Ldm hgc
MOT S 6 DAC DIEM CAU TRUC VA DA DANG LOAI CAY GO
CUA RinVG Tir NHIEN TRANG THAI HIAI 0 SlTOfN D 6 N G VA SU^OfN TAY TAI P H A N K H U PHUC HOI SINH THAI CUA VU'OOV QUOC GIA BA VI, HA N O ICao Thi Thu Hien', D6 Hiru Huy^
^'^Truong Dgi hgc Ldm nghiep TOM TAT
So lieu duoc thu thap tu 8 6 ti€u chuan tam thai (OTC) tai suon D6ng va suon Tay ciia phan khu phuc hoi sinh thai, vuon Qu6c gia Ba Vi, Ha Ngi. M6i OTC co dien tich 5000 m^ (50 m x 100 ra). Trong m6i OTC, tit ca cac cay CO duong kinh tir 6 cm tro len dugc xac djnh ten loai, do duong kinh va chieu cao. Ket qua cho thay ducmg kinh trung binh dao dong tir 10,28 cm dSn 12,90 cm; chigu cao tmng binh nam trong khoang 8,57 m den 9,82 m; tong tiet dien ngang quin thu tir 10,08 m^/ha din 25,48 m^/ha va trii lugng tir 50,40 m^/ha dgn 98,65 m^/ha.
So loai cay trong moi OTC bien dong tir 42 den 67 loai; trong do co 4 dgn 6 loai uu the va dong ini thg. Nhom loai uu thg chi co 6 3/8 OTC. Phan bo so cay theo c6 duong kinh va chieu cao c6 the mo phong bang phSn bo ly thuyet Weibull hai va ba tham so. Ve da dang loai, trang thai rimg IIIAI O sudn Tay da dang han so voi trang thai rimg IIIAI a suon Dong.
Tir khoa: Cau true quan thu, da dang loai cay go, h6 Sff da d^ng, tdeu phan doi, ki^u xep haing, rung tu- nhien trang thai IIIA, tang cay cao.
1. DAT VAN DE
Mac du CO dien tich nho hem so vai nhieu Vuon quoc gia (VQG) khac trong ca nuac, nhimg VGQ Ba Vi c6 tam quan trpng dac biet trong viec bao ton da dang sinh vat, luu tru nguon gen qui hiem. Tong dien tich tu nhien cua VQG Ba Vi la 10.782,7 ha (100%), trong do dien tich dat co rimg la 8.192,5 ha (75,98%). So vai dien tich dm co rung (8.192,5 ha hay 100%), rung ta nhien la 4.200,5 ha (51,27%), con lai rung trdng la 3.992 ha (48,73%). Dien tich ciia trang thai rung trung binh (IIIA2, IIIB) va trang thai rimg ngheo (frang thai IIIAl) tap trung a khu vuc nui Ba Vi vai 883,9 ha.
Nam d vi tri thuan lgi, nai giao luu cua nhieu luong thuc vat, VQG Ba Vi co he thuc vat phong phii va da dang. Thanh phan thuc vat bao gom 1.209 loai thuc vat bac cao c6 mach thuoc 633 chi cua 157 ho; 668 loai thao dugc. Vuon quoc gia Ba Vi con n6i tieng bai cac loai cay qui hiem nhu Bach xanh (Calocedrus marcrolepis). Thong tre (Podocarpus nerrifolius). Phi ba miii (Cephalotaxus mannii). Sen mat (Maldhuca pasquieri), Quyet than go (Gymnosphaera gigantea). Bat giac lien (Dysosma pleiantha (Hance)... Khu he dong vat Ba Vi co 63 loai thii, 191 loai chim, 61 loai bo sat, 27 Ioai ludng
cu va 552 loai con tning, trong do co nhieu loai dong vat CO ten trong sach do nhu Cu li lan, Chon bac ma, Gau ngua. Cay van, Cay muc, San duang, Te te, Ga loi trang... Dac biet a day CO loai S6c bay {Pertanriste pertanrista) - mpt loai bieu tnmg ciia VQG Ba Vi. Noi chung, VQG Ba Vi thuc su la nguon tai nguyen qui gia cua quoc gia.
