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KHOA HQC C Q N G N G H | IXIGHIEIM CUU DAC DIEIVI TAI SIIXIH DUOI TAIM RUIVG KIIM THUdlMG XAIMH AlVI A IVHIET DOI TAI VUOIM OUdC GIA DIDOUP IMUI BA, T I I M H LAIVI DOIXIG Hodng Dinh QuangS Ll Quang M[.]
K H O A HQC C Q N G N G H | IXIGHIEIM CUU D A C DIEIVI T A I SIIXIH D U O I TAIM RUIVG KIIM THUdlMG XAIMH AlVI A IVHIET D O I T A I VUOIM O U d C GIA D I D O U P - IMUI B A , T I I M H LAIVI DOIXIG Hodng Dinh QuangS Ll Quang Minh^ T6MTAT Nghien ctru tai sinh ttr nhien dudi tan rimg kin thudng xanh dm a nhi^t ddi d Virdn Qudc gia Bidoup- Niii Ba cho thay: td cay tai sinh chilm im the co 11 loai, frong de chilm ty 1? to cao nhat 8,79%; to loai cay tai sinh co 55 loai/ha Sd lupng cay tai sinh chii yeu co chieu cao dudi 50 cm Phan bd loai quan thi deu d dang lay truyin; dang biin d rimg ttr nhien noi co moi truong on dinh, loai de CO chi sd uu thi ldn nhat VI chat lupng cay tai sinh: sd cay tai sinh tot va trung binh cao hon nhilu sd cay tai sinh kem; theo phan bd cay tai sinh theo cap chieu cao tlii d ca cap diu cd mat cay tai sinh tren 1000 cay/ha dti so cay tai sinh dl thay thi rimg frong tuong lai Phan bd cay tai sinh fren be mat dat d dang ciim bdi giai doan dau ctia su phat trien cay rimg canh franh chua nhieu va kieu phan bo chua tan dung dupc het khong gian dinh duong; phSn bd so cay va so loai cay theo cap chieu cao deu co dang giam, dimg ham Meyer dl mo phong Tir khda: Tai sinh rimg tu nhi^n, Yuan Qudc gia Bidoup-Niii Ba LDATVANDE ludn vd CO sd khoa hpc cho vile dl xudt cdc gidi phdp ky thudt ldm sinh nhdm xtic tien tdi sinh rimg theo hudng str dung rimg bin virng Vudn Qudc gia Bidoup Ntii Bd Id mpt mau chudn ciia h i sinh thai rimg kin thudng xanh mua am a nhilt ddi, dupc ddc trung cho viing cao nguyin d Nam bd, bao gdm kieu rimg Ndm 2003 diiu tra ddnh gid ctia Viln Sinh thdi vd Tdi nguyin Sinh vat cho thay Vudn Qudc gia Bidoup - Niii Bd cd 1468 lodi thue vat, thudc 673 Chi, 161 hp, frong dd hp Lan ( Orchidaceae) nhilu nhdt Thiie vdt d ddy dupc bdt ngudn tir ludng, dd la: HI thtrc vat Himalaya- Trung Qudc, h i thue vdt Bdc Vi|t NamNam Trung Qudc vd la trung tdm da dang sinh hpc cao, cd nhieu lodi ddc hiru hep ciia Ldm Ddng vd viing phti can, vd ddc huu ctia Vilt Nam Nhilu lodi quy, hilm, ddc hiru dang cd nguy co mat ddn bdi khdng thdy cd str xudt hiln ciia ldp cdy vd ldp cdy kl can "Vi vdy van dl tdi sinh tii nhiln rimg rdt dupc quan tdm frong cdng tdc qudn ly rimg cung nhu frong nghiln cim Lap d tilu chuan diln hinh (OTC) cd diln tich 2000 m^ (40 m X 50 m) d vj tri: chdn, sudn, dinh tuong ling vdi OTC Nghiln ciru ddc diim tai sinh tti nhiln dudi tdn rimg kin tiiudng xanh am d nhi|t ddi se cho tiidy tilm ndng phdt hiln ciia rimg frong tirong lai vd kha ndng sir dting khdng gian dinh dudng frIn mdt dat rimg Tai sinh rimg Id mdt qud trinh phtic tap, nghiln ciru nd la cdn tiiiet, vira cd y nghia ca ve ly Diiu tra cdy tdi sinh theo d dang ban (ODB) cd di|n tich m^ (2 m X m), cdy tdi sinh dupc diiu fra frong cdc ODB Id nhimg