PHAN TICH DAC DIEM VA NGUYEN NHAN DIEN BIEN TAI ...

Quan ly tdi nguyen rimg & Mdi trirlmg

PHAN TICH DAC DIEM VA NGUYEN NHAN DIEN BIEN TAI NGUYEN RlTNG TINH DIEN BIEN, GIAI DOAN 2000 - 2013

La Nguyen Khang', TrSn Quang Bao^

' ThS. Truang Dai hoc Ldm nghiep

'PGS. TS. Tnrdng Bai hoc Ldm nghiep

TOM TAT

Bai bao trinh bay ket qua nghien ctru vi dac diem dien bien va cac nguyen nhan dan den tang/giam rimg t^i 40 xa thuQC 8 huyen ciia tinh Dien Bien. Ket qua nghien cttu cho thay, dp che phu rimg ctia cac xa nghien cihi tlng/giam chu yeu la do thay dfii dien tich cac Itieu trang thai rirng. Dien tich cac kieu trang thai rung tang len ehu ySu la rung phuc hoi va rimg trong. Dien tich cac kieu trang thai rimg giam la rimg trung binh, rirng ngheo va rirag hon giao go - tre niia. Nghien ciiu ciing da xac dinh dugc cac nguyen nhan lam tang/giam rirng: (1) Nguyen nhdn ldm cfio di^n tich rirng tdng len, bao gom: quy hoach bao v? rtmg theo chuong trinh 661, chiem 62,06%; bo hoa nuong ray chiem 25,25%; quy hoach khu bao tijn thien nhien Muong Nhe chiem 7,23%; trong rimg theo chuong trinh 661 ehiSm 5,03%; va trdng cay cao su chiem 0,44%. (2) Cdc nguyen nhdn ddn den mdt rimg, bao gom: Nguyen nhan true tiep nhu: d6t nuong lam ray ehiem 89,22%; rirng tre niia bi khuy chidm 5,93%; do chay rixng chidm 3,66% va do chan tha gia siic chiem 1,19%. Cac nguyen nhan sau xa (gian tiep) lam mSt rimg: dan s6 tang nhanh; di dan; thidu d5t canh tac va do quy hoach. Cac nguyen nhiin true tiep va gian tidp eo lien he vai nhau va ciing thiic dSy vide mat rtmg tai cac khu vuc nghien ciru.

Tir khoa: Dien biin rirng, dp che phu, mat rimg, REDD+, tdng rirng.

I. DAT VAN DE Dien Bien la tinh mien niii nSm a pliia

Tay bac Viet Nam, co tiem nang vS dh lam nghiep va co kha nang phat triSn san xuat lam nghiep rit Ion. Toan tinh co 602.566,42 ha dat lam nghiep, chi8m 63,01 % dien tich tu nhien cua tinh. T6ng dien tich dit co rimg ciia Dien Bien la 400.776,1 ha, chiSm 66,04% dit lam nghiep va dat ty le che phii 42%, trong do rimg tu nhien la 387.051,1 ha, chiem 96.58% dat co rimg; rimg tr6ng la 13.725 ha chi4m 3,42%. Hiu hit rimg a Dien Bien hien nay la rtmg phong hg. Dit chua sti dung cua Dien Bien con rit l<jn, toi 175.269,74 ha, chiSm 18,33% tdng dien tich tu nhien, trong do chii ylu la dit doc chi co kha nang phat triin lam nghiep. Day dugc xac dinh la nguon tai nguyen qui gia, mot the manh cho phat triin kinh t l - xa hpi ciia tinh.Truoc boi canh biln dii khi hau (BDKH), lam nghiep la mpt trong nhung

nganh co vai tro lan trong viec ngan chan va giam thieu nhirng tac dpng tieu cue ctia BDKH. Viec tham gia vao thuc hien sang kien giam mat nrng va suy thoai rtmg (REDD+) dang dugc cac cSp, nganh trong tinh dac biet quan tiim. D^ co thi dl xuit dugc nhiing giai phap cho thuc hien REDD+ thi can phai co nhirng hieu bilt vl dac dilm dien bien tai nguyen rirng, cac nguyen nhan dan den bien dpng tai nguyen rtrng (tang/giam). Muc dich ciia nghien ciiu nay nham xac dinh cac nguyen nhan dan din mit rirng/suy thoai rimg (sau day gpi tit la mit ning) cung nhu la cac ylu t l phat triin rimg (trdng rimg/tai sinh rvmg) (sau day gpi tit la tang rirng) tai cac khu vuc khac nhau thupc tinh Dien Bien. Tii kit qua nghien ciiu nay, nhiing chinh sach va cac giai phap se dugc de xuit va ap dung phCi hgp vai dilu kien thuc tl tai tinh Dien Bien trong qua trinh thuc hien REDD+.

