T ansac ions o he VŠB - Technical uni e si y o Os a a
Sa e y Enginee ing Se ies
Vol. VII, No. 1, 2012
32
GROSS CALORIFIC VALUE OF LEAVES, BARK, AND BRANCHES OF
SELECTED DECIDUOUS TREES
Emília ORÉMUSOVÁ1, Linda MAKOVICKÁ OSVALDOVÁ2, An on OSVALD3
1 Technical uni esi y in Z olen, Depa men o Fi e p o ec ion, Facul y o wood and science echnology, Z olen,
Slo ak Republic, [email p o ec ed]
2 Uni e si y o Žilina, Depa men o Fi e enginee ing, Facul y o special enginee ing, Žilina, Slo ak epublic,
[email p o ec ed]
3 Uni e si y o Žilina, Depa men o Fi e enginee ing, Facul y o special enginee ing, Žilina, Slo ak epublic,
[email p o ec ed]
Abs ac : I we wan o educe he l ammabili y o wood and wood ma e ials we mus be based
on deep knowledge o he composi ion o hese ma e ials, hei s uc u e and hei
elemen a y building and o he ac o s in l uencing many aspec s o hei l ammabili y.
The mos impo an aspec s o he l ammabili y cha ac e is ics a e impo an indica o s
as o he dynamics o i e de elopmen , de e mina ion o i e load and i e isk and smoke
p oduc ion and i s subsequen oxic gases. The pape deals wi h cha ac e is ics such as
l ammabili y and g oss calo i i c alue. Measu emen s we e conduc ed on six selec ed
species o deciduous ees, pa icula ly in hei lea es, wigs, ba k and wood. G oss
calo i i c alue was de e mined in o en-d y sample.
Key wo ds: G oss calo i i c alue, o es i e, deciduous ees.
In oduc ion
Fo es s a e an in eg al pa o na u e and ha e
pa amoun impo ance o man. They a e a a e
sou ce o ma e ial, which is always enewed; hei
ui s in many cases p o ide ood and i amins.
The ex ensi e o es complexes and also o es s in
he icini y o human se lemen s a e an impo an
componen o ai egene a ion and di ec he
p oduc ion o oxygen, bu also minimize he ha m ul
e ec s o a ious ai pollu an s and dus . In addi ion,
he di e si y o m and a ie y o colou s du ing
ac i e season is aes he ic and elaxing (Pagan and
Randuška, 1987).
Fo es ecosys ems excep he posi i e p ope ies,
cu en ly ep esen a dange o o es i es in ou
a ea. The cases o he pas yea con i m he p e ious
sen ence. Changes in clima ic condi ions, me hods
and sys ems in o es y and clima ic and geog aphic
condi ions c ea e an en i onmen in which o es i e
may occu . The e ms " eco ded" no only i e bu
also i s de elopmen and ha way we eco d o es
i es wi h la ge scale, high damages o o es s and
cos ly wo k o a i e-wo ks (Če ný and Šeno ský,
2010).
Mos s udies o o es i es ha e ocused on
o es s wi h dominan o coni e s wood. Howe e ,
he men ioned i es (Old Moun ains and Bošáca)
occu ed in mixed en i onmen wi h g ea e
ep esen a ion o deciduous ees. The e was a new
phenomenon, new uel - lea es ha complica e
he wo k o i emen and h ea ened a ec ing
componen s. Fo his eason we deal wi h g oss
calo i i c alue o selec ed deciduous species in his
a icle. O hese species, we selec ed hose pa s
(lea es, b anch and ba k), which con ibu e mos ly
o he de elopmen o a o es i e (Tu eko á, 2009).
Ma e ials and me hods
Selec i e deciduous wood
Red oak, Que cus ub a Linnaeus
Red Oak is 30 o 50 m all, as g owing
deciduous ee, i s c own is conical a i s , in he
elde ly age la ge and sphe ical.
Lea es: al e na e, s em is 2 - 5 cm long, he
blade in he ou line is ellip ical, 10 - 25 cm long and
5 - 15 cm b oad, a base cunea e o ounded, lobed
o sli on each side wi h 4 - 6 inden ed i egula ly
spiny lobes. The lobes a e ounded wedge-shaped
co es and cu ings mos ly do no ex end deepe han
¼ he wid h o he blade. The ob e se is ed oak
lea es ma da k g een colou , ligh e on he e e se.
Au umn colou is o ange- ed o sca le .
