Tap chi Nghi6n cihi v l Phil tiife, so 2 (100). 2013
IVIOI TRl/CiNG - SINH T H A I
HIEN TRANG CAY XANH DO THI HUE VA CAC GIAI PHAP DE HUE TRd THANH MQI D 6 THI XANH M A U Ml/C
Tran Thi Tuyl't Mai' Trin Ngpc Bay, Trin Vdn Cat"
1. Dglt vd'n d e
Hien nay Viet Nam dang day manh qud trinh dd thi hda vi ddy Id xu thd' phdt trien eua xa hpi diTOng dai. The nhiing, dd thi hda thieu ben vu^g se tdc dpng tieu CLTC dl'n mdi tnrdng sinh thdi. Trong tinh hinh d nhiem mdi trUdng ngdy cdng diln bien xa'u nhir hien nay thi viee xay dUng cdc thanh phd' ed ha tdng xanh diiOc ddc hiet coi trpng. Cdc ly thuyet ve ha tang xanh da nhan manh dl'n npi dung cay xanh dd thi. Tren the gidi da cd nhieu quan diem khde nhau vl tao lap vd bao ve mdi trudng sinh thai trong cac dd thi, nhUng hau het cdc quan diem dlu dl cao vai trd cay xanh dd thi. Cdy xanh do thi (hay cdn gpi Id cay xanh suf dung edng cdng trong dd thi) gdm cay xanh cdng vien, cay xanh vUdn hoa, cay xanh difdng phd', duge xem la mdt trong cdc chi so' quan trpng de thil't kl' xay dimg, ddnh gid dd thi. Theo ddnh gia eua nhieu chuyen gia, thanh phd' Hui' Id mdt trong so' it thdnh phd' cd nhieu cay xanh vao loai nha't niidc ta. Do dd cay xanh dd thi (CXDT) d thdnh phd' Hue can duoc duy tri, bao v6 vd phdt triln theo hiTdng bin viftig.
2. Hi$n t r a n g cay x a n h d6 thi of t h a n h p h o Hue 2.1. Di$n tich dat cdy xanh do thi
Vdo ndm 2005 thanh phd Hue cd 43 cdng vien, diem xanh vdi dien tich 89,3ha vd 54.000 eay bdng mdt cdc loai doe cdc tuyen dufdng vd ede diem dan eo.
Vdi mat dp binh quan 200 cdy xanh/lha (theo TCXDVN362:2005) thi dien tich cd cay xanh dtfdng phd' vd cdc diem dan cii dat 270ha. Nho vay dien tich cay xanh todn thdnh phd' Id 360ha. Vdi dan so cua thanh phd la 326.000 ngUdi, 40.000 sinh vien hpc sirdi vd khoang 40.000 khdch vang lai thi dien tich cay xanh binh quan ddu ngirdi khoang lOm^/ngUdi [6], dat tieu chuan quy dinh trong TCVN.
Bdng 1. Tdng hpp tilu chuan diln tich dd't eay xanh dd thi
Lo9i do thj
£)$c biet I v i l l I l l v i l V V
Ti§u chuan dat cay xanh sii dyng cong cpng (m^/ng)
1 2 - 15 1 0 - 12 0 9 - 1 1 0 8 - 10
Tieu chuan di't c i y xanh cdng vien (m^/ng)
7 , 0 - 9 , 0 6 , 0 - 7 , 5 5,0 - 7,0 4 . 0 - 6 , 0
Tieu chuiin dat cay xanh vUdn hoa (m7ng)
3 , 0 - 3 , 6 2 , 5 - 2 , 8 2,0 - 2,2 1 . 6 - 1 , 8
TIgu chuan dat cdy xanh dt/dng pho
(mVng) 1,7-2,0 1,9-2,2 2 , 0 - 2 , 3 2 , 0 - 2 , 5 Ngudn: TCXDVN 362: 2005 - "Quy hoach cay xanh sd dung cdng cdng Irong cac do thi-Tieu chuin t h i l t k l "
Khoa Dja ly, Trudng D^i hpc Su phgm Hue.
Hpe viSn cao hpP ng^nh D|a 1^, TrUdng Dai hpc SU pham H u i .
Tap chi Nghi&n cdu vk Phat tri^n, s6 2 (100). 2013
Thdnh phd' Hue dang phd'n da'u trd thdnh dd thi loai 1 trirc thudc trung uong nen tieu chuan dd't cdy xanh/ngudi phdi d md'c 12-15m^/ngUdi.
Ndm 2012, thdnh pho' Hue cd 58 cdng vien, diem xanh, 4 vUdn uom vdi tdng dien tich 108,812ha [2], dipn tich dd't cdy xanh tdng 1,2 ldn so vdi ndm 2005.
