丰塔纳城市绿化总体规划丨美国加利福尼亚丨Design Workshop,Inc.

丰塔纳是南加州内陆中心的一座不断发展的城市，拥有广阔的商业环境。位于圣贝纳迪诺山脚下的地理位置致使丰塔纳目前和未来的居民面临着空气污染的问题，为此，市政官员制定了一个为期 30 年的计划，旨在增加城市整体的树木覆盖率（目前仅为 0.36%），改善空气质量并创造一个更加友好的居住环境。通过保护现有树木，调整城市主干道的规模以服务绿地而非汽车，丰塔纳将在一个全新的框架下发展：节能减排，同时改善居民的空间公平性。

– 2020 年评审委员会

In the heart of Southern California’s Inland Empire, Fontana is a growing city within a largely commercial setting. Considering the issues of air quality issues resulting from its position at the base of the San Bernadino Mountains for current and future residents, city officials have worked to develop a three-decade plan to increase overall tree coverage—currently just 0.36 percent—to improve air quality and create a more hospitable environment. By preserving existing trees and re-sizing several thoroughfares to emphasize canopy over cars, Fontana has set a framework that will reduce its emissions and improve spatial equity for its residents.

– 2020 Awards Jury

ASLA

Design Workshop, Inc.

项目概述 PROJECT STATEMENT

丰塔纳位于加利福尼亚州的半干旱内陆地带，其空气质量低于加州 95%的区域。丰塔纳的城市森林覆盖率仅为 0.36%，显著低于洛杉矶盆地内的其他社区。如若再考虑城市的交通要道、庞大的工业中心、频繁发生的区域火灾以及预期内的人口增长，落后且不健全的景观法规面临着越来越大的发展压力，这一形势在未来将变得更加严峻。

基于量化的研究，“丰塔纳城市绿化总体规划”试图借助科学知识从各个维度对空气质量进行探索。该计划的愿景是营造一个多尺度的绿色基础设施，使其能够影响城市的发展模式、改善居民健康，同时为丰塔纳创造一个有弹性的未来。设计团队通过双语社区参与活动来推进规划过程，主要分为“发现”、“指导”、“确定优先次序”和“实施”四个步骤。凭借着可以被灵活沿用至其他社区的工作方法，该计划直接引发了政策的变化，其总体目标是在 2050 年之前将树木覆盖率提高至 5%——涨幅超过 1300%，展示了变革性的意义。

Landlocked within California’s semi-arid Inland Empire, residents of Fontana are exposed to air quality that is worse than 95% of census tracts in California. Its urban forest – a mere 0.36% coverage – is distinctly less than other communities in Los Angeles Basin. This statistic, when considered with the influence of major transportation corridors, notable industrial hubs, frequent regional wildfires, and projected population growth, is at further risk as outdated and unconsolidated landscape regulations face increased development pressures.

Grounded by quantitative research, the Fontana Urban Greening Master Plan applies scientific knowledge to explore various dimensions of air quality. In doing so, the Plan creates a multi-scalar, green infrastructure vision that influences development patterns, improves individual health, and creates a resilient future for Fontana. Through bilingual community engagement, the design team implemented a four-step planning process – Discover, Guide, Prioritize, and Implement. Transferable in its approach for other communities, the Plan achieved immediate policy change with its ambitious, long-term goal of increasing tree canopy coverage to 5% by 2050 – a transformational increase of over 1300%.

▲城市绿化的迫切性：丰塔纳的居民呼吸着全美国质量最差的空气。相互冲突的盛行风使污浊的空气滞留在盆地内，在太阳辐射、臭氧、挥发性有机化合物和细颗粒物的共同作用下，会产生有害的烟雾。The Urgency for Urban Greening: Residents of Fontana, California are exposed to some of our nation’s poorest air quality. Conflicting wind patterns trap pollution generated within the Basin against a mountainous perimeter. This pattern, when exacerbated by radiation, ozone, VOCs and fine particulates, produces smog. © Design Workshop, Inc.

