Cdng nghiep riing
NGHIEN C i r u ANH HUCfiVG CUA TUOI CAY, VI TRI TREN THAN CAY DEN MOT SO TINH CHAT VAT LY CUA LUONG
{Dendrocalatnus barbatus Hsueh et D. Z. Li)
N g u y e n Vi^t H u - n g ' , P h a m V a n C h i r o n g ^ 'Trudng Dgi hoc Nong Ldm Thdi Nguyen
Trudng Dai hoc Ldm nghiep
T O M T A T
Do tuoi sinh trucmg va vi tri tren than cay (goc, than, ngon) anh hirong ro net den tinh chat vat ly ciia Luong (Dendrocalamus barbatus Hsueh et D. Z. C\). Nghien ciiu nay da tien hanh xac dinh duoc su thay doi mot so tinh chat viit ly cua Luong theo tu6i cay va vi tri tren than cay, nhu: khdi lugng rieng, do co rut. Ket qua cho thay, a cac cap tuoi de tai nghien ciiu cac tinh chat vat ly c6 su bien dong tit goc den ngon: khoi lugng rieng co ban bien dgng trong khoang 0,424 - 0,638 g/cm^, kh6i lugng neng 6 do km 12% biln dgng trong khoang 0,564 - 0,795 g/cm^. Do co nit theo chieu xuyen tam va tiep Uiyen khi man dat den do am 0% lan luot bien dong trong khoang 6,77 - 14,76% va 6,37 - 11,22%. Do co nit theo chilu xuyen tam va n6p tuyen khi mlu dat den d6 Sm 12% lan lirgt bien dgng trong khoang 4,99 - 12,05% va 4,37 - 9,19%. Tuy nhien 6 cap tuoi tir 4 - 5 nam, sir thay d6i ve khoi lugng rieng va dp co nit la khong Ion.
Tir khoa: Chieu cao, dg co riit, khdi lirp'ng rieng, Ludng (Dendrocalamus barbatus), tuoi cky.
1. D ^ T VAN DE
Tren the gioi va a Viet Nam da co nhirng nghien ciiu ve tre, cac nghien cuu chti yeu nghien cuu ve cac tinh chat ciia tre va ve kha nang ung dung tre trong cac ITnh vuc nhu san xuat van san, van sgi (MDF), san pham Composite, cot va gian chong 16... Tuy nhien, tai Viet Nam, cac nghien cuu ve anh huong tuoi cay, vj tri tren than cay den tinh chat cua h-e noi chung va ve tinh chat vat ly noi rieng cung khong nhieu.
Xiaobo Li (2004), da nghien cuu sir bien doi ve khoi luong neng ciia tre (Phyllostachys pubescens) khi mlu dat den do am 12% thay doi theo tuoi (1, 3, 5) va chieu cao cung nhu theo duong kinh. Ket qua cho thay theo tuoi cay khoi lugng rieng tang len hi tuoi 1 - 5 , trong do hr tuoi 1 - 3 co su bien dpng ro ret, tir 3 - 5 su bien dgng do khong dang ke. Theo chieu cao, sir bien dpng ve khoi lugng rieng tang len tu goc den ngpn. Theo chieu ngang, khdi lugng rieng a ngoai (sat vai cat) cao hon a phan ben trong (sat vai rupt).
AS Nordahlia (2012), da nghien ciiu su bi6n dpng cua tre (Gigantochloa levis) ve khoi lugng rieng tir g6c d6n ngon va cua tuoi 2 va 4. Ket
qua cho thay khoi lugng rieng cira G. levis tang len tir goc den ngpn va tang len theo tuoi cay.
Tuoi 2 bien dpng tir goc den ngon trong khoang 693 - 755 kg/m^, tuoi 4 bien dgng h-ong khoang 700 - 802 kg/ml
Theo Tnmg tam nghien ciiu quoc gia ve tre ciia Trung Quoc da nghien ciiu ve tinh chat ctia tre cho thay, doi voi Mao tnic (Moso) khoi lugng rieng cua Mao tnic tang dan tir goc den ngpn, tang dan tir tuoi 1 - 4 va on dinh tir tu6i 4 - 7.
