KHOA HOC C 6 N G N G H E
JAXH HUOIXIG CLIA M O T S O MHAIM TO SIIVH T H A I DEIXI TAI SIIXIH D U O I TAIXI RUIXIG L A ROIXIG THUOIXIG XAIXIH
VUOIXl O U O C G I A XUAIXI SOIXI
Nguydn Ddc TiidnS Ngd Thd Long^, Biii Thd Ddi^
T6MTAT
Rimg la rSng thudng xanh tai Vudn Qudc gia Xu^n Son co mat dd c&y tai sinh dudi tan rat cao, bidn ddng 8.415 -15.433 cay/ha tuy theo tiang thai rung voi su xudt hidn cua 66 - 111 lo^. Nghien ciru su dung phan mdm phan tich tuong quan khong dinh hudng (DCA - Detiended Correspondence Analysis) da xac dinh dupc cac nhan td dirdng kinh (Dj^), chieu cao (Hvn), dudng kinh tan (Dt),tift didn ngang (G), dd tdn cheva chi sd dien tich ]k (LAI) cua tang cay cao co anh buong ro rdt d^n mat do va chidu cao cua cay tai sinh duoi tan rimg. Vdi mat do cSy tdi sinh, Dt co anh huong manh nhdt vdi hd sd tirong quan 0,74; vdi chidu cao cay tii sinh, H^ cd anh hudng manh nhdt vdi hd sd tuong quan la 0,725. Trong 21 lodi cSy tai sinh chii yeu dugc phan tich: m|t do cua 8 loai, chieu cao cua 11 lo^ cd quan hd ty Id thuan vdi cac nhan td anh hudng, tiong khi do m$.t dp cua 3 loai va chieu cao cua 3 loai cd quan hd ty Id nghieh vdi cac nhan td sinh thai.
Tur khda: Phin tich tuong guan khdng dinh huong (DCA), nhan tdsinh thai, tai sinh dudi tan rung.
I.BATVJUUIIE
Vudn Qudc gia (VQG) Xudn Son cd tdng didn tich 15.048 ha, vdi rimg la rdng thirdng xanh chidm uu thd. Qua trinh tdi sinh tu nhidn d rimg noi ddy mang tinh ddc tnmg cua tdi siidi rimg nhiet ddi. Su xudt hidn mpt the he cdy con eua nhiing lodi cdy gd d dudi tan ning, Id hdng hong rimg cd the tim thdy d tdt cd cac hang thai: tu rimg non phuc hdi (IIA) den tigng thai rimg hi tac ddng manh (IIIAl) vd rimg giau nguydn sinh (IV); trong dd hinh thiie tdi sinh dudi tdn ning la phd bidn vd dien hinh hon ca. Sinh tnrdng vd phat tridn ciia cay tai sinh noi ddy chiu tae ddng tdng hpp ciia cae nhan td sinh thai nhu dnh sang, nhidt dp, lupng mua, ddt, tham mue... va dac bidt Id cdc nhan td cd tinh canh hanh cao nhir edy bui, tham tuoi.... Tuy nhidn, edc nhdn td smh thai ndo ed dnh hudng quan hpng hon? eo hdi tdn tai va sinh tnrdng cua cac lodi eay dd ed thd gia nhap va thay thd ldp eay d tang eay cao hong tuong lai phu thudc vao nhan td hoac nhdm nhan td ndo? dang la nhiing van dd can dupe lam rd. Do dd, xdc dinh dupc cdc nhan td smh thai vd miic dd tac ddng oia ehung ddn qua tiinh tdi smh dudi tan rimg la mdt hong nhiing dieu kidn quan trgng de hirdng tdi muc tidu quan ly tai nguydn rimg mdt each ben vung tai VQG Xudn Son.
2. VAT L£U VA PHUONG PHAP T B I HAIW
2.1. I4p OTC vd thu t h ^ sd l i ^ ngodi hidn tnidng
Truong Dai hoc Hting Vuong Tnrdng Dai hoc L3m nghiep
Tai khu rimg nghidn ciiu, lap 42 d tidu chudn tam thdi hinh vudng cd didn tich 900 m^ (30 m x 30 m) d edc hang thdi rimg 6 khu vuc niii ddt ciia VQG Xuan Son, mdi trang thai bd tii 6 d. Trdn OTC tam ttidi bd hi 09 d dang ban (ODB) 25 m ^ S m x 5 m).
