Xác định tỉ lệ diện tích điều tra trữ lượng rừng tự nhiên

KHOA HQC CdNG NGHfi

XAC OIIMH Ti t e DlflXi TlCH DIEU TRA TRLT LUQIMG

RIJlXIG TU IVHl£lV

va Tidn HinhS Luang Thj Phuong*,

Ph?m Thd AnfaS VQ Tidn Hung*

T6MTAT

xay dung dupe phirong phap xac dinh tru lupng cho c^c 16 rimg tu nhidn a nuoc ta la vdn dd co y nghia

khoa hpc va thuc tidn. Nghidn cuu ndy buoc ddu da xac dinh dupe h^ sd bidn dpng tru lupng va ^ 1^ di^n

tich didu tra tru lupng cho cic 16 rimg co hang tiiii vA di$n tich khic nhau tiiupc cac tinh vimg TSy Bac vd

D6ng Bic Vi§t Nam, ddng tii6i cho tiily, h^ sd bidn dpng tm lupng c6 xu huong giam din khi didn tich 6

mdu tang ldn vd 6n dinh theo ki^u trang tiiii rimg. Kdt qua nghidn cthi gop phin hoan tiii$n quy hinh

hu6ng ddn c6ng tic didu tra tru lupng cho cdc 16 rung tp nhidn.

Tu kh6a: H6 sdbidn ddng trOlugng, kich tiiudc d miu, tyl$ di$n tich diiu tra.

LDATVANDE

Hidn nay d Vidt Nam, vide didu tra ddnh gid tdi

nguydn rimg ndi chung vd rimg ttr nhidn ndi ridng

tidn quy m6 didn tich ldn da dupe thtrc hidn trdn co

sd ban dd hidn trang rimg dtrpc xdy dtmg tir dnh vidn

tiidm. Thd nhung, vide didu tra trii lupng cho ciic Id

rimg cu tfad tfai chua cd quy trinh hudng dan ky thudt

ndo dupe xdy dung cd co sdr khoa hpc. Cd noi sir

dyng phuang phdp d tidu chuIn didn hinh dd xdc

djnh trir lupng. Phuong phdp nay cd han chd Id

khdng xdc djnfa dupe sai sd ciia trii lupng; dO chinh

xdc d a kdt qua didu tra phti thudc vdo mtic dO dai

didn cua d tidu chuan. Ngodi phirong phdp d tidu

chuIn didn hinh, d fad thdng cung hay dupe sii dting.

Phuong phdp ndy cd uu didm Id tinh dai didn cao,

nhung cin phai bidt tnrde ti Id didn tich didu tra todn

didn cho mdi Id rimg tuong ting vdi dO chinh xdc vd

didn tich d mlu cho trude. Dd tii ngfaidn cthi nfadm

gidi quydt vin dd ddt ra a trdn.

L MUC Tiai, NOl DUniG VA PHUUNG PHAP NGHfiV CUU

1. Mt^c tidu

Xdc djnh dupe ti 1$ didn tich didu tra, sd d mau

cin bd tri tuong ting vdi dp chinh xdc cho trude cua

dc Id rimg tir nhidn khi didu tra trii lupng.

2. NOi dung nghidn cihi

- Xdc djnh bidn dOng trir lupng cho d c d mlu cd

didn tich kfadc nfaau;

- Xdc djnfa ti 10 didn ticfa didu ti-a todn didn tuong

img vdi do chinh xdc cho tnrdc.

' Trudng D?ii hpc Lam nghipp

3. Phuong phdp nghidn cthi

Ddi tugng nghidn cuu: Rimg ti/ nhidn thudc kidu

rimg gd Id rOng thudng xanh Otidu trang thdi phuc

hdi vd tini sinh da bj tdc dOn^.

D/a didm nghidn ctiu: MOt sd tinh midn ntii pfaia

Bdc Vidt Nam.

Thu tiiip sd idu: So UOu dupe tiiu tiidp ti-dn 24 Id

rimg ttr nhidn, trong dd: Didn Bidn 7 Id, Son La 5 Id,

Hda Binh 3 Id, Ydn Bdi 4 Id, Bic Giang 5 Id; gdm cdc

ti-ang tiiai: IIB (5 Id), IIIAI (4 Id), 111^2 (5 Id), 111*3 (5 Id),

IIlB(51d).

Trdn mdi Id bd tri tir 5 ddn 10 d mlu theo

phuong phdp fad thdng cdch ddu trdn tuydn. T^i mdi

vj tri da chpn, sd Udu didu tra dupe thdng kd tfaeo d c

d hinh trdn ddng tdm cd didn tich tuong ling: 0,01 ha,

0,02 ha, 0,03 ha, 0,04 ha, 0,05 ha. Sd Udu tiiu tiidp dr

d c d Id dudng kinh ngang ngtrc vd chidu cao viit gpn

ciia timg dy cd dudng kinh tir 6 cm tra ldn. Vide bd

tri cdc d mlu cd diOn tich khic nhau sd Id ca sd cho

vide lira chpn didn tich d mlu hpp ly.

Ngodi ra, ngfaidn cihi cdn sii dting sd Udu d a 15

d dinh vj ciia Vidn Khoa fape Ldm nghidp Vidt Nam.

Trong d, mdi cdy ddu d tpa dO. 6 mdi d bd tii hd

tiidng theo tuydn 16 didm, tai mdi didm bd tri cdc d

mlu hinh trdn ddng tdm vdi didn tich tuong ting nfau

ti-dn.

Xuly sdliiu: Trin moi Id xdc ldp 1 dudng cong

cfaidu cao tir sd Udu dudng kinh vd chidu cao d d c d

mlu. Dudng cong cfaidu cao dupe xdc djnfa tir quan

hi H = a + b.\ogD.

Ddy Id phuong trinh tfaicfa fapp nhlt md td quan

fad H/D cho ddi tupng nghidn cthi. Trii lupng dupe

NCNG NGHlfP VA PHAT TRI^N N6N G TH6N Kt 1 - THANG 8/2011 89