Qudn ly tdi nguyen rimg & Moi tru&ng
^j PHAN TICH DAC DIEM VA NGUYEN NHAN DIEN BIEN TAI NGUYEN Rl/NG T I N H DIEN BIEN, GIAI DOAJS 2000 - 2013
La Nguyen KhangS Tran Quang Bao 'ThS. Truang Dgi hge Ldm nghiep
^PGS. TS. Tru&ng Bgi hoc Ldm nghiep
TOM TAT
Bai bao trinh bay k^t qua nghien cmi v6 dac diem diln bien va cdc nguyen nhSn dan den tang/giam rimg tai 40 xa thugc 8 huy^n ciia tinh Dien Bien. Ket qua nghien curu cho thSy, do ehe phii riing ciia cac xa nghifin ciiu tang/giim chu yiu la do thay dfii dien tich cac kieu tr^ng thai rihig. Dien tich cac kieu tr^ng thai rimg tJng 16n chu yfiu la rung phuc hfii va riing trfing. Difin tich cac kiSu trang thai riing giam la rirag trung binh, rimg ngheo va rung hfin giao gfi - tre mia. Nghien ciiu ciing da xac djnh dugc cac nguyfin nhan lam t5ng/giam riing: (I) Nguyen nhdn ldm cho diin lich ritng tdng len, bao gdm: quy ho?ch bio v | rirag theo chuang trinh 661, chiem 62,06%; bo hoa nucng riy chiem 25,25%; quy hoach khu bao tfin thien nhien Mucmg Nhe chiem 7,23%; trfing rvtng theo chuong trinh 661 chiem 5,03%; va trong cay cao su chifim 0,44%. (2) Cdc nguyen nhdn ddn din mdt rung, bao gdm: Nguyfin nhan true tiep nhu: dfit nuong lam ray chiem 89,22%; rimg tre mia bj khuy chifim 5,93%; do chay rimg chiem 3,66% va do chan thi gia siic chiem 1,19%. Cac nguyen nhan sau xa (gian tifip) lam mat rimg: dan sfi tang nhanh; di dan; thieu dat canh tac va do quy ho^ch. Cac nguyen nhan true tiep va gian tiep co lien he vdi nhau va ciing thiic day vific m^t riing t^ii cac khu vuc nghien ciiu.
Tii khda: Dien biin rung, d^ ehe phd, mdt rirng, REDD+, tdng rimg.
I. DAT VAN DE
Dien Bien Id tinh mien niii nam o phia Tay bac Vi?t Nam, co tiSm nang v6 ddt lam nghiep va co khd ndng phdt triSn sdn xudt lam nghiep rat lan. Todn tinh co 602.566,42 ha dat ldm nghiep, chiSm 63,01 % dien tich tir nhien ciia tinh. Tdng dien tich dat co rimg ciia Dien Bien la 400.776,1 ha, chi8m 66,04% ddt lam nghiep vd dat ty le ehe phu 42%, trong do rung t^r nhien la 387.051,1 ha, chiem 96.58% dat co rimg; rimg trfing la 13.725 ha chiem 3,42%. Hdu hit rimg a Dien Bien hi^n nay la rimg phong ho. Dat chua su dyng ciia Di§n Bien con rit lon, tdi 175.269,74 ha, chiSm 18,33% tdng dien tich tu nhien, trong do chu yeu Id ddt d6c chi co kha nang phdt trien lam nghiep. Day dugc xdc dinh la ngu6n tai nguyen qui gid, mot th^
manh cho phat trien kinh te - xa hpi ciia tinh.Trudc boi canh bien doi khi hau (BDKH), lam nghi?p la mpt trong nhfing
nganh co vai tro ldn trong viec ngan chan va gidm thieu nhimg tdc dong tieu cue cua BDKH. Viec tham gia vdo thuc hien sdng kien giam mat rimg va suy thodi rimg (REDD+) dang dirge cdc cap, nganh trong tinh dac biet quan tdm. DS co the de xuat dugc nhung gidi phdp cho thuc hien REDD+
thi can phdi co nhihig hieu biet ve dac diem dien bien tai nguyen rimg, cdc nguyen nhan dan den bi6n dgng tdi nguyen rirng (tang/giam). Muc dich ciia nghien ciiu nay nham xdc dinh cac nguyen nhan ddn den mdt rimg/suy thoai rimg (sau day ggi tdt Id mat rimg) ciing nhu la cdc yiu t3 phat tri§n rirng (trong rirng/tai sinh rimg) (sau day ggi tat la tang rimg) tai cdc khu vuc khac nhau thugc tinh Dien Bien. Tir k6t qua nghien cuu nay, nhung chinh sdch va cdc gidi phdp se dugc de xuat va dp dung phu hgp voi diSu kien thiic te tai tinh Di?n Bien trong qua trinh th^c hien REDD+.