Tuy nhien, cac hoat dpng su dung dat, khai thac tai nguyen va dot rung lam nuang ray 6 viing dem va phan khu phuc hoi sinh thai trong qua khii da lam mat di nhieu khu rimg nguyen thuy, lam anh huong tai cau tnic va da dang loai, lam bien doi nguon thuc an va noi cu tni ctia nhieu loai dgng vat va thuc vat quy va hiem.
Cho den nay van chua co nhihig nghien cuu ve cau tnic quan thu va da dang loai cay go doi vai nhimg trang thai rimg a suon Dong va suon Tay thupc khu phuc hoi sinh thai tai VQG Ba Vi. Do vay, bai bao nay giai thieu ket qua nghien cuu cau tnic quan thu va da dang loai cay go doi vai trang thai rung llUi thupc khu phuc hoi sinh thai tai VQG Ba Vi. Nhijng thong tin tir nghien ciiu nay gop phan bo sung nhiing hieu biet ve ket cau loai cay g6, cau tnic quan thu va da dang loai cay go doi voi kieu rimg kin thuong xanh am nhiet doi tai VQG Ba Vi.
2. PHlTONG PHAP NGHIEN CUXl 2,1. Phirung phap thu thap so lieu
TAP CHI KHOA HQC VA C 6 N G NGHE LAM NGHIEP SO 1 - 2019 45
Ldm hoc
Doi tugng trong nghien cuu nay la rimg tu nhien trang thai IIUi theo he thong phan loai cua Loeschau a dp cao 700 m so vai muc nuac bien.
Tren moi vi tri dia hinh lap ngau nhien 4 6 tieu chuan (OTC), dien tich mdi OTC la 2500 m^ (50 X 50 m).
Trong moi OTC da lap tien hanh dieu tra tang cay cao ve cac chi tieu sau:
- Danh dau va dem toan bp so cay trong 6 tieu chuan;
- Xac dinh thanh phan loai, ten loai (nhiing loai khong biet ten hoac khong ro ten thi ghi ki hieu la sp);
- Do duang kinh ngang nguc (Di 3) ciia tat ca cac cay co duong kinh Ion hon hoac bang 6 cm bang thuoc kep kinh d6 chinh xac 0,5 cm;
Do chieu cao vut nggn: Dung thuoc Blumeleiss vai dp chinh xac 0,5 m.
Toan bp cac so lieu do dem t&ig cay cao dugc ghi chep theo mau bieu dieu tra tang cay cao.
2.2. Phuong phap xu ly so lieu
a) Mgt so chi tieu ve nhdn to dieu tra qudn thti Cac nhan to cau tnic bao gom mat do (N), duong kinh binh quan (i'l.s), chieu cao binh quan {Hyfj), tong tiet dien ngang (G), va hu lugng (M).
b) Cong thirc to thdnh theo chi so IV%
Phuang phap xac dinh miic dp quan trpng (Important Value- JV) ciia Daniel Marmillod, Vu Dinh Hue (1984) dupe diing dk xac dinh t6 thanh loai cay.
IV% -- (1)
Trong do;
IV%: Chi so miic do quan trpng cua loai trong quan xa.
N% la mat do tuong ddi (N% = Ni/N) va G% la tiet dien ngang than cay tuang ddi (G%
- Gi/G). Ni va Gi la mat do va tdng ti^t ngang ciia loai i.
