B NNG NGHIP V PHT TRIN NNG THN CHNG TRNH H TR NGNH LM NGHIP & I TC

CM NANG NGNH LM NGHIP

ChngCI THIN GING V QUN L GING CY RNG VIT NAM

NM 2006

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Bin son: L nh Kh Nguyn Hong Ngha Nguyn Xun Liu Chnh l: Nguyn Vn T V Vn M Nguyn Hong Ngha Nguyn B Ngi Trn Vn Hng Quang Tng H Tr k thut v ti chnh: D n GTZ-REFAS

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M u.............................................................................................................................7 Phn 1: Lch S Pht Trin v Cc Chnh Sch V Ci Thin Ging, Bo Tn Qun L Ngun Gen Cy Rng ......................................................................9 1. Lch s ci thin ging v bo tn ngun gen cy rng Vit Nam ............................91.1. Thi k trc nm 1945 ............................................................................................... 9 1.2. Thi k t nm 1945 n nm 1975 ............................................................................ 9 1.3. Thi k t nm 1975 n nm 1990 .......................................................................... 10 1.4. Thi k i mi (sau nm 1990) ................................................................................ 10

2. Cc chnh sch v ci thin ging v bo tn ngun gen cy rng ............................142.1. Cc vn bn php l v nghin cu, sn xut v qun l ging cy lm nghip .. 14 2.2. V bo tn ngun ........................................................................................................ 15

Phn 2: Cc Hot ng, Thnh Tu v Mt s Vn Tn Ti V Ci Thin Ging Cy Trng ............................................................................................18 1. Chn loi, chn xut x, xy dng rng ging v vn ging ...........................181.1. Chn loi, chn xut x, xy dng rng ging v vn ging cc loi keo .......... 18 1.1.1. Cc loi keo vng thp.......................................................................................... 19 1.1.2. Cc loi keo vng cao ........................................................................................... 27 1.1.3. Cc loi keo chu hn............................................................................................ 31 1.2. Chn loi, chn xut x v xy dng vn ging cc loi bch n ..................... 35 1.2.1. Kho nghim loi xut x ..................................................................................... 35 1.2.2. Xy dng cc vn ging bch n...................................................................... 39 1.3. Chn loi, chn xut x v xy dng vn ging cc loi trm............................. 41 1.3.1 B ging v cc a im kho nghim ................................................................. 41 1.3.2. Kho nghim ti mt s lp a chnh .................................................................. 42 1.3.3. Mt s nhn nh chnh......................................................................................... 45 1.3.4. Cc loi v xut x trm c cng nhn l ging tin b k thut .................... 45 1.3.5. Cc vn ging M. leucadendra........................................................................... 45 1.4. Chn loi v chn xut x Phi lao............................................................................. 46 1.5. Chn loi v chn xut x Lt hoa............................................................................ 46 1.6. Kho nghim xut x Thng carib.......................................................................... 48 1.7. Chn xut x Thng ba l.......................................................................................... 50 1.8. Xy dng rng ging v rng ging chuyn ho..................................................... 51

2. Chn lc cy tri, kho nghim ging v xy dng vn ging .........................512.1. Cc nguyn tc chn lc cy tri ............................................................................... 52 2.2. Chn lc cy tri v kho nghim dng v tnh Keo l trm ................................. 52 2.3. Chn lc cy tri v kho nghim dng v tnh bch n ...................................... 55 2.3.1. Chn dng v tnh Bch n ur (E. urophylla)................................................... 55 2.3.2. Chn dng v tnh Bach n caman (E. camaldulensis) ...................................... 56 2.4. Chn lc cy tri v xy dng vn ging Thng nha ......................................... 57

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2.5. Chn lc cy tri v xy dng vn ging Thng ba l.......................................... 59 2.6. Chn lc cy tri v xy dng vn ging Thng ui nga ................................. 60

3. S dng ging lai t nhin v lai ging .................................................................613.1. S dng ging Keo lai t nhin ................................................................................. 61 3.2. Lai ging Keo tai tng v Keo l trm ................................................................... 64 3.3. Lai ging mt s loi bch n .................................................................................. 65

4. Nhn ging bng gim hom v nui cy m .........................................................684.1. Nhn ging bng hom................................................................................................. 69 4.1.1. c im ca nhn ging hom.............................................................................. 69 4.1.2. Nhn ging hom Keo lai ....................................................................................... 70 4.1.3. Nhn ging hom mt s dng bch n cao sn .................................................. 70 4.1.4. Nhn ging hom cc loi cy l rng khc........................................................... 71 4.1.5. Nhn ging hom cc loi cy l kim ..................................................................... 72 4.1.6. Nhn ging hom v chit cnh mt s loi tre trc .............................................. 72 4.2. Nhn ging bng nui cy m.................................................................................... 73 4.2.1. c im nui cy m........................................................................................... 73 4.2.2. Nui cy m Keo lai .............................................................................................. 75 4.2.3. Nui cy m mt s ging bch n cao sn v bch n lai .............................. 76 4.2.4. Nui cy m mt s loi cy khc......................................................................... 76

5. Mt s vn tn ti v bin php gii quyt ......................................................765.1. Mt s vn tn ti................................................................................................... 76 5.2. Mt s bin php gii quyt ....................................................................................... 77

Phn 3: Bo Tn Ngun Gen Cy rng.....................................................................80 1. Suy gim ngun gen.................................................................................................801.1. Suy gim ti nguyn rng .......................................................................................... 80 1.2. Suy gim ngun gen cy rng v mc e do..................................................... 83 1.2.1. Nguy c mt loi ................................................................................................... 83 1.2.2. Nguy c mt mt s vng phn b ........................................................................ 84 1.2.3. Xi mn di truyn .................................................................................................. 84 1.3. nh gi mc e do ............................................................................................. 85

2. Phng php bo tn ngun gen ...........................................................................892.1. Nguyn tc chung v bo tn ngun gen cy rng .................................................. 89 2.2. Xc nh i tng bo tn v nh gi ngun gen ................................................ 90 2.3. Cc bc bo tn ........................................................................................................ 90 2.3.1. iu tra kho st ................................................................................................... 90 2.3.2. nh gi................................................................................................................ 91 2.3.3. Bo tn .................................................................................................................. 91 2.3.4. Bo tn thng qua qun l rng............................................................................ 93

3. H thng cc khu bo tn .......................................................................................933.1. Quy hoch h thng cc khu bo tn ........................................................................ 93

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3.2. Cng tc qun l v tnh hiu qu ca vic bo tn cc khu rng c dng ........ 95

4. Nhng vn t ra................................................................................................964.1. Nhng vn v chnh sch, th ch......................................................................... 96 4.1.1. Nhng vn tn ti ............................................................................................. 97 4.1.2. Mt s vn cn c gii quyt........................................................................ 97 4.2. Nhng vn v k thut .......................................................................................... 98

Phn 4:H Thng Sn Xut v Cung ng Ging Cy Lm Nghip ....................100 1. Hin trng h thng sn xut v cung ng ging cy lm nghip ...................1001.1. Nhu cu v ging cy lm nghip ............................................................................ 100 1.1.1. D tnh nhu cu ging hng nm theo tng giai on trng rng ca d n 661 ....................................................................................................................................... 101 1.1.2. D tnh nhu cu ging hng nm theo cc d n trng rng giai on 2006-2010 ....................................................................................................................................... 103 1.2. Hin trng v h thng ngun ging v vn m cy lm nghip..................... 103 1.2.1. Ngun ging ........................................................................................................ 103 1.2.2. H thng vn m............................................................................................. 108 1.3. Hin trng h thng t chc sn xut v cung ng ging cy lm nghip .......... 109 1.3.1. Cp trung ng (Cng ty ging lm nghip trung ng) ................................... 109 1.3.2. Cp vng ............................................................................................................. 110 1.3.3. Cp tnh ............................................................................................................... 111

2. Cng tc qun l sn xut v cung ng ging cy lm nghip..........................1122.1. Qun l sn xut v cung ng ht ging................................................................. 113 2.2. Qun l sn xut v cung ng cy con.................................................................... 114 2.3. Qun l theo h thng m s.................................................................................... 115

3. Nhng vn tn ti v gii php pht trin h thng sn xut v cung ng ging cy trng lm nghip..........................................................................1173.1. Nhng kt qu t c........................................................................................... 117 3.1.1. V chnh sch h tr v khung php l ............................................................... 117 3.1.2. Cc chng trnh pht trin ging v xy dng h thng ngun ging cy lm nghip ............................................................................................................................ 118 3.1.3. V u t xy dng c s h tng, trang thit b hin i .................................. 118 3.1.4. V pht trin khoa hc k thut, cng ngh mi................................................. 119 3.2. Nhng vn tn ti................................................................................................. 119 3.3. Cc gii php pht trin sn xut v cung ng ging cy lm nghip................. 120 3.3.1. C chnh sch ph hp........................................................................................ 121 3.3.2. Xy dng v thc thi cc chin lc quc gia di hn ....................................... 121 3.3.3. Thit lp v a vo hot ng mng li ging cy lm nghip vi s iu phi thng nht trong ton quc ........................................................................................... 121 3.3.4. To th trng ging a dng v m rng .......................................................... 122 3.3.5. Pht trin ngun lc............................................................................................ 122 3.3.6. u t thch ng cho cng tc ging cy rng................................................. 122

Ti liu tham kho.....................................................................................................131

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M u Ging l mt trong nhng khu quan trng nht ca trng rng v rng trng, c bit l rng trng sn xut. Khng c ging c ci thin theo mc tiu kinh t th khng th a nng sut rng trng ln cao. Theo Davidson (1996) th ging c ci thin c th chim n 50 60% nng sut rng trng. V th, ci thin ging cy rng nhm khng ngng nng cao nng sut, cht lng g v cc sn phm mong mun khc l mt yu cu cp bch i vi sn xut lm nghip nc ta. Hin nay mt s nc c nn lm nghip tin tin to c nng sut rng trng 40 50 m3/ha/nm trn din rng, c ni t nng sut 60 - 70 m3/ha/nm. Gn y, vi vic a mt s ging Keo lai v bch n cao sn vo sn xut, mt s ni t nng sut rng trng 30 - 40 m3/ha/nm, m ra trin vng mi cho cng tc ging v trng rng sn xut nc ta. Cng vi vic a ging mi vo sn xut l vic p dng cng ngh nhn ging hom c quy m hng trm ngn cy/nm nhiu lm trng v hp tc x. Nhiu c s nhn ging bng nui cy m cng ra i, gp phn quan trng vo vic a nhanh cc ging mi c nng sut cao vo sn xut. Kt hp s dng ging c cht lng di truyn c ci thin vi vic trng ng lp a v p dng cc bin php k thut lm sinh thch ng l nhng bin php tng hp tng nng sut rng nc ta. Mt khc bo tn ngun gen cy rng l mt khu khng th thiu to c s vng chc cho cng tc ci thin ging lu di nc ta. Trong cc nm gn y Nh nc ban hnh nhiu vn bn v qun l ging cy trng (trong c cy trng lm nghip) nh Php lnh ging cy trng v Php lnh v cht lng hng ha ca Ch tch nc, Ngh nh bo h ging cy trng v mt s Ngh nh v Quyt nh khc ca Chnh ph v cng tc ging v bo tn ngun gen cy rng lm c s cho ci thin ging cy rng nc ta pht trin. Tuy vy, cng tc ging cy rng nc ta cng c mt s bt cp nh t l ging c cht lng cao c s dng cha nhiu, nhiu ni cn s dng ging x b, vic p dng cc thnh tu ca cng ngh sinh hc vo ci thin ging mi giai on ban u. Tp "Ci thin ging v qun l ging cy rng Vit Nam" c bin son theo yu cu ca "D n H tr k thut" (GTZ) do Cng ha Lin bang c ti tr v ca Chng trnh "H tr ci cch hnh chnh lm nghip" (REFAS) l nhm cung cp mt s hiu bit v lch s pht trin, nhng thnh tu v nhng thch thc trong cng tc ging cy rng nc ta. Sch gm 4 phn: Phn 1. Lch s pht trin v cc chnh sch v ci thin ging, bo tn v qun l ngun gen cy rng do GS.TS. L nh Kh, PGS.TS. Nguyn Hong Ngha v KS. Nguyn Xun Liu bin son. Phn 2. Cc hot ng, thnh tu v mt s vn tn ti v ci thin ging cy rng do GS.TS. L nh Kh bin son. Phn 3. Bo tn ngun gen cy rng do PGS.TS. Nguyn Hong Ngha bin son. Phn 4. H thng sn xut v cung ng ging cy lm nghip do KS. Nguyn Xun Liu bin son.

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Sau khi hon thnh bn tho ln u chng ti nhn c cc bn nhn xt ca GS. TS. Nguyn Xun Qut, TS. Phm Vn Mch, Ph V trng V Khoa hc cng ngh; TS.