64 T^P CHI KHOA HQC VA CONG NGHf LAM NGHIEP SO 3 - 2014
Qudn ly tai nguyen rimg <£ Moi trucmg II- DO! TirglNG, PHAM VI VA PHlTONG
PHAP NGHIEN C\SV 2.1. Doi tvffng nghien ciru
Tren ca sa muc tieu da xac dinh, d6i tucmg nghien cmi bao g6m: (i) Dien tich rimg va dat ISm nghiep theo mdc thai gian nam 2000 den nay; (ii) Cac nguyen nhan din den mat rtmg/tang nmg.
2.2. Pham vi nghien cihi
- Ye khong gian: Nghien ciiu du(jic thuc hien tai 40 xa thuoc 8 huyen thi trong toan tinh Dien Bien, bao gom: Muong Cha, Muang Nhe, Nam P6, Tua Chua, Tuin Giao, Muong Ang, Dien Bien va Dien Bien Dong.
- vi thai gian: Nghien ciiu tap trung phan tich diln biSn rimg tai cac thai diem nam 2000, nam 2010 va hien nay.
BAN e o VI TRI CAC XA NGHIEN CC/U TAI TlNH DIEN BIEN
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ciru thupc 8 huyfn ct Bifn Bien
2.3. Phirong phap nghien cthi
Cac phuang phap nghien cihl dugc sii dung, bao gom: phuang phap xay dung khung logic dS xac dinh vjn dl cin giai quylt trong qua trinh thu thjp va xii ly s6 lieu nghien ciiu; phuang phap thu thSp s6 lieu thong tin thii cap; phuang phap thu thap thong tin sa cap (phong vSn, thao lujn nhom, khao sat thuc tl cac khu rung ngoai hien truang; phuang phap chuyen gia).
Nghien ciiu da tiln hanh phong vjn thu thap thong tin doi vai cac dli tuang khac nhau dugc lua chpn, bao gSm: UBND va Kiem lam cac cap, can bo Chi cue Lam nghiep, Phong NN&PTNT.... cac hp gia dinh, cac ca nhan, co lien quan ciia 40 xa nghien ciiu dl thu thap cac thong tin vl: lich sii thay dli su dung dit, thay dli dp ehe phti rung va cac nguyen nhan lam tang di$n tich rung va mat rimg 6 moi dia phuang.
De xac dinh lich su thay dli dp ehe phii rung, nghien cuu da su dung cong cu GIS dl phan tich thay doi sii dung djt/dg ehe phii a cac xa dugc chpn nghien ciiu vao cac thai dilm khac nhau nam 2000, 2010 va 2013.
De xac dinh chinh xac ve cac nguyen nhan lam tang rimg, mat rimg va miic dg anh huong cila mdi nguyen nhan den tang/giam rimg, nghien ciiu da su dung cong cu ArcGIS 9.3 va Mapinfo 10.0 dl khoanh ve cac khu vuc tang rung va cac khu vuc mit rirng. Khu vuc tang rimg dugc ky hieu la AR_s6 thu tif (khu vuc tang rimg co nghia la khu virc do khong CO rimg vao nam 2000 nhtmg din 2010 va hien nay da co rimg); khu vuc mit rimg dugc ky hieu la DDso thi thu (la khu vuc CO rimg nam 2000 nhung din nam 2010 va hien nay la khong con riing)
T^P CHi KHOA H p c VA CONG NGHE LAM NGHIEP SO 3 - 2014 65
Qudn ly tdi nguyen ruiig & Moi tru&ng
K.hu wsc tang rung Khu vyc mat rimg
BAN 0 6 HIEN TRANG R O N G X. MUONG MUON - H. Ml/dNG CHA - T. DIEN BIEN
Hinh 2. Bdn do dien bien rung thi hi$n cdc khu v^c tdng/mat rimg theo dffn v/ xd Nghien cuu da I i ^ chgn dai dien a cdc
huyen nghien cuu 20 khu vuc co dien tich rimg tdng len va 20 khu vyrc co di?n tich rung mat di, moi khu vuc co dien tich tiJr 100 ha tra len.
Doi vai mSi khu v\rc tdng rtmg hoac mat rimg, nghien cuu da ti^n hdnh xdc dinh vi tri ngodi th\rc dia, khdo sat hien tnrdng va phong van can bg va nguoi dan dia phuang (nguai dugc phong vdn Id can bg xa, gia lang, trudng bdn, nhflng ngudi hieu biet ve ljch su thay doi sir d\mg dat t^i khu vuc, vdi moi khu vuc da tien hanh phong van 2-3 cdn bg xa va 5-7 ngudi dan dja phuang) de xac djnb chinh xac cdc nguyen nhdn ldm tang rirag va mat rimg tai cdc khu vuc cy the.