+ Trdn OTC, dieu tra tat ea cac cdy go co Dis > 5 cm vd cae chi tidu: loai eay, chidu cao (H^, m), dirdng kinh (D13, em), dudng kinh tan (D^ m);
+ Tren ODB, didu tra cay tai sinh tdt ea cac cay gd tai sinh ed Di^ < 5 cm vdi cac ehi tidu: lodi cdy, chieu eao (Hvn, m), dudng kinh gde (Dg, cm), chdt lupng, ngudn gdc.
+ Xac dinh cdc nhan td hodn canh: Dp cao xdc dinh bang GPS cam tay, dd dde xae dinh bang la ban.
Dd ehe phu eay bui tliam tiroi va dd ddy tham muc dupc xdc dinh thdng qua d dang ban 4 m^ (2 m x 2 m).
Sd lupng 05 d/OTC, 4 d 0 bdn gde va 1 d d tam OTC.
+ Xae dinh dd tan ehe vd chi sd didn tieh la (LAD bang phuong phap gidn tidp thdng qua anh chup bang may anh ky thugt sd Canon 450D 12.1 mega pbcels, dupc gdn vdi dng ldnh bdn cdu, dat cd dinh cdch mat ddt 1,5 m. Cdc anh chup cd cimg tieu cu (f) = 4,5; tde dp chup 1/100 giay, ISO = 800, dp phan giai 1024 x 768. Tren mdi OTC chup 05 biic anh tai tii tnmg tam d va bdn gdc. LAI ciia d Id gid hj tiiuig binh thu dupc hi kdt qud phan tich 5 hue anh, su dung phdn mdm GLA^v2.0 (Gap Light Analyzer) dd xir ly dnh xae dinh dp tan che va LAI eho tiing 6 dang ban.
118 NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG /2015
KHOA HOC CONO NOHE
4>3^:f^^^^
1 !k7 iiti:
t E u k i i e i t Cmopy Ojemei!;
t Site Dpennes!
Lii 4 Kinj L&I i Rtng:
99.S4 O.lf 12.12 12.11
i.ii l.i Budc 1: Nhdp anh Budc 2: Xu ly anh Bude 3: Xudt kdt qua anh
Hinh 1. Quy trinh xii ^ dnh xdc djnh dp tdn che vd cW s6 LAI 2.2. Xdc dinh td thdnh cdy tdi sinh
Td thdnh tang cdy tdi sinh: dugc xdc dinh theo sd lugng cdy tdi sinh (N) eua timg loai vdi hd sd td thanh theo cdng thiic:
fe = - ^ x I O
' A'
Trong dd. k, la hd sd td thdnh Ioai thii i; n^ Id sd lugng cd thd Ipai thir i; N Id tdng sd cd thd didu h a dupc.
2.3. Xdc djnh dnh hudng ciia cdc nhdn td sinh tiidi tdi tdi sinh dudi tdn rimg
Mdi quan hd tdng hpp dugc xu ly bang phuong phdp phan tich tuong quan khdng dinh hudng (DCA - Dehended Correspondence Analysis) dua hdn cac ma hdn cua phdn mdm PC-ORD 5.0. Phirong phap ndy dugc thuc hidn dtra hdn vide xdp Ioai 1 ma trdn thdng qua mdi Hdn hd tuydn tinh da bidn vdi ma tran tini 2. Hai ma tran ndy thudng la cap ddi giiia bidn cua edc lodi cdy va cae bidn hoan canh. Cae hudc cua qud trinh phdn tieh theo DCA bao gdm:
(1) Tdng hgp, sing Igc duh'du vi thidt lip dc matiin:
+ Ma tran 1: Lua chpn lodi edy tdi sinh, sdp xep theo edt, thdng tin vd lodi (gdm 1 trong cac ehi tidu mat dp, dudng kinh gdc, chidu cao viit nggn eua thng lodi) va dupc sdp xdp thep cdc ddng tuong iing cac d tidu chuan. Trong nghidn eiiu nay, 21 loai cay tai smh ehu ydu da dupc lua ehpn dd phdn tich, nhirng loai cd it ed thd sd hi loai bd di giam miie dp nhidu eua kdt qua nghidn ciiu.