cdy cd dudng kinh < cm, tdng diln tich diiu fra Id 5% diln tich OTC, tuong irng vdi 25 ODB ddi vdi 01 OTC vd dupc phdn bd nhu sau: I NQI DUNG VA PHUONG PHAP NGHIEN CUU Ndi dung + Xdc dinh mat dp vd td thdnh cdy tdi sinh ctia rimg kin thudng xanh dm a nhilt ddi + Tinh da dang lodi frong quan till nghiln ciru + Danh gid chat lupng cdy tdi sinh + Phdn bd cdy tdi sinh theo cdp chiiu cao + Danh gid phdn bd cdy frIn mdt ddt rimg + Md hinh phdn bd sd cdy vd sd lodi cdy tdi sinh theo cap chiiu cao Phuong phdp nghiln ciiu ' Vudn Quoc gia Bidoup - Nui Ba -Lam Dong NONG NGHIEP VA PHAT TRIEN NONG THON KY - THANG 9/2011 85 KHOA HOC C Q N G NGHE rn rn rn rn • CZI 40 m 5m 50 m a Xac dinh mit dd vi to thinh loii ciy tii sinh theo cdng thdc Ni = ni * 100 Trong dd: Niu Ni > 5% thi lodi dd dupc tham gia vdo cdng thtic td vd ddng vai frd quan frpng frong qua trinh hinh thdnh sinh thai rimg; niu Ni < 5% thi loai dd khdng tham gia vdo cdng thiie td b Tinh da dang loai tiong quan thi nghiin cuu Dp phong phii (A) vd dd thtrdng gdp ciia loai(F): tinh ty ll A/F; chi sd uu the: C=Y(ni I N)^2 Trong dd: ni la gia tri ciia lodi I (sd lupng); N Id tdng gid tii ciia cac loai (tdng sd lupng) Nghiln cuu vl chi sd da dang loai: Dung chi sd Simpson Ddi vdi mau khdng gidi han: D = 1- y />/ A Ddi vdi mau gidi han: D = 1- y "'("' ~ *) t l N(N -\) Trong dd ni la sd cd the loai / A'^la tdng sd cd thi frong mau; pi\a ty 11 cd the lodi y frIn tdng sd c Dinh gii chit lugng ciy tii sinh: Theo cip: Tot, trung binh xiu Tdt: la nhirng cdy phdt triln cdn ddi, khdng sdu benh, la cdy xanh diu Xau: Id nhirng cdy cong keo, sdu binh, tan lech Id rung nhilu hodc chuyin mau Trung binh: la cdy trung gian ciia cdp frIn d Xie dinh phin bo ciy tai smh tiieo cip chiiu cao < 50 cm, 51-100 cm, > 100 cm e Md hinh phin bo cay tai sinh tiin bi mit dit Diing tilu chuan U ciia Clark va Evans U = (r* Va -0,5)* V» 0,26136 86 Trong dd: r: Id gid tri binh qudn ciia n ldn quan sdt; a: Id mat dp cdy tdi sinh tinh frIn mdt don vi diln tich (m^; n Id dung lupng mau quan sdt Niu U < 1,96 thi cdy rimg cd phdn bd ngdu nhiln frIn mdt ddt Niu U > 1,96 thi cay rimg cd phdn bd cdch deu frIn mdt ddt Niu U < - , % thi cay rimg cd phdn bd cum frIn mdt dat e Md hinh phin bo so ciy vi so loii ciy tii sinh theo cip chieu cao(nts/Hvn) Dl nghiln ciiu quy ludt phdn bd sd cdy vd sd loai cdy theo cap chiiu cao cd thi sir dung phdn bd ly thuylt dl md hinh hda quy ludt cau trtic tdn sd co dang phdn bd gidm theo ham Meyer cd dang: f(x) = a *e'^(-p*x) Trong dd a vd p Id tham sd ciia hdm Meyer •.KETQUANGHJENCUU Xdc djnh n t dO vd td thdnh cdy tdi sinh LTdt] idnh lodi cdy tdi sinh tai Idiu viJtc nghili STT Loai cdy 10 11 12 13 Che Com Cong De Dung Hong quang Pamu Re Thich Thdng Id d?t Thdng nang Cdc lodi khdc Tdng Sd cdy dim 161 134 126 192 169 131 133 163 126 131 137 582 2185 Tan suat 7.37 6.13 5.77 8,79 7,73 6,00 6,09 7,46 5,77 6,00 6,27 26.64 100,00 NONG NGHlfP VA PHAT TRIEN NONG THON KY - THANG 9/2011 KHOA HQC C Q N G N G H | Td thdnh rimg khdng nhirng phan dnh tinh da