In the Spring of 2013, LFUCG commissioned an urban tree canopy study, the results of which should be available sometime this winter. The stated goals of the study were twofold – the study is assigned to present a baseline assessment of our urban tree canopy “that can be used to track canopy…over time”, and the planting plan is dictated to develop “prioritized planting plans based on environmentally sensitive and socio- economically important areas” in Lexington. This study could be a vital tool in assessing our current canopy and setting goals for the future. Because it will be the first of its kind in Lexington, an accurate study of canopy fluctuation will have to wait for future assessments, but we can make some guesses about the current and future state of our canopy.
1. We are significantly below the recommended 40% canopy cover for urban areas
According to a 2010 study by the USDA and the USFS, the national average canopy cover in urban areas is 35.1%. American Forests, a national non-profit, recommends 40% canopy cover for urban areas east of the Mississippi. A study by the 2013 Natural Resources and Environmental Science class at the University of Kentucky found that the total canopy cover inside the Urban Services Area was an abysmal 21.8%. Other estimates put the total as high as 24%. Either way, we are well below the national average and the recommended coverage. The consequences are real and quantifiable. Countless studies have shown that a low canopy cover can be detrimental for the environment, economy, and human health.
Lexington is also rapidly losing large portions of its remaining forest. The Emerald Ash Borer population is reaching its peak this year, and any Ash trees left untreated are expected to be lost by the end of next summer. Bacterial Leaf Scorch is rampant among Pin Oaks, and we are seeing a rapid loss of these large shade trees in older neighborhoods. Last summer’s drought took a toll on all tree species. Anecdotally, I feel like I’ve seen a significant decline in the canopy cover this year alone. All of this leads to a second assumption.
2. The extent of canopy cover is declining, and canopy is declining most immediately in medium to high income neighborhoods.
In its bid request, LFUCG did not define ‘socio-economically important’, but one might imagine that planting projects would focus on low-income neighborhoods, which tend to have fewer trees per square mile. Canopy cover discrepancy between high and low income neighborhoods justifies the prioritization of planting in our poorest neighborhoods. That being said, public and private investment has to keep up with the decline we see throughout the city. I speculate that the decline of urban canopy in Lexington is occurring at the fastest rate in high and medium income neighborhoods.
There are two primary reasons this is happening. The most obvious reason is these neighborhoods have the most canopy to lose. When the city experiences catastrophic canopy loss, neighborhoods with the largest, oldest, and most trees are sure to be the hardest hit.
The second reason, however, is more subtle. With some exceptions, medium and high income neighborhoods have relied on the commercial landscape industry for the selection of their canopy. Commercially installed landscapes tend to be limited to a handful of species. The commercial grower’s need to for trees that grow fast and transplant well meant that trees that grow slow or are difficult to transplant were never put out in the field. The landscape designer’s love for symmetry and uniformity meant that entire neighborhoods were designed with a handful of trees in mind. The landscape contractor’s promise to guarantee trees for a year meant that trees which were difficult to transplant were difficult to finance. Only the fastest growing, most adaptable, hardiest species meet these requirements, and simply put, there aren’t many species that make the cut.
A 2003 street tree survey found that the five most commonly planted street trees – Pear, Red Maple, Pin Oaks, Sugar Maples, and Ash – made up 80% of the street tree canopy. Pin Oaks and Ash alone comprise 22% of that canopy. Ecologists have taught us that low biodiversity fosters instability, and our tree population is a perfect example.
I recently heard a gardener on a radio show, who asked,
“you know what a gardener calls a dead plant?”
and answered, “An opportunity!”
I’ve had clients who’ve used all sorts of words to describe the dead tree in their yard. I’ve yet to meet one that called it an opportunity. That being said, we do have an opportunity to invest in a diverse native canopy for the future of our city.
This year, we made a commitment at Dave Leonard Tree Specialists to plant a tree for every one we removed. As it turns out, 2013 will be a difficult year for that mission. We hope you’ll help us. If you’ve had a tree removed this year, or a space you’ve considered in the yard, let’s fill that gap. Our expert knowledge and advice will help you select the right tree for your budget, your needs, and your landscape. If cost is an issue, we can plant seedlings, or simply give you the advice you need to select the right tree for the right spot. Together we can grow an urban forest that is richer, fuller, and more diverse.