Theo M. Kamruzzaman (2008), da nghien cuu tuoi cay va vi tri tren cay c6 anh huang lan den tinh chat cua tre, tac gia da dua ra dugc su anh huang ciia tuoi va vi tri tren cay ciia 4 loai tre gom c6: Bambusa balcooa, Bambusa tulda.
Bambusa salarkhanii, Melocanna baccifera anh huang den khoi lugng rieng va dp co nit.
Ket qua cho thay tuoi cay va vi tri tren cay co anh huang den khoi lugng rieng va do co nit cua tre. Tuy nhien, o 4 loai nay deu co su bien dpng tinh chat theo nhirng quy luat khac nhau.
Juan Francisco Correal D., Juliana Arbelaez C. (2010) da nghien ciiu ve anh huang tuoi tre va vi tri tren thay cay den tinh chat vat ly cua tre Guaduaangustifolia kunt (Guadua a.k.) TAP CHI KHOA HOC VA CONG N G H E L A M NGHIEP SO 2 - 2019 95
Cdng nghiep rung
KSt qua da cho th4y su anh huong cua tuoi cay va vi tri tren cay theo chieu cao anh huang den tinh chat vat ly ciia (fuadua a.k. Ket qua phan tich cho thay tu tu6i 2 - 5 va o vi h-i khac nhau theo chigu cao co su anh huong den tinh chat ciia Guadua a.k cu thS la: kh6i lugng rieng tuoi 2, 3 biSn dgng tang len hi goc dSn ngpn 674,5 - 703,0 kg/m\ 681,9 - 828,6kg/m\ tir tu6i 4 - 5 kh6i lugng tang tir g6c den than, tir than den nggn 6n djnh. Theo tuoi cay 1 - 3 tu6i cho thay khdi lugng rieng a cac vi tri tang dan, tir tuoi 3 - 5 khoi lugng rieng 6n dinh d vj tri nggn con CO xu huong giam xuong.
F. R. Falayi, B. O. Soyoye (2014) da nghien ciiu su anh huang cua tuoi va vi tri tren cay den tinh chat cua tre Phyllostachys Pubesces. KSt qua nghien ciiu cho thay, khoi lugng rieng ciia tre khac biet giira tuoi cay va vi tri tren cay, kh6i lugng rieng tang dan tir goc den ngpn 0,641 - 0,673 g/cm^, tang dan theo tu6i cay 1 - 3, tir tuoi 3 - 5 khoi lugng rieng tuang doi on dinh.
Abd. Latif Mohmod va cpng su (1990) da nghien ciiu anh hudng cua tudi cay va vi tri tren cay ciia 3 loai tre Bambusa blumeana Schult., Bambusa vulgaris var.striata Schrad va Gigantochloa scartechinii Gamble. Ket qua cho thay loai tre B. blumeana khdi lugng rieng giam dan tir tuoi 1 - 3 , giam dan tir gdc den nggn. Ddi vdi 2 loai tre con lai khoi lugng rieng tang dan tir tudi 1 - 3, tang dan tir gdc den ngpn.
Theo tai lieu khoa hgc gd cua Le Xuan Tinh (1998) cho thay Tre gai (Bambusa bambos) dugc lay tai Ddng Trieu - Quang Nmh co sir bien dpng ve khoi luong rieng theo chieu cao than cay, cu the: khdi lugng rieng tang tir gdc den ngpn lan lugt d cac vi tri 1 m, 4 m va 7 m CO tri sd la: 0,63; 0,73 va 0,78 g/cm^
Theo tai Heu giao h-inh Khoa hgc gd (2016), cho thay theo chieu cao than khi sinh cua Tnic sao (Phyllostachis edulis) va tre (Sinocalamus affims) CO anh hudng den khdi lugng rieng. Cu the, khdi lugng rieng ciia Tnic sao tang tir tudi
1 d6n tudi 4 (0,43 - 0,63 g/cm^) va giii dn dinh dgn tudi 7, ddi vdi tre khdi lugng rieng tang tu hadi 1 d6n tudi 5 (0,49 - 0,61) va dn dinh den tudi 7.