64 TAP CHi KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014

Qudn ly tdi nguyen rimg & Moi trif&ng

II. DOI TirONG, PHAM VI VA PHl/OfNG

PHAP NGHIEN Ciru

2.1. Doi tuong nghiSn ciru

Tren ca sg muc tieu da xac dinh, dii

tugng nghien ciiu bao gim: (i) Dien tich

rirng va dat lam nghiep theo mlc thoi gian

nam 2000 din nay; (ii) Cac nguyen nhan dan

den mat rimg/tang rimg.

2.2. Pham vi nghien ciiu

Ve khong gian: Nghien ciiu dugc thuc

hi$n tai 40 xa thupc 8 huyen thi trong toan

tinh Dien Bien, bao gdm: Muong Cha,

Muong Nhe, Nam P6, Tiia Chua, Tuan Giao,

Muong Ang, Dien Bien va Dien Bien Dong.

- Ve thai gian: Nghien ciiu tap trung phan

tich diln biln ritng tai cac thai dilm nam

2000, nam 2010 va hien nay.

BAN DO VI TRi CACXA NGHIEN CLTU TAI TINH DIEN BIEN

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Hinh 1. Ban do vi tri 40 xd du^c chpn nghiin cuu thupc 8 huy$n & Bifn Bien

2.3. Phirong phap nghien cihi

Cac phuong phap nghien cuu dugc sii

dung, bao gom: phuang phap xay dung

khung logic de xac dinh van de can giai

quyet trong qua trinh thu thap va xu ly so

lieu nghien curu; phuong phap thu thap so

lieu thong tin thu cap; phuonng phap thu thap

thong tin so cap (phong van, thao luan nhom,

khao sat thuc te cac khu rimg ngoai hien

truang; phuang phap chuyen gia).

Nghien ciiu da tien hanh phong van thu

thap thong tin doi vai cac doi tugng khac

nhau dugc lira chon, bao g6m: UBND va

Kiem lam cac cap, can bg Chi cue Lam

nghiep, Phong NN&PTNT.... cac ho gia

dinh, cac ca nhan, co lien quan cua 40 xa

nghien cuu de thu thap cac thong tin v^: lich

Sli thay doi su dung dat, thay doi do che phu

rung va cac nguyen nhan lam tang dien tich

rung va mat rimg 6 moi dja phuang.

De xac dinh lich su thay doi do che phu

rimg, nghien cuu da sii dung cong cu GIS di

phan tich thay doi sii dung dat/dg che phu a

cac xa dugc chgn nghien ciiu vao cac thai

di8m khac nhau nam 2000, 2010 va 2013.

De xac dinh chinh xac ve cac nguyen nhan

lam tang rimg, mat rung va miic do anh

hirang cua moi nguyen nhan den tang/giam

rimg, nghien ciiu da sii dung cong cu ArcGIS

9.3 va Mapinfo 10.0 de khoanh ve cac khu

vuc tang rimg va cac khu vuc mat rimg. Khu

vuc tang rimg dugc ky hieu la ARso thir tir

(khu vuc tang rimg co nghia la khu vuc do

khong CO rimg vao nam 2000 nhung din

2010 va hien nay da co rirng); khu vuc m3t

rirng dugc ky hieu la DD_s6 thir thu (la khu

vuc CO rimg nam 2000 nhung din nam 2010

va hien nay la khong con rirng)

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014 65

Qudn ly tdi nguyen rirng & Moi tru&ng

Khu vuc tang rimg Khu virc mat rimg

BAN D O HIEN TRANG RLfNG

X. MI/5NG MUON - H. MUdNG CHA - T. DIEN BIEN

Hinh 2. Bdn do dien bien rirng the hien cdc khu vuc tang/mat rung theo dan vi xa

Nghien ciiu da lua chgn dai dien a cac

huyen nghien ciiu 20 khu vuc co dien tich rimg

tang len va 20 khu vuc co dien tich rimg mSt

di, moi khu vuc co dien tich tit 100 ha tra len.

Doi voi moi khu vuc tang rimg hoac mdt rimg,

nghien ciiu da tien hanh xac dinh vi tri ngoai

thuc dia, khao sat hien truong va phong vin

can bg va nguoi dan dia phuang (nguai dugc

phong van la can bg xa, gia lang, truang ban,

nhirng nguai hiiu biet v l lich su thay d6i su

dung dk tai khu vuc, voi m6i khu vuc da tien

hanh phong van 2-3 can bg xa va 5-7 nguoi

dan dia phuang) de xac dinh chinh xac cac

nguyen nhan lam tang rimg va mdt rimg tai cac

khu vuc cu the.