2.2. Ccf cau cdy trdng cua cdy xanh do thi Hue 2.2.1. Thdnh phdn lodi
Theo cdc nhd nghien cuXi d TrUdng Dai hpc Ndng Lam Hue, cdy xanh d ' thanh phd' Hue rd't phong phu, da dang, vdi hon 143 lodi thupc 54 hp thUc vdt khdc nhau. Trong dd, cdc lodi chiem Uu the nhU sau:
Bdng 2. Thdnh phan lodi cay xanh dd thi chiem UU the d thdnh phd' Hue [2][5]
S£f rupng loai _ , . . . TT ^"^ rt ' A ^ ^ " ' ° ^ '
(ten khoa hgc) CXGT H°ul **^" ^ ' ^ * ^°"*^
~ Caesalpiniaceae ^B Ban, Mdng bo trdng, PhUpng vT, Lim xet, V^ng anh. Go mat. Me, Mdng bd tfm, DiSp cdng, Phupng vSng, Muong trau, Bd egp nude, 6 mdi, Mudng hoa d^o, Mudng Xiem.
2 Arecaceae 11 Cau kieng vang, Cau, Cau tua, Cau trdng, Dodc, Thdt not, DCra, Cp dau, Ke, Lyi, Cau bgng.
3 Moraceae 9 Mit, Mft nai, Si, Da, Da blip dd, Sung, Sanh, GCfa, Bo de.
4 Apocynaceae 7 Su' Th^i, Trdc dto, Dgi 1^ tu, Dgi, Bgch ngpc anh. Thong thien. Hoa sda,
Ho thuc vdt cd sd' lupng lodi hien dien nhilu nhd't d thdnh pho' Hue Id Caesalpiniaceae (16 loai). Sau dd la cdc hp Arecaceae (11 lodi), Moraceae (9 lodi), Apocynaceae (7 loai). Chi tinh rieng 43 loai thupc 4 ho thUc vdt ndy da chiem 30,06% t6ng sd lodi hien ed trong he thd'ng CXDT cua thdnh phd' Hue.
Cdc hp thUc vat khde chi cd tU 1 den 6 lodi.
2.2.2. Cdng dung
Cd the phan biet CXDT d thanh phd' Hue thdnh 4 nhdm theo cdng dung la [5]:
- Cay dn qua vd cho bdng mdt;
- Cay eho bdng mdt;
- Cay cho bdng mdt cd hoa dep;
- Cay cho go vd cd gid tri kinh te.
Tuy theo vung phdn bd' md ty le eua cdc nhdm cay xanh phan theo cdng dung khdc nhau.
Bdng 3. Ty le phan bd' cua cdc nhdm CXDT theo edng dung d thdnh ph^
Hue [2]
TT Nhom cay xanh phan theo cdng dung Vung phan bo
^ ^ ^ DUdng phd (%) Cdng vl6n (%)'*' ^ 1 An qua va bdng m^t 6,8 1,90 2 Bdng mat Se'e 21,50 3 Bdng mat ed hoa d^p 50,4 23,22 4 Cho gd va cd gia trj kinh te gio 1,72
" Trong cdng vien cay eanh ehi^m ty 1$ ldn nhat: 51,66%.
!^ :
Tap chi Nghien ciJu v4 Ph4l tri&, stf 2 (100). 2013
1 2 3 4 5 6
Dio < 10cm 1 0 < DjO < 2 0 e m 20 < D^ < 40cm 40 < Dgg < 60cm 60 < Dgo < 80cm Dioo > 80em
Bang 3 cho tha'y nhdm cay ed edng dung cho bdng mdt ed hoa dep chiim ty le ldn nhd't, nhdm cdy cho bdng mdt chiim ty le khd ldn, nhdm cay dn qua vd bdng mdt, cho go vd cd gid tri kinh te ehi chil^m ty 11 khdng ddng kl. Khi hau cua thanh pho' Hui' cd mua ndng eung Id miia mUa it, thudng xuyen chiu anh hudng cija gid phon tay nam khd ndng, mua mUa ngdn nhUng cd lupng mUa ldn, do dd viee phdt t r i l n rdng rai nhdm cdy cho bdng mdt vd ddc biet Id nhdm cay cho bdng mdt ed hoa dep se phdt huy dUpc tdc dung gidm nhiet vdo mua ndng, giam tdc hai xdi Id, njfa trdi da't dai vdo mCia mUa, dong thdi cdn ldm tdng my quan cho thanh phd.