Theo Daniel Marmillod, loai cay nao cd IV,
> 5% la loai cd y nghia ve mat sinh thai. Theo Thai Van Trung (1978), nhdm dudi 10 loai cay cd tdng IV|%. > 50% tdng ca thd tSng cay cao thi chiing duac coi la nhdm loai tru thd (con gpi la uu hgp thuc vat).
c) Quy lugt phdn bd so cdy theo ca duong kinh vd chieu cao
Cac md hinh ly thuydt la phan bd giam dang ham Meyer, phan bd khoang each, phan b6 Weibull hai va ba tham sd dugc lua chpn dk md ta cac phan bd thuc nghiem N/Du, N/HVN.
d) Da dgng lodi cdy go
De danh gia da dang loai cay gd, gop 4 OTC d mdi vi tri (sudti Ddng va sudn Tay) thanh 1 OTC. Ca sd dg gdp 4 OTC d mdi vi hi la cd su ddng nhat ve phan bd dudng kinh ciia ca 4 OTC. Tieu chuan Kolmogorov-Smimov dugc diing de kiem tra su ddng nhat nay.
De xac dinh va danh gia miic do da dang loai cay gd cho trang thai rung IIIAI d hai vi tri sudn Ddng va sudn Tay, ba chi sd da dang sau dugc dung la sd loai, chi sd Simpson va chi so Shannon-Wiener (theo Gove, Patil, Swilden va Taillie (1994, chuong 12)).
- Sd loai Asc:
Asc=i:U{;^}iri = s (2) - Chi so Simpson Asi:
^si=i:un-^i]ni = i-iUi^i'' (3)
- Chi sd Shannon-Wiener ASK:
^sh= I.Ui{-logni]ni = -ZUiT^ilogUi (4) Trong dd: TTJ = — la ty le ciia loai i;
n, la sd ca the cua loai i;
N la tdng sd ca the;
s la sd loai.
e) Ho Sff da dgng
Hd so da dang dugc dung de danh gia miic do da dang loai cay gd cho trang thai rung IIUi d sudn Ddng va sudn Tay. Hai kieu hd so da dang dugc diing la:
- Kieu phan ddi:
.P>-
(5)Trong dd, khi ^ ^ -1, A.i la sd loai, khi ^ = 0, Ao la chi sd Shannon-Wiener va khi ^ = 1, A] la chi sd Simpson.
- Kieu xep hang:
Ti = T.Uj+,nfvaij=l,,,..,s-l (6) Trong do: T^-0 and To - 1. Neu cac ho sa
da dang Tj khong giao nhau thi trang thai rCmg nao CO ho so Tj nam tren se da dang hon, nh 46 TAP CHI KHOA HOC VA C 6 N G NGHE LAM NGHIEP SO I - 2019
Lam hgc cac hd so da dang Tj ma giao nhau thi khdng hanh tinh toan xac dinh cac dai lugng ve mat cdtr^ng thai rimg nao da dang hon. 36 N (cay/ha), dudng kinh binh quan (O1.3), 3. K E T Q U A VA T H A O LUAN chidu cao binh quan (H„„} tdng tidt dien ngang 3.1. Cau t r u e qu^n t h u ( I G / h a ) , thd tich va hii lugng (M/ha). Kdt qua
Tu sd lieu thu thap dugc d trang thai rimg ^ugc tdng hgp trong bang 1.
tu nhien IIIAI tren 8 d tieu chuan (OTC) d hai vi tri dia hinh la sudn Ddng va sudn Tay, tien
Vi tri Suon Dong
Suon Tay
OTC 1 2 3 4 1 2 3 4
Bang 1. IMdt so dac N (c3y/ha)
1644 1900 1424 1292 1464 1664 1064 1108
trimg cau true ciia tr^ng thai Di s (cm)
11,43 11,20 12,90 12,59 10,74 10,40 10,28 11,37
H„„ (ra) 8,84 9,65 9,82 8,78 9,71 9,23 8,91 8,57
rtmg IIIAl G (mVha) 20,70 21,91 25,48 21,57 15,18 15,90 10,08 13,07
M(ra'/ha) 82,32 95,13 98,65 85,52 66,32 66,04 50,40 50,41 Mat dp cay tren cac OTC 2500 m dao ddng hoac phan tram (Nguyen Van Them, 2002).
