D6 Khac HCing vd Dtg T9P cbi KHOA HOC & CONG NGHE 134(04): 115- 120
DANH GIA DA DANG THANH PHAN LOAI THI/C VAT VA NGUYEN NHAN LAM SUY THOAI THAM THU'C VAT 6 HUYEN VI XUYEN, TINH HA GIANG
06 Khac Hiing', Hoang Thj Hudng', Vu Huyin Trang', Le Ngpc Cong^"
'Trud'ng Cao ddng Sit pham Hd Giang 'Truang Dai hoc Suphgm-Dai hoc Thdi Nguyen TOM TAT
Trong 3 kieu tham thuc vat (tham cd, tham cay byi, rimg thti sinh) da thdng kfi duac 557 loai thu^c 393 chi, 114 hp cua 5 nganh thyc v3t bdc cao co m^ch' Nganh Thong dat, nganh Co thap biit, ngdnh Duong xi, ngdnh Thong vd ngdnh Ngpc lan. Trong do 15 hp c6 tir 10 loai trd len (chiem 42,01% ting sd lodi), co 13 chi co tu 4 loai tro len (chilm 12,39% tdng s6 lodi), co 33 loai thyc vdt quy hilm co yong Sdch do Viet Nam (2007) va 7 lodi dupc ghi nhan trong Nghi djnh 32 ciia Chinh phu. Phan ldn cic loai cay thong ke dupc diu id cac lodi tiSn phong ua sang vi co the bit gap chiing mpc tren dat sau khai thac kiSt, tren cac cho trong ciia riing sau khi nhung cdy g5 Idn bj chat ha. Tuy c6 thdnh phdn thyc vdt phong phii vd da dang nhimg thdm thyc v§t d huyen Vi Xuygn lai dang bj suy giam ding kl cd vl dien tich vd chdt lugng ma nguyen nhdn chii yeu Id do cac ho^t dpng khai thac gd, thai thac cui, khai thac lam san ngodi g6 khde va chdy rimg...
T&' khda: Rieng thu sinh, Ihdm thuc vgt, thdm cdy bui, ihdm co, huyin Vi Xuyin DAT VAN DE
Huyen Vj Xuyen nam trong vimg ndi thap cua tinh Ha Giang vdi dac diem khi b§u, dia hinb, tb6 nhudng da dang, dien tich rirng tuong ddi ldn (tong dien ti'ch rirng la 102.072,06ha va dp che phli la 68%). Trong dd cd mgt phSn dien tich rirng nam trong Khu bao tdn thien nhien Tay Cdn LTnb va cac Khu bao tdn rimg ddc dung Phong Quang, Du Gia, Khau Ca nen thanh phan thue vat kba phong pbu va da d^ng vdi nhieu loai eay gd quy nhu: Lat hoa (Chukrasia tabularis), Nghiin {Excentrodendron tonkinense). Pa mu {Fokiennia hodginsii). Dinh (Markhamia slipulala)...Tuy nhien, trong nhiJng nam qua mde dil d3 ed ehinh sach giao dat, giao rii'ng den tijrng hg gia dinh cua Chinh phii, nhung do dan so tang nhanh, do nhu cau cupc song hang ngay... nen nhilu dien tich riing bj khai thac can kiet lam eho rimg ngay cang bj suy thoai nghiem trgng.
DOI TUONG v A PHUONG P H A P NGHIEN CUU
Doi tiTOTig nghien cuu
Cae kieu tham thyc v|t 6 huy?n Vi Xuyen, tinh Ha Giang gdm: tham cd, tham cay bui va rimg tbu sinh.
