SC DUNG QGIS VA PHAN TICH THlT BAC (AHP) D £ PHAN CAP NGUY CO CHAY RITNG TAI HUYEN MU'OfNG CHA, TINH DIEN BifeN

Bill Manh Himg, Nguyen Thanh Thuy Van Truang Dai hoc Ldm nghiep

T 6 M TAT Chay rung da va dang la mot vin dl dang duoc quan tam. Chay rimg da gay thiet h i Ion ve ngucri va tai san cho nhiiu huyen miln niii, trong do co huyen Muang Cha. BSng viec ke thira va dieu tra cac tai li?u vl diau kien kinh tl xa hoi, cac loai ban d6 hien co n-en dia ban huyen Muong Cha, nghien cim da xay dyng dugc 9 lop ban d6 tuong img voi 9 nhan t6 co thi anh hucmg tai nguy co chay rimg: dp doc, hudng phoi, d$ cao, khoang each din song su6i, den duong giao thong, dSn khu dan cu, din nuong rdy, loai trang thai rung va loai dat, Sau do cac lop dirge phan loai theo 5 cip chay rimg tir 1 din 5. Trong do, 1 la khu vuc co nguy co thSp va 5 la khu vuc CO nguy co chay rimg cao nhdt. Phucmg phap phan tich thu b|c AHP dugc sii dung dl tim va xep hang dugc frong s6 cho 9 nhan tl anh hucmg. Trong do cac nhan to anh huang Ion nhit ten chay rung la loai rung, khoang each din nuang riy, khoang each din khu dan cu va dg cao. Trgng so cua cac nhan to anh hucmg 16n nhit nay dao dgng ni 0,16 xuIng toi 0,12. QGIS dugc su dung kit hgp voi cac trgng si tim dugc, cac lap ban dl duoc cbing xip va san phim cu6i ciing thu dugc la ban do phan cip nguy ca chay rimg tai huyen Muong Cha. Dien tich toan huyen dugc chia thanh 5 cip chay rung. Trong do, tong dien tich ciia cap Thap va Cue ky nguy hiim tuong img la khoang 17 va 19 nghin ha. Cip Trung binh, Cao va Nguy hiem co dien tich 1cm hon, dao dgng tir 41 din 50 nghin ha. Do chinh xac ciia ban do nguy co chay rimg tuang doi cao, tren 80% so vcfi so li u phong vin trong 3 nam gan day. Tir khoa: Chay rirng, Mirong Cha, phSn tich thir bac, QGIS.

1. DAT VAN DE 6 Viet Nam, chay rimg la mot trong nhung

van de dang duoc quan tam. Bdi le, trong nhimg nam gan day, nhieu khu vuc da xay ra chay rimg va de lai hau qua va thiet hai nghiem trgng ve ngudi va tai san (Ha Cdng Tuan va cdng su, 2004). Chay rimg con lam anh hudng xau tdi mdi trudng khdng khi, mdi tnrdng nude va dat d nhieu dia phuang. Theo thdng ke cua bd Ndng nghiep va phat trien ndng thdn, tinh den thang 12 nam 2016, Viet Nam da xay ra 2.792 vu chay, trong dd cd 388 vu chay rimg vdi 3.309 ha rimg bj chay (Ha Cong Tudn va cdng su, 2004; Nguyen Ngpc Thach va cdng su, 2017). Trong vai thap ky gan day, biSn ddi khi hau vdi nhimg dot ndng han keo dai bat thudng da lam cho chay rimg trd thanh tham hoa ngay cang nghiem trong. Theo sd lieu cua Cue kiem lam, d Viet Nam binh quan mdi nam xay ra hang tram vu chay rimg va dien tich bi thiet hai la hang chuc nghin ha (Ha Cdng TuSn va cdng sy, 2004).

Chay rimg la mpt van de Idn, thudng xuyen xay ra khong chi ddi vdi tinh Dien Bien ma cdn ddi vdi cac tinh khac tai Viet Nam, dac biet cac tinh mien nui. Chay rimg gay anh hudng nghiem trpng ve mat vat chSt va con

ngudi tai nhieu huyen trong tinh, trong do c6 huyen Mudng Cha. Nhiing nam qua, cdng tac quan ly bao ve rimg, phdng chay chira chay rimg (PCCCR) tren dia ban huyen Mudng Cha ludn duac quan tam trien khai tir huyen den ca sd. Tuy nhien, do anh hudng cua thdi tiet, khi hau khac nghiet, nSng ndng keo dai cpng vdi viec thieu y thiic trong viec su dung lua cua ngudi dan nen van xay ra mdt sd vu chay rung.