tu 1064 - 1900 cay/ha, dudng kinh trung binh Khi bieu thi td thanh theo sd cay, cac he sd td dao ddng tir 10,28 - 12,90 cm, chieu cao trung thanh dugc xac djnh theo chi sd phan mudi. Td binh nam trong khoang 8,57 - 9,82 m, tdng tiet thanh tang cay gd cdn dugc phan anh thdng dien ngang quan thu tir 10,08 - 25,48 m^/ha va qua chi sd phan tram ve muc do quan trpng cua trir lugng bien ddng trong khoang 50,40 loai trong quan xa (IV%). Chi sd IV% danh gia 98,65 m^/ha. Theo Thdng tu sd 34/2009/TT- miic dp quan trpng cua loai tren ca sd xem xet BNNPTNT thi cac OTC thudc ddi tugng la tdng hgp cac chi tieu gdm mat do tuong ddi va rimg ngheo. tiet dien ngang tuong ddi, chi sd IV% cua loai 3.2. Ket cau loai cay go nao dd cang cao thi loai dd cang cd y nghTa Cau tnic td thanh ciia tang cay gd chi thanh quan trpng ve phuong dien sinh thai. Ket qua phan va ty le sd lugng don vi ca the (hoac the tinh td thanh tang cay cao theo chi sd quan tich than cay, tiet dien ngang than cay) ciia loai trpng cho cac OTC d hai vi tri dia hinh (sudn so vdi chi tieu tuang ung cua tat ca cac loai Ddng va sudn Tay) dupe trinh bay d bang 2.
hinh thanh ning, dan vi tinh theo phan mudi
Bang 2. Ket cau loai cay go doi v6i trang thai rirng IlIAi Vi tri OTC So loai ^**.'''^'*!!.!1!" Cong thirc t6 thanh
• gia CTTT ^ Suon
Dong
Suon Tay 1 2 3 4 1 2 3
67 43 42 54 66 59 51
4 5 5 4 5 6 4
19,4 M + 12,8 CDL + 5,8 TT + 5,7 Kh + 56,2 CLK 24,1 M + 16,5 K h + 11,1 CDL + 10,1 D + 6,9 S + 31,4 CLK
19,3M+18,2SS + 8,lB + 7,lKn + 6,9Kh + 40,4CLK 17,9 M +13,1 SS+ 9,9 HQ +7,8 Kh + 51,2 CLK 15,5 Sx + 6,8 Rrx + 6,7 Ch + 6,5 Hn + 6,4 Kh + 58,0 CLK
18,1 S x + 11,1 C h + 10,9 Rrx + 7,0 Tn +6,1 Hn + 5,2 Hq+41,5 CLK
18,5 Tn + 7,0 Sx + 6,4 Mt + 5,8 Hn + 62,4 CLK 10,4 Tn + 8,9 Tr + 5,4 Kh + 5,0 Pm + 70,3 CLK Chu thich: M: MS: CBL: Che dudi luon: TT. Thdu tdu: Kh: Khdo: B: Bdng: S: Soi: SS: Sau sau: Kn:
Khdo nude: HQ: Hodc quang: Sx: Soi xanh: Rrx: Rdng rdng xanh; Ch: Cheo: HN- Ha nu: Tn: Thdnh ngach; Mt: Mdi tdp; Tr: Trdm; Pm: Phdn md; cdc lodi khdc: CLK.
T A P C H I K H O A H O C VA C 6 N G N G H E LAIVI N G H I E P SO I - 2019 47
Ldm hoc
Ket qua bang 2 cho thay, sd loai cay trong mdi OTC bidn ddng tir 42 ddn 67 loai nhimg sd loai cay tham gia vao cdng thiic td thanh chi cd tu 4 den 6 loai. Thanh phan loai trong CTTT d hai vi tri la sudn Ddng va sudn Tay khdng khac nhau nhieu va it loai cay cd gia tri ve mat kinh td. Nhdm loai uu the chi cd d 3/8 OTC, OTC 2 va OTC 3 sudn Ddng va 3 OTC (OTC 1, OTC 3 va OTC 4) d sudn Tay khdng xuk hien nhdm Ioai cay uu the. Cac Ioai cay tm thd chii yeu la: Md, Sdi xanh, Thanh ngach, Sau sau, Khao... Cac loai cay cd mat trong CTTT chu yeu la nhirng loai ua sang nhu: Bdi Idi, Thanh ngach, Khao va nhiing loai trung tinh nhu Thau tau... Nhirng loai cay trong cdng thiic td thanh da sd la cay cd dudng kinh nhd, chua cd nhidu gia tri ve kinh td nhung cd gia tri sinh thai cao trong qua trinh phuc hdi rung, vdi vai trd la nhung cay tien phong tao lap, phuc hdi hoan canh rung quy luat tu nhidn len cap cao hon, tao mdi trudng sdng cho cac loai ddng vat, thuc vat hoang da khac.