66 TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014

De lugng hoa anh huong ciia cac nguyen

nhan lam tang/giam rimg, tai moi khu vuc

dugc chgn nghien ciiu da tien hanh xac dinh

phan tram dien tich rimg tang 16n hoac mat di

theo timg nguyen nhan tac dgng, tir do tinh

toan ty le phan tram anh huang ciia cac nguyen

nhan lam tang/giam rimg theo dien tich doi

timg nguyen nhan.

m . KET QUA NGHIEN ClTU, THAO L U ^

3.1. Lich sur thay doi sv dung dat/do che phii rung

Theo ket qua phan tfch GIS, cac ban d6 bi6n

dong (lich sir) sur dung dSt/thay d6i che phu

cua cac xa nghien cihi theo timg huyen dugc

mo ta nhu sau:

Qudn ly tdi nguyen rirng & Moi tru&ng

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Bdn do thay doi do che phti ciia cdc xd nghien cuu

tai huyen Diin Biin Dong Bdn do thay doi do che phii cda cdc xd nghien cuu

tai huyen Tuan gido

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Bdn do thay doi do che phu cua cdc xd nghien ciru

tgi huyen Mu&ng Ang Bdn do thay doi do che phd cda cdc xd nghien cihi

tgi huyen Muong Chd

Bdn do thay doi do che phu Bdn do thay doi do che phd cua cdc Bdn do thay doi do che phii cua

ciia cdc xd nghien ctru tgi xd nghiin cuu tgi khu vvc huyen cdc xd nghien ctru tgi huyen

huyen Tua Chita Muang Nhe vd Nam Pd Dien Bien

Hinh 3. Bdn do thay doi dg che phii ciia 40 xd nghien cuu &Bien Bien

K6t qua phan tich thay doi do che phii rimg ciia cac xa nghien ciiu dugc thi hien o bang 1.

TAP CHI KHOA HQC VA CONG NGHE LAM NGHIEP SO 3 - 2014 67

Qudn ly tdi nguyen ring Jc Moi tru&ng

TT

(1)

1 2

3 4 5

6 7 8 9 10 11 12 13 14 15

16 17

18 19 20 21

22 23

24 25

26

27 28

29

30

31

32

33

34

35

36

37

38

39

40

Xa

(2)

PiiNhi

Chieng So Keo Lom NaSon

NaSay Muang Miin Phinh Sang Quai Cang Ta Ma Ang Cang

Muang Dang Muong Lan Hira Ngai Muang Tiing Sa Long

Huoi X6 Tua Thang

Chung Chai Leng Su Sin Muang Nhe

Muong Toong NamKe Nam Vi

Pa My Quang Lam

Sen Thirgng

Sin Thau Cha Nua

Si Pa Phin

Cha cang

Na Bung

Na Co Sa

NaHy

NaKhoa

Pa Tan

Muang Loi

Muang Pon

Nua Ngam

Thanh An

Vluang Nha

Bang 1. rhay doi dp che phu cua rdng & cdc xd nghiin cuu

Huyen

(3)

Dien Bien Dong

Dien Bien Dong

Dien Bien Dong Dien Bien Dong

Tuan Giao Tuan Giao Tuan Giao

Tuan Giao Tuan Giao Muang Ang Muang Ang

Muang Ang Muang Cha Muang Cha

Muang Cha Tiia Chua Tua Chiia

Muang Nhe Mirong Nhe

Muang Nhe Muong Nhe

Muong Nhe Muong Nhe

Muong Nhe Muang Nhe

Muang Nhe

Muong Nhe NamPo

NamPo

NamPo

NamPo

Nam P6

NamPo

NamPo

NamPo

Dien Bien

Dien Bien

Dien Bien

Dien Bien

Dien Bien

ni

(4)

16.53

9.58 5.45

1.04 33.62

57.80 32.58

19.48 42.50 11.91

7.60 12.23

30.72 61.26

36.07 39.28

34.43 72.65

62.57 57.74

43.19

72.67 50.99

38.31 34.31

79.34

57.21

55.87

4.50 40.52

36.79

30.48

44.60

29.01

40.27

13.85

33.38

31.44

2.16

20.05

Nam 2010 (%) (5)

23.86

20.18

18.77 14.24

34.79 50.32

34.09 24.50

36.71 23.31

30.37 23.48

39.30 38.08 48.62

25.66

44.76 66.80

63.86

54.45

47.79 59.74

45.97 37.42

42.91

53.98

53.45

43.81 2.72

40.74

23.68 39.70

31.82

28.52

56.55

27.81

47.80

31.30

13.19

29.94

Nam 2013

(%) (6)

25.95

20.06 18.80

12.80 24.30

42.50 43.88

23.90 43.20

24.10

32.30 25.40

40.24 38.12

46.48

38.78 41.06

66.38

61.01 55.15

75.35

59.93 48.55

42.44

44.73

56.99

53.83 45.50

2.73

42.95

25.89 31.84

27.50

39.63

58.81

40.00

51.00

39.00

24.00

43.00

(%) (7)