Lira rimg va cac nhan td anh hudng lua rimg la nhimg van de dupe de cap trong nhieu nghien cim trudc day. Cac nghien cihi nay da het ke cac nhan td chu yeu anh hudng tdi lua rimg nhu: Loai hinh che phu, do ddc, hudng phai, cac yeu td kinh te xa hpi nhu gan dudng, gan khu vuc dan cu... (Ha Cdng Tuan va cpng su, 2004; Claudia F Caceres, 2011; AE Akay va A Erdogan, 2017). Viec dy bao va phan cap nguy CO chay rimg da dupe ti^n hanh nhd cong nghe GIS va viln tham va th6 hien duac nhieu uu diem. Trong cac phan mem duac su dung de thuc hien cac bai toan phan tich GIS trong xay dung ban dd nguy ca chay rimg thi QGIS la mdt phan mgm duac quan tam trong nhiing nam gan day. Bdi le, day la phan mem "3M": Manh, md va mien phi (Alex Mandel va cpng sy, 2016). Tuy nhien, viec khai thac va umg

38 TAP CHI KHOA HOC VA CONG NGHE L A M NGHIEP SO 2 - 2019

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dung nd trong quan ly tai nguyen rung va lua rimg d Dien Bien cdn nhieu han che.

Nghien cdu nay tap trung chu yeu khai thac va su dung phin mem QGIS dk thye hien cac bai toan phan tich khdng gian tren ca hai doi tupng Raster va Vector de xay dyng ban do dy bao nguy ca chay rimg cho huyen Mudng Cha. Nghien cdu se su dung phuang phap phan tich thu bac (AHP) de tim tra trpng sd cho cac nhan to ty nhien, kinh te va xa hdi anh hudng tdi nguy ca chay rung (Imtiaz Ahmed Chandio va cdng sy, 2013). Tir dd phan cap va thanh lap ban dd vdi ty le 1:50.000 cho khu vyc nghien cuu. 2. PHirONG PHAP NGHIEN CUtl

2.1. Khu v^c nghign ciru Nghien cuu dupe tien hanh tren dia ban

huyen Mudng Cha cua tinh Dien Bien. Huyen Mudng Cha cd 1199,4209 km^ di$n tich hr nhien. Huyen Mudng Cha giap cac huyen Sin Hd, Nam Nhun (Lai Chau) va thi xa Mudng Lay ve phia Bac, giap huyen Tiia Chua va huyen Tuan Giao ve phia Ddng, giap huyen Mudng Ang ve phia Ddng Nam, giap huyen Dien Bien ve phia Nam, giap huyen Nam Pd va Lao ve phia Tay. Cd dudng bien gidi giap vdi huyen Mudng May, tinh Phong Sa Ly, nude Cong hda dan chu nhan dan Lao dai 24,4 km.

2.2. Phuomg phap thu thdp so lieu Sd lieu ve tinh hinh chay rirng, sd luong vu

chay rimg trong 3 nam 2016, 2017 va 2018, sd lieu ve khi tupng thuy van, sd lieu ve tai nguyen rimg va sd lieu ve tinh hinh kinh te xa hpi trong huyen dupe ke thira tu Uy ban nhan dan huyen va chi cue kiem lam tinh Dien Bien.

Nghien ciru cilng da ke thira va khai thac cac dii lieu ban dd va md hinh sd dp cao dupe cung cap tren cac ngudn tin cay nhu: ban dd kiem ke tai nguyen rimg, ban dd dat cua tinh Dien Bien ngudn hJ chi cue Kiem lam Dien Bien, md hinh sd dp cao (DEM) duac tai tir trang web ciia Alaska, Canada vdi dp phan gian khdng gian la 12,5 m.

2.3. Phirffng phap xur ly so lieu 2.3.1. Co" sd khoa hgc ciia chay rirng vd cdc nhan td dnh hudng tdi chay rung

Chay rimg chi xay ra neu cd sy ket hpp

ddng thdi cua ba nhan td ca ban bao gdm: Chat duy h-i sy chay (Oxy), chat bj chay (Vat lieu chay) va ngudn nhiet gay chay (Be Minh Chau, 2012). N8u thi^u mpt trong ba yeu td nay thi sy chay se khdng xay ra nhu ft-ong tam giac lua dudi day.