项目说明 PROJECT NARRATIVE

城市绿化的紧迫性

空气污染每年在美国造成超过 5 万人死亡，或导致各种类型的疾病。南加州的内陆地区由于地理位置的影响，其空气质量一直处于全国倒数的行列。盛行的圣塔安娜风与东向的太平洋风相遇，使污浊的空气持续滞留在盆地，同时受到附近山脉的“围困”。不仅如此，过多的太阳辐射、臭氧、挥发性有机化合物和细颗粒物污染会使情况进一步恶化，并产生有害的烟雾。

丰塔纳（人口 21 万）位于圣贝纳迪诺山脚下，是一座以重型商业和工业发展为主的城市，它被三条主要公路贯穿，并且拥有大面积的公路和空地。该市同时还是一个种族多样化的城市——71%的人口为西班牙裔——家庭收入中位数为 7.1 万美元，低收入人口主要集中在城市中部。对于希望维持普通生活水平的居民而言，丰塔纳是一个有吸引力的选择。预计在未来五年，该城的人口增长率为 4.4%。然而，丰塔纳目前的景观法规存在过时、散乱和执行不严的问题，快速的城市开发进一步导致了实施上的混乱和审批时间的拖延。

目标

基于这些数据，丰塔纳市政府和南加州政府协会（SCAG）委托景观设计师为城市绿化制定新的总体规划方案，以增加整个城市的绿植覆盖率、改善多模式交通并促进经济发展；同时还要整合各类法规并更新政策，在改善城市面貌的同时，有效地节约水资源并降低维护成本。此外，该计划还将以最新通过的《丰塔纳前进总计划》《活跃交通计划》和《加州节水景观示范条例》为基础，在遵循以上政策和法规的前提下，将总体规划的目标提升到“如何直接改善空气质量”的层面。

城市之肺

几个世纪以来，公园空间一直被景观设计师视为“城市之肺”，因其能够改善空气的质量。然而，实际改善的程度到底如何？景观设计师是否能够给出科学的证据来支持这个长久以来的观念？令人感到惊讶的是，几乎没有实证数据和研究被专门用于证明这一观点。据项目团队所知，本次计划是景观设计师首次通过整合相关研究、计算效益和交流影响来对该观点进行论证。

社区参与

项目团队通过双语社区参与活动来推进规划过程，主要分为“发现”、“指导”、“确定优先次序”和“实施”四个步骤。首先，三次社区研讨会和两次在线调查收集了居民对视觉偏好、优先事项和未来期望等方面的反馈，并测试了居民对两种不同景观的包容度和接受度，即更加“本土”的原生耐旱景观，和目前占主导地位的、需要大量灌溉的非原生绿色景观。最终，团队采用了以本地植物和节水种植材料为主的绿化方案，这个过程从很大程度上改变了人们对“美化”项目的固有看法，并且使他们了解到树木的多种益处，以及城市绿化如何帮助他们实现建立完整社区的目标。

空间平等性

过去的研究反映了树木覆盖率和收入水平之间的相关性，并得出了以下结论：空气污染和城市热岛带来的消极影响不成比例地落在了有色人种和低收入人群的身上。在丰塔纳也是相同的情况。为应对这一问题，该计划试图通过改善全体居民的生活条件来实现空间的公平性。最初的几个步骤是依据洛杉矶盆地内的同等级城市来建立基线和目标。丰塔纳的城市树木覆盖率仅为 0.36%，远远低于其他具有相似人口数量的城市，例如兰丘库卡蒙加和雷德兰兹等。在与比弗利等更加赋予的社区相比时，差异就变得更加明显。在城市范围内，根据人口统计学和 CalEnvironScreen 3.0 的叠加数据显示，丰塔纳本就有限的绿地还存在分布不均的问题。此项分析也进一步激发了市民对于空气污染研究工作的支持（占 80%），同时确立了在 2050 年之前将城市的树木覆盖率提升至 5%、未来提升至 25%的宏伟目标。

重写规则：制定兼顾场所和空气质量的景观规划方案

规划方案树立了建造多尺度绿色基础设施的愿景，旨在影响城市的发展模式、改善个人健康和生活质量、节约水资源、引导和净化雨水径流、提升视觉辨识度，为丰塔纳的社区和更广泛的盆地区域创造一个更具弹性的未来。

1) 树木尺度

景观设计师利用 i-Tree 工具和国家树木效益计算器对丰塔纳市现有的 71574 棵行道树进行了初步分析。可量化的效益指标包括：1）大气碳吸收；2）雨水拦截；3）土地价值增益；4）能源节约；5）年度美元收益。这些指标均与单独的物种相对应。在今天，丰塔纳的行道树库存每年能带来 680 万美元的收益。然而，与空气质量相关的收益在不同物种之间存在很大差异。例如，一棵加州月桂树每年可以吸收 486 磅碳、2.30 磅臭氧和 1.30 磅 PM10；相比之下，一棵加州扇棕榈每年只能吸收 33 磅碳、0.06 磅臭氧和 0.04 磅 PM10。在被分析的树木列表中，加州月桂树和加州扇棕榈的数量比为 1：3710，如果将这一数量颠倒过来，那么将可以吸收目前 14 倍的碳、38 倍的臭氧和 32 倍的 PM10。项目团队对碳固存量、挥发性有机化合物、臭氧消减量和花粉量也进行了类似的测算，并结合社区的意见，对其他环境因素（包括耗水量、地下水补给潜力、抗旱性、抗风性、耐火性和美观度等）进行了综合考量，最终定制出了一个独具特色的树木种植方案。