+ Ma tran 2: Chiia thdng tin ciia 12 nhdn td hoan canh, gom: dudng kinh 1,3 m (Djg), chidu cao vut ngpn (Hvn), dudng kinh tan (Dt), tdng tidt dien ngang (G). dp tan che ff>TC), didn tich la (LAI), sd lupng cay/d ciia tdng cay cao; dp cao, dg ddc, hudng phoi ciia dia hinh, dd che phd eua cdy bui tham tuoi vd dd day ttiam mue.
(2) Logarit hda ca 2 ma tran nhdm Idm giam miie dd ehenh ldch giua cdc gid tii nghidn cuu thdng qua vide nen ede gia tri eao va md rdng cac gid tri thap.
(3i Phan tich vi xuit kdt qua
Trong phan ket qud, mdi gid tri "Eigen" ttrong ling vdi mdt phdn cua tdng phuong sai thd hidn d mdi true tpa dp, dp ldn eua mdi gia hi eigen cho ta bidt phuong sai duoc thd hidn hong moi true tpa dd va miie dp tin cdy cua kdt qua phan tieh. Mdi quan hd giua ede bidn thugc 2 ma hdn dupc danh gid gian tidp thdng qua tuong quan vdi hai true tpa dp hong khdng gian 2 ehieu. Quan he giiia 1 bidn vdi 1 hong 2 true theo dang dudng thing dugc thd hidn qua hd sd tuong quan (r), trong khi r^ didn ta ty Id phuong sai cua bidn dugc gidi thieh bang true tpa dp dd.
Trong tpa dp khdng gian 2 chidu, cdc ODB dugc thd hidn d dang ddu chdm nhd; loai cdy d dang hinh sao va gdn nhan tdn loai ndm phan tan, mdi Hen hd eiia ehung vdi cac true dua hdn khoang each hidn thi.
Lodi cay ndo phdn bd gdn vdi mui ten hidn thi cua bidn hoan eanh theo 2 chidu dupc danh gia la cd mdi quan hd chat vdi bidn dd va ngupc lai.
3. KET QUA N O B I CUU VA IHAO LUAN
3.1. D ^ trung coban tdng cdy cao cdc trying thdi rimg khu vuc nghidn cihi
Ket qua d bang 1 eho thay, mat do tdng edy cao giiia cae trang thai ning bidn ddng tir 417 cdy/ha (TTTAI) den 676 cay/ha (IIB) va khdng cd su khac biet giiia cae trang thai rimg. Dp tan ehe bidn ddng hr 0,52 (jm ddn 0,9 (iV), LAI tir 0,99 mVm^ OIA) ddn 3,10 m^/m^ (IV) tang theo ede trang thai rimg.
Cae chi tieu smh trudng: dudng kinh D13, ehieu cao vut ngpn (Hvn). chieu eao dudi cdnh (HdJ, dien tieh tan (S^, tdng tidt dien ngang (G) tang theo hang thai rimg. Ket qua phdn tieh thdng kd cho thdy cdc ehi tieu smh tnrdng cd sir khac bidt y nghia giiia cac hang thai rimg.
NONG NGHIEP VA PHATTRIEN NONG THON - KY 1 - THANG 1/2015 119
KHOA HQC CdNG NOHl
TTR IIA IIB IIIAl IIIA2 IIIA3 IIIB IV
N (cay/ha) 569"
676"
417"
504"
537"
635"
502"
Bang 1. D ^ tnmg t^ns c ^ DTC
0,52"
0,66' 0,70"
0,74=
0,81' 0,82=
0,90^
LAI 0,99"
1,71' 1,73' 1,95"
2,31=
2,34' 3,10*
Di3(cin) 10,71"
12,80' 17,82=
18,95=
20,04=
21,57=
29,04''
cao bamr & ^ rtJDiK H „ ( m )
6,11"
8,21' 12,61=
10,89=
11,24=
11,38=
15,01"
H j j m ) 3,73"
4,52' 7,246'
6,84' 7,09' 7,50' 10,24=
S t W 1,87"
2,59' 3,22=
3,20=
2,95'=
2,96'=
3,41=
__gG_(mVha) 5,80"
10,30"' 13,30"
17,93=
23,24="
29,67"
43,59=
Ghi chii: a,b, li cac ky tu bieu thi muc dd ddng nhit, sai khic ciia dai lmmg quan sit dugc kiSm tia bing tidu chuan One-way ANOVA vdip < 0,05.