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Phm c Tun, Ph Cc trng Cc lm nghip; TS. H Huy Thnh, Gim c Trung tm nghin cu ging cy rng (Vin Khoa hc Lm nghip Vit Nam); v ca Cng ty ging lm nghip Trung ng. Cc bn nhn xt nh gi cao c gng ca nhng ngi bin son v gp mt s kin c th bn tho hon chnh hn. Bn vit ny tip thu cc kin ng gp, c thay i kt cu trong phn m u v mt s chnh sa khc. Tuy c bin tp bc u, song v c bn chng ti vn gi cc v cch vit ca tng tc gi ngi c tin lin h. Mt khc, mc du c nhiu c gng song chc chn khng trnh khi thiu st, mong ngi c gp v lng th. Nhn dp ny chng ti xin cm n Ban iu hnh cc D n REFAS v GTZ cng nh cc nh khoa hc v qun l c nhng ch bo qu gi chng ti chnh sa cho cun sch ny. Cc tc gi

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Phn 1: Lch S Pht Trin v Cc Chnh Sch V Ci Thin Ging,Bo Tn Qun L Ngun Gen Cy Rng 1. Lch s ci thin ging v bo tn ngun gen cy rng Vit Nam C th chia lch s ci thin ging cy rng Vit Nam thnh bn giai on ch yu: trc nm 1945, t nm 1945 n nm 1975, t nm 1975 n nm 1990 v thi k i mi (t nm 1990 n nay). 1.1. Thi k trc nm 1945 Thi k trc nm 1945 ci thin ging cy rng nc ta ch yu l hot ng t pht ca ngi dn trong cc h gia nh gn vi mt s k thut chn ging v chit ghp cy n qu nh Nhn, Vi, Cam vng ng bng Bc B. n nhng nm 1930 mi tht s c hot ng ci thin ging cy rng, khi cc nh lm nghip ngi Php xy dng cc khu kho nghim cho Lim xanh (Erythrophloeum fordii), Ngn hoa (Grevillia robusta), Bch qu (Ginkgo biloba), Long no (Cinnamomum camphora), Bch n caman (Eucalyptus camaldulensis), Bch n (E. robusta) v.v... mt s vng sinh thi chnh trong nc. Mt s khu kho nghim mt s ni nh Cu Cm Ngh An tn ti n u nhng nm 1960 v mt s ging nh Ngn hoa n nay c trng trng th mt s ni. 1.2. Thi k t nm 1945 n nm 1975 y l thi k khng chin chng Php v chng M. Lc ny nhim v chnh ca c nc l u tranh gii phng dn tc, nn cc hot ng v ci thin ging trong vng gii phng ch yu l cung cp ging cho trng rng, cc hot ng ci thin ging ch c tin hnh mt s ni c iu kin. min Nam gia nhng nm 1950 xy dng c cc khu kho nghim loi c tnh cht trng th ti Lt cho 18 loi Bch n nh Eucalyptus saligna, E. microcorys, E. camaldulensis, E. punctata, E. robusta, E. citriodora, E. globulus, E. botryoides, E. maideni, E. longifolia, E. resinifera v.v., trong cc loi E. microcorys v E. saligna n nay vn l nhng loi c kh nng thch ng kh nht v sinh trng nhanh nht ti vng ny. Mt s khu tp hp ging v trng th cho mt s loi cy g c gi tr kinh t ti Trng Bom (ng Nai), Lang Hanh (Lm ng), Bun Ma Thut (c Lc) cng c xy dng trong thi k ny. Tip n, trong nhng nm 1960 xy dng cc khu kho nghim loi cho mt s loi cy l kim nh Pinus kesiya, P. caribaea, P. patula, P. taeda, P. massoniana, P. elliottii, P. radiata, P. taiwanensis, P. pinea, P. longifolia, P. thunbergii, Fokienia hodginsii, Cupresus benthami, C. pyramidalis, C. funebris, C. macrocarpa, Calitris obtusa, C. robusta, C. cupresiformis v.v. Cng thi gian ny mt s loi keo thuc chi Acacia trong c Keo l trm (Acacia auriculiformis) v Mimosa (Acacia podalyriifolia) cng c a vo kho nghim. min Bc Cng ty ging c thnh lp vo nm 1963 nhm sn xut ging cung cp cho nhu cu trng cy ph xanh, trng rng phng h chng ct bay ven bin, trng cy phn tn v cung cp ging cho cc "Tt trng cy". Phng nghin cu ging cy rng thuc Vin Lm nghip ra i cng vi vic thnh lp Vin vo nm 1961 c mt s nghin cu bc u v xy dng rng ging v bo qun ht ging cho mt s loi cy nh B , M, Phi lao, Bch n, v.v.

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Rng Sao en (Hopea odorata) 50 tui c trng th u tin ti Bun Ma Thut (nh L nh Kh, 2005)

1.3. Thi k t nm 1975 n nm 1990 Sau khi gii phng min Nam vo nm 1975 cng tc ci thin ging c iu kin hot ng trong iu kin ha bnh v thng nht t nc. Tuy vy thi k t nm 1975 n 1990 hot ng ci thin ging ch yu l kho nghim loi v xut x cho mt s loi cy mt s tnh min Bc, trong c kho nghim xut x cc loi thng do d n Sida ti tr nh Pinus caribaea, P. oocarpa, P. kesiya, P. merkusii v cc loi thng khc vng Trung tm Min Bc. Mt s loi bch n ch yu cng c kho nghim xut x trong thi gian ny nh Bch n caman (Eucalyptus camaldulensis), Bch n tr (E. tereticornis), Bch n liu (E. exserta), mt s loi keo cng bc u c trng th mt s vng. Thi k ny cng bt u c nghin cu v chn lc cy tri v xy dng vn ging cho cy M (Manglietia conifera), Thng ba l (Pinus kesiya), Thng nha (P. merkusii), cng nh c nghin cu v ht ging, song kt qu t c trong thi k ny khng nhiu. Chn lc cy tri v xy dng vn ging bng cy ghp cng c Cng ty Ging lm nghip thc hin cho Thng ba l Lang Hanh v Xun Th thuc tnh Lm ng v Thng nha Lang Hanh (Lm ng) v Th Lc (Qung Bnh), M Cu Hai (Ph Th) vo cui nhng nm 1970 v u 1980. Cng ty Ging lm nghip cng l n v cung cp hng ngn tn ging cho cc chng trnh trng rng ph xanh v trng cy phn tn cc a phng (trong c "Tt trng cy"). 1.4. Thi k i mi (sau nm 1990) Thi k sau nm 1990, c bit l khong 10 nm gn y, l thi k cng tc ci thin ging cy rng hot ng mnh m nht v c hiu qu nht. y l thi k t nc c nhng chuyn bin quan trng theo hng i mi, m ca v hi nhp vi kinh t th gii nn cng tc ci thin ging cy rng cng c nhng chuyn bin mnh m. Chng ta c iu kin xy dng cc kho nghim ging trn cc vng sinh thi chnh. C th chia hot ng ci thin ging trong thi k ny theo cc ni dung sau y:

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- Kho nghim loi v xut x. Ngoi vic tip tc theo di v m rng cc kho nghim loi v xut x cho cc loi thng v bch n ni trn chng ta xy dng thm cc khu kho nghim loi - xut x cho mt s loi cy ch yu nh Bch n uro (E. urophylla), cc loi E. grandis, E. pelita, E. cloeziana v.v. mt s vng sinh thi chnh trong nc. u nhng nm 1990 bn cnh vic tip tc xy dng cc kho nghim loi - xut x cho cc loi bch n, mt lot kho nghim cho cc loi keo vng thp nh Keo l trm (A. auriculiformis), Keo tai tng (A. mangium), Keo l lim (A. crassicarpa), Keo nu (A. aulococarpa) v Keo qu xon (A. cincinnata) c xy dng nhiu ni trong nc. Nm 1993 kho nghim cho cc loi keo chu hn nh A. tumida, A. difficilis, A. torulosa v.v. c xy dng ti Tuy Phong (ni c lng ma 700 - 800mm/nm) thuc tnh Bnh Thun. Cc nm 1994 - 1996 kho nghim xut x cc loi keo vng cao nh A. mearnsii, A. melanoxylon v.v. c xy dng ti Lt (1600m trn mt bin), ni Ba V (600m trn mt bin) v mt s ni khc. Trong cc nm 1993 - 1995 mt lot cc kho nghim xut x cho cc loi trm nh Melaleuca leucadendra, M. cajuputi v.v. c xy dng trn mt s lp a t ngp phn mt s tnh ng bng sng Cu Long. Nm 1994 kho nghim xut x Phi lao (Casuarina equisetifolia) c xy dng vng ct ven bin thuc cc tnh Thanh Ha, Ngh An, Qung Nam v Bnh Thun, sau l kho nghim xut x Phi lao i (Casuarina junghuniana) ti Nng v Ba V. Ngoi ra, kho nghim xut x Xoan chu hn (Azadirachta indica) cng c xy dng ti Ba V (H Ty) v mt s ni khc vo nm 1996. Tuy Ba V Xoan chu hn sinh trng km, song ti Ninh Thun c mt s ging thch nghi v sinh trng tt trn t ct kh hn ven bin. Nm 1999 kho nghim xut x cho Lt hoa (Chukrasia tabularis) c xy dng mt s tnh min Bc.

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100 90Thnh phn rut bu Lm t NK NK P

T l tham gia tng i (%)

80 70 60P Nhim vi khun NK

P

Lm c Lm c

50NK

40 30P Lm c Ci thin ging Ci thin ging Ci thin ging

20 10 0

Lm c Ci thin ging

Nm 0

Nm 1 Tui

Nm 3

Nm 6

S tham gia tng i ca ci thin ging v cc bin php k thut lm sinh trong sinh trng ca cy v tng trng th tch g ca mt s loi Keo v Bch n trong 6 nm trn mt s lp a cc nc nhit i (theo Davidson, 1996). Nm 0 l giai on vn m, nm 1l nm u sau khi trng, v.v.

- Chn lc cy tri, kho nghim ging v xy dng rng ging, vn ging nc ta mi tht s bt u t u nhng nm 1980, khi c cc nghin cu v chn ging cho cy M (Manglietia conifera), sau l chn ging Thng nha c lng nha cao (1987-2000), chn ging S cho vng Lng Sn (1988 - 1990), chn ging Thng ui nga (1994-2000) v Thng ba l (1996-2000) sinh trng nhanh. Cng vi vic chn lc cy tri chng ta xy dng c cc vn ging bng cy ghp cho Thng nha c lng nha cao ti Ngh An, Qung Ninh, H Ty v Vnh Phc; cho Thng ui nga ly g ti Lng Sn. n nay mt s vn ging pht huy tc dng cung cp ging c ci thin cho sn xut, mt s vn ging cn c u t v nng cp mi p ng yu cu ca giai on mi. Vic chn lc cy tri c sinh trng nhanh c cht lng thn cy tt cng c thc thin cho cc loi Bch n caman v Bch n ur, qua kho nghim dng v tnh chn c mt s dng c nng sut cao a vo sn xut. n nay c 5 dng Bch n ur c cng nhn l ging tin b k thut pht trin trn din rng vng Trung tm min Bc. T nm 1999 ln u tin vic chn ging chng chu bnh v sinh trng nhanh c thc hin cho Bch n caman, qua kho nghim dng v tnh chn c hai dng c nng sut cao v chng bnh hi l cho vng ng Nam B. T kt qu kho nghim xut x v chn lc cy tri chng ta xy dng dc mt s rng ging v vn ging cho mt s loi cy nh Keo tai tng, Keo l trm, Keo l lim, Bch n uro, Bch n caman, Bch n pelita (E. pellita), Trm l di (Melaleuca leucadendra) v.v. Trong cc nm 1995-2000 rng ging chuyn ha t rng sn xut ca mt s loi cy khc nh Thng ba l, Thng ui nga (P. massoniana), Sa mu (Cunninghamia lanceolata), P

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mu (Fokienia hodginsii), Phi lao, Trm trng (Canarium album), Vng trng (Endospermum chinensis), Hunh (Tarrietia javanica) cng c Cng ty Ging lm nghip xy dng ti mt s vng trong nc. - S dng ging lai t nhin v lai ging l mt lnh vc c p dng nc ta t u nhng nm 1970 khi c pht hin v nghin cu v ging lai t nhin gia Bch n camam (E. camandulensis) v Bch n (E. robusta) (L nh Kh, 1970), song mi tht s c thnh tu ni bt vo u nhng nm 1990, khi pht hin, chn lc v kho nghim mt s dng Keo lai t nhin gia Keo tai tng vi Keo l trm c nng sut cao gp 1,5- 2 ln cc loi cy b m, lai to c mt s t hp lai v chn lc c mt s dng v tnh c nng sut cao gia hai loi cy ny, cng nh gia cc loi Bch n caman (E. camadulelsis). Bch n ur (E. urophylla) v Bch n liu (E. exserta). - Nhn ging sinh dng trong ci thin ging cy rng nc ta c thc hin theo tng bc khc nhau. K thut ghp c p dng xy dng vn ging Thng ba l v Thng nha t nm 1978, sau c p dung xy dng vn ging Thng nha c lng nha cao, Thng ui nga, M, Tch (Tectona grandis), v.v. Hin nay k thut ghp cng ang c p dng c kt qu nhn ging Trm trng, Su, Macadamia (Macadamia intergifolia), v.v. Nhn ging hom c th nghim nc ta t nhng nm 1960, song mi c p dng quy m sn xut trong khong 10 nm gn y, khi cc ging cy c nng sut cao nh Keo lai, cc ging Phi lao 601, 701 v mt s dng bch n cao sn (chn trong nc v c nhp t Trung Quc) c a vo sn xut. Ngoi ra, k thut nhn ging hom cnh cho mt s loi cy khc nh Lung v cc ging tre mng cng ang c p dng trn quy m sn xut. Nui cy m cho cy rng tuy mi c p dng nc ta t sau nm 1993, khi nh nc cho nhp cng ngh nui cy m v mt s dng bch n cao sn ca Trung Quc, n nay c p dng rng ri nhiu c s trong c nc nhn ging Keo lai v mt s dng bch n cao sn. - Bo tn ngun gen cy rng l mt lnh vc mi c thc hin nc ta t nm 1987, khi Nh nc c ch trng bo tn ngun gen cho cc ging cy trng vt nui v vi sinh vt quan trng nht. n nay mt h thng cc vn quc gia v khu bo tn thin nhin cng nh mt s vn su tp thc vt c xy dng gp phn tch cc vo vic lu gi ngun gen cy rng nc ta lm c s cho cng tc ci thin ging sau ny. Cc hot ng bo tn ngun gen cng gp phn lm r mc e da, phng thc khai thc v bo tn cho mt s loi cy quan trng nht. - Ban hnh cc quy trnh, quy phm v cc tiu chun cng nhn ging cy lm nghip. Ging cy trng lm nghip l mt b phn ca ging cy trng, v th vic qun l ging cy trng lm nghip cng phi tun th cc quy nh chung v qun l ging cy trng ca Nh nc. tng bc a cng tc sn xut v qun l ging cy trng lm nghip vo n np nm 1993 B lm nghip ban hnh quy phm xy dng rng ging, vn ging v rng ging chuyn ha m n nay vn c gi tr. Trong cc nm sau B lm nghip cng nh B Nng nghip v Pht trin nng thn ban hnh nhiu tiu chun v ht ging cho mt s loi cy trng quan trng nht, trong c tiu chun ngnh v phng php kim nghim ht ging cy trng lm nghip c ban hnh nm 2001. Nm 1996 Chnh ph Vit Nam c Ngh nh v qun l ging cy trng trong c quy nh v kho nghim v s dng ging trong sn xut. Nm 1998 B Nng nghip v Pht trin nng thn ban hnh Tiu chun cng nhn ging cy trng lm nghip, sau c sa i v b sung vo nm 2003. Nm 2001 chnh ph c Ngh nh bo h ging cy trng trong quy

