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Urban Trees and Greens

Where are the trees?

Presentation by Kalpavriksh on the Urban Greens Project

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In a city trees are found in:

City forests, Hills ifany

Parks and gardens

Roadsides ie. avenuetrees

Residential Colonies

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The basic need for Treesto

grow well are:

Free soil space forhealthy growth

Space for roots to

spread Space for the canopy

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Problem Area 1: Tree roots are notvisible and hence tend to be neglected

Trees have deep as wellas lateral roots

Lateral roots spreadhorizontally as far as thecanopy spreads (Thumbrule)

Roots need soil air andwater that nourish thetrees.

Lateral roots areconcentrated just beneaththe surface soil.

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Problem Area 2: A pavement is usuallya narrow strip of space for pedestrians

and trees. This space is left as free soil space

or is cemented with concrete. Concreted pavements severely

restrict root aeration and water

percolation. In summer they become very hot

during the daytime and the lateralroots get scorched in the process.

During monsoons, deep roots aregenerally submerged in water andthe aerial roots have to do all theroot aeration.

Cementing prevents this rootaeration and trees die duringmonsoon, a time when theyshould be flourishing.

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Problem Area 3: Concreting/Cementing of pavements leads to:

Large scale tree deaths

More flooding of roads during monsoon Prevention of groundwater recharge

Huge amount of malba if dug out causing

disposal problem.

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The process of Cementing/Concreting of pavements also

involves: Removal of the top soil whichis most fertile and nutrientrich, to make space for thecement concrete mixture.

Cutting off the lateral rootswhich are concentrated in thetop soil.

Use of Stones/ bricks,cement, tiles, badarpur which

are all eco degrading High Expenses. Cash strappedmunicipalities divert funds forcementing as a priority

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Materials and resources used incementing/concreting

Stones/ bricks, cement, tiles, badarpur are all ecodegrading.

Rocks are mined and broken into stones. Mining theAravallis is a serious eco- problem. Stone crushingand rock breaking cause severe air pollution. Tilemaking is highly energy intensive. Cement mfg. .

Concreting is also a very expensive moneywise. Cashstrapped municipalities divert funds for cementing asa priority.

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Bird diversity in a city depends

on : Geographical location The type of natural

vegetation present

The type of cultivatedvegetation present.

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Parks and Gardens will attract varietiesof birds only if they have :

Native trees Bushes, shrubs and

hedges

Climbers and vines

Undergrowth

Reeds/ Groundcovers

Grassy patches

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In the present Urban Scenarioall parks andgardens are being:

Planted with only ornamental trees that havelittle utility for birds.

Landscaped with high-maintenance lawns

Tiled with cemented pathways that are notuseful for jogging and daily walkers

Enclosed with high stonewalls with grill workinstead of green hedges.

Provided with avoidable lighting and uglyfountains.

Provided with shops which further reduces the

green space

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Ideally a park should be left

undisturbed as far as possible: The native vegetation alongwiththe undergrowth should not becleared and replaced withornamental plants. The cost ofupkeep and water/ manurerequirements rise steeply.

Walkpaths should not becemented Construction with cement/

concrete and steel should beminimal

Each park should have its uniquecharacter and designs should not

be homogenized. Lighting should be only throughsolar energy

Fallen leaves and other greenwastes should be compostedwithin the park itself

Water harvesting designs must beintegrated.

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As corrective action (Delhi), since mostroads have negligible pedestrian movement

whereas vehicular load is heavy

On the few roads with heavy pedestrian load, sidewalksmay be concreted with porous tiles after leaving sufficientspace around tree base

On most roads with low pedestrian load, the sidewalksshould be left green and grassy with no cemented work.On many such roads, including colony roads, that havealready been cemented, the tiles need to be uprooted andreplaced with greenery.

Central verges not to be cemented but have runninghedges to prevent headlight glare and pedestrian crossing.

Water harvesting on roadsides to benefit avenue greenery

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Other points

All parks should be parks of Indian Diversity (In Pune for e.gthere is a Japanese Garden which has been made at a hugeexpense of more than a couple of crores of rupees)

Wild grass on roadsides are best to prevent dust. These

should not be uprooted as is the general practice. Trees should not stand alone and must be interconnectedwith hedges and grasses

Excessive pruning and lopping of trees and hedges/ shrubs

should be avoided especially in the wrong season. Space between boundary walls and roads should not be

cemented.

There is no reason to cement driveways

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Thanks