dang sinh vdt md cdn cho biit gid tri kinh t l ctia rimg dl tir dd d l xudt cdc biin phdp ky thudt lam sinh nhdm ndng cao ndng sudt vd chdt lupng rimg Td thdnh cdy tdi sinh dupc thi hiln qua bang Qua bang cho thdy frong rimg kin thudng xanh dm d nhilt ddi td lodi cdy tdi sinh chilm tm thi Id: Che, Cdm, Cdng, De, Dung, Hdng quang, Po mu Re, Thich, Thdng la det Thdng ndng, frong dd Cdng vd Thich chilm ty 1| thdp nhdt 5,77%; De chilm ty ll cao nhdt 8,79% Td lodi cdy tdi sinh frIn la 55 lodi, sd lodi tham gia vao cdng thtic td thdnh chinh 11 lodi Cdng thiic td thdnh rimg ciia khu vtrc nghiln ctiu: 0,88 De + 0,78 Dung + 0,75 Re + 0,74 Che + 0,63 Thdng ndng + 0,61 Cdm + 0,61 Po mu + 0,60 Hdng quang + 0,60 Thdng Id det + 0,58 Cdng + 0,58 Thich + 2,67 Cdc lodi khdc Mat dp cdy tdi sinh ciia cac lodi cay go binh qudn d ca 03 vj tri dat trung binh 3642 cdy/ha- 5123 cdy/ha Nghiln cuu vl tinh da dang lodi frong qudn till Kit qua diiu fra vd tdng hpp dupc thi hiln d bang Bang Phdn bd lodi cdy tdi sinh theo d^ phong phii vd dd thudng gdp STT 10 11 12 Loai cdy Che Com Cong De Dung Hong quang Pamu Re Thich Thong la det Thong nang Tdng A 0,07 0,06 0.06 0.09 0.08 0.06 0.06 0.07 0.06 0,06 0.06 F 0.36 0,20 0.15 0.65 0.60 0.17 0.20 0,62 0.17 0,19 0.21 A/F 0,19 0,30 0,40 0.14 0.13 0.35 0.30 0.11 0.35 0,32 0,29 Trong dd A Dp nhilu hay dp phong phti ciia lodi; F: Dp thudng gdp ciia loai Theo Odum, 1971; Verma, 2000 niu loai ndo cd ty sd A/F > 0,05 tiii lodi dd cd dang phdn bd contagious (\ky truyin) Qua bang ta thdy tdt cd cdc lodi frIn diu phdn bd d dang Idy truyin, dang phd biin d rimg tii nhiln vd tiiudng gdp d noi cd mdi tiirdng dn djnh Nhirng lodi De, Re, Dung phdn bd diu vd rdt hay gdp frong rimg ( cd F > 0,5), Che miic tiiudng gdp frong rimg (0,25 < F < 0,5), cdn lai cdc lodi miic it gdp frpng rimg Nhu vdy ddi vdi rimg kin N6NG NGHlfP VA PHAT TRIEN N O N G T H N thudng xanh dm d nhilt ddi, lodi De, Dung, Re ddng vai frd chinh, cd dnh hudng ldn din qud trinh hinh thdnh rimg sau Nghiin cuu vi chisiuu thi(C): Bdng Chi sd uu till ciia cdc lodi STT 10 11 12 13 T6n loai Che Com Cong De Dung Hong quang Pomu Re Thich Thong Id det Thdng nang Cac loai khac Tong So lupng 161 134 126 192 169 131 133 163 126 131 137 582 2185 C (chi sd uu the) 0,005 0,004 0.003 0.008 0,006 0,004 0.004 0,006 0,003 0,004 0,004 0.071 Khi nghien ctiu vl chi sd uu thi cdc lodi ta thdy loai De cd chi sd uu thi ldn nhdt sau dd den Dung Re, Che; day la nhirng lodi ddng vai frd quyet djnh ddi vdi xu thi hiln ddi eda qudn the frong qud frinh phat friln ciia rimg Nghien cuu vi chi si da dang loir Dimg chi sd Simpson Ddi vdi mau khdng gidi ban: D = l - ^ / ' / ^ = 1-0,121= 0,879 1=1 Ddi vdi mdu gidi han: D = 1- y n'(n'-^) = 0,8795 t t N(N -]) nghia Id frong mdt qudn thi cd 1(X) cdp cd thi s6 cd 12 cdp cd thi cimg lodi, cdn lai 88 cdp cd thi khdc lodi; diiu cho thdy sir da dang ciia lodi frong qudn thi ciia khu vuc nghiln ciiu Ddnh gid chdt lupng cdy tdi sinh - Ddi vdi cdy tai sinh cd chieu cao dudi 50 cm: Ty 11 cdy tdt va cdy trung binh dat 