Hinh 1. Tam giac lira (Cong ty Nguyen Gia Phat, 2018)

Cd rat nhieu cac nhan td anh hudng tdi chay rimg, anh hudng tdi qua trinh duy tri ngpn lua cung nhu sy lay truyen cua lira tir khu vyc nay sang khu vyc khac. Cac nhan td thudc 3 nhdm ddi tuong Idn la: Dieu kien dia hinh, thdi tiet khi hau, kieu rimg va loai dat, cac hoat dpng lien quan den con ngudi va cac yen td khac.

a. Dieu kien dia hinh Dia hinh anh hudng tryc tiep hoac gian tiep

den chay rimg va lien quan tryc tiep den sy phat trien cua dam chay, cd tac dpng ngan chan cac he thdng gid, hinh thanh cac khu vyc tieu khi hau khac nhau tao ra cac khu vuc thudng xuyen cd mua hoac khu vyc khd han. Dia hinh thudng bao gdm cac yeu td nhu: dp ddc, do cao, hudng phoi va mat dp sdng sudi (Le Thi Thoa, 2016).

Khu vyc cd dia hinh cao thudng khd han keo dai, nang va dao dpng nhiet dp Idn han rat nhiiu so vdi khu vyc thap, d sudn ddc do khac hudng phoi nen nang lupng nhan duoc la khac nhau, sirdn ddc cdn tao dieu kien thuan lgi cho cac dong ddi luu phat trien manh so vdi cac vimg khac (Chengcheng Gai va cpng sy, 2011).

b. Dieu kien thdi tiet khi hdu Thdi tiet va cac nhan td khi tupng la mdt tac

nhan cho su phat sinh va phat trien cua mdt dam chay rimg. Yeu td co ban anh hudng den

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019 39

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chay rimg va dy bao chay rimg nhu sau: - Nhiet do: La yeu td gay anh hudng fryc

tiSp d6n qua trinh chay rimg, lara khd, nd vat lieu chay, lam dp am khdng khi giam va mat dat ndng len. Vai tro cua nhiet dp anh hudng tdi sy nit ngan qua trinh khd cua vat lieu chay.

- Dp am: Anh hudng hoac tich cue hoac tieu eye d8n qua trinh chay rimg. Dp am cang cao thi dp km vat lieu chay cang cao, cang khd gay chay va nguac lai.

- Gid: La nhan td anh hudng nhieu den chay rimg, gid thuc day lam khd vat lieu chay, lam biing phat dam chay va lam nhanh toe dp dam chay len gap nhieu lan (Le Thi Thoa, 2016).

c. Kieu rirng vd logi ddt Kieu rimg va loai thye bi cd lien quan tryc

tiep den nguon vat lieu chay, tinh chat va khdi lupng cua vat lieu chay do dac di6m cua kieu rimg va loai thye bi quyet dinh, tir dd dan den tinh d§ bat lua va quy md dam chay.

Loai dat khac nhau hay ndi each khac thanh phan CO gidi cua dat khac sau se anh hudng tdi kha nang giii nude, giii am cua dat cdng khac nhau. Tir do anh hudng tdi dp am cua vat lieu chay d tren cac loai dat la khdng gidng nhau. Vi vay, dat cd anh hudng kha Idn tdi viec phat

Bang 1. Djnh muc phan

sinh va lan truyen dam chay. d. Cdc hogt dgng cua con ngirai Nhigu hoat dpng san xuat cua con ngudi co

th§ la nguyen nhan d§n d6n chay rimg. Cu th^ nhu ddt rimg lam nuong ray, dot than, dot thuc bi de thu nhat kim loai, hun khdi de lay mat ong va nhiiu hoat ddng khac cd the gay chay rimg. Ngoai ra, mdt sd hoat ddng xa hdi khdc ciing cd th^ din den chay rCmg nhu: Tre em chan trau ddt lira dh sudi am, ddt huong di tao md. Phong tuc tap quan ddng bao dan tpc tha den frong cac ngay le hdi vo y gay chay. Khach tham quan du lich sinh thai trong rimg vd y gay chay. Cac hoat ddng da ngoai va ban dan that cd the gay chay rimg.

e. Mgt sd nguyen nhdn khdc Mdt sd nguyen nhan gay lira khac nhu:

Gidng set, cac vat lieu cd kha nang hpi tu anh sang, d Viet Nam cdn do vat lieu chien hanh de lai, do than chay ngam...