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nh iu kin cc ging cy trng c bo h v cch thc tin hnh bo h. Nm 2004 nh du s chuyn bin mnh m v cng tc ging vi s ra i ca Php lnh ging cy trng. Ngoi ra cn c nhiu quyt nh ca Nh nc v bo v rng v xy dng cc vn quc gia, khu bo tn thin nhin to iu kin cho cng tc bo tn ngun gen hot ng c kt qu. Hin nay ngnh Lm nghip ang chun b ban hnh mt s vn bn v qun l ging cy trng lm nghip gp phn tng nng sut rng trng nc ta. Nt ni bt khc trong cng tc ci thin ging cy rng thi k ny l c s hp tc v gip nhiu mt ca cc t chc quc t nh Sida-SAREC ca Thy in, CSIRO v ACIAR ca Australia, DANIDA ca an Mch, cng nh ca UNDP, IPGRI, JICA v mt s t chc quc t khc. Nh s gip ca cc t chc ny m cng tc ging cy rng ca nc ta c nhng chuyn bin mau chng theo xu hng chung ca th gii. 2. Cc chnh sch v ci thin ging v bo tn ngun gen cy rng 2.1. Cc vn bn php l v nghin cu, sn xut v qun l ging cy lm nghip Nhn thc r tm quan trng v mc nh hng ca vic s dng ging tt i vi s thnh bi ca cng tc trng rng, Nh nc v ngnh lm nghip ban hnh cc vn bn php qui v nhng chnh sch h tr nhm tng cng vic qun l cht ch qu trnh nghin cu, sn xut v cung ng; ng thi khuyn khch s dng ging c cht lng dn dn c ci thin trong trng rng. Ni bt nht l cc vn bn php qui v nghin cu, sn xut v qun l ging cy lm nghip sau y c ban hnh v p dng trong ton quc, l:

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Q 264 (22/7/1992) ca B Lm nghip v u t pht trin ging lm nghip bng ngn sch nh nc, xy dng v pht trin h thng ngun ging ci thin. HD 08/KHKT (24/5/1993) ca B Lm nghip Hng dn tng cng xy dng v pht trin h thng ngun ging v vn m cp tnh. Q 804/Q-KT (02/11/1993) ca B Lm nghip ban hnh Qui phm k thut xy dng rng ging, vn ging v rng ging chuyn ho. Q 556/TTg (12/9//1995) ca Th tng chnh ph v C cu rng phng h v s dng ht ging cc loi cy bn a qu. Ngh nh s 07/CP, ngy 05/02/1996 ca Chnh ph v qun l ging cy trng. Thng t s 02/NN-KNKL/TT, ngy 01/3/1997 ca B NN&PTNT. Hng dn thi hnh Ngh nh 07/CP ca Chnh ph v: Kim tra cng nhn ging mi, cy m, ngun ging. Kho nghim hoc sn xut th ging mi chn to, ging nhp khu v ging a t vng ny sang vng khc.

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Quyt nh s 124/198/Q/BNN/KHCN ngy 31/8/1998 ca B NN&PTNT ban hnh Tiu chun cng nhn ging cy trng lm nghip (TCN 17 - 98). Quyt nh s 178/1999/Q-TTg ngy 30/8/1999 ca Chnh ph ban hnh Qui ch ghi nhn hng ha lu thng trong nc v hng ha xut nhp khu. Thng t s 75/2000/TT-BNN-KHCN ngy 17/7/2000 ca B NN&PTNT Hng dn thc hin Quyt nh s 178/1999/Q-TTg ngy 30/8/1999 ca Chnh ph. Quyt nh s 34/2001/Q-BNN-VP ngy 30/3/2001 ca B NN&PTNT ban hnh Qui nh v iu kin kinh doanh trong mt s lnh vc thuc ngnh trng trt v chn nui.

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Thng t s 62/2001/TT-BNN ngy 05/6/2001 ca B NN&PTNT Hng dn thc hin Quyt nh s 46/2001/Q-TTg ngy 04/4/2001 ca Chnh ph v Qun l xut nhp khu hng ha thi k 2001-2005. Quyt nh s 86/2001/Q/BNN-KHCN ngy 23/8/2001 ca B NN&PTNT ban hnh Qui nh tm thi cng b tiu chun cht lng hng ha chuyn ngnh nng nghip. Quyt nh s 58/2001/Q-BNN-KNKL ngy 23/5/2001 ca B NN&PTNT ban hnh Danh mc ging cy trng, vt nui qu him cm xut khu, Danh mc ging cy trng, vt nui c nhp khu. Ngh nh s 13/2001/N-CP ngy 20/4/2001 ca Chnh ph v Bo h ging cy trng mi. Thng t s 119/2001/TT-BNN ngy 02/12/2001 ca B NN&PTNT Hng dn thi hnh Ngh nh s 13/CP ca Chnh ph v bo h ging cy trng mi Quyt nh s 199/Q-BNN-PTLN ngy 22 thng 1 nm 2002 ca B NN&PTNT v Chin lc pht trin lm nghip giai on 2001 - 2010, trong Ging cy lm nghip l mt trong 6 chng trnh c u tin vi ba mc tiu: m bo cung cp ging cht lng cao ca cc loi cy chnh. Thit lp c ch th trng thch hp trong sn xut, cung ng v s dng ging. p dng cng ngh truyn thng v tin tin trong sn xut, nhn ging v ci thin ging.

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Quyt nh s 188/2003/Q-BNN ngy 23/1/2003 ca B NN&PTNT ban hnh Tiu chun cng nhn ging cy lm nghip (04TCN - 64 - 2003). Lnh s 03/204/L/CTN ngy 05/4/2004 ca Ch tch nc CHXHCN Vit Nam ban hnh Php lnh ging cy trng. Quyt nh s 13/2005/Q-BNN ngy 15/3/2005 ca B NN&PTNT ban hnh Danh mc ging cy trng lm nghip chnh, Danh mc ging cy trng lm nghip c php sn xut kinh doanh, Danh mc ging cy trng lm nghip phi p dng tiu chun ngnh, Danh mc cc loi cy ch yu trong trng rng sn xut theo 9 vng sinh thi lm nghip.

- Quyt nh ca Chnh ph ban hnh Ngh nh x pht vi phm hnh chnh v ging cy trng. 2.2. V bo tn ngun Nm 1991, Nh nc ban hnh Lut bo v v pht trin rng, sa i b sung nm 2004 v nm 1994 l Lut bo v mi trng cng nh nhiu vn bn di lut khc l c s php l c bn cho cng tc xy dng v qun l h thng rng c dng ny. Nm 1991, Chng trnh Hnh ng Lm nghip Nhit i ra i gp phn quy hoch tng th t lm nghip trong phm vi ton quc. Vi c gng ca nhiu nh khoa hc, Sch Vit Nam c son tho trong Tp I, phn ng vt (xut bn nm 1992) bao gm 347 loi; Tp II, phn thc vt (xut bn nm 1996) gm 350 loi him v c nguy c b e do. V lnh vc nghin cu bo tn ti nguyn di truyn, sut t nm 1988 cho ti nay, Chng trnh Bo tn ngun gen quc gia do B Khoa hc, Cng ngh v Mi trng (nay l B Khoa hc v Cng ngh) ch tr v u t gp phn ng k vo thnh cng ca cng tc bo tn ngun gen nc ta. nh hng chin lc, la chn hnh thc v la chn cc loi cn bo tn c bc u a ra xem xt v tip tc hon thin.

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V mt quc t, Vit Nam tham gia nhiu chng trnh nh Chng trnh con ngi v sinh quyn (MAB - Man and Biosphere) ca UNESCO, Cng c RAMSAR (Cng c quc t bo v t ngp nc) m Vn quc gia Xun Thu (Nam nh) c ghi vo danh sch cc vng t ngp nc c tm quan trng quc t, c bit l ni ca chim nc vo nm 1989 v Vit Nam tr thnh thnh vin th 50 ca cng c ny. Vit Nam cng tham gia k cng c CITES (Cng c quc t v bun bn cc ng thc vt hoang di b e da) vo nm 1994 v nh vy nc ta cng ng vo i ng quc t kim sot v qun l vic bun bn cc loi hoang di. Nm 1993, Vit Nam k Cng c v a dng sinh hc, cam kt h tr cc c gng bo tn trn th gii v trong nc. Cng c c ph chun vo thng 10/1994 v do vy Vit Nam ang hnh ng theo tinh thn ca Cng c ny. C th l K hoch Hnh ng a dng sinh hc (BAP - Biodiversity Action Plan) ca Vit Nam do B Khoa hc, Cng ngh v Mi trng ch tr son tho c Th tng Chnh ph ph duyt ti Quyt nh s 845/TTg ngy 22 thng 12 nm 1995. Cng vo nm ny, bn tho K hoch Hnh ng Mi trng (Environmental Action Plan) do B Khoa hc, Cng ngh v Mi trng phi hp vi Ngn hng Th gii (WB), T chc Pht trin Quc t ca Canaa (CIDA) v Trung tm nghin cu pht trin quc t ca Canaa (IDRC) c son tho. Cc vn bn v thi im quan trng c lin quan n bo tn ngun gen cy rng v bo v a dng sinh hc Vit Nam l: 1962. Quyt nh 72/TTg thnh lp Vn quc gia Cc Phng. Ngh nh 39/CP ca Hi ng Chnh ph ban hnh iu l tm thi v sn bn chim th rng. 1986. Quyt nh 194/CT cng nhn 87 khu rng cm. 1986. B Lm nghip ra quyt nh s 1171/Q ban hnh quy ch qun l rng c dng. 1987. Quyt nh 582/Q-NSY, ngy 02/11/1987 ca Ch nhim UB KH-KTNN quy nh tm thi v nhim v, quyn hn ca cc c quan bo tn, lu gi, s dng ngun gen. 1989. Quyt nh 433 ca B Lm nghip nh ch khai thc v xut khu 7 loi g qu him (lt, nghin, ging hng, trc, cm lai, g , mun) 1989. Thnh vin ca Cng c RAMSAR. 1991. Ban hnh Lut bo v v pht trin rng. 1991. K hoch quc gia v mi trng v pht trin bn vng. 1991. K hoch Hnh ng Lm nghip nhit i (TFAP). 1992. Ngh nh 17/HBT ca Hi ng B trng v thi hnh Lut bo v v pht trin rng. 1992. Ngh nh 18/HBT v cm khai thc 13 loi cy v 36 loi ng vt v hn ch khai thc 19 loi cy v 10 loi ng vt. 1992. Thng t 13/LN-KL ca B lm nghip hng dn thc hin N 18/ HBT ca Chnh ph. 1993. Ch th 130/TTg ca Th tng Chnh ph v qun l v bo v ng thc vt qu him. 1993. Ch th 283/TTg ca Th tng Chnh ph v thc hin cc bin php cp bch qun l g qu him. 1993. K v nm 1994 ph chun Cng c v a dng sinh hc. 1994. Ban hnh Lut v Bo v mi trng.

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1994. K Cng c CITES. 1995. K hoch hnh ng a dng sinh hc (BAP). 1995. Bn tho K hoch Hnh ng v Mi trng (VNNEAP) 1996. Sch Vit Nam, phn thc vt. 1996. Quyt nh 821/TTg ca Th tng Chnh ph v khai thc, xut khu sn phm g p mu. 1996. Ch th 18 NN-PTNT-CT ca B trng B NN-PTNT v nh ch khai thc g p mu & ng ca tt c cc tiu khu rng c P mu phn b. 1997. Ch th 06 NN-PTNT/CT ca B trng B NN-PTNT v thc hin nghim ngt ng ca rng P mu, nh ch khai thc thu mua g p mu. 1997. Quyt nh 2177/1997/Q-BKHCNMT, 30-12-1997 v vic ban hnh quy ch qun l v bo tn ngun gen thc vt, ng vt v vi sinh vt. 1999. Quyt nh 242/1999/Q/TTg ngy 30-12-1999 ca Th tng Chnh ph v iu hnh xut nhp khu hng ho nm 2000, trong c cc loi ng vt hoang d v ng thc vt qu him c lit vo hng cm xut khu do B NN - PTNT hng dn. 2001. Quyt nh 08/2001/Q/TTg ngy 11 thng 1 nm 2001 ca Th tng Chnh ph v vic ban hnh Quy ch qun l rng c dng, rng phng h v rng sn xut l rng t nhin.