3.2. Mat do td ttidnh ldp cdy tii sinh dudi tdn Ket qua xae dinh mdt dO vd td ttidnh lodi cay r^ng khu vuc nghidn Clhl smh dudi tan rimg d 7 ti-ang tiiai dupc ttie hidn d
bang 2.
Bang 2. Mdt dp, td thdnh lodi cdy tdi sinh dudi tdn rimg TTR
M IIB IIIAl IIIA2 IIIA3 IIIB IV
Sdloai 66 74 87 87 80 111 102
MM do (cay/ha) 8.415 + 4.285"
9.041 + 3.908"
11.157 ± 2.885"
11.757 + 2.779"' 15.211 + 3.822' 15.433 + 3.577' 15.257 ±3.439'
Cong thuc to thanh Ioai
2,00 Mdi + 1,30 Mro + 1,10 Bga + 0,70 Hqt + 0,58 Snh + 4,32 LK (61 loai) 1,94 Mdi + 1,45 Lau + 1,02 Snh +1,00 Bga + 0,64 Lxe + 0,55 Pma + 3,39 UC (68 loai)
1,56 Va + 1,05 Chv + 0,87 ltt + 6,52 LK (84 loai)
1,49 Gt + 0,92 Va + 0,84 Trt + 0,66 Lv + 0,51 Soi + 0,50 Chv + 5,07 LK (81 loai)
1,22 Tdu + 1,02 Va + 0,99 Trt + 0,88 Lv + 0,50 Chv + 5,38 LK (75 loai) 1,13 Gt + 0,92 Lv + 0,81 Vsa + 0,51 Tdu + 6,64 LK (107 loai) 0,97 Gt + 0,97 Lv + 0,58 Trt + 7,47 LK (99 loai)
Ghi chi: TTR Trang thii rdng; Mdi Man dia; Mro: Mo roi; Bga: Ma gac; Hqtia: Hoic quang tia; Snb:
Sing nhung; Lau: Liu; Lxe: Um xet; Pma: Phin mi; Va: Ving anh; Chv: Chia vdi; Tri: Trim tring; Lv: Ldc vimg; Gt: Gdi tiing; Soi Sdi; Vsa: Vo san; Tdu: Trong dQa; IK- Loii khic; a,b, li cic ky tu biSu thj miic do ddng nhit, sai khic ciia dai lugng quan sit dugc Idem tia bing tidu chuin One-way AND VA vdip < 0,05.
Kdt qua d bang 2 cho thay, thanh phdn loai cay tdi sinh dudi tdn ning Id rdng thirdng xanh rdt da dang, bien ddng tir 66 loai (hang thdi 11^ ddn 111 lodi (IIIB). Mat dd cay tdi sinh tir 8.415 cdy/ha (IIA) ddn 15.433 cdy/ha (IIIB); khoang bien ddng vd mat dp cdy tdi smh dia cac trang ttidi rimg rdt ldn tir 2.779 cdy/ha aiIA2) den 4.285 cdy/ha OIA). Mat do cdy tdi sinh ed su khac bidt rd rdt giiia nhdm hang thai rimg tir IIA ddn IIIA2 (nhdm a) vdi nhdm hang thdi rimg tii IIIA3 den IV (nhdm b). Ddi vdi ede ti-ang thdi ning phuc hdi (IIA, IIB), td tiianh lodi chu ydu
gdm eae loai ua sang nhu: Mdn dia, Ba gac, Lim xet, Md roi, Hoac quang tia,... trong khi dd, cdc hang thai rimg sau khai thac (III) va rimg nguydn smh (IV) cd su tham gia chii ydu eua ede lodi ehiu bdng: G6i trdng, Vdng anh, Ldc vung, Tram trdng, Trgng diia, Chia vdi, Vd san, Sdi.