=(6)-(4) 9,42

10,48 13,35

11,76 -9,32

-15,30 11,30

4,42 0,70

12,19

24,70 13,17

9,52 -23,14

10,41

-0,50 6,63

-6,27

-1,56

-2,59 32,16

-12,74

-2,44

4,13 10,42

-22,35

-3,38

-10,37

-1,77

2,43

-10,90

1,36

-17,10 10,62

18,54

26,15

17,62

7,56

21,84

22,95

Kilu rirng thay doi

(8)

Rimg phuc hoi

Rimg phuc hoi va rirng ngheo Rimg phuc hoi va rirag go -tre nira

Rirng phuc h6i va rirng g6-tre nua Rimg phuc hoi Rimg ngheo va rirng trung binh

Rimg phuc hoi va rirng nui da voi Rimg phuc hoi va rimg trong

Rimg nui da voi Rimg ph\ic hoi va rirng tr6ng

Rimg phuc hoi

Rimg phuc hoi va rimg trong

Rimg phuc hoi

Rimg giau, liing TB, limg ngheo va limg TN Rimg trung binh va rirng phuc hoi

Rimg phuc hoi va rirng nui da voi Rirng phuc hoi

Rirag trung binh

Rimg phuc hdi

Rimg tmng binh va rimg g6 - tre nira Rirag phuc hoi va rimg tr6ng

Rimg trung birrh va rimg go - h-e nira

Rimg trung binh va rimg go - tre nua

Rimg trung binh va rimg go - tre nira

Rimg phuc hoi Rimg giau, rimg TB, rimg n^ieo\a rimg TN

Rimg iTung binh, rimg ngheo va rimg TN

Rimg trung binh

Rimg ngheo va rimg trong

Rirag phuc hoi va rimg g6-tre nua

Rirag giau va rirng trung binh Rimg phuc hoi

Rirag trung binh va rirag ngheo Rirag phuc hoi

Rirag phuc hoi

Rirag phuc hoi

Rimg phuc hoi va rirng trfing

Rirag phuc hoi va rirng trdng

Rirag phuc hoi va rirng trdng

Rimg phuc hoi va rimg trdng

6S TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014

Qudn ly tdi nguyen rung & Moi tru&ng

Ket qua bang 1. cho thay cac xa co do che phii rimg tang len chu ySu la do tang len v6 dien tich rimg phuc hoi va rimg trong, cac xa CO dp che phii rimg giam xu6ng chii yiu la do giam dien tich rimg giau, rimg trung binh, rimg ngheo va rung h6n giao go - tre niia. Cu the su thay doi ve do che phii rung a cac huyen nghien ciiu dugc phan tich nhu sau:

Huyen Dien Bien Dong: Ty le che phii cua rimg o cac xa dku tang manh tir 9-13%, phin lan la do sir tang len ciia rimg phuc hoi va rung hon giao go - tre niia.

Huyen Tuan Giao: Trong 5 xa nghien ciiu ciia huyen Tuan Giao, 3 xa co do che phii rimg tang tu 0,7-11,3% va dat do che phii tir 24-43%. Hai xa con lai la Muong Mun va Na Say thi do che phii rimg giam tuong iing la 15,30% va 9,32%. Nhiing xa co do che phii tang phan Ion do su thay doi cua rirng phuc hoi, hai xa co do che phu giam thi chii yeu dien ra a cac trang thai CO tru lugng go cao nhu rimg trung binh, rimg ngheo va rimg tren niii da.

Huyen Muang Ang: Mac du ty le che phu ciia rimg nam 2013 khong cao, xong da tang rat nhieu so vdi nam 2000. Trong do, xa Ang Cang va xa Muang Lan tang gap 2 lan va xa Muong Dang tang len gap hon 4 Ian. Ket qua nay phan lan la do su tang len ciia rimg phuc hoi va mgt mgt so do trong rimg moi.

Huyen Muong Cha: Hau het cac xa co ty le che phu rimg kha cao trong nam 2013. Tuy nhien do che phu o xa Mudng Timg da giam di kha nhieu so vdi nam 2000, xa Hira Ngai va xa Sa Long ty le che phii tang tir 9-10%. Su thay doi nay xay ra d hau het cac loai rimg tir rimg giau din rimg phuc hdi va rimg trdng.

Huyen Tiia Chiia: Sir thay ddi (tang/giam) vS che phii rimg chu ySu xay ra d trang thai rimg phuc hdi. Trong do, che phii rimg ciia Huoi Xd suy giam kha manh vao nam 2010 (tdi 13% tdng dien tich tu nhien, tucmg duong vdi 34.67% dien tich dat cd rimg). Tuy nhien cho din thdi dilm nay (2013) do che phu rimg

ciia xa Hudi Xd lai tang len gan dat vdi mdc nam 2000, cac kieu trang thai rung tang len chu yeu la dien tich rimg phuc hdi. Do che phii d Tiia Thang tang 6,63% so vdi nam 2000.