2.2.3. Tudi cdy
Bdng 4. Ty le cay xanh dd thi d thanh phd' Hue phdn theo dudng kinh than cdy [2][5]
TT PUdng kinh Cgy xanh cong vien (%) Cay xanh dUdng ph6"(%)
60,8 31,5 11,7 15,6 19.0 34,7 4.4 9,8 2.5 2,8 1,6 2,0 Dp tudi eua phan ldn CXDT d thdnh phd' Hue dlu d giai doan tre. Sd lieu
d bang 4 cho thd'y da so' dudng kinh cua CXDT d cd'p Dio, D^O vd D^^,, 3 cap nay chiem den 81,1%. Cap Dioo > SOem ehi chiem ty le rat khiem ton, dac diem nay la kit qua eua cdc yl'u td' tac ddng sau:
- Thiin tai (bdo, Id lut...)
Thanh phd' Hue la vung da't thudng xuyen chiu tdc ddng cua thien tai, mdt so' ndm thien tai diln ra mang tinh chd't "ky luc", "lieh si^' nhU tran bao ndm 1985 da lam gay dd hon 3.000 gd'e ed thu, dot lu ndm 2011 ed 41 eay bdng mat ngd d^, trdn lu ndm 1999 do hi nUdc ngdp sau trong thdi gian dai nen mdt lupng ldn cay xanh bi che't, cdc trdn gidng, Id'e xay ra hang ndm cung gdy thiet hai nhieu eho CXDT nhU tran Id'c ngdy 26/6/2010 da lam hang chuc cay cd thu d bd nam sdng Huong gdy, do...
- Bd thi hda
Thdnh phd' Hue dang day nhanh tie'n trinh dd thi hda. Qud trinh cai tao, ndng cap co sd ha tang diln ra tren pham vi rdng, nhieu tuyen dudng dupe md rdng... nen khdng it cay xanh bi chdt bd (do ehUa dUpc dau tu edng nghe cao phuc vu di ddi cay xanh co thu nhU cdc nUde tien tiln trong khu vUc).
Dl duy tri, bao dam mat dp cdy xanh theo diing tieu chuan, hdng ndm thdnh phd' Hui' dlu to chu'c trdng ddm cay mdi (khoang 5.000 cay/nam) nhUng phan ldn cac cay trong ddm thudng Id eay non. Hien nay cd khoang 6.500 cay xanh dudng phd' tuf 1 dl'n 3 ndm tuoi [2]. NhChig cay xanh ndy ndm tai nhilu khu vUc t r i n dia bdn nhung tdp trung nhieu nhd't Id d cac khu tdi dinh eU.
Tuy vdy, theo khao sdt thUe te cua nhdm tde gia, thdnh phd' Hue van cdn nhieu cay cd thu vd tap trung tai mdt so' khu vUc dd tao nen ve doe ddo eho ediih quan thdnh phd' nhU:
Tap chi Nghan cflu va Phit trifa, sg 2 (100). 2013
- C6ng vien Thuong Bac: 13 cay Nhac ngila tr6n 100 n4m tudi, duftng kinh goc til 0,8-l,2m; 10 cAy ThO't n6't tren 70 nim, 2 cfly B6 dl hcfn 70 nSm, dudng kinh hon 2m.
- Cong vien Kim Dong: 22 c4y DoAc hon 60 nftm.
- Cong vien Til Tuongr 11 cfly Long nao, 1 cfty Ngo dong hon 60 nSm.
- Dueing Le Du^n: 2 cay Xk cU hon 80 nSm tudi, dudng kinh gdc l,2-l,5m.
- Budng 23/8: 17 cSy X4 cU hon 60 nSm.
- Dudng Dinh Tien HoAng, Dinh Cong TrAng moi dudng c6 16 cay Nhan hon 70 nam.
- Dudng Do4n Thi Diem: 18 cay Nhoi hon 70 nSm.
- Dudng Ho4ng Hoa Thdm: 2 cay Gpi tia hon 70 nSm tudi.
- Dudng Nguyen TrUdng To (.dki khoang 1km): 13 cay Long nao, 5 cay X4 cU hon 70 nam, 5 cay Nhac ngua hon 60 nkm...
2.3. Mq.t dQ cdy xanh
Thanh phd Hue co mat dp CXDT thupc loai cao nhung phan bd khong dong deu tren toan dia ban. Theo thdng ke so bo hien nay thanh phd Hue c6 khoang 62.489 cay xanh dudng phd va cay xanh cong vien [2].