Nhirng nhan to tren day la ca sd quan hpng de ling dung cong nghe GIS xay dung ban do nguy CO chay rimg cho khu vyc nghiSn ciiu. 2.3.2. Phdn cdp cdc l&p bdn do vd quy trinh xdy drnig ban do nguy cff ckdy rimg 2.3.2.1. Phdn cdp bdn do

cap cho cac Idp ban dd

Cap Do d^nh doc

gia (")

iudng phoi

Do

(m)

K/c den SUOI

(m)

K/c den

dirong (km)

K/c den K/c den dan cir nuomg ray Kieu rimg (km) (m)

Lo i dat

I

II

III

0 - 8

8-15

15-25

Bac, Dong, Nam

Dong-BJc

Dong -Nam

<500

500-1000

1000-1300

<200

200-400

400-600

<0,5

0,5-1

1-1,5

0-1,5

1,5-2

2-2,5

>400

350 - 400

300-350

DTK, MN, NN

DTI, DTID, DT2, DT2D

RTG,

nu6c

Thit nang

Thit trung binh

Tay-n/ Tc Ar Nam, 1300- 600- . , , DTR RTTN '^ ^'-'' Tay- 1600 800 '-'-^ ^'^" ^ 200-300 " ' " T O ^ ^ ^""" '^

Tay >1600 >800 >2

HG1,HG2,TXB, TXDB, TXDK, TXDN, TXDP,

TXO, TXN, TXP

Cat pha

40 TAP CHi KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019

Cac Idp ban do sau khi dupe thu thap, k^ thira va xay dyng, se dupe phan cap lai. Cac Idp dupe phan thanh 5 cap, tuong iing vdi 5 cap chay rimg. Cac cap deu dupe xep theo thii ty: Cap tang thi nguy ca chay rimg tang. Quy dinh phan cho cac lap ban dd duoc thye hien dya vao bang sau day. Mdt sd Idp duoc phan cap dya vao khoang each (KC) tdi ddi tupng tren ban do nhu: sdng sudi, dudng giao thdng, khu dan cu, nuong r^y. Rieng ky hieu cac kieu riing duac viet theo Quyk dinh sd 689/QD-TCLN-KL ngay 23/12/2013 cua Tong cue Lam nghiep. 2.3.2.2. Phirffng phdp phdn dch thu' bdc (AHP) de xdc dinh trgng sd

Phuong phap phan tich thii bac (AHP) dupe phat trien bdi Thomas L. Saaty nam 1977. Day la phuong phap phan tich de xac dinh cac trpng sd, tir dd phan cap dupe tam quan trpng ciia cac chi tieu hoac nhan td den ddi tuong dang nghien ciiu, dya vao y kien danh gia ciia cac chuyen gia. Cu the trong nghien cim nay, AHP dupe sir dung de xac dinh tam quan trpng cua cac Idp ban dd den chay rimg. Cac bude cu the nhu sau (Phi Pham Hoang, 2017):

Bude 1: Tinh toan quy trinh hang thii i theo tdng the yeu cau n lan dupe gia tri Di theo cdng thiic:

D, =nK)"" Trong dd: n la bac cua quy trinh danh gia. Bude 2: Tien hanh xu ly quy nap, de tim ra

dupe cac trpng so ciia chi tieu danh gia theo cdng thiic:

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Bude 3: Xac dinh gia hi dac trung cao nhat cua quy trinh Xmax theo cdng thiic:

Bude 4: Tinh toan chi tieu kiem nghiem CI

c/=a™,-i)/(«-i) Trong dd CI cang nhd thg hien qua ttinh

kiem nghiem cang chinh xac.

Bude 5: Tinh toan gia tri ty le CR:

CR = CI/RI Trong do RI la ca sd binh quan cua cac chi

tieu. N6u CR < 0,1 thi k8t qua phii hpp, danh gia cd dp tin cay cao.