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Phn 2: Cc Hot ng, Thnh Tu v Mt s Vn Tn Ti V Ci Thin Ging Cy Trng 1. Chn loi, chn xut x, xy dng rng ging v vn ging Bc u tin trong bt k mt chng trnh no v ci thin ging cy rng l chn loi v xut x ph hp vi mc tiu kinh t v/hoc phng h c t ra v c c im sinh thi ph hp vi tng vng gy trng c th, chn loi cy v xut x ph hp vi tng vng mt cch chc chn phi tin hnh mt lot cc kho nghim loi v xut x. Kho nghim loi l s tp hp cc ngun ht ca mt s loi cy nht nh theo mc tiu kinh t c t ra v xy dng cc khu kho nghim so snh ging mt s vng sinh thi chnh nhm chn ra mt hoc mt s loi cy thch hp nht cho mi vng. Kho nghim xut x l bc tip sau kho nghim loi, l s tp hp ngun ht ca nhng xut x thuc cc vng sinh thi khc nhau trong nhng loi c xc nh, xy dng kho nghim so snh ging nhm tm ra mt hoc mt s xut x tt nht, c t l sng ln, nng sut cao theo mc tiu kinh t v c kh nng phng chng su bnh cng nh cc iu kin bt li khc. Trong mt s trng hp, khi nh chn ging bit c mt cch tng i y cc thng tin cn thit v loi cy nh chn lc, ngha l bit c kh nng cung cp sn phm kinh t, vng phn b ca loi, cc yu cu sinh thi v kh nng chng chu ca loi vi cc iu kin bt li, th vic kho nghim loi c kt hp vi kho nghim xut x trong cng mt ln v trn cng mt s a im nht nh. Nhng kho nghim ny c gi l kho nghim loi xut x. y l phng thc kho nghim rt ngn c thi gian i t nghin cu n sn xut v ang c p dng nhiu nc trn th gii. Ch thng qua kho nghim loi v xut x nh chn ging mi bit c mt cch chc chn (m khng phi suy on) xut x (ngun ging) thch hp nht s dng cho mt chng trnh trng rng trn mt vng sinh thi nht nh, c bit l khi a cy t ni khc n. Nh chn lc t nhin trong mt qu trnh lu di m cy rng hnh thnh tnh thch ng vi cc iu kin a l-sinh thi nht nh, hnh thnh nhng bin d di truyn ht sc phong ph c v hnh thi, tp tnh sinh trng v kh nng chu ng. Loi c phm vi phn b cng rng trn nhiu iu kin a l - sinh thi khc nhau th cng c nhiu bin d di truyn v do cng c nhiu kh nng la chn nhng bin d di truyn ph hp vi mc tiu chn ging tng khu vc. Kho nghim loi v xut x chnh l s li dng cc bin d di truyn c sn trong thin nhin mt cch c c s khoa hc, thng qua thc nghim gy trng trong nhng iu kin mi. y l phng php chn ging nhanh nht v r nht. Chnh v th m Zobel v Talbert (1984) cho rng bt lun k thut chn ging tinh vi nh th no, tng thu ln nht, nhanh nht v r nht trong cc chng trnh ci thin ging cy rng l s bo m s dng ngun ht thch hp nht cho trng rng, c bit l khi gy trng cy ngoi lai, s dng xut x thch hp l cha kha cho s thnh cng ca mt chng trnh trng rng cy ngoi lai. Cn Anderson (1966) th cho rng mt xut x ng tin cy s sn xut ra mt ging cy rng vi 90% kh nng chc chn hn l mt xut x xut sc song ch c 50% kh nng"1. 1.1. Chn loi, chn xut x, xy dng rng ging v vn ging cc loi keo Vit Nam c hn 15 loi keo acacia bn a phn b ti nhiu vng trong c nc (Nguyn Tin Bn v cs., 2003), song hu ht u dng cy bi hoc dy leo, t gi tr kinh t,1

Dn t Zobel v Talbert, 1984

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trong lc Australia (Au) c n hn 660 loi keo acaia (Boland, et al, 1984), vi nhiu loi cy g ln. Mt s nc nh Papua New Guinea (PNG) cng c cc loi acacia kch thc ln, sinh trng nhanh, d thch ng vi iu kin t trng i ni trc nc ta. V th vic nhp ni mt s loi keo nhit i t cc nc ny trng kho nghim nhm chn c loi v xut x thch hp vi mt s vng sinh thi chnh ca nc ta l ht sc cn thit. T u nhng 1960 Keo l trm (Acacia auriculiformis) c nhp vo trng th vng ng Nam B, mt s loi keo khc cng c trng th ti Lt, trong c loi A. podariifolia m v sau tr thnh cy tng trng cho vng Lt vi tn gi quen thuc l cy "Mimosa". T nm 1980, c bit l t u nhng nm 1990, mt s loi keo khc c tip tc nhp vo trng th v c a vo kho nghim nc ta. Cc loi keo nhp vo Vit Nam c chia thnh ba nhm l cc loi keo vng thp, cc loi keo chu hn v cc loi keo vng cao. n nay, sau khong 10 nm kho nghim thy c mt s loi v xut x c trin vng gy trng mt s vng sinh thi ca nc ta. Nhng loi v xut x ny c B Nng nghip v Pht trin nng thn cng nhn l ging tin b k thut. 1.1.1. Cc loi keo vng thp Cc loi keo vng thp l nhng loi c din tch trng rng ln nht nc ta. C th ni gn 40% din tch trng rng vng i thp hin nay l Keo l trm v Keo tai tng, v th nghin cu chn ging cho cc loi keo vng thp t khu kho nghim xut x n chn lc cy tri, lai ging v kho nghim ging l c ngha rt thit thc trong sn xut lm nghip. u nhng nm 1980 bn loi keo vng thp l Keo l trm, Keo tai tng (A. mangium), Keo l lim (A. crassicarpa), v Keo nu (A. alaucocarpa). c nhp trng th ti Ba V (H Ty), Ha Thng (Thi Nguyn) v Trng Bom (ng Nai). nh gi s b nm 1991 thy trong 4 loi keo c trng th nm 1982 ti Ba V v nm 1984 ti Ha Thng th ba loi keo c sinh trng nhanh l Keo tai tng, Keo l lim v Keo l trm; trong Keo l trm l loi c sinh trng nhanh trong nm u (L nh Kh, Nguyn Hong Ngha, 1991). Chn loi v xut x thng qua cc kho nghim a. Kho nghim ng b cc xut x ca 5 loi keo. Trong cc nm 1990 - 1991 thng qua cc d n UNDP mt b ging 39 xut x ca 5 loi keo vng thp c kho nghim nhm ti Chng (huyn Ba V, tnh H Ty), ng H (Qung Tr) v i Li (Vnh Phc). n nay mt s kho nghim vn cn c duy tr, mt s kho nghim khng cn na. Chng thuc huyn Ba V (H Ty) v 21o07' Bc, kinh 105o26' ng, lng ma 1680 mm/nm, thng c lng ma hn 100 mm l cc thng 5- thng 10, s gi nng l 1620 gi/nm. i Li (Vnh Phc) v 21o10' Bc, kinh 105o17' ng, lng ma 1500 mm/nm, thng c lng ma hn 100 mm l cc thng 5- thng 9, s gi nng l 1700 gi/nm. ng H (Qung Tr) v 16o50' Bc, kinh 107o05' ng, lng ma 2370 mm/nm, thng c lng ma hn 100 mm l cc thng 8- thng 12, s gi nng. Tham gia cc kho nghim nm 1990 tai Chng (H Ty) v ti ng H l cc l ht ca CSIRO (Australia) gm 13 xut x Keo l trm (A. auriculiformis), 9 xut x Keo tai tng (A. mangium), 9 xut x Keo l lim (A. crassicarpa), 5 xut x Keo nu (A. aulacocarpa) v 3

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xut x Keo qu xon (A. cincinnata). Ht ca cc xut x ny c ly t cc bang Queensland (Qld) v Northern Territoria (NT) ca Australia; cng nh Papua New Guinea (PNG) v Indonesia (Indo). Ging c trng i chng mt s ni l ni a phng ly t ng Nai (N) ca Keo tai tng v Keo l trm. Keo l trm (A. auriculiformis) c ngun gc t Australia, Papua New Guinea (PNG) v Indonesia (Indo), phn b ch yu v 8 - 16o Nam, cao 100 - 400 m trn mt bin, lng ma 1400 - 3400 mm/nm, song c th chu c lng ma 500 - 1000 mm/nm (Doran & Turnbull, et al, 1997). Keo l trm thng c kch thc trung bnh, thn ngn nhiu cnh nhnh, song trn cc lp a tt loi ny c th cao 30 m vi ng knh 80 cm v thn thng n trc (Pinyopusarerk, 1990), g c t trng 0,5 - 0,6, thm ch 0,7, nhit tr 4800- 4900 KCal/kg (Vin Hn lm khoa hc M, 1984), c th dng lm g ci, lm giy, lm g xy dng v g mc. Keo l trm nc ta c trng ln u ng Nai vo nm 1960, n nay tr thnh ni a phng c dng trng rng nhiu ni. Keo tai tng (A. mangium) c ngun gc t Australia, Papua New Guinea v Indonesia, cos phn b ch yu v 8 - 18o Nam, cao 300 m trn mt bin, lng ma 1500 - 3000 mm/nm (Doran, Turnbull, et al, 1997). Tuy mi c a vo nc ta u nhng nm 1980, song Keo tai tng ang c trng rt ph bin nhin ni. Keo tai tng c thn cy thng p, sinh trng nhanh hn Keo l trm. G Keo tai tng c t trng 0,45 - 0,50, giai on sau 12 tui c th t 0,59 (Razali & Mohd, 1992), thch hp cho sn xut g ln, g dn, vn dm, lm giy. Keo tai tng ang c trng nhiu ni lm nguyn liu cho cng nghip. Keo l lim (A. crasscicarpa) c ngun gc t Australia, Papua New Guinea v Indonesia, c phn b v 8 - 20o Nam, cao 5 - 200 m trn mt bin, lng ma 1000 3500 mm/nm, g c t trng 0,6 - 0,7 thch hp cho xy dng, lm mc (Doran, Turnbull, et al, 1997). Keo l lim l loi cy mi c a vo trng nc ta vo u nhng nm 1980, l loi c sinh trng nhanh nht trong cc loi keo vng thp, c th gy trng trn t ct ni ng c ln lp tnh ThaThin-Hu, ng thi c th sinh trng trn cc lp a t i nhiu vng trong c nc. Keo nu (A. aulacocarpa) c ngun gc t Australia, Papua New Guinea v Indonesia (Thomson, 1994). Nhng xut x c nhp vo Vit Nam ch yu cc nhm thuc v 6 20o Nam, c lng ma 1000 - 3000 mm/nm (Thomson, 1994), trong nhm xut x Papua New Guinea c kch thc ln, c th cao 40 m, nhm Australia c th c dng cy bi hoc cy g nh (Thomson, 1994). G Keo nu c t trng 0,6 - 0,7 (Keating & Bolza, 1982), c th dng sn xut giy (Clark, et al, 1991), ng thuyn v lm mc (Keating & Bolza, 1982). Keo qu xon (A. cincinnata) c ngun gc t Australia, phn b v 16 - 28o Nam, cao 150 - 800 m trn mt bin, lng ma 2000 - 3500 mm/nm, c th sng c ni c lng ma 1200 - 1500 mm/nm, cy c th cao 25 m, song nhng ni kh hn ch cao khong 10 m (Doran & Turnbull, et al, 1997), g c t trng 0,5 - 0,6, rt thch hp cho sn xut bt giy (Clark, et al, 1991). Kho nghim Chng c trng nm 1990 trn t pheralit vng pht trin trn sa thch, t tng i su (trn 50 cm), theo khi 49 cy, lp li 3 ln ngu nhin khng y . Kho nghim ng H c trng nm 1991 trn t pheralit pht trin trn dip thch. Kho nghim ny b thiu cy, ch c mt ln lp vi 49 cy, nn s liu ch c tnh cht tham kho. Kho nghim i Li (Vnh Phc) ch gm cc xut x ca Keo l trm. S liu thu thp nm 1999 cho thy ti Chng Ba V giai on 9 tui th tch thn cy trung bnh ca 5 loi keo c kho nghim l:

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Keo l lim c th tch thn cy 221 dm3/cy, Keo tai tng c th tch thn cy 191 dm3/cy, Keo l trm c th tch thn cy 192 dm3/cy, Keo nu c th tch thn cy 103 dm3/cy, Keo qu xon c th tch thn cy 94 dm3/cy.