Cac tuyen dudng c6 mat dp cay xanh dudng phd rat cao, tinh trung binh cU 10m, nhu dudng Le Loi co 1,8 cSy, Ngo Quyen 2,1 cay, Nguyen TrUdng To 1,7 cay/lOm; cac dudng Phan Chu Trinh, Phan Dinh Phung (d bd nam s6ng Huong)... cung c6 mat dp tuong tir. O b^c song Huong co cac tuyen Le Duan 2,6 cay; Nguyln Trai, Doan Thi Diem, Yet Kieu, 23/8... 2,2 cay; Le Huan 1,91 cay;
Dinh Tien Hoang 1,4 cay... Day cung la cac tuyen dudng c6 nhieu cay cd thu cho dp che phu d mUc td cao den rat cao.
Cac tuyen dudng cd mat dp cay xanh thap nhu Chu Vkn An, Mai Thuc Loan CO 0,8-0,9 cay; Nguyln Thii Hpc, Tran Phu, Vp Thi Sau.. cung c6 mat d6 tuong tu va phan ldn cac dudng thupc loai n^y cfly c6 dd che phu khdng cao.
Co nhieu nguyen nhan dan den mat dp CXDT trpng thanh phd Hue khong dong deu song nguyen nhan co ban la do he thdng ha tang dd thi chUa dUOc ddng bp, nha't la he thdng via he chUa dn dinh. Theo ke hoach, c6 nhijtlg tuyen- dudng se dUpc trdng cay xanh, nhUng khong thuc hien dUdc vi chi mdi md rpng dupc long dudng, chua 14m via h6 (Tran Phu, D4ng Huy TrU...). Tai mpt sd tuyen dudng khic cd via hk nho, hp thdng ha tang ky thuat (tho4t nUdc, dp nude, dien ngam, dien thap sAng, dien thoai...) thi cong thig'u ddng bd, thieu quy hoach, ky thuat han che cung gay trd ngai ldn cho viec trdng, bao ve cay xanh (Dien Bien Phu, I3a Trieu...). Cu the, khi k m le bd via he mpt phan r l cay bi tem gpn, cay cdn it dp bim; hp4c khi 14m he thdng thoat nude, le dudng bi d4o bdi nhieu, 14m cho nen da't bi yeu, cay xanh khd dUng vijfng trong mua mda bao. Nhieu tuyen dudng cd he thdng dudng day dien, ho4c dien thoai di qua thi cay xanh bi ch4t tuy tien khong theo dung phuong ph4p. Theo sd li6u dilu tra, thanh phd Hue hien cd khoang 3.000 cay cd thu cd nguy CO tiem ^n gay dd cao.
Y thdc cua ngudi dan cung 14 nguygn nhan c6 t i e dpng ldn ddn sU phat trien CXDT, chIng han nhu ch4t cay de lan chiem via he, che chSn tuy tien gay thieu hut khdng gian phat trien cua cay...
Tap chi Nghi&n ctfu vk Phat triln, s6' 2 (100). 2013
2.4. Phdi tri bd'cuc cdy xanh
Theo TCVN, trong cay xanh dd thi can bao dam ede tieu chuan:
- Phong phu ve chung loai cdy bdn dia vd cdy ngoai lai, ed ve dep.
- Trdng cay dam bao bd'n mua ed hoa Id xanh tuoi.
- Chpn cay trang tri phai cd gid tri trang tri cao (hinh thdi, mdu sdc, khd ndng cat xin).
Cdy xanh dd thi d thdnh phd' Hue chUa dUpc phdt trien ddng bd nha't Id cay xanh dudng phd'. Nhieu tuyen dudng phd'i tri cay xanh cdn chdp vd, gay md't my quan [1], bilu hien d cdc khia canh nhU cd qud nhieu lodi cay trong mdt tuyl'n dudng (dudng Be'n Nghe trong cdc loai Bdng, Triifng ed, PhUpng, Nhdn;
dudng Hai Bd Trung chi hon 500m ed dl'n 5 loai: Vu siJa, Sao den, Bdng ldng, Sd do cam, Phugng), hodc trdng nhilu loai cay khdng dat cdc tieu chuan eua cdy xanh dd thi (TnJng cd, Bdng, Vu siJa..). Hien nay, tuy ed mat dp edy xanh khd cao nhUng thdnh phd' Hui' van cdn nhilu tuyen dudng cd CXDT khdng bao dam cdc tieu chuan vl sd' lugng, miifc dp eho bdng mdt, kha nang cai tao mdi trudng, kha ndng trang tri, ldm dep cho thdnh phd nhU cdc dudng Tran Phu, Bl'n Nghe, Chu Vdn An, Hung Vuong, Duong Vdn An...