Trong nghien ciiu, ket qua xep hang cua 150 ngudi, bao gdm cac chuyen gia, kiem lam va ngudi dan dupe sir dung de tinh toan cac trpng sd theo phuong phap AHP. 2.3.2.3. Phirffng phdp GIS chong xep bdn do

QGIS duoc sir dung de phan cap va tao cac Idp ban dd. Ti6p dd, phuang phap phan tich khdng gian da chi tieu trong GIS (Multi-Criteria Analysis - MCA) dupe su dung trong xir ly tich hpp cac Idp thong tin ban do lien quan vdi cac trpng sd tim dupe phuang phap AHP. Ban dd nguy co chay rimg dupe thye hien theo ham tich hgfp da chi tieu sau:

N C R = | ; ( [ ( w ) l x , )

Trong do: + NCR: nguy co chay rimg; + Wj: trpng sd ciia lap thii i; + Xi: nhan td i; + n: sd lupng nhan td.

Qua trinh xay dyng ban dd dupe md ta trong hinh 2.

! 5

S

1 •I 5 i 1

1 J

• - , 1 ^ '

Phin cap. i

A/ m dosiidvnB tt^ing wluphinniji pluip AJlPdecbon; nep

1 Bia do phin cap nguv co chl\ n m j

Hinh 2. Quy trinh xSy dung ban do nguy co- chay rimg

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019

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Ban do sau khi dupe chong xep se dupe danh gia dp chinh xac bSng chi so Kappa dya vao ket qua dieu tra va phong vSn 150 diem tren dia ban huyen. Ngoai ra, nghien ciiu ddi chieu vi tri cua sd diem chay thye te, sd diem cd nguy co chay cao qua phdng van, so vdi ket qua phan loai tren ban dd de tinh phan tram, tir dd cd dupe dp chinh xac cua ban do cudi cung. 3. KET QUA VA THAO LUi.N 3.1. Ket qua phSn c4p cac Idp ban do

*A

•1 / ' a. Ban dd dp ddc

1

s^r"

' 7 ^7 •^h ^

c. Ban do do c

3.1.1. Cac Idp thdng tin ban do duyc xSy dyng

Tu ca sd khoa hpc va cac nhan td anh hudng tdi chay rimg nhu da phan tich trong phan phuong phap. Cac lop ban dd cin thiSt duoc nghien ciiu xay dyng bao gdm: Ldp ban dd dp ddc, ban do hudng phoi, dp cao, thiiy van, giao thdng, dan cu, nuong r^y, ban d6 cac loai rimg, loai dat tren dia ban huyen Mudng Cha. Cu the nhu hinh 3.

b. Ban do hudng phai

"

i J' 1 ^'

' -V>. T^ :^^frij «•.'-- - >j

pi<--y ~^V'/-^j

•U'v^- -

d. Ban do song s

e. Ban do giao thong f. Ban dd di6m dan c

Hinh 3. Cac lop ban So hien trang

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019

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Ban dd nuong ray h. Ban do loai rimg

i. Ban dd loai dat Hinh 3. Cac Idp ban do hien trang (tiep)

3.1.2. Kit qud phdn cdp cdc ldp bdn do Tir cac lap ban do hien trang ndi tren, dya

vao miic dp phan cap da dupe trinh bay trong phan phuang phap, cac ddi tupng tren ban dd dugc phan thanh 5 cap. Cac cap dupe phan tir

1 den 5. Cap I la cap it nguy ca chay rimg nhat, ngugc lai cap 5 la cap cd nguy co xay ra chay rimg cao nhat. Ket qua phan loai bang sii dung phan mem QGIS nhu sau.

t t,

' \

> t

; ^ > '. -

a. Ban dd phan cap dp ddc b. Ban do phan cap hudng phoi

Hinh 4. Cac Idp ban do da phan theo cap chay

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019 43

d. Ban do phan cap theo KC den sdng sudi

e. Ban do phan cap theo KC den dudng f. Ban do phan cap theo KC den diem dan cu

nUlt Ctp TTUM THirc Mit I

g. Ban dd phan cap theo KC den nuong ray h. Ban dd phan cap theo loai rimg

« ' <: '

PHjWCtelOlICiiT

i. Ban do phan c4p tlieo loai dit Hinh 4. Cac Idp ban dS da phan theo cSp chay (tijp)

TAP CHi KHOA HOC VA C 6 N G NGHE LAIM NGHIEP SO 2 - 2019

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3.2. Ket qua phan tich trong so bang phirong phap AHP