Nh vy 3 loi cy c sinh tng nhanh v c trin vng gy trng cc tnh pha Bc l Keo l lim, Keo tai tng v Keo l trm. Kho nghim so snh mt s xut x Keo tai tng, Keo l trm, Keo l lim, Keo nu (A. aulacocarpa) v Keo qu xon (A. cincinnata) cng c Trung tm nghin cu cy nguyn liu giy Ph Ninh xy dng ti Mang Giang (Gia Lai) trn t Bazan v t i phn ha t granit nm 1992 (Mai nh Hng, Hunh c Nhn, Cameron, 1996). S liu o m giai on 4 nm tui (1996) cho thy, Keo l lim, Keo tai tng v Keo l trm l nhng loi c sinh trng nhanh nht. nh gi sinh trng trn c hai lp a thy cc xut x Bloomfield (Qld) v Pongaki (PNG) c sinh trng nhanh nht trong 4 xut x ca Keo tai tng. Cc xut x Coen River (Qld) v King's Plain (Qld) c sinh trng nhanh nht trong 4 xut x ca Keo l trm. Keo qu xon l loi c sinh trng km nht. Keo l lim (xut x Chili-Beach - Qld) ch c kho nghim trn t phn ho t granit v l loi c sinh trng nhanh nht y. Nhng xut x c trin vng ny v c bn vn ging vi nhng xut x c nh gi v xut trc y (L nh Kh, 1996, Nguyn Hong Ngha, 1997, Nguyn Hong Ngha, L nh Kh, 1997, Nguyn Hong Ngha, L nh Kh, 2000). Nhn chung, trong cc loi keo vng thp c kho nghim ti Vit Nam th 3 loi c sinh trng nhanh nht v c trin vng nht l Keo l lim, Keo tai tng v Keo l trm. Cc loi A. aulacocarpa v A. cicnnata u l nhng loi sinh trng chm v t c trin vng gy trng nc ta. nh gi chung cho c b ging c ba kho nghim ti Ba V, ng H v i Li c th thy sau 9 - 12 nm mt s xut x sau y l c trin vng cho cc tnh min Bc: Keo l trm: Cc xut x Mibini (PNG), Coen River (Qld), Manton (NT) v Kings Plains (Qld). Keo tai tng: Cc xut x Pongaki (PNG), Iron Range (Qld), Ingham (Qld) v Mossman (Qld). Keo l lim: Cc xut x Mata province (PNG), Gubam (PNG), Dimisisi (PNG) v Deri-Deri (PNG). Keo nu v Keo qa xon: tuy c mt s xut x sinh trng tng i kh Chng, song y l nhng loi khng c trin vng gy trng Vit Nam.

b. Kho nghim xut x ca cc loi ring bit Kho nghim xut x Keo l trm Ngoi kho nghim xut x ng b cho 5 loi keo ti Chng, mt kho nghim xut x Keo l trm cng c xy dng ti i Li vo nm 1990. S liu o m nm 1999 cng cho thy xut x Coen River (Qld) l xut x c sinh trng nhanh nht ti y. Cn s liu c thu thp nm 2002 (bng 2.1) cho thy n giai on 12 nm tui cc xut x Keo l trm c sinh trng nhanh nht ti c 2 ni l Mibini (PNG), Coen River (Qld) v Kings Plains (Qld); ring

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xut x Manton (NT) vn tip tc c sinh trng nht ti Ba V, song c sinh trng trung bnh kh ti i Li. Kho nghim cc xut x Keo l trm cng c thc hin theo d n ACIAR 9310 hp tc vi Australia c xy dng vo nm 1994 ti Cm Qu (ni c t xu hn so vi khu vc Chng) thuc huyn Ba V (H Ty), ng H (Qung Tr) v Sng My (ng Nai). y l kho nghim c s tham gia ca ni a phng ng Nai lm i chng. Cc iu kin kh hu v t ai ca Ba V v ng H c gii thiu phn trn, cn Sng My l lp a v 11o05' Bc, lng ma hng nm 1640 mm/nm, s gi nng l 2650 gi/nm (nh Bu bng), cao mt bin 20m, t xm trn ph sa c, i thp dc thoi, khng b ngp trong ma ma. o m sinh trng sau 3 nm cho thy trong cc kho nghim ny, khng c xut x Coen River (l ht 16142) tham gia, th South Coen (Qld) l xut x c sinh trng tt ti Sng My v ng H, Rifle Creek (Qld) c sinh trng tt ti Cm Qu, Lower Pasco (Qld) c sinh trng tt ti ng H (Montagu et al, 1998). nh gi giai on 5 tui cho thy ti ng H xut x c sinh trng tt nht l Wondo Village (Qld) v Lower Pascoe (Qld); ti Sng My cc xut x c sinh trng tt nht l Wenlock R. (Qld), Halroyed (Qld) v Morehead (PNG); ti Cm Qu xut x c sinh trng tt nht l Halroyed (Qld) v Rifle Creek (Qld). Bng 1.1. Sinh trng ca cc xut x Keo l trm ti Ba V v i Li (1990-2002) Ti Ba V Ti i Li L ht Xut x H Vcy H Vcy L ht D1.3 (cm) D1.3 (cm) 3 (m) (dm ) (m) (dm3) 16148 Manton R. NT 21,36 17,3 310 16142 14,10 14,8 116 16106 Mibini PNG 21,15 17,7 311 16485 13,35 14,4 101 16142 Coen R. Qld 20,79 17,5 297 16106 13,56 14,2 104 16485 KingsPlains Qld 20,56 17,8 295 16484 13,30 14,5 101 16163 Elizabeth NT 19,59 17,3 261 16152 13,22 14,8 102 16152 Alligator NT 19,41 16,1 238 16154 13,15 14,3 97 16684 Bensbach PNG 19,40 17,4 257 16148 12,85 14,3 93 16158 Gerowic Crk NT 18,04 14,8 189 16684 12,65 12,5 79 16484 Morehead Qld 17,98 15,9 202 16151 12,40 13,6 82 16683 Morehead PNG 17,63 15,5 189 16163 10,50 12,6 55 16107 Old Tonda PNG 17,33 15,6 184 16107 10,93 10,8 51 16154 Goomadeer NT 16,21 15,9 164 16158 10,42 10,4 44 16151 Mary River NT 13,91 13,4 102

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S liu thu thp c cho thy ti c ba ni kho nghim ni a phng ng Nai ca Keo l trm u thuc nhm sinh trng trung bnh km hoc km nht, cc xut x Keo l trm c sinh trng nhanh nht u c th tch thn cy gp i cc xut x c sinh trng km nht, South Coen (Qld) v Coen River (Qld) l nhng xut x khc nhau. Ngoi ra, s liu thu thp c cng cho thy Sng My th tch thn cy trung bnh ca 16 xut x l 90 dm3/cy th ng H l 30,1 dm3/cy, cn Ba V l 20,4 dm3/cy. Nh vy, cng giai on 5 tui, vi mt trng nh nhau (2 x 3 m) Keo l trm ti Sng My c sinh trng th tch gp 3 ln ng H v gp hn 4 ln Cm Qu (ni c t xu hn Chng thuc Ba V). iu chng t iu kin kh hu v t ai c nh hng rt ln n sinh trng ca Keo l trm. Kho nghim cc xut x Keo l lim ti Bu Bng (Bnh Dng) Mt b cc xut x Keo l lim c trng kho nghim ti Bu Bng (Bnh Dng) t thng 4 nm 1991. Bu Bng l lp a t ph sa c v 11o17', lng ma hng nm 1640 mm/nm, s gi nng l 2650 gi/nm (nh Sng My), b ngp trong ma ma. Bng 1.2. Sinh trng ca cc xut x Keo l lim ti Bu Bng (9/1991 - 12/1999) L Xut x D1.3 (cm) H (m) V (dm3) ht 16602 16993 17869 17552 13682 13680 17561 16598 17944 17849 16128 Dimisisi Deri-Deri Morehead Bensbach Oriomo Wemenever Limal Bimadebum Claudie R. Samlenberr Jardine R. A. auri. N PNG PNG PNG PNG PNG PNG PNG PNG Qld Indo Qld VN

x21,4 21,4 21,0 20,8 19,6 19,0 19,3 19,2 18,6 17,6 16,6 8,4

v (%) 17,4 16,5 18,0 18,0 18,9 19,0 18,9 18,9 19,4 19,2 20,4 28,1

x19,7 19,6 19,7 19,3 18,9 18,7 17,2 17,6 15,0 18,0 12,4 8,7

v (%) 11,0 9,8 11,9 12,2 12,3 12,1 11,8 12,0 11,2 12,0 23,3 21,2

x390 389 390 387 339 313 285 292 241 256 169 31

v (%) 1,6 1,6 1,6 1,6 1,8 1,9 2,1 2,0 2,4 2,3 3,4 12,8

S liu o thng 12 nm 1999 (Bng 2.2) cho thy sau 8,5 nm cc xut x c trin vng nht Bu Bng l Dimisisi (PNG), Deri-Deri (PNG), Morehead (PNG) v Bensbach (PNG). Nhng xut x ny c th tch thn cy 387 - 390 dm3/cy. Trong lc cc xut x c sinh trng km nh Samlenberr (Indonesia) v Jardine (Qld) ch c th tch thn cy tng ng l 256 dm3/cy v 169 dm3/cy. Cn ni a phng ng Nai ca Keo l trm ch c th tch thn cy 31 dm3/cy. Dimisisi (PNG) v Deri-Deri (PNG) cng l nhng xut x c sinh trng tt nht ca Keo l lim ti Ba V, cn Deri-Deri (PNG) l mt trong nhng xut x c sinh trng tt nht ti ng H. Chng t cc xut x ny l nhng xut x c trin vng trong cc ni kho nghim ti nc ta. Nhn y cn ni thm l xut x Dimisisi cng l xut x c sinh trng tt nht ca Keo l lim sau 3 nm kho nghim ti Long ng thuc tnh Qung Chu, Trung Quc (Zhang Fangqiu & Yang Mingquan, 1996).

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Kho nghim xut x Keo tai tng ti ng Nam B.

Kho nghim xut x Keo tai tng do Trung tm khoa hc sn xut lm nghip ng Nam B xy dng ti Bu Bng (Bnh Dng) v Sng My (ng Nai) trong cc nm 1989 1990. S liu bng 2.3 cho thy tuy Bu Bng v Sng My l hai khu vc ch cch nhau khong 50 km ti vng ng Nam B v c kh hu ging nhau, song Keo tai tng c trng ti Sng My, ni c t su khng b ngp trong ma ma, sau 8,5 nm c th t th tch 289 - 432 dm3/cy, trong lc ti Bu Bng cy b ngp trong ma ma th tch thn cy cng thi gian y ch t 114 - 281 dm3/cy. S liu trung bnh chung cho c 3 kho nghim cng chng t iu ny. Bng 2.3. Sinh trng Keo tai tng ti Bu Bng v Sng My (1989 - 1999) Bu Bng Sng My 1 Sng My 2 (6/1990 L ht Xut x (7/1989 - 12/1999) (8/1989 - 12/1999) 12/1999) D1.3 (cm) 16591 0517 15700 0554 1667 0523 16589 0535 0579 Deri-Deri PNG Harbertb Valley Qld Cardwell Qld Tully Region Qld Bloomfield Qld Gap Creek Qld Olive River Qld Pascoe River Qld Innis Region Qld TBnh H (m) V D1.3 (dm3) (cm) H (m) V D1.3 (dm3) (cm) H (m) V (dm3) 458 329 311

19,2 17,9 282 18,6 17,0 260 18,3 16,8 240 18,0 17,3 235 13,9 15,1 132 13,8 12,6 114 17,0 16,1 211

22,0 18,0 367 23,3 17,9 432 22,4 18,6 403 19,4 18,1 299 19,1 19,1 289 21,2 18,4 358

24,6 18,0 21,5 17,0 20,3 17,8 23,3 23,0 18,5 21,9

18,0 406 18,0 414 15,3 235 17,4 359

T s liu bng 2.3 vn c th thy xut x c sinh trng nhanh c Bu Bng v Sng My l Deri-Deri (PNG), cc xut x c sinh trng km c hai ni ny l Bloofield (Qld) v Gap Creek (Qld). Bu Bng xut x c sinh trng nhanh cn c Harbert Valley (Qld), Sng My xut x c sinh trng nhanh cn c Olive (Qld) v Pascoe River (Qld). Mt kho nghim xut x khc cho Keo tai tng Bu Bng c nh gi giai on 7 tui cho thy cc xut x ni tri y l Kennedy River (Qld) v Cardwell (Qld) c th tch thn cy tng ng l 56,9 dm3/cy v 52,1 dm3/cy. Trong khi cc xut x Mossman (Qld) v Ingham (Qld) c th tch thn cy 34 - 35 dm3/cy (xut x Ingham c sinh trng nhanh nht ti Chng). Cn ni a phng ng Nai ca Keo tai tng c th tch thn cy l 21 dm3/cy (Nguyn Hong Ngha, L nh Kh, 2000). iu chng t mt s xut x c kh nng thch ng rng, c th sinh trng tt trong cc lp a khc nhau, mt s xut x ch thch hp vi mt s lp a nht nh. Nh vy, kho nghim Keo tai tng cho thy Deri-Deri (PNG) l xut x c sinh trng tt v c trin vng nht cho vng ng Nam B. Cc xut x Olive (Qld), Pascoe River (Qld) v Cardwell (Qld) l nhng xut x c trin vng trn tng lp a nht nh (m ch yu l ni khng b ngp trong ma ma).

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c. Cc loi v xut x c B NN&PTNT cng nhn l ging tin b k thut T kho nghim v nh gi cc xut x cho cc loi keo vng thp c th thy mt s xut x sau y l c trin vng nhiu vng trong nc: Keo l trm: Coen River 16142 (Qld), Mibini (PNG), Goomadeer (NT), Sakaerat (Thai.), Archer River & Tribs (Qld). Keo tai tng: Pongaki (PNG), Oriomo (PNG) v Bimadebun (PNG). Keo l lim: Dimisisi (PNG), Deri - Deri (PNG). Mt s xut x c sinh trng tt tng vng nht nh l: Keo l trm: Kings Plains (Qld), Lower Pascoe (Qld) cho cc tnh min Bc, Wondo Village (Qld) cho ng H, Melvile (Qld) cho Chn Thnh, Wenlock River (NT) cho Sng My vng ng Nam B. Keo tai tng: Iron Range (Qld), Ingham (Qld) v Mossman (Qld) cho cc tnh pha Bc, Deri - Deri (PNG), Cardwell v Pascoe (Qld) cho vng ng Nam B. Keo l lim: Mata province (PNG) v Gubam Village (PNG) cho cc tnh min Bc, Morehead (PNG) v Bensbach (PNG) cho cc tnh vng ng Nam B.

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Trn c s kt qu cc kho nghim xut x ti mt s vng sinh thi trong nhiu nm ngy 12 thng 10 nm 2000 B NN&PTNT c quyt nh s 4260/KHCN- NNTT cng nhn cc xut x thuc cc loi di y l Ging tin b k thut gy trng trn din rng nhng ni c iu kin sinh thi ph hp: Keo l trm: Coen River (Qld), Morehead River (Qld), Mibini (PNG). Keo l lim: Mata province (PNG), Deri-Deri (PNG), Dimisisi (PNG). Keo tai tng: Iron Range (Qld), Cardwell (Qld), Pongaki (PNG).