Ba k: g ay, long smoo h da k g ay ba k, scaly
hin (Aas and Riedmille , 1997).
Resea ch a icle
p. 32 - 36
T ansac ions o he VŠB - Technical uni e si y o Os a a
Sa e y Enginee ing Se ies
Vol. VII, No. 1, 2012
33
Beech, Fagus syl a ica L.
Beech is one o ou mos common species. Roo
sys em ea ly passes in o he hea shape. The ba k
is g eyish b own in young age, la e cons an ly
g ey-whi e and emains smoo h.
B anches a e om ma u e g een o b own
wigs. The buds a e long spindle, al e na e, poin ed,
buil - ow. Lea es a e al e na e, o a e, sho ly
poin ed and sho s em, wi h a b igh upside.
Physical age o beech is 200 o 500 yea s.
Beech is a imbe , which inc eases he impo ance
o de eloping chemical ea men o wood. Soil
p o ec s shading and li e en iched wi h ni ogen
and lime and a good oo ing con ibu es o i s
ae a ion. We an icipa e ha beech li e supplies
80 kg o lime o 1 h.
Beech is e y sensi i e o smoke, so i is no
a sui able ee species o ci ies. Wood is a mul iple
po ous, glossy, ha d and hea y, no a di e en colou
co e. Howe e , i o en c ea es a alse hea . (Aas
and Riedmille , 1997; M ačko á, 2005).
Whi e bi ch, Be ula pubescens Eh h
Whi e Bi ch is a medium-high (up o 20 m),
deciduous ee wi h ellipsoidal c own, i s b anches
igid s and ou a an acu e angle o equilib ium. The
ops a e usually no o e - hag wig.
Lea es: al e na e, a he igid, s em 1 o 2.5 cm
long, hai y a leas ini ially, o egg-shaped diamond
blade, ounded a he co ne s, usually sho e han
he poin ed and up u ned whi e bi ch, 3 - 5 cm long,
jus o double saw blade on he cheek mo e o less
ba e, he e e se ha e down look and la e (excep
eined lea es) bald.
Ba k: Ini ially ma -whi e, annula peels o in
hin la e al s ips, ba k is hila ious, blackish, ha d,
and is made la e (Aas and Riedmille , 1997).
Maple, Ace saccha um Linnaeus
Maple is 25 (35) m all deciduous ee wi h
a dense sphe ical c own wi h la ge b anches.
Lea es: opposi e, e y a iable size, he s em
is 17 cm long, blade 8 - 17 cm long, 10 - 20 cm
wide, wi h 5 - 7 lobes, lobes o he on ee h, ee h
sha ply poin ed and up u ned, ounded co es, on he
ob e se and e e se sligh ly glossy, pale g een. Fall
colou yellow o yellow - ed.
Ba k: ligh g ay, smoo h ba k da k g ay o
blackish, densely longi udinally hila ious, does no
peel o in scales (Aas and Riedmille , 1997).
Aspen popla (aspen), Populus emula Linnaeus
Aspen popla is apidly g owing o 30 m all
deciduous ee wi h la ge spa se c own.
Lea es: al e na e, s em side comp essed, abou
as long as 3 - 8 cm la ge, ound o egg-shaped blade
on he edge o hick blun ee h, hai y only a i s ,
ea ly glab ous, on he ace shine-g een, ligh e on he
e e se. Lea es o long shoo s a e mo e powe ul (up
o 15 cm), o a e o iangula , a he sho -pe iola e.
Ba k: Ini ially g ay-g een, long, smoo h,
black-g ay, longi udinal ba k hila ious. (Aas and
Riedmille , 1997)
Pu ple Willow, Salix pu pu ea Linnaeus
Pu ple Willow is a sh ub, some imes occu s as
a 10 m all deciduous ee. I has hin b anches, od,
and ension up igh .
Lea es: al e na e, bu opposi e, lanceola e, sho
poin ed and up u ned, he wides in he uppe hi d,
4 - 12 cm long and 1.5 cm wide, he op o he i nely
se a ed on bo h sides o he ba e, blue-g een on he
back o g ey-g een, always wi hou add lea es.
Ba k: Willow has abundan , wa e y ba k, i s
sap is hea ily cha ged wi h salicylic acid. (Aas and
Riedmille , 1997, Požgaj e al., 1997, Du enda e al.,
2010).
