Cây xanh đô thị

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Q U Y H O A C H KIEN TRUC & HA TANG

C a y x a n h

d o t h i

Nguyen Th) Thai Thanh

ABSTRACT

Urban verdure is the requirement for
environment and living quality

improvement for urban citizens.
Arrangement of verdure lines for
streets and urban green spaces such as
green public gardens, parks, isolating
verdure lines... is for maximum
devel-opment of urban natural beauty, to
make the city specific images and to
serve the living essential needs. The
factors that affecting to urban verdure
are climate, water, earth environment,
light, insects... Research for choosing
plant varieties in city and necessary
solutions for plant caring, is to cope
with the effects of hard urban
environ-ment

KTS Nguyen Thj Thai Thanh
TrUcrng Cao dang Xay dimg Cong

trinh Do thj

Yen Thudng - Gia Lam - Ha Noi
Oi dong 0983782833

001 OIEU VE CAY XANH DO THI
Cay xanh dd thi dtfpc ndi den
nhieu nhU: Td chdc cay xanh cho
cac tuyen phd, cdng vien, vudn
hoa, nhu the se khai thac dupe tdi
da ve dep canh quan thien nhien
trong dd thi.

Trong quy hoach, cac khdng
gian xanh dupe coi nhu la phdi cua
thanh phd, la mdt khdng gian chdc
nang thanh phd ban tang cho cU
dan dd thi de hp cd co hdi ddi khdi
nhUng khdi be tdng den de tha
minh trong hdn dao xanh cua thien
nhien, tan hudng khdng khi trong
lanh hiem hoi cua dd thi.

Trong kien true, cay xanh dupe
thiet ke lam phdng nen cho cdng
trinh nhd mau sac sinh ddng va cac
Idp cay tao khdng gian cd chieu sau
giup cdng trinh hda nhap vdi thien
nhien.

Bd tri cay hpp ly se che nang tdt
ma van dam bao chieu sang ttf
nhien cho cdng trinh va ddn dtfpc
gid mat vao mua he, chdng dtfpc
gid lanh vao mua ddng.

Thanh cdng trong viec khai thac
va td chdc cay xanh trong dd thj tao
nen sac thai rieng cua khdng gian,
gdp phan lam tang ve dep canh
quan va tao dupe hinh anh rieng
cua thanh phd.

BAN BIET GIVE CAY XANH?
Theo nghien ctfu cua vien
nghien ctfu cay xanh Canada (FCA),

mdt cay khde manh cd the hap thu
khoang 2,5 kg C02/nam, mdt cay
trUdng thanh cd the hap thu ttf
3000 den 7000 hat bui/m3_khdng
khi. Mdt cay trtfdng thanh cd the
cung cap Itfpng 02 can thiet cho 4
ngtfdi.

Theo nghien ctfu cua Dai hpc
Michigan State University, Urban
Forestry, stf hien dien cua mpt cay
d gan nha giam 30% Itfpng khdng
khi d nhiem. Mdt cay trtfdng thanh

hut mat 450 lit ntfdc trong da't rdi
lai tra ve khdng khi dtfdi dang hoi
ntfdc de lam mdi khdng khi. Mdt
cay phong cd dtfdng kinh 30cm,
trong mdt mua nd cd the hut dtfpc
Itfpng chat kim loai nang trong dat
nhtf 60mg cadmium, 140 mg
chrome, 820mg Nickel, va 5200mg
chi.

Theo mpt nghien ctfu cua My ve
gia trj dat d thi stf hien dien cua
mdt cay lam tang them 18% gia trj
mdi trtfdng.

Cay co ldi ich gi?

Trong bdi canh toan cau ndng
len va mdi trudng do thj dang tao
thanh nhtfng dao nhiet, thi cay
xanh la stf can thiet de cai thien mdi
trtfdng va chat luong cudc sdng
nhU: cay xanh lam giam Itfpng khi
C02, nhu ngan bui, giam tieng on,
giam nhiet bang each tao bdng
mat va chdng gid bao. Co the tiet

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kiem chi phi dieu hoa va sudi am
nhd trdng cay xung quanh cdng
trinh xay dpng. Cay giup chdng xdi

mdn va gitf da't. Cay tao nen phong
canh, cung cap noi cd tru, thdc an
cho cac loai chim va bao ve cd dan
thanh phd.