Tel 0915 462404
Phucmg phdp nghien ciiu
Phuang phap thu tbap sd lieu tryc tilp ngoai thyc dia tren eae tuyln dieu tra (TDT) va d tieu chuin (OTC). Trong mdi kieu tham bd tri tuyen dieu tra thu nhat cd hudng vudng gde vdi dudng ddng mire ca ban, cac tuyln sau song song vdi tuyen dieu tra thu nhat. Khoang each giira hai tuyln tiiy theo timg kilu tham va dia binh cu the, dao dgng tir 50-100m, chilu rdng tuyln dieu tra la 2m ve mdi phia ddi vdi rimg tbii sinh, tham cay bui va 1 m ve mdi phia ddi vdi tham cd. Tren mdi TDT tien hanh lap cac d tieu chuan va duge phan bd ddng deu d trong tirng kieu tham thyc vat.
Dien tich OTC ddi vdi rirng tbii sinh la 400m"(20m x 20m), ddi vdi tham eay bui la 16m' (4m x 4m), cdn ddi vdi tham cd la lm (1 m X 1 m). Tren TDT va OTC quan sat va ghi chep tat ea cac sd lieu ve thanh phan loai (ten Latin hoac ten dja phuang) va dang sdng cua cac loai thuc vat. Nhirng loai chua biet ten lay mau ve djnh loai.
Xac djnh ten khoa bgc, ten dia phuang cac loai cay theo tai lieu "Cay cd Viet Nam" cua Pbam Hoang Hd (1991-1993) [5], theo "Danh luc cac Ioai thuc vat Vi?t Nam" ciia Nguyen Tiln Ban (chu bien) va cgng sy (2003, 2005) [1] va tbeo cudn "Ten eay rimg Viet Nam"
115
D6 Khac Hiing vd Dtg Tap chi KHOA HOC & CONG NOn ciia Bd Ndng nghiep va Phat trien Ndng thdn
(2000) [3]. Xac djnh nhirng loai thyc vat quy hilm dya vao Sach Dd Viet Nam, 2007 (Phan thuc vat) [2] va Nghj dinh 32/2006/ND - CP ciia Chinh phu, 2006 [4].
KET QUA NGHIEN CLTU
Da dang thanh pban thuc vat trong mgt so kieu tham d huyen Vi Xuyen, tinh Ha Giang Da dang d muc dp ngdnh
Tai 3 kieu tham thuc vat ehung tdi da thdng ke dugc 557 loai thugc 393 chi, 114 hg cCia 5 nganh thue vat bae eao cd mach. Ket qua dugc trinh bay d bang 1.
Theo sd lieu d bang 1, budc dau da ghi nhan 5 nganh thuc vat bac cao cd mach, nhung thanh phan thyc vat trong cac bae xaton la khdng ddng deu. Trong 5 nganh thye vat, tbi nganh Moc lan (Magnoliophyta) ed sd hg, sd chi va Bang 1: Suphdn bS ciia
sd Ioai phong phu nhat: 102 hg (89,48%), 376 chi (95,66%), 532 loai (95,51%). Tilp din la nganh Duong xi (Poly pod iophyta) cd 6 hp (5,26%), 9 cbi (2,29%) va 12 loai (2,15%), nganh Thdng (Pinophyta) cd 3 hg (2,63%), 4 chi (1,02%) va 6 loai (1,08%), nganh Thdng dat (Lycopod iophyta) cd 2 hg (1,75%), 3 chi (0,76%), 5 loai (0,90%). Nganh Cd Thap but (Equisetopbyta) cd sd hg, sd chi va sd loai th^p nhdt: 1 ho (0,88%), 1 chi (0,25%), 2 loai (0,36%).
Trong nganh Mgc lan (Magnoliophyta), Idp Mgc lan (Magnoliopsida) cd 88 hg (86,27%), 330 chi (87,77%) va 477 loai (89,66%). So lugng cua cac hg, ehi va loai trong ldp nay ldn ban rat nhieu so vdi ldp Hanh (Liliopsida) cd 14 hg, 46 chi va 55 loai. Kit qua dugc trinh bay d bang 2.