Xy dng rng ging v vn ging cho cc loi keo vng thp Trong cc nm 1996-1998 d n FORTIP (Regional Project on Forest Tree Improvement) v ci thin ging cy rng do Trung tm nghin cu ging cy rng hp tc vi Khoa lm nghip v sn phm rng ca CSIRO vi s ti tr ca AusAD ca Australia c thc hin mt s vng ti Vit Nam. D n ny bao gm vic xy dng 35 ha rng ging v vn ging cho cc loi cy Keo l trm, Keo tai tng ti Cm Qu (H Ty) v Chn Thnh (Bnh Phc). Trong cc nm 2000-2001 thng qua hp tc vi Khoa lm nghip v sn phm rng ca CSIRO, cc vn ging cy ht ca Keo l lim li c xy dng ti ng H (3 ha) v Hm Thun Nam, tnh Bnh Thun (3 ha). u nm 2003 thng qua D n ging ca Vit Nam v vi s gip ca CSIRO 4 ha vn ging cy ht ca Keo l lim cng c xy dng ti Phong in (Tha Thin-Hu). Cc vn ging Keo l trm c xy dng gm 4 ha ti Cm Qu (139 gia nh) v 4 ha ti Chn Thnh (185 gia nh). Cc vn ging Keo tai tng c xy dng gm 3 ha ti Cm Qu (84 gia nh) v 3 ha ti Chn Thnh (168 gia nh). Cc vn ging Keo l lim c xy dng gm 3 ha ti ng H (105 gia nh), 3 ha ti Hm Thun Nam (80 gia nh) v 4 ha ti Phong in (112 gia nh).

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Ngoi ra, cn c 3 ha rng ging Keo l trm (xut x Coen River) v 3 ha rng ging Keo tai tng (xut x Pongaki) c xy dng vo nm 1993 ti Cm Qu (H Ty). Vt liu xy dng vn ging l ht th phn t do thu t cc cy tri c chn lc trong cc xut x c trin vng nht ti Papua New Guinea (PNG), cc bang Queensland (Qld) v Northern Territory (NT) ca Australia, cng nh t Sakaerat ca Thi Lan (Thai.). Ht ly t cc cy tri th phn t do ny c coi l mt gia nh (family). Nhng gia nh c trng trong cc vn ging u theo khi hng 4 cy, lp li 8 ln hon ton ngu nhin. Sau 3 nm tin hnh nh gi sinh trng ca cy theo gia nh v theo xut x trong cc vn ging c xy dng trong cc nm 1996-1998, gi li nhng c th tt nht trong cc nhng gia nh tt nht ca nhng xut x c trin vng, ta b nhng c th v nhng gia nh xu thnh vn ging ly ht (seed orchard) cung cp ging cho trng rng Vit Nam. Nhng c th ny cng nh mt s c th c chn trc tip t cc khu kho nghim xut x cng c dng nh nhng cy u dng d tuyn kho nghim dng v tnh nhm chn ging c nng sut cao v c kh nng khng bnh cho sn xut. Bng 2.4. Sinh trng ca 19 c th tt nht thuc cc gia nh v xut x tng ng ca Keo tai tng ti vn ging Cm Qu (6/1998 - 4/2000). H D1.3 Gia D1.3 H V V Xut x C th nh (cm) (m) (dm3) (cm) (dm3) (m) TB vn ging 16971 Wipim Dist.PNG 67 75 74 71 111 7,8 11,0 10,3 9,8 10,2 10,7 7,6 9,3 9,2 9,6 8,5 9,5 19,1 44,8 40,9 38,4 36,8 45,6 5. 6. 2 7. 6. 12 4. 4. 1 8. 6. 3 5. 3. 4 2. 1. 10 6. 1. 9 3. 7. 11 5. 2. 4 4. 5. 11 1. 5. 7 2. 3. 6 2. 5. 12 1. 7. 12 4. 2. 12 5. 3. 1 2. 3. 11 5. 5. 3 5. 4. 4 12,3 12,1 12,9 12,5 11,5 12,3 13,3 12,6 11,6 12,2 13,2 12,3 13,2 12,8 12,3 13,1 12,0 11,6 11,9 10,0 9,5 11,5 9,5 12,5 9,5 11,0 9,5 11,0 9,7 10,5 10,0 8,5 9,0 9,5 11,0 11,5 11,5 10,5 59,4 54,6 75,2 58,4 64,9 56,4 76,4 59,3 58,1 56,7 71,8 59,4 58,2 57,9 74,4 65,0 60,8 58,4

16992 Bimadebun PNG

16991 Gubam

PNG

115 89 101 99 91

10,6 9,6 10,1 9,3 9,7 9,5 9,4 9,8 10,2

9,0 8,3 8,7 8,3 8,2 8,7 8,9 9,1 8,7

40,6 32,2 36,1 31,7 33,2 34,9 33,3 36,0 37,0

16938 Kini WP. PNG 19286 Cardwell SO. Qld 19994 Claudie R. Qld

21 202 130 131

Cui nm 1999 vn ging Keo tai tng v Keo l trm Chn Thnh b tnh Bnh Dng ly chuyn thnh khu cng nghip nn mi vn ging c chn 50 cy tri t 50

26

gia nh tt nht nhn ging bng hom v xy dng vn ging gm cc dng v tnh u tri ti Hm Thun Nam (tnh Bnh Thun). Hin nay cc vn ging dng v tnh ny bt u c qa cung cp ging cho sn xut. C th xem th d bng 2.4 v cc cc th c chn trong vn ging l nhng cy c sinh trng vt tri r rt so vi tr s trung bnh chung ca vn ging. S liu bng 2.4 cho thy trong lc th tch thn cy trung bnh chung ca c vn ging Keo tai tng ti Cm Qu giai on gn 2 nm tui l 19,9 dm3/cy v th tch thn cy ca nhng gia nh c chn cao nht cng ch mc 31,7 - 44,8 dm3/cy th th tch thn cy ca nhng c th tt nht c chn l 54,6-76,4 dm3/cy. Nhng c th ny l nhng cy u dng d tuyn to ra cc dng v tnh c nng sut cao cho cc chng trnh trng rng nc ta. 1.1.2. Cc loi keo vng cao Kho nghim chn loi keo vng cao ti Lt Trong din tch t trng i ni trc nc ta c mt phn kh ln vng ni cao thuc dy Hong Lin Sn nh Cao Bng, H Giang, Lo Cai, Sn La, Lai Chu, mt phn vng Ty Nguyn thuc cc tnh Kon Tum v Lm ng, cng mt s din tch pha ty Ngh An. V th chn mt s cy l rng mc nhanh c gi tr kinh t, c c im sinh thi ph hp v c kh nng ci to t, lm bng cn la cho cy l kim hoc trng ring r s lm phong ph thm tp on cy lm nghip, gp phn ci thin i sng ca nhn dn min ni l rt cn thit. Nm 1996 thng qua ti ca ACIAR v vi s h tr ca CSIRO, mt b ging c loi keo vng cao ca Australia c Trung tm nghin cu ging cy rng ca Vin Khoa hc lm nghip Vit Nam phi hp vi cc n v xy dng ti mt s vng cao nh Lt (cao 1600 m), Tam o (cao 1000 m), Mc Chu (cao 1000 m) v ni Ba V (cao 600 m). nh gi s b vo nm 1997 cho thy Lt l ph hp nht trong cc a im c trng th (H Huy Thnh, L nh Kh v cng s, 1998), v th s liu c thu thp v sau tp trung cho kho nghim ti Lt. Kho nghim ti Lt c gy trng vo thng 5 nm 1996 ti Mang Linh ( Lt) cao 1600 m trn mt bin ti sn ng-nam, t feralitic vng pht trin trn Macgma acid c pH = 4,5 - 5,0, thc b l c quyt v mt s cy bi thp. Trc khi trng t c pht dn ton b, t v cy ton din bng th cng. H trng c kch thc 40 x 40 x 40 cm, bn lt 0,5 kg phn vi sinh. B ging c kho nghim gm 42 xut x thuc 14 loi keo vng cao do CSIRO ca Australia cung cp. Cc xut x c trng theo hng 20 cy, khong cch cy l 2 x 1,5 m, b tr 4 ln lp ngu nhin. Bng 2.5. Sinh trng v cc ch tiu cht lng cy ca cc loi keo vng cao c kho nghim ti Lt (5/1996 - 5/2000) T l sng Kh sau khi trng Sinh trng sau 48 thng S nng (%) Sc thng S Loi x chng sng thn thn 6 48 H D1.3 V su v (%) 3 thng thng (m) (cm) (dm ) (1) 7 84,0 65,0 9,5 8,7 39,0 8,1-17,4 2,44 4,01 3,54 1,11 A.mearnsii (2) 6 67,9 10,0 8,6 42,4 8,1-13,6 2,46 4,02 3,60 1,12 A.mearnsii 1 47,5 6,95 7,08 19,0 17,4 2,37 3,96 3,18 1,06 A.mearnsii - L

27

Loi A. binervata A. chrysotricha A. cincinnata A. dealbata A. decurrens A.elata A.fulva A.glaucocarpa A.implexa A.irrorata A.melanoxylon A.parramattensis A.silvestris Ghi ch:

T l sng sau khi trng S (%) x 6 48 thng thng 1 85,0 68,7 1 61,2 21,3 4 68,7 13,1 4 2 3 2 3 3 3 6 2 1

Sinh trng sau 48 thng

H D1.3 V v (%) (m) (cm) (dm3) 7,9 7,7 30,2 12,5 2,38 4,30 6,6 5,2 9,1 30,3 2,13 4,43 3,5 2,2 0,9 7,1-150,0 1,54 4,88

Kh nng Sc thng S chng sng thn thn su 3,49 1,14 3,44 1,22 3,39 1,09 3,70 3,05 2,79 3,48 3,01 3,05 3,17 3,06 3,14 3,46 1,04 1,01 1,00 1,08 1,10 1,00 1,24 1,05 1,04 1,04

76,2 50,6 7,0 6,5 17,5 14,1-28,8 2,24 4,68 73,8 15,0 6,0 4,7 6,4 32,9-40,0 2,09 4,42 65,8 35,8 5,8 5,4 12,2 16,9-32,7 2,30 4,82 76,9 59,4 8,8 6,3 18,4 16,5-17,9 2,56 4,91 85,4 25,0 7,6 5,5 15,3 11,9-47,3 2,17 4,81 84,1 54,2 4,9 3,1 4,6 27,4-66,1 1,79 4,91 87,5 66,5 7,3 7,5 24,9 12,7-19,4 2,31 4,33 78,9 56,3 5,3 4,6 8,7 14,8-89,3 1,92 4,81 87,0 56,3 6,4 5,4 12,1 24,6-24,8 2,14 4,51 72,5 46,3 8,6 7,6 27,3 13,1 2,46 4,24 (1) Trung bnh ca c 7 xut x (k c ca Lt - L) (2) Trung bnh ca 6 xut x mi c nhp

iu kin kh hu Lt c nhng c trng chnh l: Nhit trung bnh hng nm 18,3 , ti cao trung bnh l 23,3oC, ti thp trung bnh l 14,3oC, ti thp tuyt i c th n 0,1oC (thng 1 nm 1932), ti cao tuyt i l 31,5oC (thng 3 trong nhiu nm), lng ma trung bnh hng nm l 1730 mm/nm, tp trung ch yu vo thng 4 n thng 10, nhiu nht l thng 9 v thng 10 (Nguyn Trng Hiu, 1990). iu chng t Lt l ni c iu kin kh hu mt v t thay i trong nm.oC

S liu thu thp l chiu cao, ng knh, th tch thn cy, t l sng, s thn (tnh t cao cch gc 0,5 m), thng thn cy (cao nht 5 im, thp nht 1 im) v sc sng (cao nht 3 im, thp nht 1 im). S liu thu thp v t l sng giai on 6 thng v 48 thng tui sau khi trng cho thy giai on 6 thng tui tt c cc loi cy c gy trng u c t l sng tng i cao (bng 2.5). Nhng loi c t l sng cao nht nh A. irrorata, A. glaucocarpa, A. implexa, A. mearnsii, A. parramattensis v A. binervata c th t 84 - 87,5%, loi c t l sng thp nht l A. chrysotricha cng c t l sng 61,2%. n giai on 48 thng (4 nm tui) mt s loi vn gi c t l sng cao nh A. mearnsii (67,9%), A. binervata (68,7%), tip l A. irrorata (66,5%), mt s loi c t l sng gim i r rt, in hnh l A. cincinnata t l sng ch cn 13,2%. C 4 xut x ca A. cincinnata u c mt s b cht hon ton, trong xut x Frinch Hatton (Qld) thm ch b cht c 3 3 ln lp. Loi c t l sng thp tip theo l A. decurens (t l sng ch t 15%) v c mt s b cht hon ton. Mt s xut x ca A. dealbata cng c mt s b cht hon ton. nh gi mt cch tng hp c th ni n giai on 48 thng tui Keo en (A. mearnsii) l loi c trin vng nht, cc xut x mi nhp vo Vit Nam u c sinh trng v t l sng

