evaluation of urban forestry and housing patterns in awka metropolis of anambra state, nigeria

8/11/2019 Evaluation of Urban Forestry and Housing Patterns in Awka Metropolis of Anambra State, Nigeria

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Journal of Environment and Earth Science www.iiste.org

ISSN 2224-3216 !a"er# ISSN 222$-%&4' (nline#

)ol.4* No.14* 2%14

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Evaluation of Urban Forestry and Housing Patterns in Awka

Metropolis of Anambra State, Nigeria

+,++* . /.* (0IENSI* E. +. EEN+JI* E. E.

e"artment of ,eogra"h5 and eteorolog5* 7acult5 of Environmental Sciences* Nnamdi +8i9iwe niversit5

+w9a* Nigeria.!. . 0. $%2$* +w9a* Nigeria.

Abstrat

:his stud5 evaluated ur;an forestr5 and housing "atterns in +w9a metro"olis of +nam;ra State in Nigeria* with

the aim of esta;lishing the trend of housing and ur;an forestr5 < ur;an greening in the stud5 area over a "eriod of

ten 5ears 2%%1-2%1%# and to suggest wa5s of im"roving ur;an agriculture for a ;etter environmental =ualit5 in

+w9a and other cities with high rate of develo"mental "ro>ects < ur;ani8ation. In other to esta;lish this trend* the

linear regression and correlation coefficient of the land use data over the time "eriod was calculated using the

conce"t of housing and ur;an forestr5 as a ;enchmar9. :he data anal5ses confirmed that there is a significant

correlation ;etween housing "attern ur;ani8ation# and the vegetal distri;ution of trees forestr5# in +w9a. +lso*

housing and ur;an forestr5 in +w9a metro"olis is s"atiall5 distri;uted in s"ace? as shown in the results from the

satellite imageries. :he result of the least s=uare regression showed that the rate of forest dis"lacement is as a

result of the increasing structural develo"ment in the stud5 area. :he wor9 thus concluded ;5 recommending the

ado"tion of some tree "lanting techni=ues among ur;an structures and the re"lacement of failed trees ;5 new one

to ;e underta9en ;5 the government* ur;an "lanners* land develo"ers* the communit5 and ever5 individual.

!"# $ntrodution

!"! %akground to Study

r;an forestr5 or ur;an greening is an integrated a""roach to the "lanting* care and management of all

vegetation in cities* towns* townshi"s and informal settlements in ur;an and "eri-ur;an areas. r;an greeningincludes the com"onents of ur;an forestr5* ur;an agriculture or "ermaculture and agroforstr5* shown in the

figure ;elow.

Fig. 1: Urban Agroforest

r;an forestr5 can ;e defined as an integrated a""roach to the "lanting* care and management of trees in ur;an

and "eri-ur;an areas of secure economic* environmental and social ;enefits for ur;an dwellers.r;an agriculture "roduces and mar9ets foods and fuel largel5 in res"onse to the dail5 demand of consumers

within a town* cit5 or metro"olis* on land and water dis"ensed throughout the ur;an and "eri-ur;an area.

!ermaculture is a sustaina;le form of agriculture highl5 a""ro"riate to ur;an areas* and com"rises a s5stem of

farming and gardening that com;ines "lants* animals* ;uildings* water* the landsca"e and "eo"le in a wa5 that

"roduces more energ5 than it uses.r;an agroforestr5 is the com;ination of agriculture and forestr5 on the same land with livestoc9 or cro""ing

enter"rises running underneath a regime of widel5 s"aced trees either simultaneousl5 or in se=uence.

+ll these com"onents can ;e a""lied to im"rove the =ualit5 of environments in the ur;an areas* generall5 in o"en

s"aces. r;an o"en s"ace management is not onl5 confined to "ar9s and roadsides ;ut includes household

gardens* factories* ;usiness areas* mine dum"s* transmission lines* flood "lains* ta@i ran9s* roofto"s* schools*

clinics and churches.r;an forest and trees contri;ute to a ;etter =ualit5 of living environment in cities* for e@am"le ;5 im"roving air

=ualit5 and conse=uentl5 the health of ur;an residents. :he leaves of trees can ta9e u" man5 "ollutants e.g.o8one* nitric acid va"our* nitrogen dio@ide* ammonia* sul"hurdio@ide and "articles aerosols and dust#. Some of

these "ollutants can cause serious health "ro;lems. :rees also "rovide valua;le shading from the sun. +n

Urban Agroforestry

UrbanForestry

UrbanAgriculture


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individual tree can "rovide a sun "rotection S!E# of 6 to 1%* which means a level of e@"osure to ultraviolet

radiation of one si@th to one-tenth of full sun N7 1&&.

05 offering an attractive environment for recreational activities* ur;an forest* ma5 seduce "eo"le with a

sedentar5 lifest5le to ;ecome more active during their leisure time. +ctivities such as recreational wal9ing and

c5cling alread5 have a "ositive effect on oneAs health. +shcroft 2%%2* ,rahn and Stigsdotter 2%%3#.