Cac trang thai rung trong nghien cuu nay la rirag tai sinh sau nuong ray, sau khi rimg dugc bao ve tdt qua trinh dien thd thir sinh trdn hai vi tri nay dien ra ddng thdi song song nhau va ddu khdng bi tac ddng trong qua trinh dien the, didu nay cho thay rimg d hai sudn chu yeu la cac loai ua sang mgc nhanh, mat khac ngudn gidng tir cay me lan can d pham vi nghien ciiu Bang 3. Ket qua mo phong cho 8 OTC & swim Dong va saim
thanh ph4n loai chu ydu la cay me gidng nhu cac loai trong bang 2.
3.3. C5u true cua trang thai rung IIIAi Phan bd sd cay theo c i p dudng kinh bieu thi su s4p xdp cac ca thd cay rimg theo dp Idn ciia kich thudc than cay. Dp Idn cua dudng kinh than cay va tudi cua cay cd mdi lien he chat che vdi nhau. Vi the, phan bd N/D ddi khi Cling dugc su dung de md ta mdt each dan gian phan bd cay theo tudi. Su hieu biet ve cau tnic N/D CO y nghia Idn ca ve sinh thai hpc va ky thuat lam smh. Ve sinh thai hpc, phan tich ciu tnic than cay cho phep hieu dugc tinh phiic tap cua quan xa thirc vat than gd, phan tich tiem nang sinh hpc va quan he canh tranh giiia cac loai, xac dinh tac dpng ciia mdi trudng den cay rimg... Vd lam sinh, su hieu biet phan bd N/D cho phep ling dung cac bien phap ky thuat nuoi dudng va khai thac cay rimg trong kinh doanh rimg. Ddi vdi rimg tu nhidn hdn loai cd tuoi khac nhau, cau tnic than cay la ca sd dd phan tich tidm nang sinh hpc va tidm nang kinh te cua cac loai cay, ddng thdi qua dd lua chpn loai cay thich hgp theo cac muc dich kinh te khac nhau.
Phan bd N/Di 3 dugc md phdng bang phan bd giam dang ham Meyer, phan bd khoang each va phan bd Weibull hai tham sd, ket qua da lua chpn dugc dang phan bd phu hgp do la phan bd Weibull hai tham sd.
phSn bd thuc nghiem N/Du TSy theo ham Weibull hai tham so Vj tri
Suon Tay
Suon Dong
OTC 1 2 3 4 1 2 3 4
a 1,0 1,2 1,0 1,0 1,1 1,1 1,0 1,3
X 0,170 0,177 0,217 0,097 0,174 0,122 0,139 0,146
3,542
x'
1,133 4,03 9,957 9,456 5.146 19,186 8,652
X 05(k)
12,6 9,49 11,1 14,1 15,5 12,6 21,0 18,3
Kit lu^n Ho*
Ho*
Ho*
Ho*
He*
Ho*
Ho*
Ho*
Bang 3 cho thay ca 8/8 OTC cd gia tri x iinh nhd han gia tri x^05(k), nghTa la quy luat phan bd sd cay theo dudng kinh (N/D| 3) ciia rimg tu nhidn trang thai IIIAI tai hai vi tri (sudn Ddng va sudn Tay) cua khu vuc nghien cd thd md
phdng tdt bang phan bd Weibull. Nhin chung, phan bd sd cay theo cd dudng kinh cua 8 OTC ddu tuan theo quy luat sd cay giam dSn hi cap kinh nhd den Idn va cd gia tri Idn nhit tai co kinh 8 cm. Hien tugng nay phan anh cac dac TAP CHI KHOA HOC VA CONG NGHE LAM N G H I f P SO 1 - 2019
Ldm hgc trung c a ban ciia rung tu nhien nhu: rimg cd
nhieu Ioai cay vdi dac tinh sinh hpc va tudi khac nhau, chiu su tac ddng ciia nhieu nhan td khac nhau (quan xa thuc vat, khi hau, dat...).