28

cao hn ni a phng ca Lt c trng lm i chng. Trong lc cc xut x mi nhp c t l sng 61,2 -76,2% v th tch thn cy 28,4 - 55,2 dm3/cy th ni a phng Lt c trng lm i chng c cc ch tiu ny tng ng l 47,5% v 19 dm3/cy. R rng A. mearnsii l loi c trin vng nht, c bit l mt s xut x nh Bodalla (New South Wales - NSW), Nowra (NSW), Nowa Nowa (Victoria - Vic) v Berrima (NSW) (bng 2.5 v 2.6). Trong cc loi cn li ch c mt s xut x ca A. melanoxylon, A. dealbata v A. irrorata l c trin vng, cc loi khc u khng c trin vng cho trng rng ti Lt. Nhng loi v xut x c t l sng thp v sinh trng km th d cc ch tiu cht lng c t im cao, cng khng c ngha trong trng rng. Mt s xut x Keo en c trin vng gy trng Lt Theo di cc xut x Keo en nm 2003 cho sau 7 nm kho nghim cc xut x mi nhp u c sinh trng nhanh hn r rt so vi ni a phng Lt, trong cc xut x Bodalla, Nowra, Nowa Nowa v Berrina l nhng xut x c sinh trng nhanh nht (bng 2.6). Nhng xut x ny c th tch thn cy l 41,0 - 55,2 dm3/cy, gp 2,1 - 2,9 ln th tch thn cy ca ni a phng Lt (19,0 dm3/cy). Tuy trong cc xut x c mt s cy b su hi,song vn c nhiu cy khng b su hi, sinh trng rt nhanh v c thn cy thng p. Nhng cy ny c th l ngun cung cp ging trng m rng vng Lt v trng th mt s ni c iu kin tng t. Lubulwa v cng s (1998) dng phn mm chng trnh bn kh hu ca Booth v Jovanovic (1994) xc nh vng c th gy trng Keo en Vit Nam. Theo bn ny th mt s vng ni cao thuc cc tnh Cao Bng, H Giang, Lo Cai, Lai Chu, Sn La, Ngh An, Kon Tum v Lm ng l nhng ni c th gy trng Keo en nc ta. Vic xy dng mt s kho nghim xut x cho loi ny nhng ni c iu kin tng t nh Lt l rt cn thit. Nhn y cn ni rng Keo en l loi cy l kp lng chim hai ln, c phn b v 34-43o Nam, cao khong 850 m trn mt bin. Keo en l loi cy a tc dng c th trng lm ci, sn xut bt giy, lm cy che bng cho Ch, lm bng cn la cho cy l kim. y cng l loi cy c kh nng ci to t. V Keo en c n 40% tannin (Vin Hn lm khoa hc M, 1980), khi trng Trung Quc mt s xut x c th t n 43% tannin (Fang Yulin et al, 1994, Li Jiyuan, et al, 1994). G Keo en c hm lng bt giy c th n 52% (Clark, et al, 1994), tng ng hm lng bt giy ca cc loi Keo tai tng v Keo l trm ca ta c phn tch ti Nht (Takashi Hibino, 1996). Nghin cu Indonesia cho thy g sy kh c th t nhit tr 4650 Kcal/kg, nn loi cy ny cng c coi l cy trng lm ci cho vng cao ca cc nc nhit i (Vin Hn lm khoa hc M, 1980). Sri-Lanka loi cy ny cn c trng che bng cho Ch. Vic gy trng bc u nc ta cho thy Keo en l mt loi cy sinh trng nhanh, thch hp vi iu kin sinh thi vng ni cao v c th trng lm bng cy xanh cn la cho mt s loi cy l kim nh Thng ba l. Nm 1843 Keo en c nhp vo n trng lm ci, nm 1884 c nhp vo Nam Phi sn xut tannin (Boland, et al, 1984), hin nay ang c trng vng ni cao nhit i ca nhiu nc trn th gii nh n , Trung Quc, Sri-Lanka, Indonesia, Brazil v mt s nc Trung M, ng Phi, Trung Phi v Nam Phi. Ring Brazil n nm 1993 c 200.000 ha Keo en c gy trng lm ci v sn xut giy (Higa, Resende, 1994). Tm li, t kho nghim cc loi keo vng cao trong thi gian qua c th thy: Trong cc loi keo vng cao c kho nghim ti Lt sau 4 nm mi thy mt s xut x ca Keo en (A. mearnsii) l c sinh trng nhanh nht, c sc khe v thng thn

29

cy thuc nhm kh nht trong cc loi keo vng cao c kho nghim, tip c th l mt s xut x ca A. melanoxylon v A. irrorata.

30

Bng 2.6. Sinh trng ca cc xut x Keo en v Keo g en giai on 7 tui ti Lt (1996-2003). H D1.3 V D tn L ht Xut x 3 (cm) (dm ) (m) (m) v% 16246 16621 16380 18607 18979 18975 A. mearnsii Nowra NSW Bodalla NSW Nowa Nowa VIC Berrima NSW Blackhill VIC Bungendore NSW Lt VN A. melanoxylon Mt. Mee Qld Raveshoe Qld Mt. Linsay NSW Kannunah Tas 13,5 13,6 12,3 12,6 12,5 11,7 10,4 10,7 9,6 8,5 8,4 13,4 13,8 10,8 13,7 12,4 14,1 13,4 10,5 15,3 17,4 17,8 12,2 12,1 11,3 10,5 11,0 10,6 10,8 11,2 8,7 7,3 7,0 v% 19,3 22,0 14,8 17,8 20,4 19,5 18,5 17,1 20,6 24,8 20,9 93,0 92,9 74,6 71,0 67,9 59,4 59,7 59,6 35,7 24,6 22,9 v% 8,3 8,7 9,0 9,7 11,0 12,1 10,9 11,4 16,6 23,5 21,9 5,6 5,7 5,5 5,7 5,5 5,2 4,6 4,9 4,3 4,0 3,8 v% 12,9 13,3 7,8 11,2 10,4 12,9 8,5 14,7 14,4 13,5 19,2

17263 15821 19001 19494

Ghi ch: Ft = Xc sut ca F tnh; Sd = Khong sai d. Ngoi Keo en th Keo g en (A. melanoxylon) cng l mt loi keo vng cao c gi tr kinh t ln, thng cao 10 - 20 m, cao nht c th n 35 m, ng knh c th t 50 cm, cc thung lng m c th t 100 cm. Keo g en c phn b v 16 - 43o Nam, cao 1250 1500 m trn mt bin (Boland, et al, 1984). G ca Keo g en thng c mu en nh g mun ca nc ta, nn l loi cy c gi tr lm mc v m ngh. Nm 2000 B NN&PTNT c quyt nh s 4260/KHCN- NNTT cng nhn cc xut x Bodalla v Nowa Nowa ca Keo en (A. mearnsii) cng nh xut x Mountain Mee ca Keo g en (A. melanoxylon) l Ging tin b k thut trng trn cc lp a vng ni cao ca nc ta. 1.1.3. Cc loi keo chu hn Vit Nam l nc c din tch ct ven bin kh ln, trong c mt s vng Bnh Thun v Ninh Thun c lng ma hng nm ch t 600 - 800 mm/nm. V th vic kho nghim mt s ging cy thn g chu hn trng trong vng l rt cn thit. Ngoi ra, mt s i ct vng Trung B ni tuy c lng ma khng thp song do i ct cao, nc ngm qu thp nn cy trng khng th s dng, cng cn c loi cy trng thch hp chng sa mc ho. Kho nghim cc loi keo chu hn c xy dng ti Tuy Phong thuc tnh Bnh Thun. y l mt trong nhng ni c lng ma thp nht nc ta, lng ma hng nm thng khong 600 - 800 mm v ch tp trung trong mt thi gian ngn (thng l thng 5 v cc thng 9 - 10), nhiu thng c lng ma rt thp hoc hon ton khng c ma, trong lc lng bc hi li rt ln. y cng l ni c c ba dng ct khc nhau l ct vng ven bin, ct trng di gia v ct pha trong c tui c nht (L B Tho, 1977), trong ct trng l nhm ngho cht dinh dng nht. su 0 - 20 cm ct trng ch c 0,07 - 0,5% mn v di 0,01% m tng s, trong lc ct c cc ch tiu trn tng ng l 0,3 - 1,3% v 0,02 - 0,06% (Hong

31

Xun T, 1996). t nng nng v kh hn ca nhng thng cui nm 1997 v na u nm 1998 lm cho hn 400 ha Keo l trm b cht hn v 500 ha b kh ho nng, trng thi gn cht. V th, kho nghim chn loi cy c kh nng chu hn cho vng ny c ngha ht sc quan trng trong chng trnh trng rng phng h ven bin v chng sa mc ha nc ta. Mi mt loi keo chu hn c phn b t nhin v 12o24'- 23o45', cao 40-400 m trn mt bin, lng ma 387-1280 mm/nm ti Australia c trng kho nghim vo thng 9 nm 1993 ti Bu l vng ct trng kh hn in hnh ca Tuy Phong (Bnh Thun). y l ni c a hnh tng i bng phng, ni cao nht v ni thp nht cch nhau 0,5 m. Trong cc nm 1990-1992, ti y trng th Keo l trm song b cht, nn thng 9 nm 1993 khu vc ny c dng kho nghim cc loi keo chu hn. Kho nghim c trng theo khi 30 - 50 cy (tu theo s cy c c ca mi l ht) v c lp li ngu nhin 4 ln. Khong cch h trng 2 x 2 m, mi h bn lt 1,0 kg phn chung hoai. Cc ch tiu c nh gi trong kho nghim l t l sng v sinh trng. - T l sng T l sng l ch tiu quan trng nht khi nh gi kho nghim cc loi cy chu hn. Nhiu loi cy c gi tr kinh t cao, song khng th gy trng trn cc vng t kh hn v b cht ngay trong v kh hn u tin. Kt qu kho nghim ti Tuy Phong cho thy sau khi trng 10 thng cc loi cy vn gi c t l sng rt cao (74,9 - 93,0%) v khng c s khc nhau ng k gia cc loi. Sau hn 2 nm (giai on 26 thng) t l sng ca mt s loi bt u gim xung v cng xut hin s khc bit ng k gia cc loi. Nhng loi c t l sng thp nht l Mung en (42,5%), A. longispicata (40,4%), Keo l trm (51,4%) v A. elachantha (52,8%). Nhng loi vn duy tr c t l sng cao l A. torulosa (88,5%), A. cowleana (87,5%), A. holosericea (86,7%) v A. neurocarpa (81,3%). Sau ma kh hn khc nghit ko di cui nm 1997 u nm 1998 ch cn A. torulosa gi c t l sng 78,9%. Nhng loi c t l sng tng i kh nh A. tumida (47,9%), A. holosericea (40,3%) v A. difficilis (36,0%). Nhng loi c t l sng qu thp nh Keo l trm ch cn sng 5,3% v Mung en ch cn 16,0% (bng 2.7). A. torulosa c t l sng cao nht c th l do c ly t xut x Elliot, NT, ni c lng ma hng nm khong 500 - 600 mm, cn cc loi khc u c ly nhng ni c lng ma hng nm t 600 - 800 mm tr ln (Parkinson, 1984). Tuy vy, theo s liu tnh ton t chng trnh my tnh BIOCLIM ca Booth (1998) th cc loi A. colei, A. cowleana, A. elachanta, A. longispicata, A. neurocapa v A. tumida cng u c ly t nhng ni c lng ma thp di 800 mm/nm. V th cha th gii thch y nguyn nhn ca nhng loi c t l sng thp ti Tuy Phong. S liu bng 2.7 cng chng t vic nh gi t l sng nhng vng c iu kin kh hn c bit v c s thay i gia cc nm th phi qua nhng nm c iu kin kh hu c bit khc nghit (nh nm 1997 - 1998) th vic nh gi tnh chu hn mi tht s c ngha.

32

Kho nghim xut x cc loi keo chu hn ti Tuy Phong tnh Bnh Thun (1993-1998) (nh L nh Kh)

- Sinh trng ca cc loi keo chu hn sau gn 6 nm (70 thng). S liu c o vo thng 7 nm 1999 ti Tuy Phong (bng 2.7) cho thy sau gn 6 nm A. difficilis vn l loi cy c ng knh ngang ngc (22,8 cm) v chiu cao (7,5 m) ln nht trong kho nghim. Tip theo l A. tumida, A. longispicata v A. torulosa. Cc loi keo cn li u c ng knh v chiu cao thp hn r rt so vi A. difficilis. T s liu bng 2.9 cn c th thy ng knh thn cy ca A. difficilis vt A. tumida 66%, vt A. longispicata 88% v bng 2,6 ln A. torulosa. Chiu cao thn cy ca A. difficilis cng vt 3 loi trn tng ng l 14%, 19% v 36%. Tuy vy, nh phn trn trnh by, A. longispicata sau gn 5 nm ch c t l sng 3,8% nn loi ny khng c ngha thc t v trng rng. Khi c tnh th tch thn cy (ly h s hnh dng f = 0,4) c th thy th tch thn cy ca A. difficilis vt A. tumida 37,6% v gp 4 ln A. torulosa, gp 4,6 ln A. holoseracea. difficilis cng l loi sau 3 nm c sinh trng nhanh nht v c t l sng cao hn so vi A. holoseracea ti Ratchaburi ng nam Thi Lan (Chittachumnonk & Sirilak, 1991). T kho nghim Tuy Phong cng c th ni A. holoseracea (thng c gi l Keo l sim hoc Keo mc) hin ang c trng mt s ni ti nc ta cha phi l ging tt nht v tn l tha, cnh nhnh ln v t l sng khng cao. Cui cng, cn ni rng A. difficilis l loi c nhiu thn cy hn A. tumida v A. torulosa. A. difficilis cng l loi c ng knh tn cy (5,8 m) vt hn hn A. tumida (4,4 m) v A. torulosa (4,0 m), v th y l loi c kh nng che ph t rt ln. Tuy vy, A. torulosa l loi c t l sng cao nht, tip theo l A. tumida ri mi n A. difficilis. V th nhng ni iu kin kh hu qu kh hn th nn trng A. torulosa. Mt kho nghim khc v cc loi keo chu hn ti Ba V cng c xy dng t nm 1993. Kt qu theo di n nm 2000 cho thy ba loi cy c trin vng nht vn l A. difficilis, A. tumida v A. torulosa, trong A. difficilis l loi va c t l sng cao nht, va c sinh trng nhanh v tn l pht trin nht. V th, Trung tm nghin cu ging cy rng trng nh mt loi cy tin phong lm bng che ban u khi trng mt s cy bn a nh Lim xanh (Erythrophloeum fordii) v cho kt qu rt tt.