cdc taxon thuc vdl d KVNC
NGANH s6
luring Tyle
So iirpiig Tyle
(%)'
So Tylf
Thong ddt
(%)
(Lycopod iophyta) Co thdp but (Equisetophyta)
Duong xi (Polypodiophyta)
Thong (Pinophyta)
Mpc lan (Magnoliophyta)
2 1,75 I 0,88 6 5,26 3 2,63 102 89,48
0,76 0,25 2,29 1,02
5 2 12 6
0,90 0,36 2,15 1,08
Cong Bang 2:
Nganh Mgc lan (Magnoliophyta)
Lap Moc lan (Magnoliopsida)
Lop H^nh (Liliopsida) TSng
ri4 100,00 393 100,00 557 100,00 So lupng hg, chl vd lodi Irong ngdnh Mgc Ian cr KVNC
Hp Chi So lu-ong Ty le (%) So luong Ty 1^ (%)
88 86,27 330 87,77 14 13,73 46 12,23 102 100,00 376 100,00
Loii SS luong Tif U (%)
477 89,66 55 9,34 532 100,00 Da dang & miec dd ho
O cac kieu tham thuc vat ehung tdi da thdng ke dugc 114 hg. Trong dd hg cd sd loai nhieu nhat la hg Thau dau (Euphorbiaceae) vdi 40 Ioai (chilm 7,18% tdng sd loai), sau do din bg Dju (Fabaceae) cd 23 loai, hg Dau tdm (Moraceae) co 19 loai, ho Hoa thao (Poaceae) cd 17 loai, hp Long nao (Lauraceae), hg Ca phe (Rubiaceae) va hg Ciic (Asteraceae) diu cd 15 loai, cac hg Na 116
D6 Khde Hiing vo Dig T^p chi KHOA HOC & CONG NGHE 134(04): 115-120 (Annonaceae), True dao (Apocynaceae), hg
Ngu gia bi (Araliaceae) va hg Vang (Caesalpiniaceae) cd 12 loai, hg Trinh nir (Mimosaceae) va hg Cd roi ngua (Verbenaceae) cd 11 Ioai, hg Xoan (Meliaeeae) va hg Dan nem (Myrslnaceae) ed 10 Ioai, hg De (Fagaceae) va hg Cam (Rutaceae) ed 9 loai Ngoai ra 5 hg cd 8 loai la hg Hoa mdi (Lamiaceae), hg Hoa hdng (Rosaceae), hg Trdm (Sterculiaceae), hg Day (Tiliaceae) va hg Lan (Orchidaceae); 3 hg cd 7 loai la: hg O rd (Acanthaceae), hg Bo hdn (Sapindaceae) va hg Nho (Vitaceae); 6 ho cd 6 Ioai, 9 hg cd 5 loai; 11 hg cd 4 loai; 16 ho ed 3 loai; 22 hg cd 2 loai. Cd 24 hg chi cd duy nhat mgt loai nhu: hg Rang mac diep (Hymenopbyllaceae), hg Sau sau (Altingiaceae), hg Vdi voi (Boraginaeeae), bg Ken (Hippocastanaceae)... Trong 114 hg da gap d KVNC, thi cd 15 hg cd tir 10 loai trd len (chiem 42,01% tdng sd Ioai). Sd lugng hg cd tir 10 Ioai trd len duac thdng ke d bang 3.
Phan ldn cac loai cay thdng ke dugc deu la eae loai tien phong ua sang vi cd the bat gap ehung mgc tren dat sau khai thac kiet, tren cac ehd trdng eiia rirng sau khi nhQng cay gd ldn bi ch^t h?.
Bang 3: Cdc hg thuc vdt
Cac Ioai cay gd ldn cd gia tri kinh te hoac gia tn su dung cao nhu: Lat hoa {Chukrasia tabularis), Nghien {Parapentace tonkinense).
Re huong {Cinnamomunparthenoxylon), Gidi xanh (Michelia mediocris)...con lai rat it.
Nguyen nhan ciia tinh trang nay la do rirng ty nhien bj tan pba nang ne, ngudn gidng bi thieu hut lam giam kha nang tai sinh cua cay con. Do vay, trong qua trinh phuc hdi can cd nhirng bien phap bao ve, gay trdng hoac xiic tien tai sinh tu nhien de bao tdn ngudn gen.
