"Zoning For Storm Water & Trees"

Prof. Buck Abbey, ASLA, CELA ©all rights reserved. Louisisana State Univeristy, Baton Rouge, Louisiana

Abstract. The police power of zoning is a significant tool for preserving and planting trees. A new landscape code demonstrates how stormwater and trees should be included in every zoning ordinance.

Zoning for trees is a relatively new concept to many. Zoning for trees and storm water, is an idea that has not been tested but will be soon within one of America’s wettest states. A ‘model storm water landscape code’ is being drafted by the Louisiana Department of Environmental Quality on behalf of the United States Environmental Protection agency that will bring zoning, storm water and trees together in form of zoning standards.

Cities are built according to some very specific requirements that are regulated by state law and local policy.

Zoning ordinances and building codes are the two principle tools used for building communities.

Building codes set forth design standards, commonly accepted construction practices and agency requirements that must be met by builders for all types of construction. Building codes must be followed by designers, builders and contractor in order to build communities that they are safe for human occupancy. Building codes provide design standards and building specifications for such building components as occupancy use, electrical, structural, plumbing, carpentry, masonry, glazing, seismic and hurricane resistance. Standard building codes,¹^. where most life safety issues are found, do not pertain to site design. Nor do these codes provide standards or requirements for development, land clearing, tree preservation, water conservation, site storm water management or landscape construction.

Subdivision codes, are closely related to the building codes and are used to develop raw land into suburban developments. These codes often will contain requirements for drainage but in all cases those requirements are for ‘centralized drainage systems’ that are connected from one property to another by use of pipe, ditches and canals.

Zoning, the other source of community building regulation sets forth broad standards to promote the health, safety and welfare of the community by setting design and planning standards for land use, intensity of use, building bulk, height, setback, access and parking.²^. In recent years zoning has changed toward setting forth policies of urban design, quality of life and economic development. In the last forty (40) years, zoning ordinances have become concerned with the physical aspects of building cities that are not covered by the building codes but would include trees, open space development, water consumption for irrigation and storm water management.

Trees and Zoning

Trees are becoming an important aspect of zoning and planners need to understand how trees are an additional site zoning concern that complements setback, bulk, height and land use. Planners need to know how to properly craft zoning regulations to maintain nature and its various elements such as air, climate, soil and storm water within the city. When communities use zoning to protect trees, it is important to adopt storm water and on-site storm water management regulations at the same time. Trees and storm water are natural partners. Trees need water and storm water is better managed if trees are part of the storm water management plan. When building sites are zoned for both trees, and storm water, more land is available for planting and preserving trees.

Zoning is the tool created to ensure community health and to allow for more livable places. Trees bestow upon towns and cities social, environmental and economic benefits that make the community a fit place to live. Trees and other vegetation filter pollutants from air, provide shade for homes, buildings and parking lots and cleans contaminates from storm water. Trees and preserved habitats within a community such as a forested wetlands or stream bank buffers can detain storm water runoff, reduce flooding and abate the erosion of productive nutrient rich soils. Maintained woodlands within cities provide habitat for animals and create desirable living and working places for citizens. Plantings increase property value, attract shoppers to businesses and provide relief from summer sun and tropical storms.

Communities who manage their urban forests and preserve nature in the city do so through zoning. To keep a city healthy, it must be zoned to preserve trees and other vegetation and maintain an appropriate percentage of undeveloped land in which nature is allowed to fully function. And that is true for each and every building site as we will see later. Zoning of sensitive lands, lands containing many trees, is something that cities should do, and have the authority to do. But some communities do not, in that they do not understand how to zone for trees.

Planning commissioners and professional planners ensure that nature in the city is cared for by enacting ‘comprehensive landscape codes’ that specify minimum standards for the preservation of nature in the city. This is done especially in regard to trees and rebuilt landscapes. To maintain trees it is important to have site development regulations that control land clearing, encourage habitat preservation, and require tree protection of special trees, water conservation and on-site storm water management. In recent years, city after city across the nation have turned to this type of local regulatory action as a means of ensuring better site design and acceptable community design standards for its green infrastructure.

Zoning for trees and places on building sites in which they may grow can complement the traditional zoning prerogatives of use, density, bulk, height and setback. Space zoned for planting are now part of the primary components of modern day zoning in communities that have enacted comprehensive landscape codes. The first step in zoning for trees is to set aside a percentage of land on each building site so trees will have a place to grow their roots and spread their branches. The fundamental truth is, without a place to grow, trees can not grow in the city and that is the main problem to be solved and storm water management may be part of the solution. The same land set aside for planting or preserving trees can also be used to capture, filter, and infiltrate storm water using a variety of site design methods that are coming into common use.

