roadside landscape

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ROADSIDE LANDSCAPE CONTENTS VALUE OF ROADSIDE LANDSCAPE KEY PLAYERS IN ROADSIDE MANAGEMENT LANDSCAPE VEGETATION MANAGEMENT PROCESS ROADSIDE GRADING LANDSCAPING ELEMENTS AND FIXED OBJECT LOW GROWTH VEGETATION FUNDAMENTAL PRINCIPLES MINIMISING DISTURBANCE PROTECT VEGETATION MANAGE WEEDS MINIMISE SOIL EROSION VALUE OF GOOD ROAD LANDSCAPE KEY ISSUES OF ROADSIDE LANDSCAPE FIRE MANAGEMENT

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value of roadside landscape, its management ,the services , landscape elements , roadside grading ,etc.

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Page 1: Roadside Landscape

ROADSIDE LANDSCAPE CONTENTS

VALUE OF ROADSIDE LANDSCAPEKEY PLAYERS IN ROADSIDE MANAGEMENT LANDSCAPE

VEGETATION MANAGEMENT PROCESSROADSIDE GRADING

LANDSCAPING ELEMENTS AND FIXED OBJECTLOW GROWTH VEGETATIONFUNDAMENTAL PRINCIPLESMINIMISING DISTURBANCE

PROTECT VEGETATIONMANAGE WEEDS

MINIMISE SOIL EROSIONVALUE OF GOOD ROAD LANDSCAPE

KEY ISSUES OF ROADSIDE LANDSCAPEFIRE MANAGEMENT

Page 2: Roadside Landscape

VALUE OF ROADSIDE LANDSCAPE :

Roadsides are often the only place where remnant vegetation or species of rare or endangered plants are found which have great value for nature conservation.

In addition to their natural features, roadside areas have value for historic and social reasons.

It is common to find survey markings on trees, old bridges, ceremonial tree plantings and aboriginal sites within the road reserve.

Travelers use the shade and amenity of roadsides, especially travelling long distances.

Collectively these features of roadside landscape can contribute to the tourism value of a region.

VEGETATION MANAGEMENT PROCESS

ROADSIDE MANAGEMENT FRAMEWORKRoadside management principles

Roadside vegetation management plans

ROAD CONSTRUCTION PRACTICE

Code of practiceMinimising disturbance

Topsoil strippingCleaning machinery.

ROAD MAINTANANCE PRACTICE

Code of practiceNatural regeneration

Weed controlMowing practice

Fire managementTree removal and pruining

Machinery use.

KEY PLAYERS IN ROADSIDE MANAGEMENT LANDSCAPE

The department of main roads, local government authorities and the community are the key players.

The department of main roads is responsible for construction and maintenance of all state-controlled roads.

Within the department, road construction and maintenance involves planners, design, construction and management managers, and construction and maintenance gangs.

The department may however, transfer maintenance responsibility to the local government once a road is constructed.

LANDSCAPING ELEMENTS & FIXED OBJECTS

Landscaping elements may consist of natural as well as manmade features, e.g., groundcovers, flowers,trees, and pavers.

Many of these features such as most groundcovers and pavers allow a vehicle to safely pass over them and, therefore, do not pose a significant risk to an errant motorist.

However, other features may be considered fixed objects and are, therefore, potential safety hazards.

In general, a fixed object is any object that cannot be driven over safely by an errant vehicle.

ROADSIDE GRADING

Since operational safety can be affected by the landscape, a continuous length of the highway must be visible to the driver (sight distance) and a lateral run out area (clear zone) must be traversable and free ofphysical obstructions.

Clear zones provide areas for drivers of errant vehicles to regain control after running off the road.

Setback distances are measured to the face of the fixed object from the traveled edge line of the adjacent roadway.

For facilities with curb and gutter, setback distances are measured from the face of curb to the face of the object. Bike lane and parking lane widths may be included in the setback distance.

For trees, this measurement shall be taken to the face of the trunk 2 feet above the ground line.

Large trees and shrubs may be planted within the setback limits specified in this guide where the likelihood of an impact by an errant vehicle is negligible; for example, on cut slopes above a retaining wall or behind existing longitudinal barrier.

Page 3: Roadside Landscape

Swamp Flax cultivars

Phormium tenax cultivars.The standard swamp flax grows to 3 - 4m and forms a large plant, which is generally not suitable for low growing highway situations.