Ly do trong cay trong do thi
7. Cdy cd<i> tdc dung vdi tdm ly </i>

Mau sac cua cay lam giam bdt
hanh vi trong cudc sdng. Chung ta
nhan thay rang, cay trdng d benh
vien giup benh nhan hdi phuc sdc
khde nhanh han.

<i>2. Cdy cd tdc dung vdi khdng khi </i>

Cay hap thu C02 va thai 02 giup
khdng khi trong lanh.

Cay hut nddc dddi Idng da't va
tra lai khdng khi dddi dang hai
nuac lam khdng khi mat me han.

La cay va than cay can giu bui va
lam giam am thanh, tieng on thanh
phd. Nha't la loai cay cd vd san sui
va la thd rap, bui bam lai cay khi
mUa xudng "cat bui lai trd ve vdi
cat bui".

Trdng cd tren san da't hoac bai
da't trdng se ngan bui sinh ra td da't
vao mdi trudng.

<i>3. Cdy cd tdc dung Idm sach mdi </i>
<i>trUdng ddt </i>

Mdt so loai cay than gd cd kha
nang hap thu dupe cac chat kim
loai nang trong da't d nhiem nhu
chat Pb, Cd, Co, Zn, Cu nen cay cd

Arbre-Paris
the lam giam dupe cac chat ddc hai
xam nhap tdi ngudn nddc ngam
khu vUc dan cU.

<i>4. Cdy cd tdc dung ngdn tieng on </i>

Am thanh phan xa qua lai nhieu
lan qua cac tan cay se giam lupng
am thanh dang ke. Vi vay, thiet ke
cac Idp cay trdng xen ke cay bui,
cay tha'p tang va cay cao de giam
bdt am thanh den cac cdng trinh.

<i>5. Cdy cdi thien he sinh thai </i>

Tao dieu kien cU tru cho chim,
cdn trung, va cac ddng vat khac.

ThUc te la so lupng cac loai chim
khac nhau tuy thudc vao cay trdng.
Cac yeu td anh hudng den cay
xanh do thj

7.<i> Khi hdu </i>

<i>Do</i> la nhiet dp va dp am khdng
khi.

Mua he, anh nang chieu xudng
be mat be tdng (cdng trinh, san,
dudng, he phd'...) va phan xa len
than va la cay lam cay ndng han
nhu'ng cay trdng d khu vpc ndng
thdn.

Mua ddng, thdi tiet khd hanh,
gid lua thudng xuyen, dp am khdng
khi it nen cay thie'u nUdc, dat khd
lam giam kha nang hut khoang
chat cua re cay. Vi vay, cay xanh dd
thi thoat hoi nude manh han cay
xanh trong khu vuc lam nghiep tu
nhien.

<i>2. Mdi trUdng nUdc </i>

Nude rat can cho cudc sdng cua
cay, d dd thi chat lupng va luu

lupng nUdc han che, bdi hau het be
mat san vudn dudng phd deu la be
tdng, mat dp xay dung cdng trinh
trong dd thi Idn, nen khi mUa
xudng khdng chay tran tren mat
da't va tham xudng da't nhu d mdi
trudng tu nhien, ma phan Idn nude
mUa se thoat vao he thdng cdng
cua dd thi, chi cd mdt phan rat nho
dupe tham xudng Idng dat de nuoi
cay.

<i>3. Mdi trUdng dat </i>

Chat lupng cua dat rat quan
trong cho cay trdng:

- Da't nhieu se dam bao sU gan
ket va try vUng cua cay de chdng
lai gid bao.

- Da't gitf nUdc, gid dupe chat
dinh dudng can thiet cho su tang
trudng va sU sdng cua cay.

- Da't cho phep he thdng re cay
hd hap nhd vao dp tai xdp.

NhUng trong cac khu vUc do thj,
dat ngheo chat dinh dudng, chat

hep va bi nen chat bdi cac mang
khdi be tdng cua cac tda nha, san,
dudng va via he, Van de nay da
ngan can re cay di chuyen vao
trong Idng da't, va khd khan de hut
cac khoang chat.

Ben canh dd, d nhiem moi
trudng da't dang la van de, cac chat
ddc hai td cac cdng trinh nha d, nha
may, cd the la thai true tiep cung co
the chi do rd ri da cd nhu'ng anh
hudng den sU sdng cua cay nhU
rung la, benh, chet.