Le Thu Hidn (2003), da nghien ciiu xac dinh dugc tinh chat vat ly ciia cay Ludng va Tnic sao. Kdt qua cho thay Ludng cd tinh chat vat ly khac so vdi cua Tnic sao d ciing mpt cap tudi.
Ddi vdi Ludng (Dendrocalamus barbatus Hsueh et D. Z. IA) mai chi cd nhimg de tai nghien ciiu ve tinh chat vat ly cua 1 cap tudi, 1 vi hi ma chua co nhung nghien cuu sau ve anh hudng ciia tudi cay, vi tri den tinh chat vat ly.
Nghien cim nay se lam ro dugc su bien ddng ve mdt sd tinh chat vat ly: khdi lugng rieng, dp co rut cua Ludng theo tudi cay va vi tri tren cay.
2. PHlTONG PHAP NGHIEN ClTU 2.1. Vat lieu nghien cihi
Vat lieu sit dung trong nghien ciru nay la cay Ludng d cac cap tudi 1, 2, 3, 4 va 5 nam dugc khai thac tai huyen Quan Hoa, tinh Thanh Hoa.
2.2. Phu(mg phap nghien ciru a. Phucmg phdp chon cdy lay mdu Cay lay mau dugc thuc hien theo Tieu chuSnGB/T 15780-1995.
Tai noi lay mau, moi cap tudi dugc lay 5 cay cd tinh dai dien cao, 5 cay dugc lua chpn d cimg 1 cum hoac 2 cum gan nhau, tuy nhien cac cap tudi tir 1 - 5 deu dugc lay tir ciing mot cum, khdng chpn nhiing cay cd khuyet tat.
b. Phuang phdp chgn vi tri tren cdy thi nghiem
De thuc hien qua trinh lay man thi nghiem d cac vi tri tren cay duoc thuc hien theo phuang phap cua tac gia Xiaobo Li (2004). Qua trinh thuc hien thi nghiem cita 5 cap tudi d cac vj tri khac nhau tren than cay dugc tign hanh nhu sau: B§t dau tinh tir Idng thii 2 hi duai len den long thii 31 dugc chia lam 3 phan dai dien cho ph§n gdc (duai), phSn than (giira), phin nggn (tren), mdi phan gdm cd 10 long. Trong mdi
96 TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019
Cdng nghiep rimg phan, long thii 3 dugc diing dd xac djnh vat ly,
dam bao cac vi tri dugc liy gidng nhau d cac cap tudi.
c. Phuang phdp xdc dinh cdc tinh chdt cua Luong
Xac dinh tinh chSt vat ly cua ludng dugc ap dung theo Tieu chuSn GB/T 15780-1995.
Phuang phdp xdc dinh khdi lugng neng Kich thudc: lO^lOxt, mm (frong do t la chieu day thanh ludng).
Sd lugng mlu: 30 mlu/cap tudi/1 vi tri.
Dieu chinh do am mlu: Dp Sm cua cac m l u thi nghiem can dugc didu chinh ddn 12% theo dieu kien mdi trudng chuSn vdi nhiet do 20''C, dp am tuong ddi 65% de xac dinh Khdi lugng rieng va dp co riit Thdi gian dat mau trong mdi trudng chuan tir 15 - 20 ngay cho dgn khi cac mlu thi nghiem dat dp am 12%.
Cac mlu thi nghiem se dugc didu chinh dp am theo 2 giai doan:
- Giai doan 1; khi dp am mau hi trang thai bao hoa thoat am vg do km thang bSng 12%;
- Giai doan 2: khi dp am man tir 12%i vg trang thai khd kiet (0%).
Xac dinh khdi lugng rieng theo cong thiic:
( l ) v a Py-- (2) Trong dd:
p^,Py- khdi lugng rieng cua mau khi dp am w% va khdi lugng neng ca ban, g/cm'.