66 TAP C H I K H O A H Q C VA C O N G NGHli; L A M NGHIfiP SO 3 - 2014 DS lugng hda dnh hudng cua cdc nguyen nhdn lam tang/giam rimg, tai moi khu vyc dugc chgn nghien cuu da tiSn hanh xac dinh phan tram dien tich rimg tang len hoac mat di theo tirng nguySn nhan tdc dgng, tir do tinh toan ty le phdn tram anh hudng cua cdc nguyen nhan lam tang/gidm rimg theo dien tich doi timg nguyen nhdn.
m . KET QUA NGHIEN CUtJ, THAO L U ^ 3.1. Lich su-thay do! sirdiingdat/dg ehe phu rtog
Theo ket qua phdn tich GIS, cac bdn d6 bien dgng (lich sir) su dung ddt/thay ddi ehe phu ciia cac xa nghien cuu theo timg huyen dugc mo td nhu sau:
Qudn ly tdi nguyin rimg & Moi tru&ng
Bdn do thay doi dg ehe phu cua cdc xd nghien cuu Bdn do thay doi do ehe phu cua cdc xa nghien cuu tgi huyen Diin Bien Dong tgi huyen Tudn gido
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Ban dd thay ddi do ehe phu cua cdc xd nghien cuu Bdn do thay doi do ehe phit cita edc xd nghien ciru Igi huyen Mircmg Ang tgi huyen Mucmg Chd
Bdn dd thay doi dg ehe phu Bdn do thay doi do ehe phd cua cdc Bdn do thay doi dg ehe phd cua ctia cdc xd nghien am tgi xd nghien cdu tai khu vuc huyen cdc xd nghien cim tgi huyen
huyen Tua Chita Muang Nhe vd Ngm Po Dien Bien
VXnh'i, Bdn do thay ddi do ehe phd cda 40 xd nghiin cuu & Biin Bien KSt qua phan tich thay ddi do ehe phii rirag ciia cdc xa nghien cuu dugc the hiSn d bdng 1.
TAP Cffl K H O A H Q C VA C O N G N G H E L A M N G H I E P SO 3 - 2014 67
Qudn ly tai nguyen rirng «t MSi tru&ng
Bang 1. Thay ddi do ehe phu cia rung 6 cdc xa nghiin cuu
TT
(1) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 IS 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) PuNhi Chieng Sa Keo Lom NaSon NaSay Muang Miin Phinh Sang Quai Cang TaMa Ang Cang Mucmg Dang Mucmg Lan Hira Ngai Muong Tiing Sa Long Huoi X6 Tua Thang Chung Chai Leng Su Sin Muong Nh6 Muimg Tcjong Nam Ke N ^ Vi Pa My Quang Lam Sen Thu(?ng Sin Thau Cha Nua Si Pa Phin Cha cang NaBung Na C6 Sa NaHy NaKhoa Pa Tan Muong Loi Muong Pon Nlia Ngam Thanh An Muong Nhi
Huy|n
(3) Dien Bien Dong Di?n Bien Dong Dien Bien Dong Dien Bien Dong Tuan Giao Tuan Giao Iuan Giao Tuan Giao Tuan Giao Muong Ang Mucmg Ang Muong Ang Mucmg Chi Muong Cha Mucmg Cha Tua Chiia Tua Chiia Mu6ng Nhe Mu6ng Nhe Muong Nhe Muong Nhe Muong Nhe Muong Nhe Muong Nhe Muong Nhe Muong Nhe Muong Nhe N^mPo Nam Po NamPo N | m P 6 NamPo NamPo N^mPo Nam pa Dien Bien Di^n Bien Dien Bien Dien Bien Dien Bien
^am 2000
(%)
(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
(%) («)
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
TJIS
(%)
(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 rimg thay doi
(8) Rimg ph\ic hQi
Rimg phuc hoi va rimg ngheo Rimg phuc hoi va rimg go -tre niia Rirng phyc h6i v i rirng g6-tre nua Rimg phyc hoi
Rirng ngheo va rirng trung binh Rimg phuc hoi va rirng nui da voi Rirng phuc hfii vi rimg trong Rirng nui da voi Rimg phyc hoi va rirng trong Rimg phyc hoi