Nguyen nhan din ddn kidu phan bd nay la do quy luat dao thai tu nhien, do cac ca thd cung loai cd tudi khac nhau, do nhidu loai cd hinh thai va kich thudc khac nhau.
Cac OTC dugc lap trong phan khu phuc hdi sinh thai, day la ddi tugng rimg dugc uu tidn thuc hien (tac dgng) cac bien phap ky thuat ldm sinh nhu: khoanh nudi xiic tien tai sinh tu nhidn hoac khoanh nudi xue tidn tai sinh cd
trdng bd sung cac loai ban dia, nham nit ngan qua trinh dien the thiic day nhanh qua trinh hdi nguyen he sinh thai rtmg. Do do can tia bdt cac cay cd chat lugng xau d cac cap kinh bi ii dpng va cay phi muc dich dd md rdng khdng gian dinh dudng, tao didu kidn cho nhirng cay muc dich sinh trudng va phat trien tdt.
3.4. Quy luat p h a n bo so cay theo c& chieu cao ( N / H V N )
Kdt qua md phdng phan bd sd cay theo cd chidu cao cua 8 OTC trang thai IIUi d sudn Ddng va sudn Tay duac tdng hgp d bang 4.
Bang 4. Ket qua mo phong phSn b6 thuc nghiem N/Hvt cho 8 OTC fr sufrn Bong va suom T5y theo ham Weibull ba tham s V i t r i
Suon Tay
Suon Dong
OTC 1 2 3 4 1 2 3 4
P
2,3 2,3 2,7 2,3 2,3 2,7 2,8 2,3
r
5,5 4,9 5,3 5,3 5,6 5,4 5,2 5,2
^
4,9 4,9 3,9 3,9 3,9 4,9 3,9 3,9
p-value 0,087 0,121 0,116 0,101 0,104 0,099 0,115 0,091
Mirc y nghia 0,05 0,05 0,05 0,05 0,05 0,05 0,05 0,05
Kh lu^n Ho*
Ho*
Ho*
Ho*
Ho*
H„*
B ?
Kdt qua d bang 4 cho thay, phan bd Weibull ba tham sd md phdng tdt (Ho^) cho phan bd thuc nghiem sd cay theo co dudng kinh (p- value > 0,05). Cac phan bd N/H d 9 OTC ddu cd dang lech trai (P < 3), sd cay tap trung chii yeu d cd chidu cao thap tir 7 m den 9 m nen can cai thien tinh hinh rimg bang cac bien phap ky thuat lam sinh nhu tia thua loai bd nhiing cay cd pham ch§.t kem, gia trj kinh te khdng
cao, de tao khdng gian sinh trudng hgp Iy cho cac loai cay kd can sinh trudng va phat tridn.
3.5. Da dang loai cSy gS theo chi so da d a n g va ho SO" da dang
3.5.L Chi so da dgng
Ket qua tinh chi sd da dang Ioai cay go cho 8 OTC d hai vi tri sudn Ddng va sudn Tay dugc tdng hgp trong bang 5.
So loai Shannon - Simpson
Bang 5.