Huyen Mudng nhe: Ket qua phan tich cho thay rang hau nhu do che phu d cac xa d huyen nay bi giam tir 1-22%, Hai xa Mudng Toong va Quang Lam (huyen Mudng Nhe) cd do che phii rimg tang, dang luu y la xa Mudng Toong nam 2013 cd do che phii rimg tang so vdi nam 2000 va 2010 len tdi tren 30%. Cac trang thai rimg giam chu yeu la rimg trung binh, rimg rirng hdn giao gd - tre niia. O cac xa cd dien tich rimg tang len chu yeu la rimg phuc hoi va rimg trdng

Huyen Nam Pd: La huyen mdi dugc thanh lap nam 2012 ciia tinh Dien Bien, cac xa cua huyen nay chii yeu dugc chuyen tir huyen Mudng Cha va Mudng Nhe sang. Do che phu rtmg ciia cac xa trong huyen cd su thay ddi (tang/giam) ngoai viec cd su thay ddi ve cac kieu trang thai rung thi cd mot phan nguyen nhan do thay ddi ve dia gidi hanh chinh cua cac xa sau khi thanh lap huyen mdi.

Huyen Dien Bien: do che phii ciia rimg d cac xa nghien ciiu thugc huyen Dien Bien deu tang manh tir 7-26%,. Su thay ddi nay chu yeu la su tang len cua rimg phuc hdi va rirag trdng.

3.2. Nguyen nhan dan den su thay doi do che phu rimg

Tren ca sd ket qua phan tich bien dpng lich sii Sli diing dat d phan 3.1 cho thay, dp che phii rimg tai cac xa nghien ciiu cd tang len hoac giam di, de xac dinh nguyen nhan din den su thay ddi nay, nghien ciiu da tien hanh dieu tra thuc dia bao gom: phdng van can bp, ngudi dan va khao sat thuc dia tai 40 khu vuc, trong do cd 20 khu vuc cd dien tich rimg tang len va 20 khu vuc cd dien tich rimg giam (mat rtmg). K8t qua cho phep xac dinh chinh xac nguyen nhan dan din su

tang len hoac giam di cua rimg.

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014 69

Qudn ly tdi nguyen rimg & Moi trucmg

3.2.1. Nguyen nhdn ldm tdng rimg

Trong 20 khu vuc c6 dien tich rimg tang c6 01 khu vuc vai ky hieu AR_287 la co su khac nhau giua ban do va thuc te. Trong ban do thay ddi dien tich rimg thS hien ring, vao nam 2010 didm nay la co rung, tuy nhien khi phong van can bo va nguai dan dia phuang cimg voi kiem chiing thuc td, thi vao thai gian tit truac nam 2010 ddn nay, khu vuc nay la vimg san xuat

nuong riy cua nguai dan dja phuong. Mm vay, trong 20 khu vuc tidn hanh nghien cuu thi CO 19 khu vuc la co thong tin dung voi ban do, do la vao nam 2000 cac khu vuc nay khdng co rimg va den nam 2010 va hien nay thi co rimg. Nghien curu da tien hanh xay dung ban do hien trang rimg nam 2000 va 2010 ciia cac xa nghien ciiu de thay dugc su tang len ciia dien tich rimg a cac khu virc dieu tra.

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Ban do hien trang rirng xa Mudng Tiing ndm 2000 Bdn do hiin trgng rimg xd Muang Tiing ndm 2010

Hinh 4. Vi du minh hpa ve khu vuc tdng rirng (AR_217) &xa Mu&ng Tung -Mu&ng Chd

Ket qua phdng van tai 40 xa va nghien ciiu thuc te tai 19 khu vuc dai dien cd dien tich rimg tang len thudc 8 huyen da cho thay cac nguyen nhan chu yeu lam cho dien tich rimg d tinh Dien Bien tang len, bao gdm: (1) Quy hoach phuc hoi rimg theo chuong trinh 661, (2) Bd hda nuang ray; (3) Trdng cay cao su;

(4) Trdng rimg theo chuang trinh 661; (5) quy hoach khu bao tdn thien nhien Mudng Nhe. Tiiy theo timg huyen ma cd mdt hay nhieu nguyen nhan chu yeu cimg tac dpng lam tang rimg. Ket qua tdng hgp sd lugng cac nguyen nhan lam cho dien tich rimg tang len dugc the hien d hinh 5.