Just visuall5 e@"eriencing a natural sitting reduces stress* this stress relief is as measured through muscle tension;lood "ressure in green and non-forested environment lrich et al 1&&1#. oreover* viewing or visiting natural

environments com"ared to ;uilt ur;an environments without natural elements after stressful or mentall5 fatigued

situations* "roduces greater "h5siological changes toward rela@ation and faster recover5 of attention-demanding

cognitive "erformances !arsons et al 1&&'#. Besearch has shown that even =uite ordinar5 ur;an green areas

have a stress-reducing influence in ever5da5 life. In Sweden* ,rahn and Stigsdotter 2%%3# demonstrated that the

more often one visit to green areas the less often one re"orts sic9ness from stress.

+ utch research confirmed that the relationshi" ;etween the amount of green s"ace in the living environment

and self-re"orted health is "ositive* even after controlling for relevant socio-demogra"hic and socio-economiccharacteristics e )ries et al 2%%%#.

In "articular* forest edges* which are man5 in ur;an settings* are essential for human aesthetic e@"erience and

visual "erce"tion. + well-designed edge consists of mi@ture of ;ush and tree s"ecies* which have not onl5

aesthetic ;ut also ecological im"ortance Cucas 1&&1#.

r;an greening has /limatic Engineering effects* Ecological 0enefits and enhances +ir Dualit5. If green s"acesand trees are wides"read in ur;an areas* it will "rovide an effective means to im"rove air conditions locall5 and

"rovide shelter from ultraviolet radiation. Nowa9 et al 2%%2#. + recent large-scale stud5 in the est idland

region of England estimated the overall removal rates of air "ollutants ;5 the ur;an forest to ;e nota;le. Stewart

et al 2%%1#. :he availa;le data suggests that "lanting additional trees on land theoreticall5 availa;le for this

"ur"ose could lead to a significant reduction in concentrations of air;orne "articles in the est idlands once

these trees have matured. !lanting of all availa;le land could achieve a reduction of u" to 2% of small air;orne

"articles.

r;an forestr5 moderates and modifies the climatic characteristics of the ur;an areasF one of the "rimar5 causes

of this modification is that in the "rocess of ur;ani8ation* vegetated land surfaces are converted into concrete and

as"halt surfaces Both* 2%%2#. :he tem"erature difference ;etween air a;ove concrete runwa5s and ad>acent

grass can ;e as much as 4%/. :his is due to the reflectivit5 al;edo# differences ;etween the surfaces !omerant8

et al 2%%%#. ar9 "avement materials can store more heat than natural surfaces and lighter-coloured materials

oulas et al* 2%%4? S5nnefa et al* 2%%6#. :rees have considera;le a""lications in the develo"ment of ;etter

ur;an livelihoods and environments. :hese comfort and other ;enefits can ;e affected negativel5 ;5

unfavoura;le human activities e.g. ;ush ;urning* deforestation* use of to@ic chemicals or fertili8ers for various

agricultural "ur"oses and the "aving of the natural environment etc.

5drogra"hs show how ur;ani8ation increases the "ea9 flow intensit5 and =uantit5 during rainfall events. r;an

forests and trees can reduce surface runoff and thus alleviate the strain from the ur;an sewage s5stem and

dam"en "ea9 flows of streams. :he main wa5s that individual trees reduce runoff are ;5F

:he interce"tion of "reci"itation* which is stored and


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:o ;e "recise* ur;an agriculture is an im"ortant as"ect of the ur;an econom5 and the =ualit5 of life in ur;an

areas. It thus ;ecomes "aramount to evaluate the im"acts of housing develo"ment on ur;an forestr5 in +w9a*

where ur;ani8ation is at its "ea9 now.

!"& Aim and 'b(etives

:he main aim of this stud5 is to esta;lish the trend of housing and ur;an forestr5 < ur;an greening in the stud5

area over a "eriod of ten 5ears 2%%1-2%1%# and to suggest wa5s of im"roving ur;an agriculture for a ;etterenvironmental =ualit5 in +w9a and other cities with high rate of develo"mental "ro>ects < ur;ani8ation. :o

achieve this aim* the following o;>ectives were "ursued?

I. to assess the locational "attern and "ercentage distri;ution of ur;an structures in +w9a*II. to assess the locational "attern and "ercentage distri;ution of ur;an forests and trees in +w9a

metro"olis*

III. to assess the s"atial relationshi" ;etween ur;an structures and ur;an forests and trees in +w9ametro"olis and

I). to assess the changes ;rought a;out ;5 the ra"id ur;ani8ation on ur;an forest and trees in the stud5 area.!") *ESEA*+H HP'-HES$S

oF :here is no significant correlation ;etween housing "attern and the vegetal distri;ution of trees in +w9a.

1? there is a significant correlation ;etween housing "attern and the vegetal distri;ution of trees in +w9a.

!". S+'PE 'F -HE S-U/

:he stud5 was focused on the housing and ur;an forestr5 in +w9a metro"olis* targeting to ma" out theforested


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+w9a is "redominantl5 a low l5ing region on the western "lain of the anu Biver with all "arts at 333 meters

a;ove sea level.