3. HvCdng d e n mQt dd thi x a n h mSu mi^c 3.1. Vai tro cua cdy xanh trong cdc do thi
Cay xanh cd tdc dung tich cUc ve nhilu mat, Id yl'u to' cd kha ndng cai thien rd ret mdi trUdng sd'ng cho con ngUdi [4].
- Chdn gid vd gidm tieng on
Neu tdn phu cua cay chiem 10% ed the ldm giam td'c dp cua gid tir 10-20%.
Vdnh dai cay xanh rpng 29m^, cdy cao 12m ed kha nang lam giam tieng on tren dudng cao td'c tir 6-10 decibels [Envirocast, 2003].
- Cdi thiin chdt luang khdng khi
Cdy xanh hdp thu cdc tdc nhdn d nhiem khdng khi nhU NO^, CO, SOj, Og, khdi, bui..., theo udc tinh ed the lam giam ham lugng khdi bui den 6%
[Envirocast, 2003]. Cay xanh ven dUdng cd the ldm giam sUc ndng cua mat dudng trung binh tCr G-S^C [CUFR, 2001]. Cdy xanh trong mot san rdng trudc nhd cd the ha'p thu hang ndm mdt luong khoang 4,5kg khi d nhilm vd ngdn chdn 150kg CO^ tii khi quyen [CUFR, 2001].
- Cdi thien ngudn nUdc cda cdc thuy vUc
Cdy xanh ha'p thu chat d nhiem tif nUdc chay trdn bl mdt nhd cdc chiic ndng thd'm va loc nUdc mUa thdng qua bp r l vd Idp da't da, luu tru" lai trong ddt ldm giam lugng nUdc tap trung vao nguon nude mdt vd tang trQ lugng nUdc ngam. Mpt cdy xanh pho biln ed kha ndng chdn giuf mpt lugng nude mua trung binh tir 200-290 lit t r i n mot ndm [Envirocast, 2003 vd CUFR, 2001]. Tdn phu cua cay cd kha nang chdn giO" tCf 10-40% lugng mua tuy thudc vdo loai cay vd kiiu mUa [Envirocast, 2003]. Kha ndng tham Ipe vd giO" nUdc mUa cua cdy phu thupe vdo tinh chd't da't dd, loai cdy, ty 11 trung binh khoang 11 cm/gid [Envirocast, 2003].
Tap chi Nghi&n ctfu vi Phdt trign, s6 2 (100). 2013
- Gidm nguy ca xdi Id thuy vUc, ngdp ung dd thi
Cay xanh dn dinh dd't dd bdng bp r l , gdp phdn ldm gidm xdi Id nhd ldm giam tde ddng trUc tie'p cua nUdc mUa dl'n dd't dd [Hartman, 1987]. Tham thuc vdt phia ngodi vCing ven thuy vUc cung gidn til'p ldm gidm xdi Id cho thuy vUc nhd ldm yeu di ddng chdy bl mdt vd gidm lUOng nUdc mUa chdy vdo thuy vuc, han che tinh trang ngdp ung trong dd thi [Envirocast, 2003].
- Bdo vi da dgng sinh hoc
Cdy xanh eung ca'p vung cU tru, nguon thd'c dn cho cdc lodi sinh vat trin can va thuy sinh.
- Gidm chi phi sd dung ndng lugng
Do tdc dung dilu hda khi hdu (ldm mdt vdo mua ndng, ldm d'm vdo mua lanh) cdy xanh cd the ldm giam chi phi suf dung ndng lugng tijf 20-25% hdng ndm eho mdt gia dinh. Cac cay xanh cd dp tuoi tir 10-15 ndm c6 kha ndng giam chi phi dilu hda nhiet dp tir 10-20% [Envirocast, 2003].
- Cdi thien sdc khde tinh thdn cho con ngiCdi
Ve dep eua cay xanh tao tdm ly thoai mdi, giam thieu edng thdng do lao dpng, tang cam gidc hUng phan cho con ngUdi.
3.2. Khai thdc tdc dung cua cdy xanh phuc vu cdi t^o khi hg,u 3.2.1. T&ng cUdng dien tich cd cdy xanh, do che phu cua cdy xanh Td'c dp dd thi hda duge day manh ddng nghia vdi vile thu hep dien tich dat ndng nghiep, tdng diln tich dd't cdng trinh do dd gay bien doi manh Idp phu thue vdt theo chieu hudng suy gidm (neu khdng kip thdi can thiep). Thanh phd' Hue' ed khi hdu nhiet ddi am gid miia vdi ddc diem la. miia ndng it mia, chiu anh hudng manh cua gid phon tay nam khd ndng. Mua lanh am Udt, rpUa nhilu, chiu anh hudng cua gid mua ddng bde lanh. Tdng cudng cdy xanh Id biln phap hufu hieu, r l tien de giam thieu tinh khdc nghiet eua khi hau d thdnh pho' Hue. De eay xanh cho hieu qua cao nhat can dap ufng cac van de co ban sau:
- Bdo ddm ty li cdy xanh theo TCVN
Cdc khdng gian xanh trong dd thi phai gdn ket vdi nhau bdng eac dUdng phd' ed trdng eay va cdc dai eay dl hinh thdnh mot he thd'ng xanh lien tuc. Tdn dgng mpi dien tich da't (ven hd, kenh rach, dai phdn cdch, san thugng nha d...) de phat then cay xanh.