3.3. Anh hudng tdng hgp cQa nhdn td hodn canh ddn tdi sinh dudi t ^
3.3.1. Anh hudng den mat do ciy tii sinh dudi tin ning (bang 3)
TT 1 2 3 4
B4ng 3. Quan hi KiOa cic nhto t6 anh h u t a g v6i cdc tn)c tpa do ueu chuln Nhan td hoan canh
D,, (cm) H„(m) D,(m) G(ra^
T r u c l r 0,675 0,721 0,740 0,561
r"
0,456 0,521 0,548 0,315
True 2 r 4),513 -0,346 -0,231 -0,446
r' 0,263
0,12 0,053 0,199
Sig (trucl)
0,00 0,00 0,00
L_(w)
120 NONG NGHIEP VA PHAT TRIEN NONG THON - Kt 1 - THAfj 2015
KHOA HOC C 6 N G N G H t
5 6 7 8 9 10 11 12
DO tin che LAI (rnVm^
Sd eay/6tc (cay) B6 ddc C) DO cao (m) Hudngphoi
DCP ciy bui, tham tuoi (%) D0 diy tham muc (cm)
0,639 0,553 -0,337
•0,149 0,254 .0,278 .0,197 0,325
0,408 0,306 0,113 0,022 0,065 0,077 0,039 0,106
-0,293 -0,296 0,308 0,251 .0,356 A069 0,327 A026
0,086 0,088 0,095 0,063 0,126 0,005 0,107 0,001
0,00 0,01 0,01 0,33 0,34 0,35 0,08 0,18 Kdt qua d bang 3 cho thay, hong 12 nhan td hoan
cdnh dupe danh gia, cd 7 nhan td tdn tai quan hd ed y nghia vdi true 1, gdm dudng ldnh 1,3 m, chidu eao viit ngpn, dudng kinh tan, tdng tidt didn ngang, dd tdn che, LAI va sd eay (theo tidu chudn Spearman, Sig <
0,05). Trong dd, dudng kinh tan cua tang cdy cao (Dt) ed quan hd chat nhdt vdi true 1 vdi he sd tirong quan r
= 0,74 vd hd sd tuong quan kep r^ = 0,548; tidp ddn Id H™ vdi r = 0,721; Dj^ vdi r = 0,675...; ehi sd didn tich Id
(IAI) chi ed r = 0,553 (r^ = 0,306). Trong khi do, cae nhdn td dp ddc, dd cao dia hinh, hudng phoi hoan todn khdng ed anh hudng gi ddn true toa do 1. Todn bd cac nhdn td hodn canh khdng ttid hidn mdi quan hd cd y nghia vdi true 2. Nhu vay, cae nhan td cau tnie cua tdng cay cao ed anh hudng ddn mat dp cua 21 loai eay tdi sinh chu ydu dtrdi tdn rimg khu vuc nghidn ciiu, trong do dirdng kinh tan eua tdng edy cao la nhdn td cd anh hudng manh nhat
Bdng 4. Quan hd giua mdt dQ cAy tdi sinh vdi true tpa dQ tidu chudn
STT Loai cay Sig (tiTJC 1) STT Loai cdy Sig (true 1)
a gac -0.827 0,00 12 Mo la nho -0,315 0,05
Trudng mat 0,701 Nong 0,27 0,05
Chd xanh 0,426 0,06
Man^a •0,445 0,11
Trim tiing 0,18
Vdng anh Miu chd li nho
Lim xet Gdi trang
Roirung Tau mit
Gdi ndp Mo roi
Phan ma 21 Ldc vung 0,84
Sang nhung -0,214
Hinh 1. K^t qud xdc dinh anh hudng ciia cdc nhdn \&
hodn cdnh tiM m^t dp cay tdi sinh dudi tdn [Gii tri Eigen: tine 1 (0,454), tivc 2 (0,250); miic dd thd hidn phuong sai: tivc 1 (56,4%), tiuc2 (2,4%)].