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TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3-2014

Qudn ly tdi nguyen rung & Moi tru&ng

Trong cac nguyen nhan chu yeu lam tang rimg thi, Quy hoach phuc hoi rimg va trdng rimg theo chuang trinh 661 la 2 nguyen nhan lam tang rimg d h4u hit cac huyen trong tinh Dien Bien. Chuang trinh 661 dugc thuc hien tit 1998 den nam 2010 tren pham vi ca nude, Dien Bien la mdt trong nhiing tinh trgng dilm trong chucmg trinh nay, chinh vi vay ma hoat dgng phuc hdi rimg va trdng rimg dugc thuc hien gan nhu trong toan tinh. Ben canh do nguyen nhan lam tang rimg do bd hda nuang ray d nhiing nai cd dieu kien khdng thuan lgi cho san xuat hoac d gan khu vuc dan cu sinh sdng, nham muc dich bao ve ngudn nude va bao ve lang ban ciing dugc thuc hien d nhieu noi trong tinh. Mdt nguyen nhan khac lam tang rimg la do trdng cay Cao su. Tir nam 2007 trd lai day nhieu dien tich dat lam nghiep cua tinh Dien Bien dugc chuyen ddi

trdng Cao su. Cho din nay, nhieu dien tich Cao su trong tinh da trd thanh rimg, vi vay day cung dugc xem la mgt trong nhiing nguyen nhan lam tang rung. Cac huyen cd dien tich trSng Cao su ldn nhu Dien Bien, Mutrag Cha, TuSn Giao, Dien Bien Ddng. Ngoai ra, cdn nguyen nhan khac lam tang rung la quy hoach khu bao tdn thien nhien Mudng Nhe tap trung d huyen Mudng Nhe.

Trong cac nguyen nhan lam tang rimg, mdi nguyen nhan khac nhau cd tac ddng khac nhau lam cho dien tich rimg tang len, cd nguyen nhan lam cho dien tich rimg tang nhieu, cd nguyen nhan lam cho dien tich rimg tang it hon. De xac dinh miic dp tac dpng cua timg nguyen nhan lam cho dien tich rimg tang, nghien ciiu da tien hanh lugng hda miic do tac ddng ciia mdi nguyen nhan. Ket qua lugng hda the hien d hinh 6.

Hinh 6.Tyli% muc dp dnh hu&ng cda cdc nguyen nhan dan den tdng rirng theo dien tich ritng tdng len

Nguyen nhan chinh lam tang rimg chu yeu la do quy hoach bao ve rimg theo chuang trinh 661 dugc triin khai tai cac dia phuong vao khoang tir nam 2000 - 2009, nguyen nhan nay chilm ty le 62,06%, tiep den la do bd hda nuang riy (25,25%) quy hoach khu bao tdn

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014

thien nhien Mudng Nhe (7,23%). Cac nguyen nhan khac cung lam tang rimg nhung chiem ty le nhd bao gdm: Trdng rimg theo chuong trinh 661 (chiem 5,03%), va trdng cay Cao su (chilm 0,44%).

71

Qudn ly tdi nguyen rirng & Moi tru&ng

Hinh 7. Rirngpliac boi theo chuffng trinh 661

tai khu vuc AR_I03, xa Nam Ke

3.2.2. Nguyen nhdn ldm mdt rimg

Ket qua nghien ciru tai 40 xa va khao sat

thuc dia tai 20 khu vuc dai dien mat rirng

cho phep xac dinh chinh xac sd luang va cac

Hinh 8. Rimg gan long bdn duffc phuc hdi tot sau

nirffng ray tgi khu vuc AR_248, xa Sa Long

nguyen nhan lam mat rimg. Nghien ciiu ciing

da tien hanh xay dung biin do mat rimg cac xa

nghidn ciiu dd thSy ro dugc vi tri, dien tich ciia

cac khu vuc mat rimg.

Ban do Men trang rimg xa Leng Su Sin nam 2000 Ban da hien trang rimg xa Leng Su Sin nam 2010

Hinh 9. Vidtf minh hga vi khu vuc tang ritng (DD_32; DD_35)

&xd Leng Su Sin - Mu&ng Nhe

Ket qua nghien ciiu cho thay co hai nhom nguyen nhan dan ddn mat rirng o Dien Bien

do la: Nguyen nhan sau xa (gian tiep), bao

gdni: (1) Dan sd tang nhanh; (2) Di dan; (3)

Thieu dit canh tac va (4) do quy hoach ba loai

rung vao nam 2006 da chuydn ddi mot s6 dien

tich dat lam nghiep co phan bd rai rac va

manh miin sang dat san xuat nuong r iy va quy

hoach phat tridn cay cao su vao nam 2008 da

chuydn doi nhirng dien tich rimg ngheo, rirng

ngheo kiet phan bd a do cao duai 600 m so

vtii muc nuac bien sang trdng cay cao su va

Nguyen nhan true tidp, bao gdm: (1) Do ddt

nuong lam ray; (2) Rimg bi chet (chu yeu la

rimg tre niia do bi khuy); (3) Chay rimg; va

(4) Chan tha gia siic.