74,2% ; ty ll cdy xau dat 25,8% - Ddi vdi cdy tdi sinh cd chiiu cdo 51-100 cm: Ty ll cay tdt vd cay trung binh dat 82,7%; ty ll cdy xau dat 17,3% Ddi vdi cdy tdi sinh cd chiiu cao frIn 100 cm: Ty ll cdy tdt vd cay trung binh dat 78,9%; ty le cdy xau dat 21,1% KY - THANG 9/2011 87 KHOA HQC C Q N G NGHE Qua phdn cap ddnh gia chat lupng cay tai sinh ta triln ciia chting frong tirong lai va frd thdnh rimg thay ty 1| cdy tdi sinh d frang thai tdt vd trung binh d phdt triln tdt cd gid tri Trin thue t l khu rimg ndy it mpi cap chiiu cao gap gdn ldn so vdi cdy xau; ty 11 bj tdc ddng, dupe bao vl vd tri phdt triln tdt so cay tai sinh xau giam dan theo cap chiiu cao; diiu lupng vd phdn loai nhilu dd tinh da dang cho thdy tilm ndng cay tai sinh vd kha ndng phat sinh hoc thue vdt cao Xdc djnh phdn bd cdy tdi sinh theo cdp chiiu cao Bang Phdn bd cdy tdi sinh theo cdp chiiu cao Phdn bd cay tdi sinh theo ca p chieu cao STT Loai cay Tong Tdn sudt > 100 cm 100 cm thi ca loai deu cd sd lupng va chilm ty ll thap nhat, ddc biit Po mu Kit qua nghiln ciiu phdn bd cdy tdi sinh frIn bl (1,1%); diiu dupc ly giai la nhiing cdy hat frdn mdt dat ghi d bang cho thay: Qua trinh phdn bd cdy liic nhd rat cdn cdc dieu kiln sinh thai nhir Dp am tai sinh fren b l mdt dat rimg chii ylu la phdn bd ciim ldn, dat toi xdp, nhieu miin, dp che phii cao nhtmg hay la tai sinh theo dam, bdi vi frong giai doan ddu frong qud trinh phat friln va ldn lln rat can str tdc cua str phat triln cay rimg, su canh franh giira cdc ca dpng dl md dp tan che, giiip cho cay quang hpp, thi, giiia cdc lodi chua manh, mdi quan h i giira cdc Trong khu vuc nghiln ctiu chira gdp cdy Po mu ndo lodi chii ylu van la quan h i dm, ddn dan cd sti chpn cd dudng kinh nhd hon 10 cm, chiiu cao khoang 24 lpc va canh franh d l tdn tai Vl mdt lam sinh kilu m, frong dd cay Po mu me cd dudng kinh 1-2 m phdn bd chua tdn dting hit khdng gian dinh 88 NONG NGHI|P VA PHAT TRIEN NONG THON - KY THANG 9/2011 KHOA HOC C Q N G NGHE dudng ctia cay rimg, dd cdn phdi cd biin phap ldm sinh tdc ddng d l dua chiing vl dang phdn bd ngau nhiln hodc phdn bd each diu bdng cdch tia bdt cdy nhd, kem phdt triln, sdu blnh, ddng thdi md ddn dp tdn che Kit qua nghiln oiu phdn bd sd cdy vd sd lodi cdy tdi smh theo cdp chiiu cao Quy ludt phdn bd sd cdy vd sd lodi cdy tai sinh theo cdp chiiu cao phan dnh su sinh trudng va.phdt triln ctia ldp cdy tdi sinh dd, ddnh gia mtic dp phong phti vl sd lupng vd thdnh phdn lodi vd tilm ndng ciia nhirng cdy tdi sinh frong tuong lai se thay thi cdy rimg hiln tai Phdn bd sd cdy vd sd lodi cdy tdi sinh theo cdp chiiu cao nhin chung cd dang giam, vi vdy cd thi diing ham Meyer dl md phdng Kit qua dupc thi hiln d bang Bdng Md hinh hda quy ludt cdu tnic tdn sd sd cdy(n/ Hvn) vd sd lodi cdy tdi sinh theo cdp chiiu cao(n-L/Hvn) Phdn bd n/Hvn Phdn bd nL/Hvn a a B P 560,473 0,0063 32,144 0,004 Phuong frinh phdn bd sd cdy theo cap chiiu cao Id: N = 560,473*exp(-0,0063*Hvn) Phuong trinh phdn bd sd lodi cdy theo cdp chiiu cao: uu thi, diiu dd till hiln tinh da