<i>4. Anh sdng </i>

Cay ludn true tiep tiep xuc vdi
cac tia cdc tim ngoai trdi, ddi khi tac
ddng cua thdi gian chieu nang ca
ngay cdn gay nguy hiem cho cay
khdng kem tac hai cua cudng dp
chieu nang.

Ngoai ra mdt anh hudng tren
mdc binh thudng den sir phat trien
cua cay xanh tren dudng phd chinh
la anh sang nhan tao tu cac cdt den
cao ap dpc theo duang giao thdng,
trong cdng vien va trong cac khu

vUdn dao khac.

5.<i> O nhiem khong khi </i>

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TL/ NHIEN

Thoat ho'i nifdc
binh thudng

Re cay phat trien tot

DO THI

Thoat ho'i nu'o'c manh

•
i_{_7__i}

Re cay kho phat trien

0 nhiem khong khi cung la yeu
to anh hudng nghiem trong den
sdc song cua cay. Nhucac khi NO va
N02, CO, S02.

Khu vdc do thi, 6 nhiem dpc hai
chu yeu la do khi thai td 6 to (N02),
nhdng dac biet la nganh cong
nghiep (S02). Bui khdi den bam vao
than, la cay ngancanspquang hpp.

<i>6. Sau benh </i>

Hien cd cac loai cdn trung, ray
nau va cac benh nam do vi khuan tan
cdng cay trdng. Cdn trung va sau
benh khdng nhu'ng an pha cay ma
cdn truyen tai cac benh nam den cay.

CHAM SOC NHUNG CAY XANH TRONG DO
TH| NHI/THE NAO?

Dd thi khdng phai la mdi trifdng

ly tddng de cay cdi phat trien tp
nhien, tham chi do cdn la mdi
trddng khac nghiet va day nhdng
han che ton tai, vi vay cay trdng
phai chpn de cd the dd'i phd vdi
thdi tiet, vdi chat Idpng mdi trddng
sdng dd thi de phat trien khde
manh.

Tru'dc het phai chon gidng cay
trong cho do thj

Gid trong mdi trddng tu nhien
yeu hon nhd vao sU san sui va ram
rap cua cay cdi, nhung trong dd thj
lai thudng xuyen cd gid lua, sdc gid

Idn nha't la mua mUa bao, vi vay cay
trdng trong dd thi, dac biet la cay
tren dudng phd phai cd re bam sau,
than cay khi trudng thanh phai Idn
va cay phai khde manh.

CS Phap, do yeu cau cua thiet ke,
nen nhdng cay bdng mat trdng
thanh hang thudng xuyen dupe
chinh sda hinh dang, do la ngudn
gdc dan den tinh trang sdc khde
cua cay xa'u di. VI vay, de tranh anh
hudng den sdc khde va giam bdt
kinh phi cho viec cat tia tao hinh
cho nhung cay phat trien qua khd,

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chung ta nen chpn nhu'ng loai cay
co sure khoe, thich nghi vdi moi
trudng cu the td gidi han kich
thudc, den kha nang hda nhap khi
hau mdi trudng giup cay phat trien
dupe d dia hinh chat hep khdng
cho phep cay phat trien qua kho
trong dd thi.

Cham sdc cay xanh do thj

Ddi phd vdi nhu'ng anh hudng
cua mdi trUdng dd thj khac nghiet,
cay xanh khdng tranh khdi su can

cdi va tam vdc cua cay be nhd hon
rat nhieu so vdi cay xanh trong mdi
trudng tu nhien.

<i>1. Cham</i> sdc<i> theo cdc chu ky phat </i>

<i>trien cua cdy xanh do thi </i>

Trong mdi trudng dd thi, Cac
chu ky phat trien cua cay van cdn
tuong tu nhu trong mdi trudng tu
nhien. Vi vay, sU cham sdc va
nhdng tac ddng cua con ngudi van
duy tri tuan thu vdi cac chUc nang
sinh hpc va dap dng cho mdi giai
doan phat trien cua cay.

• Hau het cay xanh trong thanh
phd dupe sinh ra td cac vddn uam,
cay thudng luu lai vudn uam
khoang td 5 den 20 nam va trong
quang thdi gian do, re va hinh dang
cay dupe tdng budc hinh thanh.