Da dang a muc do chi
Tai KVNC da thdng ke dugc 393 chi thyc vat.
Chi cd nhieu loai nhat la Ficm vdi 12 loai chiem 2,15% tdng sd loai. Tiep theo la chi Fissistigma ed 6 loai (1,08% tdng sd Ioai); 3 chi cd 5 loai la Mallotus, Lithocarpus.
Clerodendrum: 9 chi cd 4 loai la Schefflera.
Garcinia. Dillenia. Elaeocarpus, Phyllanlhus, Castanopsis, Acacia, Maesa, Rubus. Cd 13 chl cd td 4 loai trd len, cae chi nay cd 69 loai (12,39% tdng sd loai). Ngoai ra cd 21 chi ed 3 loai, 58 ehi co 2 loai va 233 chi chi cd mgt loai. Sd lugng chi ed tir 10 loai trd len dirge thdng ke d bang 4.
CO tit 10 lodi tra len a KVNC
STT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Tgn khoa hge Euphorbiaceae Fabaceae Moraceae Poaceae Lauraceae Rubiaceae Asteraceae Annonaceae Apocynaceae Araliaceae Caesalpiniaceae Mimosaceae Verbenaceae Meliaeeae Myrsinaceae
Ten ho
Ten Viet Nam Ho Thau ddu Ho Dau Ho Dau tam Ho Hod thao Ho Long nao Hp Ca phe Ho Cue H o N a Ho Triic dao Hp Ngii giabi Ho Vang Ho Trinh nQ Ho Co roi ngua Ho Xoan Ho Don nem Tong
40 23 19 17 15 15 15 12 12 12 12 11 11 10 10 234
T y l f ( % ) 7,18 4,13 3,41 3,05 2,69 2,69 2,69 2,15 2,15 2,15 2,15 1,97 1,97 1,80 1,80 42,01
D6 Khac Hiing vd Btg Tap chi KHOA HOC & CONG Nl,...;.
Bang 4: Cdc chl thirc vdt c6tu4 loat tra len a KVNC STT
1 2 3 4 5 6 6 7 8 9 10 11 12 13
Ten ehi Ficus Fissistigma Mallotus Lithocarpus Clerodendrum SchefHera Garcinia Dillenia Elaeocarpus Phyllanthus Castanopsis Acacia Maesa Rubus
Ten khoa hge Moraceae Annonaceae Euphorbiaceae Fagaceae Verbenaceae Araliaceae Clusiaceae Dilleniaceae Elaeocarpaceae Euphorbiaceae Fagaceae Mimosaceae Myrsinaceae Rosaceae
Tong Ho
T i n Viel Nara Ho Dau tam H o N a Ho Thau dau H o D e Ho Co roi ngua Hp Ngu gia bi HoBira Ho So Ho Com Ho Thau dau H o D e Ho Trinh nij Ho Don nem Ho Hoa hfing
S6 loai 12 6 5 5 5 4 4 4 4 4 4 4 4 4 69
Tylf(%) 2,15 1,08 0,90 0,90 0,90 0,72 0,72 0,72 0,72 0,72 0,72 0,72 0,72 0,72 12,39 Cdc lodi thuc vdt quy hiem
Trong tdng so 557 loai tai KVNC, chiing tdi da thdng ke dugc 33 Ioai thue vat quy hiem cd trong Sach do Viet Nam, chiem 7,12% sd loai cd trong Sach dd Viet Nam (2007) [2], trong dd cd 1 loai thugc nhdm rat nguy cap (CR); 12 loai thugc nhdm nguy cap (EN); 20 loai thupc nhdm se nguy cap (VU). 7 loai trong ND 32/2006 ND - CP [4] chilm 1,26%
tdng sd Ioai da biet tai khu vyc nghien ciru va chilm 13,46% tdng sd Ioai ed ten trong ND 32/2006 ND - CP, trong dd 2 Ioai ndm trong nhom I.A va 5 loai nam d nhdm II.A. Cac loai thuc vat quy hiem duge thdng ke d bang 5.