Nhom nguyen nhan sau xa mac dii khdng

true tidp anh hudfng den tai nguyen rirag

nhung no dugc danh gia la nhom nguyen nhan

quan trgng co tac dgng lan ddn nguydn nhan

true tidp gay ra m§t rimg. Ket qua nghien ciiu

cho thay cac nguyen nhan sau xa (gian tiep)

CO mat 6 h iu hdt cac huyen trong toan tinh

Dien Bidn. Mdt sd vi du didn hinh vd nhom

nguyen nhan nay nhu tai khu vuc m i t rimg

(DD_18, xa Muong Tiing - huyen Muang

72 TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014

Qudn ly tdi nguyen rirng & Moi tru&ng

Cha) do dan sd tang qua nhanh, vao thdi di lm nam 2000 khu vuc nay chi mdi cd 76 hd tuy nhien cho d in nay da tang len 189 hd gia dinh sinh sdng. Dan sd tang nhanh dan d in nhu ciu ve dat canh tac ngay cang ldn, nhu chi sir dung tai nguyen rimg cang nhilu din din cd nhiing tac dgng tieu cue din rimg. Hay tai mdt sd khu vuc mat rimg cd DD_34, DD_35, DD_109, DD_46; DD_40, DD_23 thudc cac xa cua huyen Mudng Nhe cd hien tugng di

dan (ca tu do va theo chinh sach) dan den dan

sd d cac khu vuc nay tang len mgt each dot

bien lam cho nhu cau ve dat canh tac, nhu cau

sir dung tai nguyen rat ldn tir dd tac dgng len

cac nguyen nhan true tiep dan den mat rimg.

D I danh gia sd lugng cac nguyen nhan

true t i lp d in d in mat rirng, nghien ciiu da

t i ln hanh thdng ke so lugng cac nguyen

nhan true tiep tac dpng den mat rung theo

cac huyen (hinh 10)

Hinh 10. So lupng cdc nguyen nhdn true tiep

Sd lieu Bang 5 cho thay, sd lugng cay tai

sinh dat tri sd cao nhat (323 cay) tai nai cd

miic do tan che 0,70 (0,61- 0,70), nhieu gap

5,47 va 2,80 lan so vdi sd lugng cay tai sinh

dudi tan rimg cd miic dd tan che 0,50 (0,41-

0,50) va 0,60 (0,51- 0,60) tuang iing. Di lu

nay cd the nghT tdi kha nang cay tai sinh dang

ldm mat rumg tgi cdc huyen nghien ciru

trong giai doan can dugc che bdng nhieu hon

la nhu cau cucmg do anh sang cao. Van de dat

ra la do tan che tAng cay cao cd quan he nhu

the nao vdi chat lugng cay tai sinh? Tra ldi cau

hdi nay, de tai da tdng hgp chat lugng cay tai

sinh theo pham chat cay tdt, trung binh va xau

vdi cac miic dp tan che khac nhau.

Hinh 11. Tyli% mirc dp dnh hu&ng cua cdc nguyen nhan true dip din mat rimg

theo diin tich rimg bi mdt

TAP CHI KHOA HQC VA CONG NGHE LAM NGHIEP SO 3 - 2014 73

Quan ly tai nguyen ring & Moi truang

Trong cac nguyen nhan true tiep dan ddn mit rimg thi ddt nuong lam ray la nguyen nhan chu ydu, chidm ty Id lan lam mat rimg tai cac khu vuc nghidn ciiu (chidm 89,22%), tiep ddn la mat rimg do rimg bi chdt khuy (chu yeu la rirng tre niia) chiem 5,93%, do chay rimg (chidm 3,66%) va do chan tha gia siic (chidm 1,19%)

Ngoai cac nguyen nhan sau xa (gian tiep)

va true tidp din ddn mit rimg dugc phan tich g trdn, kdt qua nghien ciiu con cho thay co mdt sd nguydn nhan khac dan ddn mat rimg cr Didn Bidn, nhu: khai thac gd dd lam nha, do xay dung cac cdng trinh thiiy dien va chuyen ddi muc dich su dung dat theo quy hoach phat tridn cay cao su va cay ca phe. So dd md ta cac nguyen nhan dan den mat rimg d Dien Bien dugc the hien 6 hinh 12

Nguyen nhan sau xa (Nguyen nhSn gian tigp ) lam mit rimg

Dan s6 Ting tu nhien

1 Thi u dat canh tac

Sir gia tang dan so Di dan (bao gom di

dan tu do va iheo chinh

Quy hoach vung san xudt nucmg

Cung

lucmg thuc

Cung CJ )

Do canh

San ban (bat diii, lay mat ong..)

Do tre niiabi khuy

(ra hoa)

Nuoi tha dai gia sue (trau, bo)

Nhu cau venhao

tang

QHXD thuy di?n

Theo QHPT cao su, ca phe

Hinh 12. Sff do mo td cdc nguyen nhdn ddn den mat rimg tgi Bien Bien

IV. KET LUAN Do che phii rimg ciia cac xa nghien ciiu

tang/giam chu ydu la do thay ddi dien tich cac kieu trang thai rimg. Didn tich rimg or cac xa thugc cac huyen Didn Bien Ddng, Tuan giao, Muang Ang, Tiia Chiia, Dien Bien hien nay

hau hdt tang len so voi nam 2000. Dien tich rung tang chii ydu la rimg phuc hdi va rimg trdng. Ngugc lai dien tich rimg cua cac xa thugc huyen Muong Nhe, Muang Cha va Nam Pd hien nay so vdi nam 2000 thi da phin co dien tich rimg giam, dien tich rimg giam chu

74 TAP CHi KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014

Qudn ly tdi nguyen rirng & Moi tru&ng

yeu la rimg trung binh, rimg ngheo, rimg hon giao gd-tre niia.