Trong thi nghiem nay w = 12%;
- mw, mo - khdi lugng mau d dp am w%) va 0%, g;
- V„, Vmaj- thg tich man d dp am w% va the tich mau khi dp am Idn hon do am bao hoa, cm^.
He sd CO riit the tich mau thu, dua vao cdng thuc (3) tinh toan, chinh xac den 0,001%:
.y..-v«
Trong dd:
K - he s6 CO nit thd tich mau thu, %;
Vo - thd tich cua mau thir liic khd hoan toan,
Ti^;
W - ty le ham lugng nude mlu thir, %.
A: =
Khdi lugng rieng khd cua mau thii khi dp am mau 12%, dua theo cdng thirc (4) tinh toan, chinh xac dgn 0,001 g/cm'.
A2 = p J i - 0 - 0 i ( i - A : ) ( r - i 2 ) ] ^4j Trong do: p n - khoi lugng rieng khd cua mau thu d do am man 12%, g/cm^.
Phuang phdp xdc dinh do co rdt Trong nghien ciru nay dugc xac djnh do co nit khd (do co nit ciia gd tir dp am bao hoa den dp am 12%) va co nit tir dp am mau tii dp am bao hoa tdi dp am 0%. Trong nghign ciiru, dp CO nit dugc xac dinh la co nit dpc tha, co nit xuygn tam va co nit tigp tuygn.
Kich thudc: lO^lO^t, mm (trong dd t la chieu day thanh ludng).
Sd lugng mau: 30 mau/cap tudi/1 vi tri.
Qua trinh thuc hien theo tigu chuan GB/T 15780-1995.
Xac dinh dd co nit dai theo cdng thirc:
^ , . ^ ^ ^ x l O O (5)
(6) Trong dd:
- Bw, Binax- dp CO nit theo chigu dai cua mau khi thoat am tir do am bao hoa tdi dp am W ^ 1 2 % v a d d a m 0 % .
- Lmax, Lo - dp dai mau theo chieu thd (xuyen tam, tiep tuyen hoac dgc thd) khi mau cd dp am bao hoa va 0%.
- Lw - dp dai mau theo chieu thd (xuyen tam, tigp tuygn hoac dpc thd) khi mlu c6 dp am la W = 12%.
3. K E T QUA VA T H A O LUAN
3.1. Anh huOTig cua tuoi cay va vi tri tren cay den khdi lirgng rieng cua Ludng
Khdi lugng rieng la mdt chi tieu quan trpng de danh gia tinh chat gd va tre, day la chi tieu phu hgp nhat de phan doan kha nang chiu lire cua tre, gd (Vu Huy Dai va cdng sir, 2016).
Kgt qua xac dinh khdi lugng rigng cua Ludng d do am 12%) va khdi lugng rieng co ban dugc thg hien qua hinh 1.
TAP CHI KHOA H Q C VA CONG N G H E L A M N G H I E P SO 2 - 2019
Cong nghiep rimg
Hinh 1. Bi4n dgng khdi luwng rieng theo tuoi va vi tri tren cay cua Ludng Khdi lugng rieng trung binh cua Ludng d do
am 12%i va khdi lugng rieng co ban lan lupt bign dpng trong khoang 0,424 - 0,638 g/cm^
va 0,564 - 0,795 g/cm^. Su bien ddng cua ca 2 loai khdi lugng rigng trong thi nghiem theo mdt quy luat hrong ddng nhau (hinh 1). Cu the, d cac cap tudi khac nhau tir tudi 1 den tudi 5, khdi lugng neng cua Ludng tang dan theo vi tri tir gdc den nggn. Theo cap tudi cay khdi lugng rigng cua Ludng ciing bien ddi theo mpt quy luat nhat dinh. Khdi lugng rigng cua Ludng d tudi 1 la nhd nhat va tang dan den tudi 3, tuy nhign tir tudi 3 ddn tudi 5 sy bien ddng la khdng lan va cd tinh dn dinh. Su bien ddng dd ciing tuang ddng vdi kgt qua ciia mot sd cdng bd trudc vg nhihig loai tre khac (Xiaobo Li, 2004) da nghien cuu ve loai Phyllostachys pubescens (AS Nordahlia, 2012) nghien ciiu ve
loai Gigantochloa levis (F. R. Falayi, B. O.