+w9a has rainforest vegetation with two seasonal climatic conditions. :he5 are the rain5 season and the dr5

season which is characteri8ed ;5


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there has ;een even less research that investigates ;e5ond the initial distri;ution of trees to consider issues of

reforestation i""erer et al* 1&&%#.

&"& ME-H'/'1'4

:he following data are considered necessar5 for the e@ecution of the researchF

a. :he locational "attern and "ercentage distri;ution of ur;an structures in the stud5 area.

;. :he locational "attern and "ercentage distri;ution of ur;an vegetation in the stud5 area.c. Cand use dataoving over a long interval of time 2%%1 - 2%1%# trend of the time series which refers to the general dimension

in which the time series i.e. the changes in the =uantitative values of the "henomena through time# was used to

descri;e whether there is a significant decrease in ur;an forestr5 due to ur;ani8ation.

In order to find the trend* the linear regression and correlation coefficient of the land use data over the time

"eriod was calculated. :he regression anal5sis "rovides an estimating e=uation which e@"resses the functional

relationshi" ;etween the varia;les housing and ur;an forestr5#. :he visual re"resentation of their relationshi"

was shown in a scatter gram* with forestr5 and housing on the 5-a@is and the 5ear on the @-a@is res"ectivel5. :hee=uation used to e@"ress their linear relationshi" is 9nown as the least s=uare regression thusF

M a ;@

here* a is the interce"t

; is the gradient of the line

OaA and O;A were determined using the following formulas res"ectivel5.

b = xy (x) (y)

n

x2 (x)2

n

a = x - (y) . b

n n

where* @ is the housing and 5 is the rainfall amount and n is the num;er of o;servations.

:he correlation coefficient r# measures the strength magnitude# and directional of the trend. It is e@"ressed as

r = xy (x) (y)

n

x2 (x)2- y2 (y)2

n n

In order to determine whether the correlation coefficient value is statisticall5 significant* the student OtA test was

em"lo5ed using &$ level of confidence thusF

t = r n 2

1 r2

)"! P*ESEN-A-$'N 'F *ESU1-S

)"!"! Assessing t5e loational pattern and perentage distribution of urban strutures in t5e study area

:his was o;tained from two sourcesF the varia;le data from a secondar5 source the National ,eological Surve5#and from the researcherAs fieldwor9. ere* a 1%5ear data on the research varia;les were collected.


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-able .6 Perentage land use distribution for 5ousing and urban forestry in Awka metropolis

ear *esidential

Administr

ative

$ndustry and

+ommere

Hortiu

lture

Agriu

lture

't5er

7egetation

-otal

89:

#! 2' %.3 6 1$. 43 !##

#& 2' & %.3 $.& 1$.1 41. !##

#) 3% 1% 1 $ 1$ 3& !##

#. 3% 1% %.' $.$ 14.2 3&.$ !##

#0 31 1% 1 6.$ 13.$ 3' !##

#; 31 11 1. $ 14.3 3 !##

#< 31.$ 12.$ 2.$ $.$ 14.$ 33.$ !##

#= 32 13 3 $ 13.$ 33.$ !##

#> 34 14 3 $ 14 3% !##

!# 3$ 1$ 3 6 14 2 !##

-otal )!#"0 !!!"0 !;"; 00". !.)"= );&"& !###

!ource: "ationa #eoogica !ur$ey

7rom which the individual data of each varia;le was e@tracted and then the "ercentage distri;ution of the su;-

varia;les residential* administrative and industr5 and commerce# of each "henomena was gotten ;5 summing

the su;-varia;les under the ur;an concrete structures and finding the "ercentage. :hen a""l5ing the final result

to the satellite imager5 to access the visual dis"la5 of the stud5 area with this* an anal5sis is made to access thelocational "attern which was determined to ;e s"atiall5 distri;uted in s"ace.

-able 06 Perentage distribution of urban 5ousing strutures in Awka

ear *esidential Administrative

$ndustry and

+ommere

-otal

89:

#! 2' %.3 )0")

#& 2' & %.3 ) 34 14 3 0!

!# 3$ 1$ 3 0)

-otal )!#"0 !!!"0 !;"; .)=";

!ource: %esearcher&s work.

)"!"& Assessing t5e loational pattern and perentage distribution of urban forest and trees in t5e studyareas

:his is similar to what was done for the ur;an structures a;ove. It also entails e@tracting the numerical varia;les

for ur;an forest and trees from the 1% 5ear data gotten from the National ,eoha8ards and then calculating the

"ercentage distri;ution of the su;-varia;les of ur;an forestr5 orticulture* agriculture and other vegetation#.


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-able ;6 Perentage distribution of urban forestry in Awka

ear Hortiulture Agriulture 't5er 7egetation -otal 89:

#! 6 1$. 43 ;."

evaluation of urban forestry and housing patterns in awka metropolis of anambra state, nigeria

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