33

-

Mt s nhn nh chnh

nh gi tng hp ton b cc ch tiu v t l sng, sinh trng ng knh, chiu cao v s pht trin ca tn l c th thy nhng loi cy c u th r rt khi gy trng trn vng ct ht sc kh hn ca Tuy Phong l A. difficilis, A. torulosa v A. tumida (Harwood, L nh Kh, Ph Quang in, 1998, L nh Kh, Harwood, Ph Quang in, 1998). Ba V ch nn trng A. difficilis v A. tumida. Cc loi cy ni trn u c bin sinh thi rng, phn b t nhng vng c lng ma rt thp n trung bnh, c th sng trn t ct ln t tht, t nng ln t su, t t chua n t trung tnh v t kim. y cng l nhng loi cy sinh trng nhanh, c kh nng ra chi ln, i sng khng qu lu (Thomson, 1991) nn rt thch hp cho vic s dng lm cy che bng v ci to t cc vng ct kh hn v t i trc. Tuy vy, thc t kho nghim ging trong nhng nm qua cho thy A. difficilis (xut x Lake Evella) l loi c sinh trng nhanh nht trn c t ct kh hn ca vng Tuy Phong ln trn t i trc Ba V, cn A. torulosa v A. tumida sinh trng kh Tuy Phong, song sinh trng tng i km hn trn t i trc min Bc nh Ba V (L nh Kh, Ph Quang in, Harwood, 1995). vng i trc ca cc tnh pha Bc A. difficilis va c sinh trng nhanh va c t l sng 95 - 100% nn rt thch hp lm cy tin phong trc khi trng mt s loi cy bn a. Tuy vy, cn thy rng y l nhng loi keo chu hn nn t c kh nng gy trng nhng ni b ng ngp trong ma ma. Ti vng nguyn sn Australia mt s xut x trong ba loi cy ni trn c th t kch thc kh ln. V d A. tumida c th cao 15 m vi ng knh ngang ngc 45 cm, A. difficilis c th cao 8-12 m, A. torulosa c th cao 12 m (McDonald, 1997). V th, khi c iu kin kho nghim thm c th tm c mt s xut x c gi tr hn cho vng kh hn. Tuy vy, trc mt vn c th a nhng xut x c kho nghim v nh gi vo gy trng th trn din rng mt s vng kh hn nc ta, nhm p ng yu cu cp bch v trng rng phng h hin nay. Cc loi keo c xut cng l nhng loi c gi tr ln cung cp g ci, chng sa mc ha vng ct, chng xi mn v c th chng ct di ng (Doran, et al, 1997), ng thi c th dng sn xut bt giy v vn dm. Bng 2.7. T l sng v sinh trng ca cc loi keo chu hn ti Tuy Phong (1993-1999) D1,3 Tl V Loi v xut x H (cm) 3 sng (%) (cm) (dm /cy) A. difficilis NW Lake Evella NT A. tumida E. Kununurra WA A. longispicata W. Duaringa Qld A. torulosa Elliot NT A. holoseracea Blythe R. NT A. elachanta SE. Hooker Ck. NT A. auriculiformis Boggy Ck. Qld A. colei Turkey Ck. Qld A. neurocarpa Attock Ck. NT A. cowleana Wauhope NT Cassia siamea Bnh Thun VN 36,0 47,9 3,8 78,9 40,3 16,6 5,3 24,3 28,0 34,4 16,0 7,5 6,6 6,3 5,5 4,0 4,8 3,7 4,0 4,0 3,7 1,8 14,8 13,7 12,1 8,8 8,6 7,2 8,2 6,4 5,0 4,8 2,3 53,72 38,92 28,98 13,38 11,62 7,82 7,82 5,15 3,14 2,68 0,30

D tn (m) 5,8 4,4 4,5 4,0 3,6 4,3 3,2 3,6 3,2 3,3 2,2

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Keo l trm l loi khng ph hp gy trng trn cc lp a qu kh hn vng ct trng ca Ninh Thun v Bnh Thun. Trn c s cc kho nghim ny ngy 10 thng 1 nm 2001 B Nng nghip v Pht trin nng thn c quyt nh s 60/KHCN- NNTT cng nhn cc xut x ca cc loi sau y l Ging tin b k thut: - A. difficilis: xut x Lake Evella (NT), Moline (NT), Annie Creek (NT). - A. tumida: xut x Kununurra (WA) - A. torulosa: xut x Elliot (NT) 1.2. Chn loi, chn xut x v xy dng vn ging cc loi bch n Bch n l nhm cy trng ph bin trn cc lp a c dc di 5o cc tnh vng ng Nam B v mt s tnh min Bc. Bch n c cc nh lm nghip ngi Php nhp vo trng th Vit Nam t nm 1930. Hai loi c nhp thi k l Bch n caman (Eucalyptus camaldulensis), Bch n (E. robusta). Trong nhng nm 1950 xy dng c cc khu kho nghim loi cho 18 loi Bch n vng Lt nh Eucalyptus saligna, E. microcorys, E. camaldulensis, E. punctata, E. robusta, E. citriodora, E. globulus, E. botroides, E. maideni, E. longifolia, E. resinifera v.v., trong cc loi E. microcorys v E. saligna c thch ng kh nht v sinh trng nhanh nht ti vng Lt. Sau 40 nm c chiu cao 35 - 40m vi ng knh ngang ngc 50 - 60cm. Kho nghim gn y cho thy i sau ca nhng cy ny vn th hin tnh u vit v sinh trng v hnh dng thn cy. V vy ang c dng lm cy m ly ging pht trin vo sn xut. 1.2.1. Kho nghim loi xut x Kho nghim loi/xut x bch n tng i ng b mt s vng sinh thi trong c nc c thc hin t nm 1980 n nhng nm gn y. ng ch l tng kt v kho nghim xut x Bch n caman (E. camaldulensis) v Bch n tr (E. tereticornis) (Hong Chng, 1996), kho nghim xut x Bch n ur ti mt s tnh vng trung tm min Bc (Nguyn Dng Ti (1994), nh gi tng hp cc loi Bachi n (Hong Chng, 1991, L nh Kh, 1996, Phm Vn Tun v cs, 2000). y ch gii thiu mt kho nghim xut x bch n ng H (Qung Tr) l ni tp hp tng i y cc xut x ca mt s loi bch n quan trng nht. Kho nghim xut x cc loi bch n ti ng H. Kho nghim xut x Bch n c xy dng vo nm 1991 ti ng H (bng 2.8), tham gia kho nghim l cc xut x thuc loi E. urophylla, E. cloeziana v E. pellita, E. tereticornis, E. camaldulensis v E. grandis. nh gi kho nghim nm 1996 cho thy sau 5 nm trng cc loi bch n c trin vng nht trong kho nghim ti y l E. urophylla, E. cloeziana v E. pellita, cn E. grandis tuy c sinh trng nhanh vng cao Lt, song li sinh trng tng i chm vng thp ng H (L nh Kh, 1996). Bch n ur (Eucalyptus urophylla) c nguyn sn Indonesia, phn b t 7o30 n 10o v nam v 122 - 127o kinh ng trn cc dc ni v trong cc thung lng trn cc loi t bazan, dip thch (schits) v phin thch, i khi mc ni vi. Bch n ur phn b cao 300 2960 m trn mt bin (ch yu l cao 1000 - 2000 m), lng ma trung bnh hng nm 600 2200 mm vi 2 - 8 thng kh. Cc o chnh c Bch n ur phn b t nhin l Flores (Egon v Lewotobi), Adona, Pantar, Alor, Wetar v Timor. Ni nguyn sn Bch n ur c th cao 25 - 45 m, c bit c th cao 55 m, ng knh c th t 1 - 2 m (Turnbull & Brooker, 1978; Eldridge v c.s, 1993; Davidson, 1998). nhng ni thp Bch n ur c th mc ln vi Bch

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n E. alba (Martin and Cossalter, 1975 - 1976). Bch n ur l loi cy thch hp vi cc lp a c t su m cc tnh min Bc, Bc Trung B v Ty Nguyn. Cc xut x c trin vng nht cho vng Trung tm min Bc l Lewotobi v Egon Flores (Nguyn Dng Ti, 1994; L nh Kh, 1996). Egon Flores cng l mt trong nhng xut x c trin vng nht Mang Linh v Lang Hanh ca vng Lt (L nh Kh, 1996; Phm Vn Tun v c.s, 2000). Cn vng ng H xut x c sinh trng nhanh nht trong c kho nghim l Lembata (bng 2.10), trong iu kin canh tc cha cao sau 8,5 nm xut x ny c chiu cao 13,2 m vi ng knh ngang ngc 11,4 cm, th tch thn cy 154,4 dm3. Kho nghim xut x kt hp xy dng vn ging cho thy ti Cm Qu t mng lp, ngho dinh dng th Lewotobi (Flores) l xut x c sinh trng tt nht v nhanh hn r rt so vi cc xut x cn li, cn Vn Xun trong iu kin t su trn 50 cm, xut x c sinh trng nhanh nht li l Waikui min Trung o Alor v Uhak ng Bc o Wetar. Kt qu kho nghim xut x cho E. urophylla vng Trung tm min Bc cng thy rng ti Qung Np (Ph Th) xut x Ulubahu cao 150 m ti o Wetar (gn o Alor) c sinh trng tt nht, sau l xut x Alor (c cao 800 - 1200 m), mt s ni khc, khng c s tham gia ca xut x ny th cc xut x Lewotobi Flores v Egon Flores l c sinh trng nhanh nht (Nguyn Dng Ti, 1994). Kho nghim ca Wencelius (1983) ti Cote Divoite cng thy cc xut x c sinh trng nhanh thng c ly t ngun ht cao mt bin thp ti ni nguyn sn Indonesia. E. cloeziana c phn b t nhin 15 - 26o v nam, pha nam bang Queensland ca Australia, cao 75 - 950 m trn mt bin vi lng ma 550 - 2300 mm/nm. Cy cao Bng 2.8. Sinh trng ca cc loi/ xut x bch n ti ng H (1/1991 - 7/1999) D1.3 (cm) H (m) V (dm3) L ht Loi v xut x v (%) v (%) v (%) x x x 1. E. urophylla 23645 Mt Lembata Ido 23081 Mt Egon Ido 23042 Mt Lewotobi Ido Trung bnh 14236 12602 17008 14422 12205 12202 13543 12207 14427 2. E. cloeziana Herberton Qld Helenvale Qld Woondum Qld Cardwell Qld Maitland Qld Paluma Qld Mento Qld Bakerville Qld Black down Qld Trung bnh 11,4 9,3 9,0 9,9 10,5 10,3 10,3 10,3 10,1 10,0 9,6 9,6 9,5 10,0 19,3 21,8 23,2 21,4 20,1 15,2 23,2 20,5 17,7 17,2 21,9 20,6 17,7 19,3 13,2 10,7 10,5 11,5 12,7 11,6 11,6 11,3 11,0 11,0 10,9 10,8 10,7 11,3 15,9 9,1 18,3 14,4 17,9 13,3 14,3 20,4 15,2 11,6 15,3 10,6 9,0 14,2 154,4 84,0 82,8 107,1 136,3 119,2 108,2 101,9 96,8 96,0 90,7 89,1 88,1 102,9 5,7 9,1 9,8 8,19 6,5 7,3 7,8 7,6 7,8 8,1 8,8 8,7 8,7 7,93

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15255 14211 16122 13998 16120 13826

3. E. pellita Kuranda Helenvale Kiriwo Coen Keru Bloomfield

Qld Qld PNG Qld PNG Qld

10,2 10,2 10,1 9,7 8,9 8,4 10,1 8,9 8,8 8,4 8,7 8,8 8,0 7,9 7,5 8,1 8,2 8,0 7,8

18,6 16,8 20,6 17,6 25,2 22,1 18,6 20,1 21,4 19,7 20,4 18,5 22,7 23,1 23,5 21,9 21,9 22,9 27,2 v (%) 22,2 26,1 21,8 23,1 18,2 22,3 22,9

11,3 11,1 11,0 10,9 10,2 9,8 11,1 10,2 10,2 10,0 10,1 10,1 9,1 8,8 8,7 9,2 9,5 9,1 8,7

12,6 14,9 17,4 12,6 17,0 17,2 14,3 17,6 18,6 17,7 18,0 9,7 16,8 25,6 21,2 18,3 17,0 17,5 16,5 v (%) 18,3 15,9 20,2 17,0 15,9 16,8 17,2

100,3 100,3 97,8 95,5 77,5 66,1 99,4 73,7 72,1 69,7 71,8 71,9 58,2 54,3 47,2 57,9 64,8 56,7 53,5

7,9 8,1 8,2 7,8 10,3 11,5 8,01 11,1 10,7 11,1 10,98 9,9 12,6 13,3 14,4 12,6 11,5 12,9 14,4 v (%) 15,7 21,5 22,1 22,5 23,7 29,2 19,3

Trung bnh 4. E. tereticornis 13661 Mt Molloy Qld 13660 Helenvale Qld 13666 Mt Garnet Qld Trung bnh 13289 16583 16723 14838 5. E. grandis Mt Lewis Qld Atherton Qld Paluma Qld Carwell Qld Trung bnh 6. E. camaldulensis 16720 Petford Area Qld 13695 Normaton Qld Nghia Binh VN Loi v xut x 15049 16553 12968 15325 15323 13817 Bullock Creek Qld Wrotham Qld Buderkin River Qld Camooweal Qld Julia Creek Qld Leichardt R. Ql d Trung bnh

D1.3 (cm)

H (m)

V (dm3)

x7,2 6,4 6,2 6,1 5,9 5,5 6,8

x8,6 7,6 7,4 7,4 7,2 6,6 8,0

x45,4 30,3 27,2 25,5 22,3 18,3 38,2

Fpr