Soyoye, 2014) nghien ciiu ve Phyllostachys pubesces, cac ket qua bign ddng cua cac loai do vg khdi lugng rieng tuong ddng vdi Ludng trong nghign ciiu nay. Vdi su bien ddng dd cd the dugc giai thich thdng qua giai phau cau tao ciia Ludng, kdt qua giai phau cd thg chi ra ring khi tudi cay tang len ty le cac td chirc cau tao than cay thay ddi theo. Trong do, mat do bd mach se tang Ign, ty le tg bao vach day - spi tre trong bd mach tang Ign, kich thudc Id mach lai
giam xudng. Mat khac, trong than cay hg Tre tnic bd mach la mdt trong nhimg td chiic quyet dinh den khoi lugng rieng va tinh chat cua tre tnic, do sgi tre chu yen nam trong bd mach.
Day la nguyen nhan giai thich sir bien ddng ve khdi lugng rieng ciia Ludng nhu ket qua hen.
Qua phan tich phuong sai da nhan to (ANOVA) ta thay d ca 2 khdi lugng rieng hioi cay va vi tri tren cay cd gia tri Sig. nhd hon 5%. Digu dd cd nghia rang tudi va vi tri tren cay cd sir khac biet den khdi lugng rieng cua Luong. Mat khac anh hudng tucmg tac giua vi tri va tudi cua 2 loai khdi lugng rieng ciing anh hudng den khdi lugng rigng ciia Ludng (tuoi cay c6 anh hudng den khdi lugng rigng theo vi tri tren cay). Ket qua phan tich cdn cho thay, vi tri tren cay cd anh hudng ro han den khdi lugng rigng so vdi tudi cay.
3.2. Anh h u o n g cua tuoi cay va vi tri tren cay den do co rut
Dp CO nit la chi tieu danh gia miic dp thay ddi kich thudc cua Ludng khi dp am thay doi tir trang thai bao hao den dp am thap hon. Ket qua phan tich dp co nit ciia Luong theo cac chieu, theo dp tudi va vi tri tren cay dugc the hien tai hinh 2 v a 3 .
Tii kgt qua nghien ciiru cho thay, do co nit khd cua Ludng theo chieu xuygn tam va tiep tuygn lin lugt bien ddng trong khoang 4,99 - TAP CHI KHOA H O C VA C O N G N G H E LAM N G H I E P SO 2 - 2 0 1 9
Cdng nghiep rirng 12,05%. va 4,37 - 9,19%,. Do co rut tdi da ciia
Ludng theo chieu xuyen tam va tidp hiygn lin lugt bidn dgng trong khoang 6,77 - 14,76% va 6,37 - 11,22%). Vdi kgt qua bign dpng do cho thay theo tudi cay va vi tri tren cay, khi dp am thay ddi d ca 2 giai doan ciia thi nghiem ddu bign ddi theo quy luat nhSt dinh. Khi tudi cay tang len tir tudi 1 den tudi 5 do co nit xuyen tam va tiep tuyen tai cac vi tri cd xu huong
giam xudng. Tuy nhien su bign ddng Idn nhat la tir hidi 1 ddn tudi 3, tir tudi 3 den tudi 5 su chgnh lech la khdng nhidu. Theo vi tri tren than cay, d hau het cac cap tudi dd co nit ciia Ludng cd xu hudng tang dan tir gdc den ngpn, trong do tudi 1 dp CO nit tigp tuyen cd su bien ddng khac so vdi cac tudi cdn lai. Ket qua bien dpng trgn ciing tuong ddng vdi mdt sd cdng bd trudc ciia cac loai tre khac.