• NhUng cay chua trddng thanh
dupe trdng trong thanh phd, do la
ly do no dupe cham sdc dam bao
phuc hdi td't de phat trien hai hda:
No dupe tudi nude thudng xuyen,
cd cpc dd gid cho cay ludn thang

khdng bi nghieng, do dam bao vdc
dang dudng net yeu cau den khi
cay trudng thanh. Trung binh mdi
nam, cay cao them 50cm, va den
khi trudng thanh cay cd so tudi
khoang 30 - 40 nam (tuy vao loai
cay)

• Mdt vai nam sau do, cay
trudng thanh va khdng ddi hdi bat
ky cham sdc dac biet nao.

• 0 cudi chu ky, chat lupng go
suy giam, va cd rat nhieu thanh
phan gd chet, cay bat dau thu hut
ray nau va trd len nguy hiem dd'i vdi
cU dan dd thi. Luc nay cay ddi hdi
phai dupe cham sdc dac biet vdi

kinh phi Idn de got bd phan go
chet, cat bdt canh la qua gia, va
trang bj he thdng day bao ve de
phdng trUdng hop gay canh khi
mda gid tranh gay nguy hiem cho
cd dan dd thj.

2.<i> Trdng vd chdm sdc cdy xanh </i>

<i>do thi </i>

<i>m</i> Dd'i vdi dudng phd, cay trdng
phai gid mdt khoang each nha't
djnh dd'i vdi lan dudng xe chay nhu
each diem giao cat dudng khoang
6m den 10m; each bd via 0,3 den
0,5m. Khdng nhung de tranh che
tam mat ngudi tham gia giao
thdng, khdng che khua't bien chi
dan tren dudng phd ma cdn giup
cay tranh thuang tich, tranh va dap.
• Khoang each td't nhat giifa hai
cay gan nhau tuy vao dac diem cua
tdng loai cay va thudng each xa
hon 3m.

• GiQ am cho dat, bang each tan
dung nude mua, nude thai sinh
hoat da qua xd ly tudi cho cay xanh
theo djnh ky hoac hang ngay nhd
vao he thd'ng tudi cay tu ddng hoac
cac vdi phun cua cac xe bdn
chuyen nganh.

• Phun thudc trd sau benh dinh
ky, nhung phai dam bao khdng anh
hudng den sdc khde ngudi dan.

• Cat tia nhung canh la d dp cao
dddi 7m; nhu'ng canh cd anh
hudng den cac cdng trinh xay

dung, den he thd'ng dudng day
dien va cat bd nhu'ng canh cd kha
nang bj gay (muc, mpt, sap gay)

• Thay cay mdi cd kich cd tuong
dng vdi cay bi chet hoac mat

• Duy tri va phat trien nhu'ng
cay di san.

• Cay ludn phai dd'i phd vdi he
thd'ng dudng dng ha tang ky thuat
dd thj nhU: cap dien thoai, dudng
ong cap, thoat nude va rat nhieu
nhu'ng yeu to khac, vi vay trudc khi
trdng can phai tinh toan dp tru cho
cay trdng d dung nai va cd tinh
toan den kha nang phat trien va
chiem hdu khdng gian trong tuong
lai nhd nghien cdu tudi thp, tudi
ngung phat trien va hinh dang cua
cac loai cay.

<i>3. Bdo ve cdy xanh do thi: </i>
<i>m</i> To chdc tuyen truyen ve vai
trd, tac dung ciia cay xanh dd thi
ddi vdi ddi sdng, van hda cua dan
cu dd thi.

• Thiet lap cac nhdm cdng tac

bao quan va gin gid cay xanh dd
thi. thudng xuyen theo ddi tinh
trang sdc khde cay xanh

• Mpi ngudi deu cd trach nhiem
giir gin va bao quan cay xanh do
thj.

• Trang bj nhu'ng cdng cu de
bao ve su tan cdng ciia con ngudi,
phUOng tien giao thdng va ddng

vat den cay. •

TAI LIEU THAM KHAO

1. Bourgery, C. et Mailliet, L. 1993.
L'arboriculture urbaine. Collection mission du
paysage. Institut pour le Developpement
Forestier.

2. Buntinx, B.1998. Methodes
non-destruc-tives d'estimation de la vitalite des arbres
urbains. Travail de fin d'etudes. ULB.

3.
4. Garance.voyageuse.free.fr/botanique/
programme2006.pdf

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