Mufc bdo dam td'i thieu dd'i vdi dd't cay xanh suf dung cdng cdng trong dcfn vi d (tQc tilu chuan dd't cay xanh quy hoach cho mgt khu ddn cU, bao gom sdn choi, vUdn hoa,...) Id 5.000m^ ngodi don vi d la 6-7m7ngadi, ty le da't cdy xanh danh cho nhd d, nha cdng cpng, nhd mdy tCf 20-30% [3].-
- Uu tien phdt trien cdc cdy xanh cd do tdn phd rgng, phdt trien nhanh, kiiu ddng dep
Cdc cay dat yiu cau gom Long nao (tan rdng. Id xanh td't quanh ndm, Id cay CO kha ndng hd'p thu cac ion kim loai ndng (nhU chi) ldm sach moi trUdng), Mud'i (dl trdng, tda bdng td't, kiiu ddng va vdm tan dep), Bdng ldng tim, Bbig
Tap chi Nghi&n culu vk Phit triln, sd' 2 (100). 2013
ldng nUdc (cd ddng dep, than xu xi, it thdng, cdnh nhieu gdn nhu ndm ngang lam eho tan cdy cd nhieu tang), Lim xet cdnh (nhieu cdnh nhdnh mpc da phuong), Lim xet Bdc Bp, Nhac ngUa, Sd'u, Xd cir
3.2.2. Bdo vi cdy xanh
De on dinh mdt dd che phu eua CXDT, van de bao v$ cay xanh can duge dde biet quan tam trong quy hoach, thil't kl' dd thi.
- Quy hoach cdy xanh bin vdng
Gan k i t quy hoach cay xanh vdi quy hoach dudng sa, cdng vidn, khu ddn cU, khu edng nghiep. Tao khdng gian sd'ng thieh hgp cho edy xanh phat trien tu nhiln vd bin viJng.
Iju tien trdng cdc lodi cdy xanh cd tuoi thp cao nhU Sao, Dau, Lim xet, Me, Ddi ngUa, Xd cuf, Cau vua... Dd Id cdc lodi eay ed than to, cao, tdn ldn, go chdc, sd'ng ldu (trin 50 ndm, thdm ehi vdi trdm ndm), khdng trut Id theo mua, sdc la dep, re dn sau, rdng khdng phd le dudng... Bd' tri trong dpc theo ede true Id ldn, khu dan eU cao cap, edng vien, vUdn hoa, eac ddi tudng niem, quang trudng, mang xanh trong khu cdng nghiep... NhUng mang xanh rdng, cao tuong xUng vdi khdng gian rdng se gdp phdn tdn gia tri cdc cdng trinh xdy dUng [1].
- Ap dung tiin bg ky thudt vdo viec trSng vd bdo vi cdy xanh
Chi trong nhflng cay xanh "gid'ng" khde manh, chdc chan sd'ng 100%, da cd bp re td't, dugc tao tan mdt cdch bdi ban, phu hgp vdi vi tri trong trong dd thi. Tao tan giup "ddn" to gdc, ha thd'p vd dUdng he thd'ng nhdnh cap I, H va dieu chinh vira phai he thd'ng canh mang la. Chd'ng hoac budc day chang cho cay mdi trong trong 2 ndm dau de cdy bdm chat re vdo dat. Mat dp trdng phu hgp cho tdlig loai cay xanh phdt trien tU nhien va khi cay da trudng thdnh Ididng giao tan.
Hdjig ndm can tien hanh tao tdn, tia cdnh it nha't mdt lan vao dau mua bao. Viec tao tdn phai dat dugc dp eao quy dinh va tao cho cay xanh can dd'i thudng xuyen. Khi eUa cdnh phdi son bit mdt, de han che co hdi nam benh xdm hai lam mue thdn, mue re cdi.
Dau tu cdng nghi de di ddi nhUng cay ldn, trdnh tinh trang chat bd vd trong lai nhiJng eay non gay han ehe kha ndng sinh trudng, cay phdt trien khdng dong deu, de phdt sinh viec trong dam thay the gay ton kem, mat my quan.