O hese ees, was p epa ed samples o lea es,
b anches and ba k o u he sea ch. Remo ed
samples we e homogenized o he same size, and
d ied a 0 % mois u e (o en-d y sample).
De e mina ion o g oss calo i i c alue wi h he
bomb calo ime ic me hod
The essence o de e mining g oss calo i i c
alue is comple e combus ion o mass o olume
o l ammable subs ances in pu e oxygen a a gi en
p essu e. Wa e , which bu ned, con ained l ammable
subs ance, is exc e ed in he liquid s a e.
Fig. 1 Calo ime ic equipmen IKA C5003 con ol
The calo ime ic de e mina ion o g oss calo i i c
alue was pe o med acco ding o he s anda d ISO
1928. Calo i i c alue was de e mined o all hese
b oad-lea ed ees, especially he lea es, b anch and
ba k.
p. 32 - 36
T ansac ions o he VŠB - Technical uni e si y o Os a a
Sa e y Enginee ing Se ies
Vol. VII, No. 1, 2012
34
Fo expe imen al de e mina ion o g oss calo i i c
alue, calo ime e IKA C5003 con ol de ice is used
(Fig. 1). Used equipmen mee s he equi emen s
o s anda d EN ISO 1928 and ČSN EN 14918
(Kalo ime ický sys ém IKA C 5000, 1999).
Calo ime ic measu emen is based on he ac
ha in he calo ime e , he combus ion p ocess
occu s unde p ecisely de i ned condi ions. Fo his
pu pose, o he decomposi ion is gi en a weighing o
sample con aine s o uel, i igni es and measu es he
empe a u e ise in he calo ime ic sys em. Speci i c
g oss calo i i c alue o he sample is calcula ed om
he ollowing:
• sample weigh o uel,
• hea capaci y (C) calo ime ic sys em,
• inc ease he wa e empe a u e in he inne
con aine , a measu ing de ice.
To op imize he bu ning p ocess, he
decomposi ion essel mee s wi h pu e oxygen
(99.95 %). P essu e o oxygen in he a mosphe e
decomposi ion essel was 3.0 MPa. Accu a e
de ec ion o g oss calo i i c alue is based on he
equi emen ha he bu ning ook place unde
p ecisely de i ned condi ions. The applicable
condi ions a e based on he ollowing assump ions:
• empe a u e o he subs ance o be bu ned,
empe a u e be o e bu ning is 22 °C,
• wa e i lled in he subs ance and he wa e o med
du ing combus ion o compounds con aining
hyd ogen a e p esen in he liquid s a e a e bu ning,
• he e is no oxida ion o a mosphe ic ni ogen,
• gaseous decomposi ion p oduc s a e oxygen,
ni ogen, ca bon monoxide and sulphu dioxide,
• he eminde is a solid ash.
To ensu e exac ly ep oducible measu emen
esul s, he calo ime ic sys em is calib a ed a e
launch, a e main enance, he eplacemen o pa s
and he ans e o he calo ime e o a di e en
loca ion in pe iodic in e als (once e e y wo
mon hs). Las calib a ion o he used calo ime e
was made on Janua y 10, 2011, when he calo ime e
was se o hea capaci y o 10 736 J.°C-1.
A he calib a ion, he hea capaci y (C alue)
o calo ime ic sys em (amoun o hea equi ed o
hea he calo ime ic sys em by 1 °C) is epea edly
de e mined. The essence lies in he de e mina ion
o he mo chemical bu ning no mal (ce i i ed
benzoic acid) o known calo i i c alue, unde he
same condi ions, he same equipmen and he same
p essu e essel as de e mined by he g oss calo i i c
alue samples. Regula calib a ion is absolu ely
necessa y o main ain he accu acy o measu emen s
(STN ISO 1928, 2003).
Calo i i c alue was de e mined o samples
es ed a 0 % mois u e (o en-d y samples). The g oss
calo i i c alue is calcula ed o each es acco ding
o he ela ion:
(1)
whe e HOan calo i i c densi y in he e e ence s a e
analysis o mois u e [J.g-1], C hea capaci y o he
calo ime e [J.°C-1], ΔT inc ease o he empe a u e
in calo ime ic sys em du ing he combus ion
expe imen [°C], Qz excess ene gy om he igni ion,
igni ion o co on i b es, he auxilia y combus ion
subs ance, ene gy p oduced a HNO3 [J], m mass o
bu n subs ance [g].