Tuoi ciy Tnni cay
Hinh 2. Bien d$ng do co rut xuyen tam theo tudi va vi tri tren thSn cay cua Ludng
Hinh 3. Bien dong do co riit tiep tuyen theo tuoi va vi tri tren than cay cua Luong Vdi su bien ddng do cd the giai thich thdng
qua viec giai phau mau Ludng, do dac digm cau tao thay cay hg tre tnic, ty le tg bao vach day - sgi tre cd quyet dinh dang kg dgn do co nit cua tre. Ty le te bao vach day Idn dan den dp CO nit Idn. Cac nghien ciiu vg giai phau thanh tre ciing da chi ra rang mat dp bd mach tre tang tir gdc den ngpn do dd dp co nit ciia Ludng ciing tang len hi gdc den ngpn. Ddi vdi
su bien ddng ve dp tudi cua Ludng cung cd thg la do khi tudi cay tang len dan den khoang trdng trong cac td chiic cau tao thanh tre giam xudng dan ddn dp am bao hoa sgi tre giam gay ra.
De danh gia sir tuong quan giira tudi cay, vj tri tren cay cua Ludng dgn dp co nit, kgt qua dugc tien hanh phan tich phuong sai da nhan td (ANOVA). Kgt qua phan tich cho thay d dd co TAP C H I KHOA H O C VA CONG N G H E LAM N G H I E P SO 2 - 2019 99
Cong nghiep rdng
nit xuyen tam va dp co nit tigp tuyen d ca 2 giai doan cho thiy mdi cay, vi tri trdn cay dgu cd gia h-j Sig. nho han 5%. Didu do cd nghia ring tudi va vi tri trdn cay cd su khac biet den dp co nit xuyen tam va co nit tiep tuydn ciia Ludng. Kgt qua phan tich cdn cho thiy vi h-i va mdi cay cd gia tri Sig. nho han 5%, cd nghTa la anh hudng tuong tac giiia vi tri va tudi ciia 2 giai doan ciing anh hudng den dp co nit xuygn tam cua Ludng (tudi cay cd anh hudng den dp CO nit xuyen tam theo vi tri tren cay); cdn ddi vdi CO nit tigp tuygn cd vi tri va tudi cay cd gia tri Sig. Idn han 5%. cd nghia tudi cay khdng anh hudng den do co nit tiep tuyen theo vi h-i h-en cay. Kgt qua phan tich ciing cho thay, vi tri tren than cay cd anh hudng ro hon den dp co nit xuyen tam va tigp hiyen so vdi tudi cay.
4. KET LUAN
Tinh chat vat ly ciia Ludng bien ddi theo vi tri va tudi cay la kha ro. Sir bien ddi ve khdi lugng rieng, dp co nit cac chieu theo tudi cay va vi tri tren cay bien ddng theo mdt quy luat nhat dinh.
Theo tudi cay: Khdi lugng ridng khd (W ^ 12%i), khdi lugng rieng co ban tai cac vi tri bien ddng theo mpt quy luat nhat dinh, su bien ddng dd cua Ludng d tudi 1 la nhd nhat va tang dan den tudi 3, tuy nhien tir tudi 3 den tudi 5 su bign ddng la khdng loTi va cd tinh on dinh. Do cd nit mlu ddn dd am 12%) va co nit tdi da cua Ludng khi dp am thay ddi deu bidn ddi theo quy luat nhat dinh. Khi tudi cay tang len tir tudi
1 dgn tudi 5 dp CO nit xuyen tam va tiep tuygn tai cac vj tri cd xu hudng giam xudng. Tuy nhien sir bien ddng Idn nhat la tii tudi 1 ddn tudi 3, tir tudi 3 den tudi 5 su chenh lech la khdng nhieu
Theo vi tri trdn cay: Su bien ddng vg khdi lugng rieng va dp co nit cua Ludng cd bien ddng theo mdt quy luat kha ro. Tai cac tudi ma dg tai nghien cmi, khdi lugng rieng co ban va
khoi lugng rieng khd ciia Ludng tang dan theo VI tri tir gdc ddn nggn. CJ hau het cac cap hioi dp CO nit ciia Ludng cd xu hudng tang dan tir gdc den ngpn, trong dd tuoi 1 dp co nit tiep tuyen cd su bien ddng khac so vdi cac tuoi cdn lai.