Xay dung quy eay xanh du ldn bdng cdng tdc quy hoach nhdng khu vUe VUdn uom, cdng vien d vung ngoai vi thanh phd' de cung cap ngudn eay xanh phuc vu cho cdng tdc chinh trang dudng phd', nha't la nhihig dudng pho dugc md rpng, nang cd'p.
3.3. Khai thdc cdy xanh trong ton tg.o my quan do thi
Cdc ddc diem ve mdu, hinh ddng cua Id, hoa, than cay... cua cay xanh tao nen nhUng cam thu khdc nhau tuy theo khu vUe phdn bd'. Su phd'i tri gida eac loai edy xanh eung dem lai nhCfng tdc dung tham my khdc nhau. Dde diem eo kinh cua thdnh phd' HUG ddi hdi su tuong tdc phii hgp cao trong bd' tri cay xanh de vLfa bao dam muc tieu cai tao mdi trUdng viia bao dam ve my quan rieng eua thdnh pho'.
Tap chi Nghi&n culu v^ Phdt triln, stf 2 (100). 2013
- Bdo ddm sU phd hgp gida ddc diim cdy xanh vd ddc diim vung phdn bd Cdc lodi Suf cd hoa thom, mdu sdc trang nha... nen trdng canh dinh chiia, khu trien lam; cdy Tiing, Bdch cao, th^ng it rung Id nIn trong d noi trang nghiem; ede lodi Phugng tim, vdng, dd cd mdu sdc dep nen trong ven bd sdng, ho; cdc true dudng nhdnh, cdc cdng vien nhd thudc cdc khu ddn cU, phti hgp vdi ede eay xanh ed tudi thg ddi (tren 30 ndm), thUdng cd r i dn sdu, rgng, cd Id hpa dep..., Id vd trdi rung khdng gdy d nhiem nhU Bdng ldng (bdng tim), Bdng Ddi Loan (tdn Id tao tang), Bd cap nUdc (hoa kit chum mdu vdng)..,
- Ba dgng hda cdy trdng
Moi mpt lodi cay deu cd cdc thdi ky ra hoa, rung Id theo thdi gian khdng gid'ng nhau. Do dd can da dang cay trong (nhUng khdng nen trdng qud nhieu lodi tren cung tuyen dudng de trdnh tinh trang edy eao, thd'p, to, nhd... qud khdc biet, gdy phan cdm) tren nguyen tde phdt huy Uu diem ciia ta't cd cdc lodi cay vd dung UU diem cua cay ndy de han che nhugc diem cua cay kia. Vi du, trong xen Lim xet cdnh (Phugng vdng) vdi Lim xet Bdc Bg (Hodng linh).
- Tdn trong tinh lich sd cua cdy xanh gdn liin vdi lich sd cua do thi Hui Nhilu dudng phd' d thdnh phd' Hue trudc ddy gdn liln vdi mgt loai cay ddc thu ndo dd da tao nen mgt n i t rilng cua vdn hda Hue. Vi nhieu ly do md nhilu noi nhdng lodi cay gdn hen mot thdi vdi thanh phd' (Sd'u d dudng Ben Nghe, Dodc d dudng Dd'ng Da, Me d Pham Ngu Lao, Phugng d dudng Ll Dudn...) bi bil'n md't hoac hi pha tap bdi nhdng loai cay khde. Dilu ndy da pha vd phong each tdn tao vd net rieng cua thdnh phd'.
Di ddi cae loai cay khdng bao dam tinh an todn, tham my, ve sinh... nhU eay Ba dau {Hura crepitans L, loai cd mu doe lam sung mdt, nhdc dau, trdi dn nhieu se bi rdi loan tieu hda, than ed gai, nhdnh gidn de gay); Keo Id tram (Acacia auriculiformis Benth, ed tdn Id ram vd nhdnh de bi tdch khdi than trong mua mUa bao); Dda (Cocos nucifera L, qud to, khi rOi xud'ng gay nguy hiem); Sung (Ficus giomerata Roxb, qua chin thu hut ru6i muoi, gay md't v§
sinh); Triic ddo (khdng an todn cho ngudi vd nguon nUde sinh hoat)...
4. Ket l u ^ n
Dd thi xanh Id hudng phdt trien cua nhan loai. Quy hoach dd thi xanh phai tao ra khdng gian xanh - day Id tieu chuan trudc het eua dd thi xanh.