Rimg phyc hoi va rimg trong Rimg phuc hdi
Rimg giiu, riiiig IB, rimg n ^ ^ vi riing TN Rirng trung binh vi rimg phuc hoi Rirag phuc h6i v i rirng mii da v6i Rirng phuc hoi
Rirng trung binh Rirng phuc hoi
Rimg liung binh vi rimg go - tie niia Rimg phyc hoi va rimg trong Rimg tmng binh vi rimg g6 - tte niia Rimg trung binh vi rimg g6 - fae niia Rimg trung binh vi rimg go - tie nira Rimg phuc hoi
Rirng giiu, rimgTB,rungn^KO\aiiingTN Rimg tnmg binh, rimg ngheo vi rirng TN Rirag ttung binh
Rirag ngheo va rimg trfing Rirag phuc hoi va rimg gfi-tre niia Rimg giiu va rimg trung binh Rirag phyc hfii
Rirag trung binh va rimg ngheo Rirag phyc hfii
Rimg phyc hfii Rirag phyc hfii
Rimg phyc hfii v i rirng trong Rimg phyc hfii v i rirng trfing Rimg phyc hfii va rirag trfing Rimg phyc hfii v i rirag tifing TAP CHi KHOA HQC VA CONG NGHE LAM NGHIfP SO 3 - 2014
Ket qua bang 1. cho thdy cdc xa co do ehe phu rtmg tdng len chii ySu Id do tang len ve dien tich rimg phuc hdi vd rimg trong, cdc xa CO do ehe phii rung giam xudng chii yen la do giam dien tich rung giau, rimg trung binh, rung ngheo va rftig hon giao gd - tre nua. Cu the su thay ddi ve do ehe phu rimg d cac huyen nghien cuu dugc phdn tich nhu sau;
Huyen Dien Bien Dong: Ty le cbe phu cua rimg d cac xa deu tang manh tii 9-13%, phdn ldn la do su tang len cua rimg phuc hoi va rimg hon giao gS - tre nura.
Huy?n Tuan Giao: Trong 5 xa nghien cuu cua huyen Tuan Gido, 3 xa cd do ehe phii rimg tdng tir 0,7-11,3% va dat dg ehe phu tir 24- 43%. Hai xa cdn lai la Mudng Mim va Na Sdy thi do ehe phii rirag gjdm tucmg umg la 15,30%
va 9,32%. Nhimg xa co do ehe phii tang phan ldn do sir thay ddi ciia rimg phuc hdi, hai xa cd dg ehe phii gidm thi chii yeu dien ra d cdc trang thdi cd trfi lugng gd cao nhu rimg tnmg binh, rung ngheo vd rimg tren niii da.
Huyen Mudng Ang: Mac du ty le ehe phii ciia rung nam 2013 khdng cao, xong da tang rat nhieu so vdi nam 2000. Trong dd, xa Ang Cang va xa Mudng Lan tang gap 2 lan va xa Mudng Dang tang len gap ban 4 lan. Ket qua ndy phdn ldn la do su tang len cua rung phuc hdi va mgt mgt sd do trdng rimg mdi.
Huyen Mudng Cha: Hau het cac xa cd ty Ie ehe phu rimg khd cao trong nam 2013. Tuy nhien dg ehe phii d xa Mudng Tung da gidm di khd nhiSu so vdi nam 2000, xd Hira Ngai vd xa Sa Ldng ty le ehe phu tang tir 9-10%. Su thay ddi nay xdy ra d hau het cdc lo^i rung tir rimg giau dSn rimg phuc hdi vd rung frdng.
Huy?n Tua Chiia: Sir thay ddi (tang/giam) vd ehe phii rimg chii yeu xdy ra d trang thai rung phyc hdi. Trong dd, ehe phu rirag cua Hudi Xd suy gidm kha manh vao nam 2010 (tdi 13% tdng di$n tich ty nhien, tuang ducmg vdi 34.67% dien tich ddt cd rirag). Tuy nhien cho dSn then diem nay (2013) do ehe phii rirag
Qudn ly tdi nguyen rung & Moi tru&ng ciia xa Hudi Xd l^i tang len gin d?t vdi mdc nam 2000, cdc kieu trang thai rirag tang len chu yeu la dien tich rimg phuc hoi. Do ehe phii d Tua Thang tang 6,63% so vdi nam 2000.