AHP duoc sir dung de phan tich trpng sd sau khi nhan dupe ket qua xep hang cua cac chuyen gia, kiem lam va ngudi dan. AHP la phuang phap dugc Saaty phat trien tir nhiing nam 80. Trong trudng hpp nay, AHP dya tren viec so sanh giiia 9 nhan to anh hudng tdi kha

Bang 2. Ma tran so sanh giira cac

nang chay rimg nhu: dp ddc (DD), hudng phoi (HP), dp cao (DC), KC d6n sdng sudi (SS), KC dgn dudng giao thdng (DGT), KC din khu dan cu (KDC), KC dkn nuong ray (NR), loai trang thai rimg (LR) va loai ddt (LD). Sau do se chu^n hda ma tran va tinh tra cac trpng sd cho mdi nhan td. Tdng gia tri cua trpng sd ludn phai bang I.

nhan td anh hudng toi kha nang chay Nhan to

DD

HP

DC

SS

DGT

KDC

NR

LR

LD

Nh9n to DD

DD 0,079

HP 0,100

DC 0,118

SS 0,112

DGT 0,086

KDC 0,125

NR 0,132

LR 0,158

LD 0,091

DD

1,00

1,27

1,49

1,42

1,09

1,58

1,67

2,00

1,16

HP

0,79

1,00

1,18

1,12

0,86

1,25

1,32

1,58

0,91

DC

0,67

0,85

1,00

0,96

0,73

1,06

1,12

1,34

0,78

Bang 3. Ma tran ct

HP

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

DC

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

SS

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

SS

0,70

0,89

1,05

1,00

0,77

1,11

1,17

1,41

0,81

luan hoa DGT

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

DGT

0,92

1,16

1,37

1,31

1,00

1,45

1,53

1,84

1,06

va kit q

KDC

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

KDC

0,63

0,80

0,94

0,90

0,69

1,00

1,06

1,27

0,73

ua trong

NR

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

NR

0,60

0,76

0,89

0,85

0,65

0,95

1,00

1,20

0,69

so

LR

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

LR

0,50

0,63

0,74

0,71

0,54

0,79

0,83

1,00

0,58

LD

0,079

0,100

0,118

0,112

0,086

0,125

0,132

0,158

0,091

LD

0,87

1,10

1,29

1,23

0,94

1,37

1,44

1,73

1,00

Trong so

0,08

0,10

0,12

0,11

0,09

0,12

0,13

0,16

0,09

Ket qua phan tich AHP cho thay cac nhan td anh hudng quan trpng nhat den chay rimg la loai rimg, khoang each den nuong ray, khoang each den khu dan cu va dp cao. Ket qua nay kha tuang ty vdi nghien ciru ciia Nguyen Ngpc Thach va cdng sy vao nam 2017 tai tinh Son La. Ket qua tinh toan ty le phii hgp CR la 0.000 nhd hem 0,1 rat nhieu, nen ket qua la phii hpp va dp tin cay rat cao (Phi Pham Hoang, 2017; Liu Chunchu, 2018). 3.3. Ket qua phan c3p nguy cff chay rirng 3.3.1. Ket qud bdn do nguy cff chay rimg

Tir ket qua tinh toan trpng so cho cac nhan td anh hudng tdi nguy ca chay rimg dupe nghien ciiu. Phuang trinh tuyen dinh da bien dugc sir dung de chdng xep cac ldp ban dd trong QGIS de tinh toan nguy co chay rimg (NCCR) cho rimg khu vyc nhu sau:

NCCR - 0,08*DD + 0,10*HP + 0,12*DC + 0,11*SS + 0,09*DGT + 0,12*KDC + 0,13*NR + 0,16*LR + 0,09*LD

Ket qua ban dd phan cap nguy ca chay rimg cho rimg khu vyc dugc nhu hinh 5.

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019

Ldm hoc

Hinh 5. Ban flS phan cSp nguy cff chay rung huyen Mirdng Cha

Ket qua thdng ke dien tich tuong iing cua timg cap chay riing dupe the hien trong bang dudi day. Nhu vay, phan bd dien tich cd dang chuan, tap trung chii yen la cap trung binh, cao va nguy hiem. Ngugc lai cap cue ky nguy hiem

va cap thap cd dien tich it ban, tuong img la khoang 19 nghin va 17 nghin ha. Ty le nay tuong ty nhu ket qua ciia mdt sd nghien cihi khac tai Son La (Nguyen Ngpc Thach va cpng sy, 2017).