2) 场地尺度

除了针对单个物种提出建议外，项目团队还思考了如何将城市绿化融入城市形态当中。在与交通规划师的密切合作下，景观设计师选出了一系列优先级的街道，其中涵盖了所有的街景类型和层次结构。在为每条街道塑造独特性的同时，该规划还重新组织了尺度过大、主要为汽车服务的街道，为树木和林下植被的生长提供了充足的空间，同时还改善了步行和骑行空间的舒适度。

随后的重点是为公共和私人土地的使用定制最优方案。考虑到丰塔纳 82%的土地为私人所有，景观设计师从每种不同的土地使用类型中挑选出案例场地，并为之提供了最佳的专业方案。设计在优化功能性的同时，最大程度地发挥了城市绿化的潜力。每个类型的场地都经过了前后测量对照，主要的评测依据包括树木覆盖率、景观面积、可渗透和不可渗透表面以及温室气体减少量等。

3) 城市尺度

在城市尺度上，该计划建立了一个全市范围的、可供未来实施的框架。该框架由绿色街道和绿色场所组成：绿色街道包括所有公路和步道的最佳方案，实现了一个互联的绿色系统；绿色场所则包括所有土地使用类型的最佳方案。城市北部和南部边缘的部分地区被界定为火灾风险区，在该区域内只允许按照特定间距种植指定的耐火树种。从整体上看，该框架使全市的温室气体减少了 1.58%。

保护的理由

对既有树木的保护能够对整个城市的树木覆盖率产生重大的影响。随着树木体积的变大，它们的生长速度也不断加快，因此树龄越大的树木在效益上也增长得最快。在丰塔纳，由于缺乏对树木保护行为的执行和监管，多年来有大量的树木遭到移除。假设这些树木得到了适当的保护且树冠直径能够顺利扩大至 24 英尺，在不种植新树的情况下，仅靠保护既有树木就可以让丰塔纳在 50 年内实现 5%的树木覆盖率。因此，规划还提出加强相关政策和法规的实施，使树木成为宝贵的社区资产。

实施

该计划为洛杉矶盆地内外的城市提供了以研究为基础的方法示范，以帮助它们改善交通、提高宜居性、实现空间公平和改善空气质量。在今天，该计划已被采纳为丰塔纳城市总体规划的一部分，它为改善丰塔纳的建筑和景观环境提供了一份全面的、具有前瞻性和政策执行力的指南。

▲实现空间公平性：在丰塔纳，空气污染和城市热岛带来的消极影响不成比例地落在了有色人种和低收入人群的身上。该计划将初期阶段的城市绿化工作优先安排在贫困和弱势社区。Addressing Spatial Equity: In Fontana, the impact of air pollution and urban heat island falls disproportionately upon people of color and lower income populations. The plan prioritizes early phase urban greening to occur in disadvantaged neighborhoods.©Southern California Association of Governments

▲“发现”、“指导”、“确定优先次序”和“实施”：在 18 个月的时间里，景观团队分四个阶段实施了双语社区参与过程。该计划提出的方法可以灵活转移至其他社区，受到了公众的持续支持，并且直接引发了政策的变化，其总体目标是使树木覆盖率提高 1300%以上。Discover, Guide, Prioritize and Implement: Over the course of 18 months, the landscape architect executed a four-step, bilingual community engagement process. Transferable in its approach, the Plan achieved sustained public support and immediate policy change with its goal of increasing canopy by over 1300%.© Design Workshop, Inc.