Huyen Mudng nhe: Ket qua phdn tich cho thay rang hau nhu do ehe phii d cac xa d huyen ndy bi giam tir 1-22%, Hai xa Mudng Toong vd Qudng Lam (huyen Mudng Nhe) cd do cbe phii rirag tang, dang luu y la xa Mudng Toong nam 2013 cd do ehe phii rung tang so vdi nam 2000 vd 2010 len tdi tren 30%. Cac trang thdi rimg gidm chu yeu Id rimg tnmg binh, rimg rimg hdn giao gd - fre niia. O cac xa cd dien tich rimg tang len chii yeu Id riing phuc hdi vd rimg frong
Huyen Nam Pd: La huyen mdi dugc thanh lap nam 2012 cua tinh Dien Bien, cdc xa ciia huyen nay chii y^u dugc chuySn tir huyen Mudng Cha vd Mudng Nhe sang. Dg ehe phu rimg cua cac xa frong huyen cd su thay ddi (tang/giam) ngodi viec cd sir thay ddi ve cdc kiSu trang thdi rung thi cd mgt phan nguyen nhan do thay ddi ve dia gidi hanh chinh cua cdc xa sau khi thdnh lap huyen mdi.
Huyen Dien Bien: do ehe phii ciia rimg d cdc xa nghiSn cuu thudc huyen Dien Bien deu tang manh tir 7-26%,. Su thay ddi nay chu yeu la su tang len ciia rimg phuc hdi vd rirag frong.
3.2. Nguyen nhan dan den sy thay doi do ehe phu rimg
Tren co sd ket qua phan tich bien dgng lich su sii dung ddt d phan 3.1 cho thdy, dg ehe phii rimg tai cac xa nghiSn cuu cd tang len hoac gjdm di, dS xac dinh nguySn nhdn ddn dSn sy thay ddi nay, nghiSn cuu da tiSn hanh dieu tra thyc dia bao gdm: phdng van cdn bg, ngudi dan vd khao sat thyc dia tai 40 khu vyc, trong do cd 20 khu vyc cd dien tich rimg tang Ien va 20 khu vuc cd dien tich rung gidm (mat rimg). KSt qua cho phep xac dinh chinh xdc nguyen nhan ddn dSn su tang ISn hoac gidm di cua rimg.
T^P CHI KHOA HQC VA CONG NGHE LAM NGHIEP SO 3 - 2014 69
Qudn ly tdi nguyen rumg & Moi tru&ng 3.2.1. Nguyen nhan ldm tdng rimg
Trong 20 khu vyc cd dien tich rimg tang co 01 khu vuc vdi ky hieu AR_287 la cd sy khdc nhau giiia bdn dd va thyc tS. Trong ban do thay ddi di?n tich riing thS hien rdng, vao nam 2010 diSm nay la co rirag, tuy nhien khi phdng van can bg vd ngudi dan dia phucmg cimg vdi kiem chiing thyc tS, thi vdo thdi gian tir tnrdc nam 2010 dSn nay, khu vyc nay la vimg sdn xuat
nuang ray ciia nguoi dan dja phuang. N h i ^ vay, frong 20 khu vyc tien hanh nghien cim thi CO 19 khu vuc Id cd thong tin diing vdi ban dfi, dd la vao nam 2000 cac khu vuc nay khdng c6 rirag va den nam 2010 va hien nay thi cd rimg.
Nghien ciiu da tiSn hdnh xay dyng bdn do hi|n trang rimg nam 2000 va 2010 ciia cdc \l nghiSn ciiu dS thay dugc sy tang len cua dien tich rimg d cdc khu vyc diSu tra.
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Bdn do hien trgng rinig xd Muang Tiing ndm 2000 Hinh 4. Vi du minh hga ve khu v^c tdng rung Ket qud phdng van tai 40 xa va nghien cuu thyc te tai 19 khu vyc dai dien cd dien tich rimg tdng len thugc 8 huyen dd cho thay cac nguyen nhan chu yeu ldm cho dien tich rimg d tinh Di?n Bien tdng len, bao gom: (1) Quy hoach phuc hdi rimg theo chuang trinh 661, (2) Bd hda nuang ray; (3) Trong cdy cao su;
Bdn dd hien trgng rung xa Muang Tiing nam 2010 (AR_217) &xa Mudng Tdng-Mudng Chd (4) Trdng rCmg theo chuang trinh 661; (5) quy hoach khu bdo ton thien nhiSn Mudng Nhe.
Tiiy theo tung huyen md cd mdt hay nhieu nguyen nhdn chu yeu cimg tdc dgng ldm tang rung. KSt qud tdng hop sd lugng cac nguyen nhan lara cho dien tich rimg tang len dugc the h i ? n d h i n h 5 .