Cae nguyen nhan Iam suy thoai rirng d huyen Vi Xuyen tinh Ha Giang
Hoat dpng khai thdc go
Hoat dpng khai thac gd trong viing rii'ng dac dung, rirng phdng hd va rirng diu nguon d Ha Giang dien ra gay gat trong vdng 4 -5 nam trd lai day. Do lgi nhuan tir khai thac go Nghiin, Dinh Ien tdi vai trieu ddng/ngudi/ngay nen cae doi tugng Iam tac hk chip thii doan dl tan pha rirng. Hang tram, tham ehi hang nghin cay go Nghiin, Trai (nhdm IIA) cd thu cd dudng kinh tir 0,8 - 1,5m da bj ddn ha, cit thdt trong sy bat luc ciia cae ca quan chirc nang. Hang nam lugng gd tjch thu dugc chi la mdt phan rat nhd so vdi lugng gd da khai 118
thac. Day la nguyen nhan quan trgng lam cho chat lugng ctia rirng bi suy thoai.
. Khai thdc Iam sdn khac ngodi go - Khai thac ciii: Do thu nhap eua da sd eae hp dan trong huyen cdn tbSp va theo thdi quen smh ho^t nen ciii dugc sir dung lam chat dot la chil yeu. Ngoai ra, nhu'ng hd gia dinh ngheo khdng ed dat san xuat, kbdng cd von dau tu da vao rimg khai thac eiii de ban nham tang them thu nhap cho gia dinh. Lugng cui khai thac giai doan 2010 - 2013 d huyen Vj Xuyen dao ddng 136.820 - 227.780ste/nam.
Khai thac lam san ngoai gd khac: Sd li?u bang 4.8 cbo thay, cd nhieu loai lam san ngoai gd da bi khai thac d huyen Vj Xuyen (14 loai), trong do khai thac tre, nua, lulng 238.000 - 339.300 eay/nam; khai thac nua, triic, giang 143.000-316.680 cay/nam; bong chit 56 - 65 tSn/nam; thao qua 636 - 830 tan/nam; mang tuai 38 - 113 tSn/nam...TSt ea cac loai tren diu dugc sir dung trong hd gia dinh, ban va xuat khau qua bien gidi vdi lgi nhuan cao, nen tinh trang khai thac diln ra kha phd bien. Ngoai ra, thu rirng cflng bj sdn bat de lam thyc pham, dugc pham cung diln ra kha phd bien.
Do vay, khai thac lam san ngoai gd cung la mot trong eae nguyen nhan Iam suy ki?t t^i nguyen da dang sinh hge ciia rimg.
Do Khac Hung vd Dtg Tap chi KHOA HOC & CONG NGHE 134(04): 115-120
Bang 5: Danh luc cdc lodi ihuc vdl quy hiim a K VNC
Ten khoa hpc Ten Vift Nam SDVN
2007 N D 3 2
2006 .Annamocarya sinensis (Dode) J. Leroy
Anoeclochilus calcareus Aver.
Aquilaria crassna Pierre ex Lecomte Ardlsia silveslris Pitard Canarium tramdenum Dai & Yakov.
Castanopsis hyslrix A DC.
Castanopsis lecomtel Hickel & A. Camus Cinnadeniapaniculata (Hook, f.) Koesterm Clnnamomum balansae Lecomte Cinnamomum parlhenoxylon (Jack.) Meisn.
Chukrasia tabularis A Juss.
Dalbergia lonkinensis Prain Drynariafortunel (Kuntze.) J. Smith Excentrodendron tonkinense (Gagnep.) Chang & Miau Fallopla multiflora (Thunb.) Haraldson Garcinia fagraeoides A. Chev, Goniothalamus vietnamensis L.
Gymnoslemmapenlaphyllum (Thunb.) Makino Leucosceptrum canum Smith
Madhucapasquieri (Dubard) H. J. Lam Manglietia fordiana Oliv
Markhamia stipulata (Wall.) Seem, ex Schum.