▲发现问题和需求：对既有条件的分析揭示出了一些可以通过规划来解决的社会和环境问题。丰塔纳是一座以重型商业和工业发展为主的城市，它被三条主要公路贯穿，并且拥有大面积的公路和空地。Discover Issues & Needs: Analysis of existing conditions revealed social and environment needs that could be addressed through the Plan. Fontana is transected by three major highways and includes heavy commercial and industrial use with large expanses of pavement and tracts of vacant land.©Southern California Association of Governments

▲转变观念：三次社区研讨会和两次在线调查从很大程度上改变了人们对“美化”项目的固有看法，并且使他们了解到树木的多种益处，以及城市绿化如何帮助他们实现建立完整社区的目标。Changing Perceptions: Three community workshops and two online surveys helped citizens move beyond initial perceptions of a “beautification” project, instead educating them on the multiple benefits of trees and how urban greening can support their goals of becoming a complete community.©Southern California Association of Governments

▲保护的理由：执行和监管的懈怠导致丰塔纳的树木大量流失。在不种植新树的情况下，仅靠保护既有树木就可以让丰塔纳在 50 年内实现 5%的树木覆盖率。因此，规划还提出加强相关政策和法规的实施，使树木成为宝贵的社区资产。

The Case for Preservation: Absence of enforcement has resulted in significant canopy loss for Fontana. By just preserving existing trees, Fontana could potentially reach 5% coverage in 50 years. A proposed policy strengthens preservation regulations to allow trees to become an invaluable community asset.

© Design Workshop, Inc.

▲不同树木之间的差异：与空气质量相关的收益在不同物种之间存在很大差异。项目团队对一系列环境因素进行了综合考量，包括耗水量、地下水补给潜力、抗旱性、抗风性、耐火性和美观度等，最终定制出了一个独具特色的树木种植方案。Not All Trees Are Created Equal: Benefits associated with carbon sequestration, volatile organic compounds, ozone reduction and pollen differ significantly amongst species. The team synthesized benefits with other environmental considerations, including water consumption, groundwater recharge potential and drought-wind-and fire-resistance to produce a distinct palette.©Southern California Association of Governments

▲城市绿化框架：在城市尺度上，该计划建立了一个实施框架。绿色街道包括所有公路和步道的最佳方案，实现了一个互联的绿色系统；绿色场所则包括所有土地使用类型的最佳方案。Urban Greening Framework: At the city scale, the Plan establishes a framework for implementation. Green Streets are composed of best scenarios of all street types, vegetated highways and gateways, achieving a connected green system, while Green Places include all land use typologies.©Southern California Association of Governments

▲绿色街道：景观设计师利用 i-Tree 工具和国家树木效益计算器对丰塔纳市现有的 71574 棵行道树进行了初步分析。可量化的效益指标包括大气碳吸收、雨水拦截、土地价值增益、能源节约以及年度美元收益。这些指标均与单独的物种相对应。Green Streets: The landscape architect analyzed the city’s 71,574 existing street trees using the i-Tree and National Tree Benefits Calculator. Quantitative benefits, including Atmospheric Carbon Absorption; Stormwater Interception; Property Value; Energy Conservation; and Annual Dollar Benefits, were identified for individual species.©Southern California Association of Governments

▲案例研究 – Sierra 大街：在场地尺度下，项目团队思考了如何将城市绿化融入城市形态当中。通过与交通规划师的密切合作，景观设计师选出了一系列优先级的街道，其中涵盖了所有的街景类型和层次结构。

Case Study | Sierra Avenue: Narrowing down into site scale, the team considered how to integrate urban greening into urban morphology. Working in close collaboration with transportation planners, the landscape architect selected a series of priority streets that covered all streetscape typologies and hierarchies.

©Southern California Association of Governments

▲案例研究 – Foothill 大道：在为每条街道塑造独特性的同时，该规划还重新组织了尺度过大、主要为汽车服务的街道，为树木和林下植被的生长提供了充足的空间，同时还改善了步行和骑行空间的舒适度，避免行人直接吸入由汽车排放的 PM2.5。

Case Study | Foothill Boulevard: While establishing a distinct character for each street typology, the Plan reorganizes oversized, car dominant streets to provide ample space for trees and understory planting, improve bicyclist comfort, and protect pedestrians against inhalation of PM2.5 directly from cars.