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Muoiig NgiiiPd Muoiia; Di^i Turlii Muong E)i^\ Tfia Clia Nile Bifin C3irto A i i g ' Bien chua70
Hinh 5.5o lufmg cdc nguyen nhan chii yku lam ting rimg » cdc huyfn nghiin ciru T^P CHi KHOA HQC VA C O N G N G H f LAM NGHI|:P SO 3 - 2014
Qudn ly tdi nguyen rung & Moi tru&ng
Trong cdc nguySn nhan chii ySu ldm tang rimg thi, Quy hoach phyc hdi rimg va frdng riing theo chucmg trinh 661 la 2 nguySn nhan lam tang riing d hdu hSt cdc huyen frong tinh Dien Bien. Chuang trinh 661 dugc thyc hien tir 1998 den nam 2010 frSn phgm vi ca nudc, Dien BiSn la mdt trong nhihig tinh frgng diem frong chucmg trinh nay, chinh vi vdy ma hoat dgng phuc hdi rung va frdng rimg dugc thyc hien gdn nhu frong todn tinh. Ben canh do nguySn nhdn lam tang rimg do bd hda nuong ray d nhihig noi cd diSu kien khdng thuan lgi cho san xudt hoac d gdn khu vyc ddn cu sinh sdng, nham muc dich bdo ve ngudn nudc vd bao ve lang ban cung dugc thyc hien d nhiSu noi frong tinh. Mgt nguyen nhdn khac lam tang rirag la do frdng cay Cao su. Tu ndm 2007 frd lai day nhieu dien tich ddt lam nghiep ciia tinh Dien Bien dugc chuyen ddi
frdng Cao su. Cho den nay, nhiSu dien tich Cao su frong tinh da frd thdnh riing, vi vay day ciing dugc xem la mdt frong nhiing nguyen nhan lam tang rimg. Cdc huyen cd dien tich frdng Cao su ldn nhu DiSn Bien, Mudng Cha, Tudn Giao, Dien Bien Ddng.
Ngoai ra, cdn nguySn nhan khdc lam tdng rimg Id quy hoach khu bao tdn thien nhien Mudng Nhe tap trung d huyen Mudng Nhe.
Trong cac nguyen nhan Idm tang riing, radi nguySn nhdn khac nhau cd tac ddng khdc nhau lam cho dien tich rimg tang ISn, cd nguySn nhdn ldm cho diSn tich rimg tang nhieu, cd nguySn nhdn Idm cho dien tich rirag tang it hon. DS xac dinh miic do tdc dgng ciia tirag nguyen nhan lam cho di?n tich riing tang, nghien ciiu da tien hdnh lugng hda miic do tdc dgng ciia mdi nguyen nhdn. KSt qua lugng hda the hien d hinh 6.
Hinh 6. Tyli% tnuc dg dnh hirdng eua edc nguyen nhdn ddn den tdng rirng theo dien tfch rung tdng len
NguySn nhan chinh lam tang rimg chii yeu Id do quy hogch bdo v? rung theo chuang trinh 661 dugc friSn khai tgi cdc dia phuang vdo khodng til nam 2000 - 2009, nguyen nhdn nay chiSm ty IS 62,06%, tiep dSn Id do bd hda nuang ray (25,25%) quy hoach khu bdo tdn
TAP CHI KHOA HQC VA CONG NGHE LAM NGHIEP SO 3 - 2014 thiSn nhien Mudng Nhe (7,23%). Cac nguyen nhan khdc cung lam tang rimg nhung chiem ty le nhd bao gdm: Trdng rimg theo chuang trinh 661 (chiSm 5,03%), va frdng cay Cao su (chiSm 0,44%).
71
Qudn ly tdi nguyen rirng <fi Mdi tru&ng
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Hinh 7. Rimg phuc hoi theo chuong trinh 661 tgi khu vg-c AR_103, xd MSnt Ke 3.2.2. Nguyen nhdn ldm mdt rimg
Ket qua nghien ciiu tai 40 xa va khao sat thuc dia tai 20 khu vuc dai dien mat rimg cho phep xac dinh chinh xac sd lugng va cac
'^idi^.Rung gdn ldng bdn duy ^ piiuc noi un MUI nucmg rdy tgi khu vuc AR_248, xd Sa Long nguyen nhan lam mat rimg. Nghien ciiu cilng da tien hanh xay dung ban dd mat rimg cac xa nghien ciiu de thay ro dugc vi tri, dien tich ciia cac khu vyc mat rimg.
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Hinh 9. Vi du minh Itoa ve lihu vue tdng rimg (DD_32; DD_35)
&xd Leng Su Sin - Mirong Nhe Ket qua nghien cuu cho thay co hai nhom
nguyen nhan dan den mat rimg o Dien Bien do la; Nguyen nhan sau xa (gian tigp), bao gfim: (1) Dan so tang nhanh; (2) Di dan; (3) Thieu dat canh tac va (4) do quy hoach ba Ioai rimg vao nam 2006 da chuyen dfii mot s6 dien tich dat lam nghiep co phan bfi rai rac va manh mun sang dat san xuat nuong ray va quy hoach phat tiien cay cao su vao nam 2008 da chuyen doi nhirng dien Iich riing ngheo, rimg ngheo kiet phan bo o dp cao ducri 600 m so vdi muc nucic bien sang trong cay cao su va Nguyen nhan true tiep. bao gfim; (1) Do dfit
nuong lam ray; (2) Rirng bj chet (chu yeu la rimg tie nua do bi khuy); (3) Chay rimg; va (4) Chan tha gia sue.