Bang 4. Dien tich tung c3p chay

d p chay rimg Thap Tmng binh Cao Nguy hiem Cue ky nguy hiem

Sd Iiromg cell 193495 496219 564566 461745 216195

Dien tich (ha) 17414,55 44659,71 50810,94 41557,05 19457,55

Dp chinh xac cua ban do nguy co chay rimg tuang ddi cao. Ly do cua ket luan nay dupe dya vao ket qua phdng van can bp kiem lam va ngudi dan trong dia ban cac xa cua huyen Mudng Cha thi h-ong 3 nam 2016, 2017 va 2018. Tdng sd vu chay trong 3 nam la 7 vy, trong do cd 5 vu nam trong cap Nguy hiem va Cyc ky nguy hiem, chiem 71,4%. Ngoai ra, nghien ciiu phdng van 50 can bd va ngudi dan trong huyen ve 150 diem cd nguy co chay cao thi cd 126 diem thudc cap Nguy hiem va Cyc ky nguy hiem, chiem 84%. 4. KET LUAN

Chay rung la mdt nguy ca Idn de dpa dgn tai nguyen rimg va qua trinh quan ly tai nguyen rung. Chay rung da va dang gay thiet hai Idn ve ngudi va tai san cho nhieu huyen mi6n nui, trong dd cd huyen Mudng Cha.

Bang viec su dyng cong nghe viln tham va GIS, vdi sy ho trg cua phkn mim QGIS, nghien ciiu da xay dyng dugc 9 ldp ban dd tuang ling vdi 9 nhan td cd th6 anh hudng tdi nguy CO chay rimg. Tir cac ldp ban dd hien

trang nay, dya vao ket qua phdng van va tham khao tir cac nghien cuu trudc, cac ldp duoc phan loai theo 5 cap chay rung tir 1 d6n 5. Trong do, 1 la khu vyc cd nguy co thap va 5 la khu vyc CO nguy co chay rimg cao nhat.

Phuong phap phan tich thu bac AHP dupe sir dung dya tren ket qua cho diem cua phdng van can bg, kiem lam va ngudi dan trong khu vyc nghien ciiu. Tir do da tim ra dupe trpng so cho 9 nhan td anh hudng. Trong do cac nhan to anh hudng Idn nhkt tdi chay rimg la loai rimg, khoang each den nuong rSy, khoang each den khu dan cu va dp cao. Trpng sd cua cac nhan td anh hudng Idn nh4t nay dao ddng hi 0,16 xudng tdi 0,12.

Bang viec su dung cac trgng sd nay, vdi su ho tro cua phan mSm QGIS, cac ldp ban dd dugc chdng xep va san pham cuoi ciing thu dupe la ban dd phan cap nguy co chay rimg tai huyen Mudng Cha. Dien tich toan dien dugc chia thanh 5 cap chay rimg. Trong do, tdng dien tich cua cap Thap va Cyc ky nguy hiem tuang ling la khoang 17 va 19 nghin ha. Cap Trung

46 TAP CHI KHOA HOC VA C 6 N G NGHE LAM NGHIEP SO 2 - 2019

Ldm hoc

binh, Cao va Nguy hiem cd dien tich Idn ban, dao ddng tir 41 din 50 nghin ha. Do chinh xac cua ban do nguy co chay rimg tuong ddi cao, tren 80% so vdi sd lieu phdng vdn trong 3 nam gan day. TAI LIEU THAM KHAO

1 AE Akay va A Erdogan (2017). GIS-based Multi-criteria Decision Analysis for Forest Fire Risk Mapping ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Informalion Sciences 4: 25.

2. Claudia F Caceres (2011). Using GIS in Hotspots analysis and forest fire risk zones mapping in the Yeguare Region, Southeastern Honduras. Pap. Resour. Anal 13: 14.