dang sinh hpc thue vat tuong ddi cao ciia khu rimg + Khi nghiln ciiu vl tinh da dang lodi ta thay lodi Dung, De, Re la nhung lodi cd vai frd quyit dinh frong xu thi biin ddi ciia qudn till ciia khu vue nghiln ciiu vd noi ddy till hiln tinh da dang lodi cao nhu frong 100 cdp cd till cd 88 cdp cd thi khdc lodi, chi cd 12 cap cd thi ciing lodi + Chdt lupng cdy tdi sinh d frang thai tdt vd trung binh dat ty 11 cao, gap gdn ldn cdy tdi sinh d frang thai xdu, dieu cho thdy tilm ndng cdy tdi sinh vd kha ndng phat triln ciia chiing frong tuong lai vd frd thdnh rimg phdt friln tdt cd gid hi + Mat dp cay tdi sinh gidm ddn theo cdp chiiu cao, sd lupng cdy tdi sinh frIn 100 cm dat frIn 1000 cdy tdi sinh/ha, dii cdy tdi sinh dl thay thi thi h i rimg frong tirong lai + Md hinh phdn bd cdy tdi sinh frIn bl mdt ddt rimg Id phdn bd cum hay la phdn bd theo ddm, vi vdy phdn bd ndy chua tan dung hit khdng gian dinh dudng frIn bl mdt ddt rimg, cdn cd sir diiu tilt phii hpp, diing cdc biin phdp ky thudt ldm sinh dl chuyin phdn bd cay tdi sinh tir dang ctim ve dang ngau nhiln hodc dang each diu Kiln nghj N_L = 32,144* exp(-0,004*Hvn) Tir phuong frinh frIn cho thay sd cdy vd sd lodi cdy tai sinh diu giam ddn chieu cao tdng, sd cdy vd sd lodi cdy chti yeu tap trung d cap chiiu cao dudi 50 cm Vl vdy cdn phai cd sir tdc ddng bdng cac bi|n phdp ky thudt lam sinh dl loai bd nhiing cdy phdt tiiln kem, tao diiu kiln cho cdy khdc phdt triln tdt, chuyin ddn hi phdn bd ciim sang phdn bd ngau nhiln hodc phdn bd cdch diu, dl lpi dting tdt nhdt khdng gian dinh dudng cho cdy phdt friln, gidi tda str ir dpng cdy tdi sinh d cap chieu cao ndy, ddn dan cac ldp cdy tang cao hiln tai si dupe thay the frong tuong lai ILK^T LUAN VAD^ NGH! L Kit ludn Tai Vudn Qudc gia Bidoup - Ntii Bd: + T r ^ g thdi rimg kin thudng xanh mua am d nhi|t ddi cd td tiidnh cdy tdi sinh 55 lodi cdy gd/ha, frong dd cd 11 lodi tham gia nhdm td thdnh lodi cdy O ca cap chiiu cao diu cd sd lupng cdy tdi sinh frIn 1000 cdy/ha, cdn ddc bi|t chii y din ldp cdy tdi sinh cd chiiu cao dudi 50 cm, cd mat dp tuong ddi cao ( 1450 cdy/ha); cdn phdi loai bd bdt nhirng cdy phdt friln kem cho sd lupng cdn lai khoang 10(X)1100 cdy/ha, ludng phdt ddy leo cdy bui thdm tuoi tao khdng gian dinh dudng tdt cho cdy phdt triln, chdt vl sinh nhirng noi cd mat dd cdy tang cao ddy dl gidm dp tan che, cdn dnh sang cho cdy tdi sinh cd triln vpng phdt trien vuon cao Quy ludt tdi sinh rimg tti nhiln rat phtic tap liln quan din nhilu ylu td, mdi mpt frang thai rimg khac thi quy ludt tai sinh rimg la khdng gidng nhau, vi vdy cdn phdi cd cdc nghiln cihi ddy dii vd tiln hdnh frong mdt thdi gian tuong ddi ddi mdi cd till tim nhung quy ludt ciia tdi smh rimg, tir dd dp dtmg dl phtic vu cho cdng tdc xtic tiln tdi sinh rimg, lam gidu rimg, nhdm hudng tdi qudn ly rimg bin virng NONG NGHIEP VA PHAT TRIEN NONG THON KY - THANG 9/2011 89 KHOA HQC CONG NGHE ly thdng ke: Kit qua nghiln ciiu thirc nghilm frong ndng- lam nghilp frIn may vi tinh NXB Ndng TAIUEUTHAMKHAO Bao Huy ( 2009) Thdng ke vd tin