PohuehueForms a tangled thicket up to 80cm or more. Well suited to coastal and dry situations. In locations where growth is easier, the plants can grow more quickly and remain somewhat open, allowing light between the long shoots.It form a thick cover of the ground. it is well suited for traffic islands where long term low growth is desired.

Muehlenbeckia astonii. Hardy coastal low growing plant that forms a very thick mass up to 1m or more

Mountain Flax Phormium cookianum.Grows to 1m. Hardy in dry conditions, both on the coast and inland

Giant umbrella sedgeSuited to damp areas, forms a dense mass 1m high

Cyperus ustulatus. Forms a dense mass up to 1m. Suited to damp areas, both coastal and inland. Frost hardy.

Toe Toe Cortaderia. fulvidafulvida grows up to 1.5m, forming a dense cover well suited for roadside planting where sight lines are not critical.

Page 4: Roadside Landscape

Prostrate Coprosma.forms a dense tangled thicket, and when planted in groups, can form a mass that is dense enough to suppress weeds and can be trimmed if necessary to maintain a requiredheight. Excellent for traffic islands or edges where low growth and low maintenance is required

Wind grass or Gossamer Grass Anemanthele lessonianaA tussock-forming grass. Plants typically grow to 80 cm tall. The leaves are flat and in open situations they turn orange. The seed heads are tall and open. The plants die back after several years, but naturally reseed and continue to form a mass cover. Excellent for traffic islands or roadside planting. Tolerates frost and dry or damp conditions.

Kiokio ferns Blechnum nova- zealandiaeIdeally suited to damp or shady batters, but does not like sunny, hot or dry locationsDo not trim below 50cm

Climbing Rata. Metrosideros spForms a dense cover that is very attractive on batters. Prefers semi shade withreasonable moisture. Various species are available, with some suiting coastal areas and others cold locations.

NZ Blueberry Dianella nigraA lily like plant that grows to 50cm high, with bright blue berries in summer. Grows inwet or dry hot conditions, but not in cold South Island locations. Suited to amenity planting.

Miniature toetoe Chionochloa species.A range of tussock grasses are available that can be used for highway situation. Possiblespecies include C flavicans and C rubra. They prefer dry conditions and withstand coldand frost. Height range from 75cm – 1.5m, so they are generally suited for berms wheresight lines are not critical. Often more suited to areas where high amenity values areimportant.

Page 5: Roadside Landscape

Rengarenga lilly Arthropodium cirratum

Low growing plant with a Lily form, prefers dry sites, needs frost free conditions,attractive white flowers.

Should be planted into bark mulch, does not like being planted into synthetic mulch. Good for high amenity areas. 50cm high..

NZ Iris Libertia sp

A range of low growing species that form a dense sward, ideally suited to traffic islands.

Orange coloured straight thin leaves, small white flowers grows up to 40cm high.

Frost hardy. Most suited to high amenity areas.Generally prefer drier areas, and thrive in full sun.

FUNDAMENTAL PRINCIPLES IN ROADSIDE MANAGEMENT

Protect rate and endangered species

Conserve species of flora of scientific value.

Preserve land degradation due to soil erosion and salinity.

Provide habitat for native fauna to maintain an ecological balance and assists wildlife movement.

Enhance the aesthetic value of roadside.

Provide shade and shelter to farmland and road users.

Minimise management costs through maintenance procedure.

Preserve historical values of roadside features.

Page 6: Roadside Landscape

MINIMISE DISTURBANCE

Trees, shrubs and groundcovers combine to provide valuable food and shelter for different types of wildlife. Existing native vegetation will require less maintenance if left undisturbed.

UNNECESSARY DISTURBANCE CAN :•Encourage weeds, which complete with native plant and increase maintenance cost and fire risk of roadside.•Prevent natural regeneration of native plants.•Increase the risk of soil erosion.

MINIMISING SOIL EROSION

Erosion removes valuable topsoil and produces sediment which inturn silts drains, rivers.

Erosion can be accentuated through unneccesary construction and maintenance practice.

PRINCIPLES FOR MINIMISING SOIL EROSION :

•Stripping and stockpiling for later use.

•Protect vegetation. It protects ground surface and slow down water runoff.

•Replant or stabilise disturbed soil.