Chi so - Wiener
Chi sd da d^ng loai cay go a surm SiroTi Dong
111 0,925 3,364
Dong va svtffn Tay V i t r i
Sirofn TSy 110 0,957 3,684 Chi sd Shannon-Wiener va chi sd Simpson
sudn Tay cao hon mdt chiit so vdi sudn Ddng (Bang 5). Tuy nhien, cd su mau thuan vd da dang Ioai cay gd giGa hai vi tri sudn Ddng va sudn Tay, cu the, ASK, Asi (sudn Tay) > Ash, Asi
(sudn Ddng), nhung Asc (sudn Tay) < Asc (sudn Ddng). Sy khdng ddng nhat nay cd thd dugc giai thich bdi su thidt hut ve da dang ndi tai ciia trang thai rimg dugc nghidn ciiu.
3.5.2. Hd Sff da dgng
T A P C H I K H O A H O C VA C O N G N G H E L A M N G H I E P SO I - 2019 49
Ldm hoc _ = ^ ^ = ^ ^ ^ = - Kieu phdn doi:
Hd so da dang Ap ciia trang thai rtmg IIIAI O sudn Ddng giao nhau vdi hd so da dang ciia trang thai rimg IIIAI d sudn Tay tai gia tri p - - 0,1 (Hinh I), didu nay giai thich tai sao hai gia
AP
120 -, Sd loai
hn Ash, As, ciia trang thai riing IIIAI d sudn Tay Idn han trang thai rimg IIUi cf sudti Ddng nhung gia tri Asc cua frang thai rtrng IUAI d sudn Tay nhd han trang thai rung IIIAI d sudn Ddng (Bang 5).
Shannon-Wiener Simpson
-1 -0.7 -0.4 -0.1 0.2 0.5 0.8 1 1.4
Hinh 1. Htt so da dang Ap cua 8 OTC trang thai rung IIIAI ff su(m Dong va suon Tay - Kieu xep hang vd da dang ndi tai, trang thai rimg IIIAI d sudn Hd so da dang Tj cua trang thai rtmg IIIAI d Tay la da dang hon so vdi hai trang thai rimg sudn Tay nam tren hd so da dang Tj cua trang IIIAI d sudn Ddng.
thai rimg IIIAI d sudn Ddng (Hinh 2). Do dd, Ti
1 11 21 31 41 51 61 71 81 91 101 111 Hinh 2. Ho sff da daing Tj cua 8 OTC trang thai rung IHAI ff sufrn Dong va sufrn TSy 4. K E T LUAN
8 OTC trong nghidn ciiu nay thupc ddi tugng rimg ngheo. Sd loai cay trong moi OTC bien ddng ttr 42 den 67 loai nhung chi cd tir 4 den 6 loai cd mat trong cdng thiic td thanh va
nhdm loai uu the chi xuat hien d 3/8 OTC.
Phan bd sd cay theo co dudng kinh cua 8 OTC ddu cd the md phdng tdt bSng phan bo Weibull hai tham sd va tuan theo quy luat so cay giam dan tir cap kinh nhd den Idn va cd gia 50 T A P CHI K H O A H O C VA C O N G N G H E L A M N G H I E P SO 1 - 2019
Ldm hoc
fri Idn nhat tai cd kinh 8 cm. Do dd c i n tia bdt cac cay cd chat lugng xau d cac cap kinh bi li dpng va cay phi muc dich dd m d rgng khdng gian dinh dudng, tao didu kien cho nhiing cay muc dich sinh trudng va phat tridn tdt.
Phan bd Weibull ba tham sd md phdng tdt cho phan bd sd cay theo cd chieu cao vdi chieu cao cua cay rimg chii yeu tap tmng d cd chieu cao thap tir 7 m ddn 9 m nen can cai thien tinh hinh rimg bang cac bien phap ky thuat lam sinh nhu tia thua loai bd nhirng cay cd pham chat kem, gia tri kinh td khdng cao, de tao khdng gian sinh trudng hop ly cho cac loai cay kd can sinh trudng va phat tridn.
Ve da dang Ioai cay gd, trang thai rimg IUAI d sudn Tay da dang h a n so vdi trang thai rimg IIIAI d sudn Ddng.
T A I L I E U T H A M K H A O
1. Nguyen Tuan Binh (2014). Dac diem lam hoc ciia rirag kin thuang xanh nhiet dai a khu virc Ma Da, tinh Dong Nai. Tgp chi Nong nghiep vd Phdt trien nong r/iOH, s6 22, T r 9 9 - 1 0 5 .
