Human Benefits From Trees? You Bet – Quantified Here!

Last month I wrote about improvements to our ecology, our environment, and eventually our necessary Food Web that are achieved by planting native trees, as well as native shrubs, forbs, et al.  This month we’ll look at direct and quantifiable human benefits derived from tree cover (native and nonnative) right here in Northeast Ohio.

First, a tiny bit of history.  Cleveland’s nickname was for over a century “The Forest City”.  Grand, historic trees living when Moses Cleaveland arrived here in 1796 are venerated in our environs.  One great place to visit some (they have four) is Lakeview Cemetery, the site of the city of Cleveland’s original arboretum, a fabulous place to enjoy nature and landscapes while socially distanced – and don’t forget we are coming up on daffodil season.  While you are visiting the Moses Cleaveland Trees, be sure to enjoy the magnificence of Daffodil Hill in season!

Urban and suburban tree canopy cover in the latter half of the twentieth century declined heavily and quickly for a number of reasons – lack of funding for public plantings and forestry services, rampant development without planning to plant or maintain trees, severely increased air pollution, and many more.  This tendency continues through the present day.  In 2000, the city of Cleveland’s tree coverage was at over 21%.  it is are now at about 18%;  it is estimated to drop to less than 15% by 2040.

Here’s another way of considering this issue.  Cleveland loses at least 75 acres of tree coverage annually, just to aging and dying of existing trees, without taking into account human interventions like cutting them down for parking lots.

Why should we worry about this?  It’s not just attractive to have trees, although the mental health benefits to humans have been proven to be significant.  But the presence of trees has direct physical health and environmental benefits that an be quantified in dollars.  The Cleveland Tree Plan identifies primary values as the following.

• removing ozone from the air and helping to improve air quality and the negative public health effects caused by air pollution

• storing carbon and reducing the amount of carbon that returns to the atmosphere as a greenhouse gas 

• shading and cooling streets and buildings mitigating the urban heat island effect and reducing the use of air conditioning

• intercepting and absorbing stormwater, which reduces erosion and the amount of water that needs to be managed and treated after a rain event, and can reduce flooding 

• improving water quality by filtering and removing pollutants 

• providing homes, food and shelter for wildlife

Judging on the basis of these categories alone, the city’s tree canopy in 2017 was responsible for $11.4 MILLION dollars in services annually.  It was worth over $3 million more to the city in 2011, the year of the next most recent survey – having lost 6.3% of its value in just over 5 years.  

Here is the specific breakdown of the reduction in dollar value based on tree canopy loss from 2011 until 2017 survey years, from the Cleveland Tree Plan.

Air quality value loss was even greater, at over 7%.  And the American Lung Association had already awarded Cuyahoga County an F – a failing grade – for air quality.

Most of us do not live in the city – is that so big an issue for us?  Obviously it is.  Ozone levels and particulates in the air do not respect neighborhood boundaries.  Asthma and cardiovascular diseases are tied directly to neighborhood tree canopy, but they are not entirely limited to only lightly treed city neighborhoods.   The same west winds that cool us in summer and bring Lake Effect Snow in winter carry bad air to us as well.

What can we do?

To maintain the current level of the tree canopy, we need to plant almost 5,300 trees annually.  Of course, these are small, young trees;  they will not achieve the same health benefits that an established tree canopy achieves.  To effectively reverse the trend, just to hold even, we must aim to plant in excess of 11,575 trees annually.  To achieve 30 % tree cover in the city by 2040 – which is the minimum goal originally established by the Cleveland Tree Coalition – we must aim to plant 28,500 trees annually, beginning in 2021.  The City of Cleveland’s commitment will only cover approximately 2,000 of these annually, and for the decade of the 2020s only.

Not only is the city of Cleveland losing tree canopy every year.  The suburbs are also.  Our club’s small grove does not begin to equate to the tree loss in Shaker Heights just due to November’s early snowstorm.  But the educational goals attached to our grove are far more important.  The most essential tree planting in financially secure environments is done on residential properties, by property owners themselves.  As I wrote last month, this is the most important focus of the Homegrown National Park.  But even if you choose not to give over 50% of your lawn area to planting (mostly native) trees, shrubs, and understory, at least you can plant trees.  Do yourself, your family, and your property value a favor.

And consider becoming involved in a greater planting plan through a community organization. The Cleveland Tree Coalition is made up of over 40 such partners. For more information on these, and for greater detail on the values trees bring to the city, your community, or your property in particular, you can find more information at www.ClevelandTrees.org.