©Southern California Association of Governments

▲绿色场所：工作重点随后转向为公共和私人土地定制最佳方案，这可以为全市贡献 12.6%的树木覆盖率。景观设计师从每个类型中挑选出了适合案例研究的场地，并概述了专业的最优方案和预期指标。Green Places: Focus then shifted towards tailoring best-case scenarios to public and private land uses, which could contribute 12.6% tree canopy coverage citywide. The landscape architect selected case study sites from each typology and outlined professional best practices and target metrics.©Southern California Association of Governments

▲绿色场所：设计在优化功能性的同时，最大程度地发挥了城市绿化的潜力。6 种类型的场地都经过了前后测量对照，主要的评测依据包括树木覆盖率、景观面积、可渗透和不可渗透表面以及温室气体减少量等。Green Places: Proposed designs and regulations maximized potential for urban greening while optimizing function. Each of the six typologies were then measured in before and after scenarios. Metrics include canopy coverage, landscape area, permeable and impermeable surface, and greenhouse gas reduction.©Southern California Association of Governments

▲影响变化：丰塔纳 82%的土地为私人所有，其中住宅所占比例最大。该计划要求增加 12%的树木覆盖率，以及 20%的景观区域、可渗透表面和绿色屋顶表面。Affecting Change: 82% of property in Fontana is privately owned, with residential accounting for the largest land use. The Plan calls for a 12% increase in canopy coverage, and a 20% increase in areas that include landscape, permeable surfaces and green roofs.©Southern California Association of Governments

▲城市之肺：自 Olmsted 以来，公园空间一直被景观设计师视为“城市之肺”。然而，实际改善的程度到底如何？本次计划是景观设计师首次通过整合相关研究、计算效益和交流影响来对该观点进行论证。Lungs of the City: Since Olmsted, landscape architects have taken it on faith that parks are the ”Lungs of the City”. But to what degree? The Plan represents the first known attempt to quantify research, calculate benefits and communicate impacts to confirm this principle.©Southern California Association of Governments

▲构建弹性未来：该计划为其他寻求改善交通、提高宜居性、实现空间公平和改善空气质量的城市提供了行动范例，目前它已被采纳为丰塔纳城市总体规划的一部分，为改善丰塔纳的建筑和景观环境提供了一份全面的、具有前瞻性和政策执行力的指南。Realizing a Resilient Future: The Plan creates a model for other cities seeking to improve mobility, human comfort, social equity and air quality. The Plan is becoming part of the General Plan, achieving a consolidated, visionary and policy-reinforced guide to transform Fontana’s built environment.©Southern California Association of Governments

PROJECT NARRATIVE

THE URGENCY OF URBAN GREENING

Air pollution causes over 50,000 deaths each year in the United States and numerous other illnesses. Geographically landlocked, the Inland Empire of Southern California consistently ranks at the top of national lists for poorest air quality. Prevailing Santa Ana winds, when combined with eastward Pacific winds, trap air pollution generated within the Basin against a perimeter of mountains. This pattern, when exacerbated by abundant solar radiation, ozone, volatile organic compounds and fine particulate pollution, produces smog.

Resting near the base of the San Bernardino Mountains, Fontana (pop. 210,000) is transected by three major highways and comprised of heavy commercial and industrial use with large expanses of pavement and tracts of vacant land. The city is ethnically diverse – 71% identified as Hispanic origin – and possesses a median household income of $71,000, with lower income demographics concentrated mid-city. For those seeking affordability, Fontana is an attractive option with population growth projected at 4.4% over the next five years. However, existing landscape regulations are outdated, unconsolidated and inconsistently implemented, causing confusion and prolonged approvals as new developments rapidly emerge.

PURPOSE

Recognizing these statistics, the City of Fontana and The Southern California Association of Governments (SCAG) commissioned the landscape architect to craft an Urban Greening Master Plan to increase citywide tree canopy, improve multi-modal mobility, catalyze economic development, consolidate various regulations, and update policies to improve visual character, conserve water and reduce maintenance. Furthermore, the Plan would build upon the recently adopted Fontana Forward General Plan, Active Transportation Plan, and the California Model Water Efficient Landscape Ordinance. Beyond such goals, the landscape architect elevated the project’s purpose to explore how such a plan can directly improve air quality.

LUNGS OF THE CITY

For centuries, landscape architects have taken it on faith that parks are the ”Lungs of the City”, capable of improving air quality. But to what degree? Can landscape architects support what we take as faith with proven scientific evidence? Surprisingly, little empirical data and research has been applied to this principle. To our knowledge, our Plan is the first known attempt to gather such research, calculate benefits and communicate impacts informed by science.

COMMUNITY ENGAGEMENT

Through a bilingual engagement process, the team implemented a four-step planning process – Discover, Guide, Prioritize, and Implement. Three community workshops and two online surveys solicited feedback on visual preferences, priorities and vision, and tested the community’s openness and acceptance of “browner” native, drought-tolerant landscape versus lush, green, over-irrigated non-native landscape that currently dominates portions of the city. Changing perceptions, the adopted plant palette now includes overwhelmingly native and water-efficient planting materials. The process helped citizens move beyond initial perceptions of a “beautification” project, instead educating them on the multiple benefits of trees and how urban greening can support their goals of becoming a complete community.