Kdt qua kidm ha su tdn tai quan hd eua 21 loai vdi true 1 (Axis 1) dugc the hidn d bdng 4 va bieu didn d hinh 1 cho thdy, mat do cay tdi sinh cua cac loai cd quan hd y nghia vdi true 1 (tidu ehuan Spearman, Sig<0,05) la Trudng mat (r =0,701). Chd xanh (r =0.663), Chia vdi (r = 0,642), Tram h-dng (r =
0,607), Vdng anh (r = 0,574), Roi rimg (r -0,471), Gdi nep (r = 0,42), Phdn ma (r =0,399); day cung la nhiing Ioai ed quan he ty Id thuan vdi edc nhan td anh hudng (r dirong). Tuong tu, cdc loai Ba gac (r - -0,827), Iim xet (r = -0,484), Sang nhung (r = -0,214) cd quan hd ty Id nghieh. Ddi vdi cdc loai edn lai, su anh hudng cua edc nhdn td hoan canh Id chua rd ret do khdng tdn tai quan hd cd y nghia vdi true 1. Ddi vdi nhiing loai cd quan hd ty Id thuan, khi nhan td anh hirdng tang ldn thi mat dd cua ehiing cd xu hudng tang vd ngupc lai, ddi vdi nhung loai ed quan he ty Id nghieh thi mat dO giam.
3.3.2. Anh hudng ddn chidu cao ciy tai sinh dudi tinning
Can Cli vdo sd hdu thong kd ehieu eao cua 21 lodi cdy tdi sinh ehu ydu, kdt qua phan tich anh hirdng cua cae nhdn td hodn cdnh ddn chieu eao cay tai smh dudi tan rimg dupc the hien d bang 5, 6 vd hinh 2.
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 1/2015 121
KHOA HOC CdNO NGHl
TT 1 3 4 6 7 8 9 10 11 12
Nhan td hoan eanh
H„(m) D, (m) Gissf)
LAI (mVm^
DO doc O D6 cao (m) Hudngphoi
BCPciybui, tham tuoi (X) D6 day diam muc (cm)
Trucl r 0,665 0,725 0,718 0,573 0,603 0,544 -0,292 -0,156 0,209 -0,221 -0,125 0,271
f 0,442 0,526 0,516 0,328 0,364 0,296 0,085 0,024 0,044 0,049 0,016 0,074
Tmc 2 r 0,531 0,357 0,157 0,413 0,198 0,26 A333 -0,245 -0,053 0,223 -0,13 -0,314
f 0,282 0,128 0,025 0,171 0,039 0,068 0,111 0,06 0,003 0,05 0,017 0,098
Sig (truel)
0,00 0,00 0,00 0,00 0,00 0,01 0,05 0,16 0,26 0,84 0,52 0,43
i
Bdng 5 cho ttiay, ddi vdi chidu cao eay tdi smh dudi tan cd 6 nhan td hodn eanh anh hudng thdng qua quan hd ed y nghia vdi true 1 (tidu ehuan Spearman, Sig<0,05), tiong dd H^ ed quan he chat nhat vdi r = 0,725 (i^ = 0,526), tidp ddn la Dt vdi r = 0,718 (i^ = 0,516);
Di,3 vdi r = 0,665 (r^ = 0,442); tdng tiet didn ngang Id r = 0,573 (r2= 0,328); dd tdn che r = 0,603 (i^= 0,364) va cua Bdng 6. Quan hd giiia chidu cao lodi
LAI r = 0,544 (r^ = 0,296). Cac nhan td cdn lai do tirong quan khdng y nglua (Sig > 0,5) ndn anh hudng cua chiing ddn ehieu cao cdy tdi sinh dudi tan la khdng ro rdt Cdc nhdn td ndy deu the hidn mdi quan hd khong cd ^ nghia vdi true 2. Nhu vay chidu cao eay tai sinh dudi tdn rimg chiu anh hudng manh nhat ciia chi^u eao viit nggn tang eay cao.