Melientha suavls Pierre Michelia balansae Dandy Morinda officinalis How Rauvolfia latifrons Tsiang Strophanthus wallichii A. DC.
Tetrapanaxpapyriferus (Hook.) C. Koch.
Paramichelia baillonli (Pierre.) S. Y. Hu Parashorea chinensis H. Wang Taxlllus graclllfolius (Schult. f.) Ban Tinospora sagillata (Oliv.) Gagnep Valeriana execia Merr.
Cho dai Kim tuyen da vol Tram huong La khdl Tram den De gai do Ca oi Sa pa Khao xanh Gil huong Re huong Lat hoa Sua Cot toai bo Nghiin Ha thu 6 do Trai l\' Beo den Dan toong Hoa bong Sen mat Vang tam Dinh Rau sang Gioi long Ba kich Ba gac la to Simg trau Thong thao Gioi gang Cho chi Moc ve ru Cu gio Nir lang
EN EN EN VU VU VU VU VU VU CR VU VU EN EN VU EN VU EN EN EN VU VU VU VU EN VU EN EN VU
vu VU
vu vu
LA
ll.A II.A I A ll.A II.A
ll.A
Ghi chd-- SDVN 2007: Sdch do Viit Nam, 2007. Trong do. CR Id rdi nguy cdp, £A Id nguy cap: VU Id se nguy cdp.
• ND sd 32/2006 ND-CP- Nghi dinh ciia Chinh phu ban hdnh ngdy 30/3/2006 cua Chinh phu vi qudn ly thuc vgt rimg, dong vdt rirng. thuc vdl rimg nguy cdp, quy. hiem Irong do- Nhom I.A cdn nghiim cdm khai thdc, sir dung vi muc dich thuang mai, Nhom ll.A cdn han chi khai thdc.sir dung vi muc dich ihuang mgl
Chdy rung
Day la nguyen n b a n lam suy thoai tai nguyen rimg mgt each nhanh c h d n g nhat, gay anh h u d n g tdi cac ho^t d g n g sdng ciia sinb vat tren mgt dien tich rgng ldn va gay ra cac hau qua xau (xdi m d n , lu lut, ban h a n . . . ) den ddi sdng con n g u d i . N g u y e n nhan chii yeu ciia chay rirng la d o boat d g n g khai thac cua con ngudi nhu: dot nirong Iam ray, ddt cac gdc eay to de khai thac than gd, ddt lira lay mat o n g . . . N g o a i ra chay rirng cdn d o nguyen
nhan thdi tiet nang ndng keo dai (thang 6, 7, 8, 9) vdi nhiet do trung binh tren 28°C va sd gid n a n g trung binh 155,26 gid.
T h e o ket qua t h d n g ke cua hat kiem lam huyen Vj Xuyen giai doan td nam 2005-2012, toan huyen cd 28 vu cbay rirng vdi dien tich rimg bi chay la 750,2ba.
Cdc nguyen nhdn khac
Lyc l u g n g kiem lam tinh Ha G i a n g ndi c h u n g va huyen Vj Xuyen ndi rieng cdn qua m d n g 119
D6 Khac Himg vdDtg Tap chi KHOA HOC & CONG N G n p so vdi quy djnh, cac trang thiet bi, phirong
tien phuc vu cho quan ly bao ve rirng cdn thieu thdn.
Ty le tang dan so cua huyen cdn kha c a o (1,2%), ddi song nhan dan cdn gap nhieu khd khan (ty le hg ngheo nam 2013 la 21,77%).
Vi vay, ddi sdng kinh te cdn phii thugc nhieu vao khai thac tai nguyen rirng.
Trinh do dan tri tbSp nen kbd t i l p can vdi cac c h u a n g trinh d y an v l rimg, nhan thiic cua ngudi dan v l tac hai eiia viee khai thac qua mirc tai nguyen rirng cdn ban che.
Cdng tac tuyen truyen phd bien, giao due ehinh sach phap luat cho nhan dan tuy da d u g c triln khai n h u n g c h u a t h u d n g xuyen, kip thdi.