SPATIAL EQUITY

Past research has drawn correlation between canopy coverage and income levels, concluding that the impact of air pollution and urban heat island falls disproportionately upon people of color and lower income populations. This correlation holds true in Fontana. As such, the Plan addresses spatial equity by improving conditions for all residents. Initial steps educated and established baseline metrics and targets as compared to peer cities within the Basin. With only 0.36% of the city’s land area possessing tree coverage, Fontana falls well below cities with similar demographics, including Rancho Cucamonga and Redlands. When compared to more affluent communities like Beverly Hills, the gap widens. At a city-scale, overlays of demographics and CalEnvironScreen 3.0 data revealed that Fontana’s limited tree canopy varies dramatically and is not equitably distributed. This analysis awoke citizens, with 80% responding in support that air pollution was worthy of the study, to establish 5% citywide tree canopy by 2050, and 25% long term.

REWRITING THE RULES: CODIFYING LANDSCAPES THAT BLEND PLACEMAKING AND AIR QUALITY

The Plan creates a multi-scalar, green infrastructure vision that influences development patterns, improves individual health and quality of life, conserves water, channels and cleans stormwater runoff, enhances visual character and creates a more resilient future for the community and greater Basin.

1) At the Individual Tree Scale

The landscape architect conducted an initial analysis of the city’s 71,574 existing street trees using the i-Tree and National Tree Benefits Calculator. Quantitative benefits, including Atmospheric Carbon Absorption, Stormwater Interception, Property Value Increase, Energy Conservation, and Annual Dollar Benefits, were identified for individual species. Today, Fontana’s street tree inventory accounts for $6.8 million of annual benefits.

However, benefits associated with air quality differ significantly among species. For example, California Laurel can absorb an average of 486 lbs. carbon, 2.30 lbs. of Ozone, and 1.30 lbs. of PM 10 per tree annually. In comparison, California Fan Palm can only absorb 33 lbs. of carbon, 0.06 lbs. of Ozone, and 0.04 lbs. of PM 10 per tree annually. Of trees inventoried, only one was a California Laurel, while 3,710 were California Fan Palms. Had these quantities been reversed, 14 times of carbon, 38 times of Ozone, and 32 times of PM 10 would have been absorbed than the existing condition. Similar measurements were calculated for carbon sequestration, volatile organic compounds, ozone reduction, and pollen. With community input, the landscape architect and arborist synthesized these measures with other environmental considerations, including water consumption, groundwater recharge potential, drought- wind- and fire-resistance, and aesthetics to produce a distinct tree palette.

2) At the Site Scale

Advancing beyond recommending individual species, the team considered how to integrate urban greening into urban morphology. Working in close collaboration with transportation planners, the landscape architect selected a series of priority streets that covered all streetscape typologies and hierarchies. While establishing a distinct character for each, the Plan reorganizes oversized, car dominant streets, providing ample space for trees and understory planting and improving pedestrian and bicyclist comfort.

Focus then shifted towards tailoring best-case scenarios to public and private land uses. Of significance, 82% of property in Fontana is privately owned. As such, the landscape architect selected example sites from each land-use typology and applied professional best practices. Designs maximized potential for urban greening while optimizing function. Each typology was then measured in before and after scenarios. Metrics include canopy coverage, landscape area, permeable and impermeable surface, and greenhouse gas reduction.

3) At the Citywide Scale

Taking the site-scale studies to a citywide scale, the Plan established a citywide framework for future implementation. The framework incorporates green streets and green places. Green streets are composed of best scenarios of all street types, vegetated highways and gateways, achieving a connected green system. Green places include best scenarios of all land use typologies. Part of the northern and southern edge of the city are defined as fire hazard zone. Within this zone, only fire-resistant species are allowed with specific spacing and clearance requirements. Collectively, the framework reduces the citywide greenhouse gas by 1.58%.

THE CASE FOR PRESERVATION

Preservation of existing trees can offer a significant impact on citywide canopy coverage. As trees grow larger, their rate of growth accelerates, so the oldest trees increase most rapidly in providing benefits. In Fontana, the lack of tree preservation enforcement and regulation has resulted in many being removed over the years. Hypothetically, just by preserving existing trees to an average of 24’ diameter tree canopy without any new plantings, Fontana could reach 5% of tree canopy coverage in 50 years. As such, a proposed policy strengthens preservation regulations to allow trees to become an invaluable community asset.