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CITY OF PLEASANTON URBAN FOREST MASTER PLAN | 117 STATUS OF THE URBAN FOREST PUBLIC AND PRIVATE TREES 2.1 Historical Context The City of Pleasanton is located in the Amador Valley, east of the San Francisco Bay. The City resides over a former large marsh complex, surrounded by grasslands and oak woodland hills. Before European influence, most trees grew in the riparian areas along the various waterways that ran through the valley and in the hills to the west of the City, with only a relatively sparse coverage of oak trees in the flatter grassland areas (SFEI 2013). After the arrival of the first European settlers, the marshes and wetlands were largely drained, and the land was converted to farmland and ranches. The City had a big population boom in the 1960’s and 1970s, resulting in conversion of much of the agricultural land to residential and commercial land uses. In 1971, the City really began prioritizing tree preservation when they created and adopted its first Tree Preservation Ordinance (Ordinance) in 1971, which has since gone through a number of updates. In the 1980s, construction began on the 850-acre Hacienda (business park) which converted old swampland to the largest commercial area in the City. Pleasanton today is recognized as a Tree City USA by the Arbor Day Foundation and has achieved 25% canopy cover city-wide. The City is aiming now to increase canopy cover in all residential neighborhoods to 25% which will also increase city-wide canopy cover in alignment with CAP 2.0 goals. 2.2 Tree Canopy Assessment The urban tree canopy provides multiple environmental services and economic value to the surrounding community. A robust tree canopy that is equitably distributed helps to create a healthier, more resilient community, and the environmental benefits and services received from the urban forest increase as tree canopy increases (Clark, et al. 1997). Likewise, low canopy cover can result in increased vulnerability to pollution, extreme heat, and associated health issues. Residents who live beneath dense tree canopy experience greater tree benefits than residents who live in areas of low tree canopy. For example, low canopy cover may be an indicator of a community’s vulnerability to pollution, extreme heat, and associated potential health issues (Wolf 2020). Trees contribute to cleaner, healthier air in urban environments through direct pollution removal (e.g., uptake via leaf stomata or intercepting airborne particles), air temperature reductions (e.g., transpiration), and reduction of urban heat islands, building energy consumption and consequent energy emissions (e.g., temperature reductions provided by tree shade). These community enhancements provided by tree canopy cover improve the quality of life for residents and businesses.