraTabebula donnell-smithii2.9660
pulgandeDacryodes spp.3666
purpleheartPeltogyne spp.8.31,860
raminGonystylus bancanus5.81,300
red cedar, eastern Juniperus virginiana4900
red cedar, southernJuniperus silicicola2.7610
red cedar, western Thuja plicata 1.6350
redwood, old growthSequoia sempervirens2.1480
redwood, second growthSequoia sempervirens1.9420
robeTabebul spp., roble group4.3960
rosewood, AmazonDalbergia spruceana122,700
rosewood, BrazilianDalbergia nigra12.42,790
rosewood, BurmeseDalbergia oliveri12.12,710
rosewood, HonduranDalbergia stevensonii9.82,200
rosewood, Indian, East IndianDalbergia latifolia10.92,440
rosewood, SiameseDalbergia cochinchinensis10.82,430
rosewood, Yucatan, MadagascarDalbergia madagascariensis12.12,720
rosewood, Yucatan, PanamaDalbergia tucurensis5.41,210
sajoCampnosperma panamensis1.9425
sandeBrosimum spp., utile group4900
santa mariaCalophyllum brasiliense5.11,150
sapeleEntandrophragma cylindricum6.71,510
sassafrasSassafras albidum2.8630
sepetirPseudosindora palustris6.31,410
serviceberryAmelanchier spp.81,800
shoreaShorea spp., baulau group7.91,780
shorea, dark red merantiShorea spp., lauan-meranti group3.5780
shorea, light red merantiShorea spp., lauan-meranti group2460
shorea, white merantiShorea javanica, lauan-meranti group5.71,140
shorea, yellow merantiShorea spp., lauan-meranti group3.4770
silverbell, CarolinaHalesia carolina2.6590
sourwoodOxydendrum arboreum4.2940
southen hackberry, sugarberryCeltis laevigata  
Spanish-cedarCedrela spp.2.7600
spruce, blackPicea mariana2.3520
spruce, EngelmannPicea engelmanni1.7390
spruce, redPicea rubra2.2490
spruce, SitkaPicea sitchensis2.3510
spruce, whitePicea glauca2.1480
sucupiraBowdichia brasiliensis12.22,750
sucupiraDiplotropis purpurea9.52,140
sumac, staghornRhus typhina3680
sweetgumLiquidambar styraciflua3.8850
sycamore, americanPlatanus occidentalis3.4770
tamarackLarix laricina2.6590
tanoakLithocarpus densiflorus6.31,420
teakTectona grandis4.41,000
tornilloCedrelinga cateniformis10.22,299
tree-of-heavenAilanthus altissima7.71,731
tulapuetaOsteophloeum platyspermum2.3512
tupelo, blackNyssa sylvatica3.6810
tupelo. waterNyssa aquatica3.9880
wallabaEperua spp.9.12,040
walnut, blackJuglans nigra4.51,010
wengeMillettia laurentii8.41,930
white-cedar, northernThuja occidentalis1.4320
willow, blackSalix nigra1.6360
witch hazelHamamelis virginica6.81,530
yellow poplarLiriodendron tulipifera2.4540
yew, PacificTaxus brevifolia7.11,600

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