Nguyen nhau chinh lam tang rimg chii ylu la do quy hoach bao ve rimg theo chuang trinh 661, nguyen nhan nay chi m ty le 62,06%, tiSp dSn la do bd hda nuong rSy (25,25%) quy hoach khu bao tdn thien nhien Mudng Nhe (7,23%). Cac nguyen nhan khac ciang lam tang rimg nhung chiim ty le nhd bao gdm: Trdng rimg theo chuong hinh 661 (chilm 5,03%) va trdng cay cao su (chiem 0,44%).

Nguyen nhan dan din mk rimg d Dien Bien bao gdm: nguyen nhan gian tilp, bao gdni: (1) Dan sd tang nhanh; (2) Di dan; (3) Thi8u dit canh tac va (4) do quy hoach. Nguyen nhan true tiSp, bao gdm: (1) Do ddt nuong lam rSy; (2) Rimg bi chit (chii ylu la rimg tre niia do bi khuy); (3) Chay rung; va (4) Chan tha gia siic. Trong so cac nguyen nhan true tiep dan den mkt rimg thi dot nuong lam ray la nguyen nhan chii ylu, chilm ty le ldn lam mat rimg tai cac khu vuc nghien ciiu

(chiem 89,22%), tiep den la mat rimg do rimg bi chet khuy (chu yeu la rung tre niia chiem 5,93%), do chay rimg (chiem 3,66%) va do chan tha gia siic (chiem 1,19%)

TAI LIEU THAM KHAO 1 Bo NN&PTNT, 2010. Bdo cdo ddnh gid kit qud

thuc hien du dn 661 viing Tdy Bac. Vien Sinh thai rung va Moi tnidng.

2. Bdo cdo tinh hinh phdt trien kinh te xd hdi cdc ndm 2010, 2011, 2012, 2013 ciia UBND 40 xa nghien cuu.

3. Cue thong ke tinh Dien Bien, Nien gidm thdng ke ndm 2010, 2011, 2012. 2013.

4. Chi cue Kiem lam tinh Dien Bien, 2013. Sd lieu theo ddi dien bien tdi nguyen rung ndm 2013.

5. JOFCA, 2012. Bdo cdo khdo sat ddc diim tu nhien vd kinh te xa hpi tinh Dien Bien nhdm thirc thi chucmg trinh REDD+. Truong Dai hoc Lam nghiep.

6. UN-REDD Vi?t Nam, 2009. Hdi thdo qudc ti vi co che REDD tgi Viet Nam: G(ri md nhiing ca che, ngudn luc mdi.

ANALYZING CHARACTERISTICS AND CAUSES OF FOREST COVER

CHANGE IN DIEN BIEN PROVINCE: PERIOD 2000 - 2013

La Nguyen Khang, Tran Quang Bao

SUMMARY

This paper presents results of research on the characteristics and the causes of increase/decrease of forest at 40 communes of 8 districts of Dien Bien province. The study results showed that the forest cover increased/decreased at study areas are mainly due to changes in area of forest types. The increased area of forest types are mainly from forest restoration and plantation. The decreased area forest types are medium forest, poor forest and mixed wood - bamboo forest. The study also identified the causes of increase/decrease in forests: (1) the reasons for the increase in forest area, including: planning for forest protection of 661 program, accounted for 62.06 %; fallow land after shifting cultivation, accounted for 25.25 %; planning for Muong Nhe Nature Reserve, accounted for 7.23 %; afforestation under 661 program, accounted for 5.03 %; rubber plantation, accounted for 0.44%. (2) The cause of forest loss, including: direct causes such as slash and bum, accounted for 89.22 %; flowering bamboo forest, accounted for 5.93 % ; forest fires, accounted for 3.66 % and grazing accounted for 1.19%. The indirect causes of forest loss are rapid population growth; migration; lack of arable land and land use planning. The direct and indirect causes of forest loss relate each other and promote deforestation in the study area.

Keywords: Forest cover change, forest cover, R£DD+, forest increase, forest decrease.

Ngiroi phan bien

Ngay nhan bai

Ngay phan bien

Ngay quyet dmh dang

GS.TS. Tran Hihi Vien

17/7/2014

13/8/2014

07/9/2014

TAP CHI KHOA HOC VA CONG NGHE LAM NGHIEP SO 3 - 2014 75