hpc frong nghilp Ha Ndi ldm nghilp Diing cho cao hpc ldm nghilp- Trudng Thai Vdn Trimg (1978) Phdn loai rimg Vi$t Dai hpc Tdy Nguyin Nam frIn quan diim sinh tiidi phdt sinh qudn till, Pham Nhdt (2001) Giao frinh Da dang sinh hpc - Diing cho Cao hpc Trudng Dai hpc Lam nghilp Ludn chiing khoa hpc chuyen hang Khu Bao tdn Thiin nhiln BiDoup- Niii Ba tiianh Vudn Qudc gia BiDoup- Ntii Bd, 2004 Nguyin Hai Tuat vd Ngd Kim Khdi (1996) Xti Nxb Khoa hpc & Ky tiiudt, Hd Ndi Nguyin Vdn Thim (2004) Ldm sinh hpc NXB Ndng nghilp Nguyin Vdn Thim (1998) Sinh tiidi rimg nhiet ddi vd phuong phdp dieu fra qudn xd thirc vat ncng Tii sach DHNL TP Hd Chi Minh, 120 frang STUDY ON CHARACTERISTICS OF REGENERATION UNDER THE CANOPY OF MOIST SUBTROPICAL EVERGREEN CLOSED FORESTS IN BIDOUP- NUI BA NATIONAL PARK, LAM DONG PROVINCES Hoang Dinh Quang, Le Quang Minh Summary Study on natural regeneration under the canopy of moist subfropical evergreen closed forests in BidoupNui Ba National Park shows that regeneration compositions predominated comprise 11 species, of which species of Fagaceae family make up the highest rate Of 8.79% The number of regeneration frees is 55 species per hectare; the height of these species is mainly under 50 cm; the distribution of species in population almost has popular contagious distribution form This foim is popular in natural forests, where have stable enviroments Fagaceae species has the highest domination index in the population For quality of regeneration trees: the good and medium regeneration frees make up much higher rate than bad regeneration frees For the distribution of regeneration tree by height ranks: The density of regeneration trees is above 1000 per hectare in all three heigh ranks, with this density it is enough the number offreeto replace upper layer frees in the future Distribution of regeneration free on the forest ground is the patchy distribution It is because in the first period of development, regeneration frees not to relate much competition from others and this distribution form does not use well the condition of nutitional space The result of researching on distribution of number free and the number of species by height ranks have the decrease form, so Meyer function can be used modelise these relationships Keywords: Natural regeneration, Bidoup-Nui Ba NationalPark Ngudi phdn bi|n: PGS.TS Vd Dai Hai 90 NONG NGHlfP VA PHAT TRIEN NONG T H N - KY - THANG 9/2011 ... cay tai sinh xau giam dan theo cap chiiu cao; diiu lupng vd phdn loai nhilu dd tinh da dang cho thdy tilm ndng cay tai sinh vd kha ndng phat sinh hoc thue vdt cao Xdc djnh phdn bd cdy tdi sinh theo... cay tdi sinh cd sir bien ddi theo cap chiiu cao, sd lupng mu cang cang cd nguy co bi thu hep frong ttr cay tdi sinh giam dan cap chieu cao tdng Sd cdy nhiln, can phai cd cdc giai phap lam sinh phii... cdy tai sinh theo cdp chiiu cao phan dnh su sinh trudng va.phdt triln ctia ldp cdy tdi sinh dd, ddnh gia mtic dp phong phti vl sd lupng vd thdnh phdn lodi vd tilm ndng ciia nhirng cdy tdi sinh frong