tdi sinh vdi tnjc tpa dQ tidu chudn STT
1 2 3 4 5 6 7 8 9 10 11
Lo^eay Baffac Tnrdng m§t Phan ma Man dia Tram tring Mau chd la nhd Chia voi Roi rimg Gdi tring Gdi nep Chd xanh
r -0,739 0,715 0,591 -0,588 0,548 0,541 0,537 0,536 0,512 0,510 0,502
Sig (truc 1) 0,00 0,01 0,00 0,00 0,00 0,00 0,01 0,00 0,01 0,00 0,01
STT 12 13 14 15 16 17 18 19 20 21
Loaieay Vang anh
Vdsan Ldc vimg Mo linhd Sang nhung
Umxet Mo roi Tiu mat
Biia Nong
r 0,480 0,452 -0,245 -0,254 0,362 -0,40 -0,138 -0,015 0,106 0,078
Sig (true 1) 0,00 0,02 0,01 0,05 0,05 0,12 0,27 0,48 0,52 0,98 Bang 6 v4 hinh 2 cho thar. Trong 21 loai cay tai sinh
nghidn ciJtu thi 14 loai cd chi^u cao cay tai sinh quan h$
•) nghia vdi true L Chiiu cao cay tai sinh cua cac lodi Trudng mjt (r = 0,715), Phan ma (r - 0,591), T r t a trang (r - 0,5*8), Mau chd la nhd (r = 0,541), Chia vdi (r - 0,537), Roi rimg (r - 0,536), Goi trang (r - 0,512), Gdl ndp (r - 0,510), Chd xanh (r - 0,502), Vang anh (r = 0,480) cd quan hd cdy nghia voi true 1 va ty le thudn voi cac nhan td anh hudng. Chidu cao eay tai sinh loai Ba gac (r = - 0,739), Man dia (r =-0,588), Lde vimg (r—0,245) CO quan he y nghia vdi hue 1 va ty Id nghieh vdi nhan td anh hudng. Cae loai edn lai khdng tdn tai quan hd ed y nghia vdi true 1 ndn anh hudng eua cac nhan td hoan canh den chieu cay tai sinh cua chung ehua ro rang.
Hinh 2. K^t qua x i c djnh anh huong cua c4c n h t o t i tdi c h i ^ cao diy t d s i n h > i t ^ [Gia bi Eigen: true 1 (0,290), true. . -). ^ ^ ^
thS hiin phtrong sai: trucl (58,7%), ^7%)1 12"* NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THA 2015
KHOA HOC CdNG NGHE
N h u vay, c a c k e t q u a p h d n tich D C A e h o t h a y , e d e ydu td e a u t n i e t a n g c a y cao: d u d n g k i n h n g a n g n g u c Di^, chidu c a o viit n g g n ( H ^ ) , d u d n g k i n h t d n QD^ v a t d n g tiet didn n g a n g , d p tdn c h e vd c h i s d didn tich la (LAI) c d d n h h i r d n g r d r e t d d n m a t d o v a c h i d u e a o c u a ldp edy tai s i n h d u d i tan r i m g . Cdc n h a n td d d c a o , d o d d c , h u d n g p h o i , d o e h e p h i i ciia eay b u i t h a m tuoi va d o d a y t d n g t h a m m u c e h u a cd d n h h u d n g r d rdt.
Kdt q u a p h d n tich eiing c h o thdy, ede lodi tra s a n g ( B a g a c , l i m x e t M a n dia, M d roi) c d x u h t t d n g t a n g m a t d o vd s i n h t n r d n g k h i c h i tidu c d u t n i e c u a t a n g c d y c a o g i a m vd n g u g c lai k h i c d c c h i tidu c a u t n i e t a n g t h i s u x u a t h i e n ciia c a e lodi T r u d n g m a t , Gdi t r d n g , C h i a vdi, V d n g a n h , Roi rimg, M d u e h d Id n h d s e tdng.
4.i(£rLUAN
M a t d o e a y c a o b i d n d p n g tii 4 1 7 c d y / h a d e n 6 7 6 c d y / h a , d o t a n e h e tii 0,52 d e n 0,9, LAI tii 0,99 m V m ^ d d n 3,10 m ^ / m ^ . C a e c h i tidu s i n h t n r d n g t a n g t h e o h a n g t h a i r i i n g .
- T h d n h p h d n lodi edy t a i s i n h d u d i t a n r i m g k h u v p c n g h i e n ciiu d a d ^ g , p h o n g phii, b i d n d g n g t h e o h a n g t h a i r i m g tir 66 d d n 111 lodi vdi m a t d o tir 8.415 d d n 15.433 c d y / h a .