Calo ime ic sys em makes i possible o se
he mode wi hou i a ion. In ha case, he ene gy
p oduced a HNO3 p oduc ion is calcula ed acco ding
o he o mula (Kalo ime ický sys ém 1999):
(2)
whe e QN ene gy p oduced a HNO3 p oduc ion [J],
N he pe cen age o ni ogen in sample [%], m mass
o bu n subs ance [g].
The measu ed g oss calo i i c alue in an
o en-d y sample s a e is ecalcula ed o w %
mois u e. The o mula o calcula ion o g oss
calo i i c alue a cons an olume o wa e :
(3)
whe e q ·g ·d g oss calo i i c alue a w % mois u e
[J.g-1], q ·g g oss calo i i c alue a 0 % mois u e
[J.g-1], MT he wa e con en in he uel, which was
ound in ial [%].
Resul s
The uel a o es i es comes om all pa o he
ee. The i s con ac is he ba k, b anches, and we
mus no o ge he lea es, which is he lea li e .
Each pa o he ee has some ep esen a ion, and
he pa s a e e alua ed sepa a ely.
Fi s , we e alua ed he lea es ha ha e a di e en
composi ion, size, shape, hickness and as con i med
by (Fig. 2), he alue o g oss calo i i c alue. The
beech has he la ges ep esen a ion pe cen age
be ween selec ed ees and i eached he second
highes g oss calo i i c alue. I is in e es ing ha he
lea es o bi ch eached he highes g oss calo i i c alue
among o he selec ed species. Fo speci i c i e, which
we men ioned in he in oduc ion, he e we e jus he
lea es which bu n o smoulde ed, c ea ing di e en
o ma ions o mo e on s eep e ain and li ano he
pa o he o es . I so a only coni e ous ees we e
p. 32 - 36
z
Oan CTQ
Hm
 

43
N
QNm

1 – 0,01
g d g T
qq M
 

T ansac ions o he VŠB - Technical uni e si y o Os a a
Sa e y Enginee ing Se ies
Vol. VII, No. 1, 2012
35
conside ed he i e isk, a e his expe imen can be
seen ha also deciduous ees lea es wi h hei high
calo i i c alue can cause some p oblems. The bi ch is
in g oss calo i i c alue ollowed by beech and maple
has he lowes calo i i c alue.
Fig. 2 G oss calo i i c alue - Lea es
G oss calo i i c alue o b anches does no exhibi
signi i can di e ence be ween he ees, see (Fig. 3).
Bi ch and willow eached he highes alue, while
popla had he lowes . Fo b anches, we chose idges
0.5 o 0.8 mm c oss sec ion and in he c ea ion o
samples o main ain he o e all s uc u e o b anches,
ba k, i bbe and woody pa s o he b anches.
The di e ence in he b anches is likely o de e mine
he s uc u e o wood holding ela i ely high densi y o
wood, making he esul s somewha homogenized. The
di e ence be ween he ees is minimal.
Fig. 3 G oss calo i i c alue - B anches
Ba k has a signi i can impac pa icula ly on he
de elopmen o i e and he ansi ion om g ound
i e on ee op. Resul s o he expe imen con i m
wha is known in scou ing, ha a ci cle o bi ch ba k
is he bes o he igni ion o i e. Calo i i c bi ch
ba k has eached he highes alue among all es ing
ma e ials hus he lea es and b anches (Fig. 4).
Resul s which can be seen on (Fig. 5) show he
es ed componen s o di e si y, lea es, b anches and
ba k o he selec ed wood species. When we plan
he expe imen , we migh e en o esee ha hese
di e ences will be g ea . Wood such as oak, bi ch,
maple and popla (no absolu e alues) ha e he
lowes g oss calo i i c alue in he lea es, ollowed
by b anches and e en ually peel which has all
es ing ees a he highes alue. The g oss calo i i c
alue o he he mal bi ch ba k has al eady been
men ioned, su p ising esul s ha e been achie ed
mainly by beech ees whe e lea has he la ges
g oss calo i i c alue among selec ed pa s, ollowed
by b anches, and he lowes g oss calo i i c alue has
ba k o beech, which is hin, smoo h, and shiny. The
willow eaches he highes g oss calo i i c alue a
b anches. I 's hei ax s uc u e and ee cha ac e .
In pa icula , we e alua ed he wood because i is
only a seconda y sou ce o i e and a seconda y uel.