Thdnh phd' Hue bUde dau dd cd nIn tang khdng gian xanh vd can duge duy tri, bao ve yd phdt trien theo hudng ben vifng. Cdc va'n dl can quan tam dl phat trien bin vifng CXDT d thdnh phd' Hue:
- Xd hdi hda viec trong vd bao ve cay xanh:
Phdt dpng phong trdo trdng eay vd tie'n hdnh dinh ky hang ndm trin cac dia ban dugc cac co quan cd tham quyIn phe duyet; Giao nhilm vu trdng vd chdm sdc cho cdc dodn the, td dan phd' dUdi sU hudng dan ky thuat cua cdn b8 chuyen mdn.
Khuyen khich ngUdi dan trong cdy tren da't d theo quy hoach chung dl trdnh tinh trang ngUdi dan tU y trdng cdc loai khdng bao dam ve mdi trUdng, my quan dd thi hoac cdc lodi cd kha ndng xdm hai ndm trong danh muc ciin.
Tap chi Nghien ciJu vk Phat tri^n, s6' 2 (100). 2013
- Ung dung cdng nghi GIS de bao ve cay xanh. GIS Id edng cu ddc luc de tich hop cdc thong tin ve h i thd'ng cdy xanh hien ed, cung ca'p da lieu de dd'i chieu, so sdnh nhdm dUa ra cdc ke hoach phdt trien CXDT nhanh chdng, kip thdi.
- Cd eac c h i tdi thich hgp de xd ly nhiftig hanh ddng phd hai cay xanh dd thi. Cae quy dinh nIn neu rd nhOng hanh ddng vi pham va cdc tliidt hai gay ra dd'i vdi cdy xanh dd thi vd hinh thdc xuf ly.
T T T M - T N B - T V C TAI LifiU THAM K H A O
1 D 6 XuSn Cdm, 2013. "Tinh da dgng vk vai tro cua nhQng c^y than c^t trong h& thdng cay xanh H u i " , ngudn: v\nflfw.doxuancam.com.
2. Trung tam C6ng vign CSy xanh thanh pho Hue, 2012. Ban tdng hgp cay di/dng phd. cdng vien, diem xanh, khu dinh cd. cic ca quan, trUdng hgc.
3. Nghj djnh 08/2005 v l quy hogch xay di/ng. Quy hoach ciy xanh sd di^ng cong cdng trong cac dd thi'Tieu chudn thidt l<e. TCXDVN 362: 2005.
t. Tran Hi6'u Nhu§, 2011. "Cay xanh vdi m6i tracing do thi - Sy ki$n tfin vinh cay dr san", tap ch(
Xay di/ng va Do thf, s6 23/2011.
5. Pham Minh Thinh, Ton That Phdp, Mai Van Pho, 2002. "Nghien cCru cay xanh do thi trong kien triic cdnh quan cua thanh pho Hue", tap san KHKT Ndng Lam nghiep, TrUdng Dgi hpc Nong Lam T P H d Chf Minh.
u. Oy ban Nhan dan thanh pho Hue, 2007. Bao do sd ket cong tac trong cay xanh thanh pho Hue giai doan 2001-2007.
7. Envirocast, 2003. Urban Watershed Forestry Manual- Part 1: Healthy Communities. Part 2:
Conserving and Planting Trees at Development Sites. Part 3: Urban Tree Planting Guide.
nemonet uconn. edu.
8 CUFR, 2001, Hoi thao Watershed Approach to Forest Conservation. The Center for Watershed Protection, www.sformwafercenter.nef.
TOM T A T
Bai viet danh gia tdng quan ve hien trgng cay xanh do thi d thanh pho Hue di/a theo cac yeu to: Di&n tich dat cay xanh do thj, cd cau cay trdng, mat dp va phdi tri bo cpc xanh. Ket qua cho thay, de co the trd thanh mpt do thj xanh m i u myc, thanh phd Hue mot mat can tap trung cai tao, chfnh trang nhflng khiem khuyet cua mdng c^y xanh do thi hign tai, mat khac, can mot quy hoach ph^t tnen cay xanh hpp ly, vita bao dam yeu cau cua mot do thi xanh hien dgi, vifa phu hpp vdi nhOng net d5c trUng ve thien nhi^n va van hPa cua vung ddt.
ABSTRACT
ACTUAL STATE OF URBAN TREES tN HUE AND SOLUTiONS TO TURN IT INTO A MODEL GREEN CITY
The article presents an overall assessment of current urban trees in Hue city, based on the data on the area of urban trees, plant structure, density and layout of green coordination The results show that, In order to become a model green city, Hue city needs to compensate for the lack of urban trees and to have a reasonable plan of the growth of trees in order to meet the requirements of a modern green city and agree with natural and cultural features of an imperial city.