Nhom nguyen nhan sau xa mac dii khfing tiuc tiep anh huong dfin tai nguyen rimg nhimg no dugc danh gia la nhom nguyen nhan quan tipng c6 tac dpng 1cm den nguyen nhan true tiep gay ra mat rimg. K6t qua nghien ciiu cho thay cac nguyen nhan sau xa (gian tiSp) co mat cr hau het cac huyen trong toan tinh Dien Bien. Mot so vi du diln hinh ve nhom nguyen nhan nay nhu tai khu vuc mit rirag
72
( D D i a , xa Muong T i n g - huyen Muong TAP C H i KHOA HOC VA CONG NGHE L A M NGHIEP SO 3 - 2014
Qudn ly tdi nguyin rdng & Moi tru&ng Chd) do dan sd tang qud nhanh, vao thdi diem
nam 2000 khu vuc nay chi mdi cd 76 hd tuy nhien cho dSn nay da tang Ien 189 hd gia dmh sinh sdng. Ddn so tang nhanh ddn dSn nhu cdu ve ddl canh tac ngay cdng ldn, nhu cau su dyng tai nguyen rirag cdng nhiSu dan den cd nhihig tdc ddng tiSu cyc den rirag. Hay tai mgt sd khu vyc mdt rimg cd DD_34, DD_35, DD_109, DD__46; DD_40, DD_23 thugc cac xa ciia huyen Mudng Nhe cd hien tugng di
dan (cd ty do vd theo chinh sach) ddn dSn dan sd d cdc khu vyc nay tang Ien mgt cdch dot bien lam cho nhu cau ve ddt canh tac, nhu cdu su dyng tdi nguyen rdt ldn tir dd tac dgng len cac nguyen nhan tryc tiSp ddn dSn mdt rimg.
De ddnh gid sd Iugng cac nguyen nhdn tryc tiep dan den mdt rimg, nghiSn cuu da tiSn hanh thdng ke sd lugng cac nguyen nhan true tiep tdc dgng den mdt rimg theo cac huyen (hinh 10)
Miiiniy NfiiiiPfi Muftiig
Ifinh 10. So lugfng cdc nguyin nhdn trgc dip Sd lieu Bdng 5 cho thay, sd lugng cay tdi sinh dat tri sd cao nhat (323 cdy) tai nai cd mirc do tan ehe 0,70 (0,61- 0,70), nhiSu gdp 5,47 va 2,80 lan so vdi sd lugng cdy tdi sinh dudi tdn rimg cd miic do tan ehe 0,50 (0,41- 0,50) vd 0,60 (0,51- 0,60) frrcmg iing. Dieu ndy cd the nghi tdi kha nang cay tdi sinh dang
ldm mdt rung tgi cdc huy$n nghien edit
frong giai doan can dugc ehe bdng nhiSu hon Id nhu cdu cudng dd dnh sang cao. Vdn dS dgt ra la do tan ehe tdng cdy cao cd quan he nhu the ndo vdi chdt lugng cdy tai sinh? Trd Idi cau hdi nay, de tai da tdng hgp chdt lugng cay tai sinh theo phdm chdt cay tdt, trung binh vd xdu vdi cdc miic do tan ehe khac nhau.