Landscape ordinances and tree preservation or protection regulations, often called ‘green laws,’ and contained within Zoning Ordinances are being written to protect nature in the city. ³^.

“Green Laws”

Landscape regulations, often referred to as landscape codes, essentially have been written to preserve locations on building site where trees and vegetation are allowed to grow. These spaces have specific names, locations and size standards in the landscape codes and are often measured by percent, linear foot, square foot, square yard or area. Figure 1.0 shows the normal disposition of the ‘geography of a development site’ and Figure 2.0 lists common design components of the landscape code. Landscape codes provide for the design and planting of such site facilities as street yards, parking lots, site service areas, landscape buffers, visual screens, irrigation hydro-zones, visual screens, and design of yard plantings that serve a variety of uses. They may also provide habitat preservation areas that preserve wetlands, stream bank buffers, forest floors, waterfront yards or old landmark trees. Plantable areas are essential for any building site for which zoning regulations can be established.

Tree Regulations

While many communities enact tree ordinances or landscape codes merely for beauty or economic development, there are other important reasons why trees are protected by legislation.

Many communities in Florida and in the west base their tree regulations around water issues. Lake Mary and St. Lucie County, Florida have crafted ordinances to conserve and reuse irrigation water that is in short supply in this sandy state. Collier County on Florida’s west coast and Volusia County on the east coast both require on-site storm water management and have standards that call for on-site storm water facilities that are locally called ‘water management areas.’ These water management areas are installed within buffers, in parking lots and within interior open spaces of each development site to allow water to percolate into the soil.

Water quality problems are a problem in several parts of the nation and tree ordinances have been written to do something about that. Maryland, New Jersey and Virginia codes have recognized this problem for over a decade so many of their local codes call for forest preservation and the use of buffers along every stream and water body.

Water soaked and flooded Louisiana is exploring on-site storm water management. Too much water and water quality impairment is a problem in Louisiana so the Louisiana Department of Environmental Quality is working on a ‘model landscape code’ that will green cities and help clean the state’s coastal waters. The model may set a new standard in pairing up trees with storm water.

Louisiana Model Landscape Code

The Louisiana Model Storm Water Management Landscape Code, contains design and performance standards for site landscaping, habitat preservation and on-site storm water management.

This model code incorporates LID strategies as the principal conceptual thread that ties all segments of the code together. Low impact development methods incorporated into this model code are based upon the idea that natural site processes and environmental forces should be applied to the design of each building site in a proactive way. LID principles driving the development of this code include a) better site design, b) minimization of impervious surfaces, c) protection of natural drainage features and existing tree vegetation, d) reduction of land disturbance activities, e) low maintenance landscaping that reduces the use of herbicides, fertilizers, pesticides and lawn grass, f) protection afforded to stream banks, lake edges, wells and water recharge areas. The management of storm water is the central idea of this model and trees and landscaping are the means to accomplish it.

LID strategies suggested in this model code promotes increased amounts of site open space set aside for decentralized storm water management and the planting of trees while minimizing site disturbance and the preservation significant habitat. This model code will also reduce the impact of development through the reduction of lawn grass, maintenance of natural drainage, the conservation of potable water and the recycling of storm water for irrigation use.

The primary purpose of this code encourages the utilization of EPA storm water best management practices (BMP’s) that reduce the use of traditional catch basins, manholes, underground pipe, head walls and off site disposal to drainage ditches and fresh water bodies. Instead, storm water BMP’s promulgated in the model as seen in Figure 3 use natural filters, soil, sunlight and vegetation, (natural systems) as the primary means of disposing of rain water in environmentally friendly ways. Natural methods using storm water BMP’s do this by modification to land surfaces that change run off characteristics, increase time of concentration and amount of infiltration. BMP’s will work to detain, filter, evaporate, absorb and infiltrate a percentage of storm water where it falls, rather than convey it to distant disposal areas at public expense.