Do phong tue, t^p quan da cd tir lau ddi nhu:
du canh du cu, phai sinh con trai hay chan tha gia siic vao rirng nen da lam cho tai nguyen rirng bi suy giam.
C h u a cd chinh sach t h u d n g , phat ro rang nen chua cd tac d u n g d g n g vien ngadi dan tich c y c tham gia bao ve rirng.
KET LUAN
He t h y c vat huyen Vi Xuyen cd thanh phan t h y c vat phong phu va da dang gdm 557 loiii
thudc 393 chi, 114 hg c u a 5 nganh t h y e vat bgc eao ed mach: N g a n h T h d n g dat, nganh Cd thap but, nganh Ducmg xi, nganh Thdng va nganh N g g c lan. T r o n g dd cd 3 3 loai t h u c vat quy h i l m cd trong Sacb dd Viet N a m (2007) va 7 loai d u g c ghi n h a n trong Nghj djnh 32 cua Chinb phii.
C a e hoat d g n g khai t h a c gd, khai thac Iam san ngoai gd va chay rirng la nhUng nguyen nhan chinh lam suy giam dien tieh va cbat lugng tham t h u c vat rirng d huyen Vi X u y e n .
TAI LIEU T H A M K H A O 1. Nguyin Tiln Ban (chii bien) va c6ng su (2003, 2005), Danh l\ic cdc lodi thuc vdl Viel Nam, Nxb Nong nghifp, Ha Npi.
2. Bp Khoa hpc va Cong nghe, Vien Khoa hpc va Cong nghe Viet Nam (2007), Sdch dd Viet Nam (phSn Thyc vat), Nxb Khoa hpc ty nhien va Cong nghe. Ha Npi.
3. Bp Nong nghiep va Phat trien Nong thfin (2000), Tin cdy rirng Viet Nam, Nxb Nong nghifp, HaN$i,
4. Chinh phu nude C6ng b o i xa h6i chu nghta Vift Nam (2006), Ngh; djnh 32/2006/ ND-CP yi qudn ly ihyc vdl rimg, dong vdl rimg nguy cdp, quy. hiim. Ha Noi,
5. Ph?m Ho^ng Hp (1991-1993), Cdy co Vi?l Nam, tap 1 - 111, Nxb Motreal, Canada,
S U M M A R Y
E V A L U A T I O N O F D I V E R S I T Y O F F L O R A S P E C I E S C O M P O S I T I O N A N D R E A S O N S C A U S I N G V E G E T A T I O N D E G R A D A T I O N
Do Khac Hung', Hoang Thi Huong', Vu Huyen T r a n g ' , Le Ngoc Cong^
'Ha Giang College of Education. 'College of Education - TNU In the 3 types of vegetalion covers (grass vegetation, shrub vegetation and second forest, there are 557 species belonging to 393 genera, 114 families of five branches of higher vascular plants such as Lycopodiophyta, Equisetopsida, Polypodiophyta, Pinophyta and Magnoliophyta. Of which, there are 15 families available over 10 species (accounting for 42.01% of total species), 13 genera available over 4 species (accounting for 12.39% of total species). There are 33 rare plant species in the 2007 Vietnam Red Data Book and 7 species recorded in Decree of Government No. 32.
Majority of statistical species are the light-demanding pioneer species growing on land exploited exhaustedly and on the area of forests without trees after large trees cut down. Although there is a rich and diversified flora, the vegetations in Vi Xuyen district is significant degradation in terms of area and quality that the main reasons is due to the activities of exploitation on logging, firewood and non-timber forest products and forest fire, etc.
Keywords: Secondary forests, vegetation, shrub, grass, Vi Xuyen district Ngdy nhgn bdi: 15/10/2014, Ngdy phdn bien-04/11/2014: Ngdy duyel dang- OS/5/2015 Phdn bien khoa hoc: TS. Dmh Thi Phuang - Trudng Dal hoc Suphgm - DHTN
Tel 0915 462404 120