Fig. 4 G oss calo i i c alue - Ba k
Conclusion
The aim o he expe imen was o e alua e he
g oss calo i i c alue, a ze o mois u e, o lea es,
b anches, ba k a wood (oak, beech, bi ch, maple,
popla and willow). Al eady on he basis o p e ious
expe imen s, which ha e been ca ied ou on coni e
wood, we ound di e ences in weigh loss and he
a e o bu ning o b anches, s em and oo s o coni e
wood. Desc ip ion and expe imen con i med he
signi i can di e ences ha we e ound also in his
case. This ac is impo an o know in o de o
cha ac e ize uel which is p esen in his sec ion and
which cons i u es a po en ial isk o he eme gence
o a pa icula cou se o o es i es. Based on hese
alues, o es managemen plans, en i onmen al
elie and o he pa ame e s can be made mo e
accu a ely o de e mine po en ial de elopmen
si e wi h i e and he di ec ion o s onge i e
de elopmen by he p esence o he ype o uel.
Acknowledgmen s
Pape was wi hin he p ojec s VEGA (GD
1/0446/12 - U iliza ion o labo a o y me hod o
combus ibili y quan i i ca ion o wood, wooden
composi es and uphols e y ma e ials).
p. 32 - 36
10 000
12 000
14 000
16 000
18 000
20 000
22 000
24 000
Calo i ic alue (J/g) (w=0%)
Oak Beech Bi ch Maple Popla Willow
Wood
10 000
12 000
14 000
16 000
18 000
20 000
22 000
24 000
Calo i ic alue (J/g) (w=0%)
Oak Beech Bi ch Maple Popla Willow
Wood
10000
12000
14000
16000
18000
20000
22000
G osscalo i ic alue
(J/g)(w=0%)
T ansac ions o he VŠB - Technical uni e si y o Os a a
Sa e y Enginee ing Se ies
Vol. VII, No. 1, 2012
36
Re e ences
AAS, G., RIEDMILLER, A. (1997). V ecko ý a las STROMY (P ak ická p í učka na u čo anie eu ópskych
lis na ých a ihlična ých s omo ). B a isla a: Slo a , 1997. 3 (in Slo ak).
ČERNÝ, O., ŠENOVSKÝ, P. (2010). Nekon enční me ódy modelo ání oz oje požá u. Sbo ník ědeckých p ací
VŠB - TU Os a a, Řada bezpečnos í inžený s í. 2010, Vol. V., No. 10, pp. 23 - 30. ISSN 1801-1764 (in Czech).
ČSN EN 14918. (2010). Tuhé biopali á - S ano ění spalného epla a ýh e nos i (in Czech).
DURENDA, L., GEFFERTOVÁ, J., ZOLIAK (2010). Ene ge ické las nos i š iepky plan ážnicky pes o anej
d e iny Salix iminalis klon- RAPP. Ac a acul a is xylologiae. 2010, No.1, pp. 85 - 92. ISSN 1336-3824 (in
Slo ak).
KALORIMETRICKÝ SYSTÉM IKA C 5000 kon ol. Ná od k obsluze, 1999. 111 p. (in Czech).
MRAČKOVÁ, E. (2005). Analýza ozme o čas íc d e ného p achu. Ac a acul a is xylologiae. 2005, No. 2, pp.
35-42. ISSN 1336-3824 (in Slo ak).
PAGAN, J., RANDUŠKA, D. 1987. A las d e ín 1 (Pô odné d e iny). B a isla a: Obzo , 1987. 360 p. ISBN 65-
013-87 (in Slo ak).
POŽGAJ, A., CHOVANEC, D., KURJATKO, S., BABIAK, M. 1997. Š uk ú a a las nos i d e a. B a isla a:
PRÍRODA, 1997. 488 p. ISBN 80-07-00960-4 (in Slo ak).
STN ISO 1928. 2003. Tuhé pali á. S ano enie spaľo acieho epla kalo ime ickou me ódou lako ej nádobe
a ýpoče ýh e nos i. B a isla a: Slo enský ús a echnickej no malizácie, 2003. 48 p. (in Slo ak).
TUREKOVÁ, I. (2009). Š údium iniciačných zd ojo d e ných p acho . Sbo ník ědeckých p ací VŠB - TU
Os a a, Řada bezpečnos í inžený s í. 2009, Vol. IV., No. 1, pp. 105 - 116. ISSN 1801-1764 (in Slo ak).
p. 32 - 36