Hinh 11. Tyl$% mire dp dnh humtg cda edc nguyen nhan true dip den mdi rung theo di$n tich rimg bf mdt
TAP CHI KHOA HQC VA CONG NGHE LAM NGfflEP SO 3 - 2014 73
Qudn ly tai nguyen rimg & Moi tnr&ng Trong cac nguyen nhan trirc tiep dan den mSt rimg thi dot nuong lam riy la nguyen nhan chu yeu, chifim ty le lon lam mat rimg tai cac khu vuc nghien cuu (chiem 89,22%), tifip d6n la mit rimg do rimg bi chet khuy (chit yfiu la rimg tre niia) chiem 5,93%, do chay rimg (chifim 3,66%) va do chan tha gia sue (chifim 1,19%)
Ngoai cac nguyen nhan sau xa (gian tifip)
va true tiep dan den mat rimg duoc phan tich a tren, ket qua nghien ciru con cho thay co mot s6 nguyen nhan khac dan den mat rung d Dien Bien, nhu: khai thac go de lam nha, do xay dung cac cong trinh thuy di?n va chuyfin doi muc dich sil dung dit theo quy hoach phat trifin cay cao su va cay ca phe. So do mo ta cac nguyen nhan dan den mat rimg or Dien Bien dupe the hifin cr hinh 12
Nguyen nhan sau xa (Nguyen nhan gian tiep ) lara mat rirng
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Nguyen nhan tivc tiep lam mat rimg
Hinh 12. Sff do md td cdc nguyen nhdn ddn den mdt rimg tgi Bien Bien IV. KET L U ^
Dg ehe phii rimg ciia cdc xa nghien ciiu tang/gidm chu yeu la do thay ddi dien tich cac kiSu trang thdi rung. Dien tich rimg d cac xa thugc cdc huy?n Dien BiSn Ddng, Tudn giao, Mudng Ang, Tiia Chua, Di?n Bien hi$n nay
hau hSt tang len so vdi nam 2000. Dien tich rCmg tang chii yeu Id rimg phuc hdi va rimg frdng. Ngugc lai dien tich rimg ciia cdc xa thugc huyen Mudng Nhe, Mudng Cha va Nam Pd hien nay so vdi nam 2000 thi da phan co dien tich rimg giam, d!?n tich rirag giam chu
74 T^P CHI KHOA HQC VA CONG NGH? LAM NGH1?P SO 3 - 2014
Qudn ly tdi nguyin rdng & Moi tru&ng
yeu la rimg tnmg binh, rimg ngheo, rirag hdn giao go-fre mia.
NguySn nhan chmh lam tang rimg chu yeu Id do quy hoach bdo v? ring theo chuang trinh 661, nguyen nhdn nay chiSm ty IS 62,06%, tiSp dSn Id do bd hda nuong ray (25,25%) quy hoach khu bdo tdn thien nhien Mudng Nhe (7,23%). Cac nguyen nhan khdc cung lam tang rimg nhung chiSm ty le nhd bao gdm: Tr6ng rung theo chuong tiinh 661 (chiSm 5,03%) va trdng cay cao su (chiSm 0,44%).
Nguyen nhdn ddn den mdt rung d Dien Bien bao gdm: nguySn nhan gidn tiSp, bao gom: (1) Dan sd tang nhanh; (2) Di ddn; (3) ThiSu ddt canh tdc va (4) do quy hoach.
NguySn nhdn tryc tiSp, bao gdm: (1) Do ddt nuong ldm rdy; (2) Rirag bi chSt (chii ySu la rirag fre mia do bi khuy); (3) Chay rimg; va (4) Chan thd gia siic. Trong so cac nguySn nhdn true tiep ddn den mat rimg thi ddt nuong ldm rdy la nguySn nhdn chu ySu, chiem ty le ldn ldm mat rimg tai cac khu vyc nghien ciiu
(chiSm 89,22%), tiSp dSn Id mat rirag do rirag hi chet khuy (chii ySu la rimg fre mia chiSm 5,93%), do chdy rirag (chiSm 3,66%) va do chan tha gia siic (chiSm 1,19%)
TAI LIEU THAM KHAO
1. Bg NN&PTNT, 2010. Bdo cdo ddnh gid kit qud Ihuc hien du dn 661 viing Toy Bdc. Vien Sinh thai rimg va Moi tmong.
2. Bdo cdo tinh hinh phdt triin lanh ti xd hoi cdc ndm 2010,2011.2012, 2013 cua UBND 40 xa nghien ciia
3. Cue thong ke tinh Di^n Bien, Niin gidm thdng ki ndm 2010. 2011. 2012. 2013.
4. Chi cue Kiem lam tinh Di?n Bien, 2013. Sd li^
theo ddi diin bien tdi nguyen rimg ndm 2013.
5. JOFCA, 2012. Bdo cdo khdo sdt dac diim tu nhiin vd kinh te xd hqi tinh Bi^n Bien nhdm thuc thi chuang trinh REDD+. Trucmg Dai hpc Lam nghiep.
6. UN-REDD Viet Nam, 2009. Hpi thdo qudc ti ve ca chi REDD tgi Vi$t Nam. Gfri md nhiing ca ehe. ngudn 1{K mdu
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, REDD+, forest increase, forest decrease.
Nguxri phan bien Ngay nhan bdi Ngfky phan bien Ngay quyet d|nh dang
GS.TS. Tran Hihi Vi£n 17/7/2014
13/8/2014 07/9/2014
TAP CHI KHOA HQC VA CONG NGHE LAM NGHIEP SO 3 - 2014 75