2 Bp Nong nghiep va Phat trien nong thon, Vu khoa hoc cong nghe va chat lirang san pham (2000). Ten cdy
rirng Viet Nam. Nxb. Nong nghiep. Ha Npi.
3. Bp Khoa hpc cong nghe, Vien Khoa hpc va Cong nghe Viet N a m (2007). Sach do Viet Nam. P h k 11.
Thuc vgt Nxb Khoa hpc tir nhien va Cong nghe. Ha Npi.
4. Vo Dai Hai (2014). Nghien cmi mot so dac diem cau true tang cay cao rung IIA tai khu virc rirng phong ho Yen Lap, tinh Quang Ninh. Tap chi Khoa hoc Ldm nghiep, sa 3, Tr.3390 - 3 3 9 8 .
5. Nguyin Thi Thu Hian, TrAn Thj Thu Ha (2014).
Nghien ciJru mot so dac diem cau true rimg tir nhien la rpng thucmg xanh tai Yuan Quoc Gia Nu Quang - Ha TTnh. Tap chi Khoa hgc Ldm nghiep, so 3, Tr. 3408 -3416.
6. Nguyen Van Hong (2010). Nghien cuu dgc diem cdu triic rimg vd xdc dmh moi quan he giita to thdnh lodi cdy go, lodi cdy tdi sinh vai lodi cdy go, lodi cdy tdi sinh cho LSNG trong rimg tu nhien thupc BQL Rimg dgc dung Huong Scm, Hd Tinh. Luan van thac si Khoa hpc Lam nghiep, Truong Dai hoc Lam nghiep.
7. Nguyen Hai Tuat, Nguyen Trong Binh (2005).
Khai thdc vd sir dung SPSS de xir ly so lieu nghien ciru trong Ldm nghiep Nxb. Nong nghiep. Ha N^i.
8. Trung tam nghien cuu tai nguyen va moi tmong (Dai hpc Quoc gia Ha Noi); Vien Sinh thai va Tai nguyen sinh vat (Vien Khoa hpc va Cong nghe Viet Nam) (2005), Danh luc cdc lodi thuc vdt Viet Nam, tap III, Nxb, Nong nghiep, Ha Noi.
SOME STRUCTURAL CHARACTERISTICS AND TREE SPECIES DIVERSITY OF FOREST STATE HIAI ON THE EASTERN AND WESTERN SLOPES OF THE ECOLOGICAL REHABILITATION ZONE,
BA VI NATIONAL PARK, HANOI
C a o Thi Thu H i e n \ Do Huu Huy^
'''Vietnam National University of Forestry S U M M A R Y
The data were collected from 8 temporary sample plots on the eastern and westem slopes of the ecological rehabilitation zone, Ba Vi National Park, Hanoi. Each plot has an area of 5000 m* (50 x 100 m). All trees with a diameter from 6 cm were marked, species were identified and diameter was measured, the height in each plot was measured for 50 random trees. The results showed that the average diameler ranged from 10 28 cm to 12,90 cm, mean height was from 8.57 m to 9,82 m, stand basa! area varied from 10 08 m^/ha to 25 48 m^/ha, and the volume was from 50.40 m^/ha to 98,65 mVha. The number of tree species in each plot varied from 42 to 67 species, but the number of species involved m the species composition ranged from four to six species.
Dominant species were found only in 3 out of 8 plots. Diameter and height frequency distributions can be fitted by using the Weibull distribution. In terms of species diversity, forest status IIIAI on the westem slopes is more diverse than those of the eastern slopes
Keywords: Dichotomous type, diversity profile, natural forest III^, overstorey, r a n k type, s t r u c t u r e a n d tree species diversity.
Ngay nhan bai Ngay p h a n bien Ngay quyet dinh dang
17/8/2018 21/01/2019 28/01/2019
T A P C H I K H O A H O C VA C 6 N G N G H E L A M N G H I E P SO I - 2019