MANAGE WEEDS

It is essential that road managers be aware of invasive weeds in their particular area.

Noxious and environmental weeds and spread during both road construction and maintenance.

PROTECT VEGETATION

Healthy vegetation is a major environmental and economic asset . It is cheaper and easier to protect existing trees, shrubs and groundcovers than it is to replant them.

IN PROTECTING EXISTING VEGETATION :

•Avoid strong materials and equipments under trees. Vehicles should not be driven under trees or over other native plants. This will damage vegetation and compact the soil, stopping air from reaching the roots.

•Fence off areas where above problems may occur. Owen mesh barrier, wire fencing or large logs can be used.

a low growth native vegetation treatment

Cyperus ustulatus. Forms a dense mass up to 1m. Suited to damp areas, both coastal and inland. Frost hardy

Batter overspray Kiokio ferns mulched to the base present abrown unattractive finish

Page 7: Roadside Landscape

THE VALUE OF GOOD ROAD LANDSCAPE

When it is designed well the landscape becomes animportant component of the road network.

It is one of the key elements that contribute to thecharacter of an area – the combination of landscape andbuilt form helps provide a unique sense of place of valueto the community.

It helps integrate or fit the road into its setting.

It provides structure and a three dimensional scale to theroad corridor.

It helps unify the road corridor environment, providinginterest and a milestone to users as well as helping createa simple, strong and intuitive driving experience.

It can be a valuable ecological asset in an area, especiallywhen adjacent land is over-developed or when existinghabitats and ecological corridors need to be augmentedand connected.

It provides shade for pedestrian areas and buildings anda setting to take a break from driving in rest areas alongthe road network.

It is valuable in terms of impact mitigation. It screensundesirable views of roads and traffic, helps filter airand water pollutants, suppresses weed growth, helpsreconnect habitat, and can help recover threatenedspecies. It also minimises the carbon ‘footprint’ of roadworks – for at least the lifetime of the landscape.

It can contribute to a safer road, for example, by screeningheadlight glare, slowing errant vehicles and helping createan intuitive, self explaining driving experience.

It helps stabilise slopes and minimise erosion.

The Norfolk Island Pines along Botany Bay are an integral part of the character of the area.

If designed without consideration of road safety, especially clear zones, the landscape can be dangerous and impair the safe operation of the road and ongoing community acceptance of roadside trees (France).

The landscape of the road corridor contributes to the quality of journey andthe quality of the area.

The clear zone varies for different speed roads. Slower speed urban roads (upper) have narrower clear zones than high speed rural roads (lower).

A successful revegetation along the median and verge two years after native seeding.

Page 8: Roadside Landscape

KEY ISSUES

When it is designed and managed poorly, landscape can bea problem:

Overly complicated designs can look inappropriate andbe expensive to maintain.

Permits for traffic lane closures for landscape maintenanceare expensive, time consuming and difficult to obtain.

Poor plant selection can result in unsuccessful, ailingplanting designs, increased bushfire risk or can beecologically damaging by introducing inappropriate orweed species.

Too much planting can block views and make thejourney monotonous for road users.

Incorrect plant sizes and densities can lead to unsuccessful,high cost maintenance outcomes and a higher risk ofweed infestation.

Poor location of planting can result in damage to theroad infrastructure, interference with utilities, obstructionof signage and problems of maintenance.

FIRE MANAGEMENT

Fire is a natural component of the environment and can be used proactively to encourage health and diversity of vegetation. The management of fire can be seen as a community responsibility that aims to:

Protect road users. Reduce the severity of fires.

Fire will burn in most areas if the soil dries out sufficiently. The behaviour of fire will depend on following factor :

The type of understorey, including grasses, groundcover, and shrubs and arrangement. The amount of fuel load. The continuity of fuel bed and its ability to spread The presence of fuel ladders such as loose bark on the trunk. Density of the canopy.

The fire history of the area should be investigated before undertaking any fire management practices.

the fire history of an area includes an identification of the frequency, seasonality, intensity and distribution of fire throughout an area. These characteristics in turn have a specific effect upon plant regeneration following a fire occurance.

Page 9: Roadside Landscape
Page 10: Roadside Landscape

Drawings serve many purposes. Artists impressions and photomontages are useful for public consultation, sketches are fine for general project team use.