3. Imtiaz Ahmed Chandio, Abd Nasir B Matori, Khamaruzaman B WanYusof, Mir Aftab Hussain Talpur, Abdul-Lateef Balogun va Dano Umar LawaJ (2013). GIS-based analytic hierarchy process as a multicriteria decision analysis instrument: a review. Arabian Journal of Geosciences 6(8): 3059-3066

4. Be Minh Chau (2012). Qudn ly lua rimg, NXB Nong Nghiep, Ha Ngi.

5. Liu Chunchu (2018). Analytic Hierarchy Process (What is AHP), Chang Jung Christian University, 71101 Changda Road, Guiren District, Tainan, Taiwan

6. Chengcheng Gai, Wenguo Weng va Hongyong Yuan (2011). GIS-based forest fire risk assessment and mapping. 2011 Fourth International Joint Conference on

Computational Sciences and OpUmization, IEEE. 7. Alex Mandel, Victor Olaya Ferrero, Anita Graser

va Alexander Bmy (2016). QGIS 2 cookbook, Packt Publishing Ltd.

8. Phi Pham Hoang (2017). Ifng dipig phuong phdp AHP vdo ddnh gid lua chgn lodi cay trdng dudng pho Hd Npi. T?p chi Khoa hgc va Cong nghe Lam nghiep, so 1: 35-42

9. Cong ty Nguyen Gia Phat (2018). Kiin thuc ca bdn ve dam chay, no, Cong ty TNHH Nguyen Gia Phat. Lien kk tai: https://nguvengiaphat.vn/kien-thuc-co-ban-ve-dam-chay-no/ (Xem ngay 26 thang 2 nam 2019).

10. Nguyen Ngoc Thach, Dang Ngo Bao Toan va Pham Xuan Canh (2017) Uhg dung viin thdm vd GIS thdnh lap bdn dS nguy cff chay rirng phuc vy phdng chong, gidm thieu thiet h(ti do chay rimg tai tinh San La, Viet Nam. Tap chi Khoa hoc DHQGHN. Cac Khoa hoc Trai dat va Moi trucmg 33(3): 53-66.

11. Le Thi Thoa (2016). A'gH_ven nhdn gdy chdy rimg. So Nong nghiep va Phat trien nong thon Thanh Hoa. Lien ket tai:

http://snnptat.thanhhoagov.vn/Default.aspx7portalid -admin&selectpageid^age. 1 &newsdetail=News.3978 &n g manager=69&ClosePortletPreferencesID-]1122 (Xem ngay 26 thang 2 nam 2019).

12. Ha Cong Tuan, Vuong Van Quynh, Doan Hoai Nam, Nguyin Phiic Thg va Do Nhu Khoa (2004). Cdm nang Ldm nghiep Phong chdy vd chua chdy rimg. Bo Nong nghiep va Phat trien nong thon, Ha Ngi, Viet Nam.

USING QGIS AND ANALYTIC HIERACHY PROCESS TO CLASSIFY FOREST FIRE RISKS IN MUONG CHA DISTRICT,

DIEN BIEN PROVINCE Bui Manh Hung, Nguyen Thanh Thuy Van

Vietnam National University of Forestry

S U M M A R Y Forest firer has been a considering issue. Forest fires have caused great damages to people and properties for many mountainous districts, including Muong Cha district. By inheriting and investigating data on socio-economic condittons and available maps in Muong Cha district, the study has budt 9 map layers corresponding to 9 factors influencing forest fire risks' slope, aspect, ahitade, distance to rivers and streams, distance to roads, residenUal areas, upland fields, forest types, and soil types. Alter that, layers are classified according to 5 forest fire risk levels: from 1 to 5. In which, 1 is the low-risk area and 5 is the area with the highest risk of the forest fire. Analytic hierarchy process is used to find and rank weighted parameters for 9 influencing factors. In which, the most important factors affecting the forest fire risk are forest types, distance to upland fields, distance to residential areas and elevation. The parameters of these most influencing factors ranged from 0.16 to 0.12. QGIS was used in combination with the founding weighted parameters, map layers were overlapped and the final product is a map of forest fire risk classification in Muong Cha district. The area of the district is divided into 5 levels of the forest fire risk. In particular, the total area of Low and Extremely dangerous levels is about 17 and 19 thousand hectares respectively Medium, High and Dangerous levels have larger areas, ranging from 41 to 50 thousand hectares. The accuracy of the forest fire risk map is relatively high, over 80%, based on interview data in the last 3 years. Keywords: Analytic hierarchy process, forest fire, Muong Cha, QGIS.

Ngay nhan bai : 27/02/2019

Ngay phan bi^n : 29/3/2019

Ngay quyet dmh d ing : 05/4/2019

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 2 - 2019