- C d 6 n h a n td h o d n c a n h t h u g c c a u t n i e t d n g c d y c a o a n h h u d n g r d r e t d e n m d t d g c a y tai s i n h d u d i tdn r i m g , h o n g d d d t r d n g k i n h t a n c d a n h h u d n g m a n h n h a t . T r o n g 21 lodi tai s m h chit ydu, m d t d o e u a 8 loai cd q u a n h d t y Id t h u a n , 3 Ioai q u a n h d t y Id n g h i e h v a 10 lodi d n h h u d n g e h u a r d r d t vdi e a e n h a n t d c u a h o a n c a n h s d n g .
- C h i d u c a o c d y tai s i n h d u d i tdn r i m g chiu d n h
n g g n e u a t a n g cdy e a o c d d n h h u d n g m a n h n h d t C h i e u c a o c d y tdi s m h c u a 11 loai c d q u a n h e t y Id t h u d n , 3 lodi q u a n h d t y Id n g h i e h v a 7 Ioai c h u a e d a n h h u d n g r d r e t vdi c d c n h a n td c u a h o d n e a n h rimg.
TiU UHI THAM KHAO
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VietNam. B a o e a o t d n g k e t d d tdi. Vidn K H L N V N . 2. H o a n g K i m N g u , P h u n g N g p c L a n , 2 0 0 5 . Smh thii rimg. N x b N d n g n g h i d p . H a N d i .
3. Hodng Thi Tuydt, 2010. Bic didm tii shih tii nhien cua thim thuc vat rung kin thieng xanh mua im nhiet ddi tai Vudn Qudc gia Bach Ma - Thiia Thidn - Hue. T r u d n g D a i h g e L a m n g h i d p -
4. Frazer, G. W., Canham, C. D., a n d Lertzman, K P., 1999. Gap Light Analyzer (GLA). Version 2.0: Imaging soBware to eidract canopy structure and gap hght tiansmission indices Irom truecolour £sheye photographs, users manual and program documentation.
Simon F r a s e r University, B u m a b y , British Columbia, a n d t h e Institute of Eco^^stem Studies, Millbrook, NewYorii.
5. M c C u n e , B., J a m e s B. Grace, D e a n L Urban, 2002.
Analysis o/Ecological Communities, MJM P r e s s , U S A 6. M e C u n e , B., a n d Mefford, M . J., 1999. PaOPD, Multivariate Analysis of Ecological Data, version 5.01.
M j M software, G l e n e d e n B e a c h , OR, USA.
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h u d n g r d r d t c u a 5 n h d n td, tiong d d e h i e u c a o v u t
E F F E C T S O F S O M E E C O L O G I C A L F A C T O R S O N R E G E N E R A T I O N U N D E R T H E C A N O P Y O F B R O A D L E A F E V E R G R E E N F O R E S T S I N X U A N S O N N A T I O N P A R K
N g u y e n D a c T r i e n , N g o T h e L o n g , B u i T h e D o i S u m m a r y
T h e regeneration density of the broadleaf evergreen of Xuan Son National Park was shown very high, from 8,415 to 15,433 tiees/ha, depending forest states, and appeared to have 66 to 111 tiee species living together.
T h e results of detiended correspondence analysis ( D C ^ indicated that factors: diameter at breast height CDbh),tiee height (H), crown diameter (Dc), basal area (G), canopy cover and LAI of the canopy tiees have obviously influenced t h e density and height of the regenerating trees. In which, t h e tiee crown diameter showed t h e stiongest correlation with regeneration density (r = 0.74); while t h e height of the regeneration tiees was stiongest affected by total tiee height with r = 0.725. Among 21 regenerating tree species analyzed:
density of 8 species, and height of 11 species had positive correlations with above-mentioned ecological factors; besides, density of 3 species and height of 3 species hade the negative correlations.
Keywords: Detiended correspondence analysis, ecological factors, under canopy regeneration.
N g u d i p h d n b i ^ n : P G S . T S . V d D a i H d i N g d y n h ^ n bdi: 2 1 / 9 / 2 0 1 4 N g d y t h d n g q u a p h d n b i ^ n : 2 1 / 1 0 / 2 0 1 4 N g d y d u y e t d a n g : 2 8 / 1 0 / 2 0 1 4
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