TAI LIEU THAM KHAO
1 Abd. Latif Mohmod, WanTarmeze WanAriffin &
Fauzidah Ahmad (1990). Anatomical features and mechanical properties of three malaysian Bamboo.
Journal of Tropical Forest Science 2(3): 227 - 234.
2. AS Nordahlia, UMK Anwar, H Hamdan, A Zaidon, MT Paridah & O Abd Razak (2012). Effects of age and height on selected properties of malaysian Bamboo (Gigantochloa levis). Journal of Tropical Forest Science 24Hy. 1 0 2 - 109
3 China National Bamboo research center (2001).
Cualtivation & integrated utilization on bamboo in China Hangzhou, P.R. China.
4. Vu Huy Dai, Vu Manh Tuong, Ta Thi Phuong Hoa, Do Van Ban, Nguyin Tii Kim (2016). Gido trinli Khoa hoc go. Nxb. Nong nghiep, Ha Ngi.
5. F. R, Falayi va B. 0 . Soyoye (2014). The Influence of Age and Location on Selected Physical and Mechanical Properties of Bamboo (Phyllostachys Pubesces). International Journal of Research in Agriculture and Forestry 1(1), pp. 44-54.
6. Le Thu Hi6n (2003) Nghien ciiu mot s6 tinh chSt vat ly va ca hoc ciia Luong va Tnic sao. Tgp chi Nong nghiep vd Phdt triin nong thdn, so 6.
7 Juan Francisco Correal D va Juliana Arbelaez C (2010). Influence of age and height position on Colombian Guadua angustifolia bamboo mechanical properties. Maderas ciencia Y Tecnologia 12(2), pp 105-113
8. M. Kamruzzaman va A. K. Bose & M. N. Islam S K. Saha (2008). Effects of age and height on physical and mechanical properties of Bamboo. Journal of Tropical Forest Science lOi'i), pp. 211 - 217.
9. Le Xuan Tinh (1998). Khoa hoc gd. Nxb. Nong nghiep. Ha Noi.
10. Xiaobo Li (2004). Physical, chemical and mechanical properties of Bamboo and its utilization potential for fiberboard manufaturing. Chapter 3 In The School of Renewable Natural Resources.
I \. ^m^W^l^Mt 0996). GB/T 15780-i995 fl-^
100 TAP CHI KHOA HOC VA CONG N G H f L A M NGHIEP SO 2 - 2019
Cong nghiep rimg
T H E E F F E C T S O F AGE AND H E I G H T POSITION ON T H E PHYSICAL P R O P E R T I E S OF BAMBOO
{Dendrocalamus barbatus Hsueh et D. Z. Li)
Nguyen Viet Hung\ Pham Van Chuong^
'Tliainguyen University of Agriculture and Forestry
^Vietnam National University of Forestry
S U M M A R Y
The physical properties of Dendrocalamus barbatus are related to the age and height position. This study determined the changes of some physical properties of D barbatus based on plant age and height position such as density and shrinkage. The results showed that the physical properties at all age levels changed from root to tip: the basic density 0.424 to 0.638 g/cm^ while the air dried density (moisture content = 12%) ranged from 0.564 to 0.795 g/cm'. The radial and tangential shnnkage of the moisture content at 0% humidity ranged from 6.77 to 14.76% and from 6.37 to 11.22%, respectively, while the radial and tangential shrinkage of the moisture content at 12% humidity varied from 4.99 to 12.05% and from 4 37 to 9 19%, respectively. The age and height on D. barbatus a significant effect on density and shrinkage. However, at age 4 and above, these properties reached a more stable state.
Keywords; Dendrocalamus barbatus, density, height, plant age, shrinkage.
Ngay nh^n bai Ngay phan bifn Ngay quyet dinh dang
: 19/02/2019 : 29/3/2019 : 05/4/2019