The secondary purpose of this model landscape code is to assist communities in enacting design standards for better site development in regard to landscape design, construction and earth friendly site maintenance methods. Through better landscape design, natural habitats can be preserved, building sites can be adequately buffered from public streets and adjacent conflicting land uses and parking lots can be built that cool the climate, filter the air and absorb storm water run off. The model code better defines the design of street yard buffers, side and rear buffers, vehicular use areas, parking lot screens and street walls. The Landscape standards that are included in this code set aside a proscribed percentage of each site for the planting of a specified number of trees, shrubs and ground covers. In addition, the code promotes more tree preservation, better plantings, effective screening, wiser irrigation use, increased water conservation and sounder landscape construction and maintenance practices. The new Louisiana Model Storm Water Landscape Code moves the issue of zoning, storm water and trees even farther

A downloadable and editable version of this ordinance will soon be available on line at www.deq.state.la.us/model code.⁴^.

NOTES

1. The International Code Council was formed in 1995 from the three biggest code councils SBCCI, ICBO and BOCA. Today the ICC code is the most commonly used and has replaced the regional codes and many of the state building code. When the words ‘standard building code’ is mentioned in this paper, it refers to any and all of the building codes.

2. The International Code Council (ICC) also publishes a standard zoning code in which landscaping is minimally mentioned. Its reference is __________________., Standard Building Code, 1997 edition, Southern Building Code Congress International, Birmingham, Alabama, 1997.

3. Many of the fundamental ideas for this paper came from the book Abbey, D.G. Buck, "U.S. Landscape Ordinances". John Wiley & Son, Inc., New York, NY. 1998.

4. The referenced material is expected to be on-line by January 2006. The Landscape Ordinance Research Project at Louisiana State University has conducted studies of landscape and tree laws since 1987. Visit their web site that provides useful information about community landscape codes, code vocabulary, design components, and technical standards. Visit LSU at www.greenlaws.lsu.edu.

NOTE TO EDITOR.

2000 Words---- not counting Handout figures below. If the handouts can not be printed in the proceedings, then strike reference to Fig 2, Fig 3 and Fig 4 above. Figure References are called out in Red ink for ease of locating.

Figures and Illustrations Follow

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Fig. 1. Landscape Code Design Components.

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Designation ………………….......…..Location……………………….......….....Purpose……………..

· Street Tree Planting Area ·Along Street ROW ·Public Tree Plantings

· Street Yard ·Between Building and Street ·Beautify Street

· Street Wall · Adjacent To Building Facing A Street. · Screen, Soften Building

· Foundation Wall · Between A Building And A VUA · Improve Pedestrian Areas

· Vehicular Use Area Interior · Islands, Medians,Bays In Parking Lots · Shade Pavements & Cars

· VUA Screen · Between Cars And Conflicting Land Use · Screening Vehicles From View

· Side Yard Buffer · Buffering Conflicting Land Use At Side · Screening Neighbors

· Rear Yard Buffer · Buffering Conflicting Land Use At Rear · Screening Neighbors

· Habitat Preservation Area · Preserved Wetland, Tree Grove or Forest · Protecting Sensitive Land

· Irrigation Hydro-zones · Site Irrigation Conservation Zones · Reduce Waste Of Water

· Stream Bank Buffer · Between Development and Streams · Filters Storm Water

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Fig. 2.0 Geography of a Development Site-Design Components

_________________ ______________________ _________________________

____________________________ ____________ ___________________ ____________

Designation…………………...…..Location……………………….......…...Purpose……………..

·Sand Filters ·Site open spaces · Collect rainfall

·Planted Buffers ·Within property edges ·Collect Runoff and Sediments

·Rain Gardens · Site open spaces ·Sheet flow to minor depressions

·Vegetative or Bio-Swales ·Along street yard buffer and side buffers ·Filter runoff

·Grassed Swales · Lawn areas within open space · Slow and filter run off

· Parking Lot Detentions · Within and around parking · Detain and filter run off

· Dry Detentions · Site open space, parking · Hold and infiltrate run off

· French Drains-Infiltration Trenches · Near buildings, parking, base of slopes ·Capture run off

· Underground Storage · Below parking lots · Capture and exfiltrate runoff

· Above Ground Storage · Cisterns and Chambers · Use for irrigation system

· Disconnected Roof Tops · Adjacent to buildings · Capture roof run off

· Porous Paving · Parking lots and driveways · Infiltrate rainfall

· Retention Wet Ponds · Site open space · Store rainfall, site amenity

· Habitat Preservation Area ·Preserved Wetland,Tree Grove or Forest · Protecting Sensitive Land

· Stream Bank, Lake Front Buffer · Between Development and Streams · Filters Storm Water

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Fig. 2.0 EPA Recommended Storm Water BMP’s in the Louisiana Model Code

Code Provision …………………..Purpose…………………………………….……………..

__________ CONTEXTUAL______________________ ______________________________

Short title Ordinance title and location within the municipal code

Policies Regarding Trees General policy toward preservation, .protection, plantings and tree care

Tree Care License Licenses, qualifications, fees

Definitions Technical definitions concerning the code

Purpose And Intent/Applicability Specific purpose of the tree ordinance

_ ________ TECHNICAL____________________________________________________

Tree Inventory/Tree Survey Tree Inventory and Analysis

Tree Disposal Requirements for disposal of vegetation

Hazardous/Diseased Trees Definition of hazardous trees

Tree Protection/Protective Fencing Tree protection during construction

Tree Preservation Credits Incentives toward preserving trees

Pruning/Planting Standards Technical operations toward trees

Tree Care Specifications Arboricultural operations

Tree Planting Tree planting operations

Tree Species Botanical and horticultural operations

Landmark /Heritage Trees Special tree protection and preservation

Planting Yards Required planting locations on development sites

Landscape And Tree Plans Tree plantings plans and specifications

Tree Protection Areas Preserved habitats for trees

Canopy Requirements Standards for replanting of trees

Landscape Requirements Standards for other plantings on development sites

Street And Park Trees Special requirements for public tree care

Public/Private Trees Policy toward public and private trees

ADMINISTRATIVE

Submittal of Plans Procedures for submitting review documents

Permits Required permits for tree removal/planting/pruning/disposal

Duties of Urban Forestry/Arborist Administrative staff responsibility

Duties of the Administrator Administrative staff responsibility/procedures

Tree Advisory Board Citizen Oversight/Advisory Tree and Landscape Commission

Enforcement & Penalty Corrective Mechanisms

Hearings and Appeals Public Notice and Due Process Proceedings

Emergency Waiver Requirements concerning trees under special conditions

Severability/Repealer Disconnection of Faulty or Contested Language

Effective Date Time That Ordinance Takes Effect

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Fig. 3.0 Common Tree Ordinance Provisions*

A study of tree laws was conducted that compared tree ordinances promoted by the USDA Forest Service to author selected ordinances from other communities that would be used as a control study. The Forest Service, ‘Tree Ordinance Index’ used as the foundation of this study is thought to be representative of typical tree ordinances found in American Communities. From this study, the essential provisions found in contemporary trees laws have been set forth in Fig. 4.0 The USDA Forest Service makes available a data base of tree ordinances found on the Urban Forestry South Expo web site http://www.urbanforestrysouth.org/Resources/Ordinances. This is a searchable data base that is organized by subject and keyword. Some of the better tree ordinances from this study can be seen in Figure 4.0.

_________________ ______________________ _________________________

………………………..…..…..Community…………Title………………………….…………

Austin, Texas- Ordinance 960328-B

Boca Raton, Florida- Article II Trees

Baton Rouge, Louisiana- UDC Chapter 18 Landscape And Trees

Charlotte North Carolina- Chapter 21, Trees

Georgia Forestry Commission- Framework Ordinance

Gwinnett County, Georgia-Tree Ordinance

Howard County, Maryland- Subtitle 12 Forest Conservation

Miami-Dade, Florida- Tree Protection Ordinance

Palo Alto, California- Chapter 18-10 Tree Preservation

Raleigh North Carolina- Chapter 8 Trees And Vegetation

Santa Cruz, California- Chapter 9.56 Preservation of Historic Trees

Southlake, Texas- Ordinance 585-B Tree Preservation Ordinance

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Fig. 4.0 Selected Tree Ordinances, LSU Tree Ordinance Index 2005

Biography

D.G. ‘Buck’ Abbey is Associate Professor of Landscape Architecture at LSU and Principal Consultant to the Louisiana, landscape architecture - planning firm, Abbey Associates, Inc. He has taught design, construction, graphics and computer technology courses at LSU since 1974. Abbey received his terminal degree from Harvard University. He is a recognized authority on municipal landscape codes and is author of the book, U.S. Landscape Ordinance, published by John Wiley & Sons, Inc.. As associate editor of Landscape Architect & Specifier News Magazine, he writes regularly on landscape codes and related municipal planning law. He provides consulting services and expert witness testimony on landscape codes and site planning nationwide.