March/April 2023: The Future of Hardiness Zones

The Future of Hardiness Zones

New tool forecasts how planting regions might shift in the coming decades

Trees are an essential part of our neighborhoods and communities. But as our climate continues to change, the type of trees we plant — and where we plant them — will likely shift as well.

The Arbor Day Foundation and The Davey Tree Expert Company recently unveiled a new online tool to help homeowners and urban foresters understand what the next decades might look like for trees in their region, specifically relating to hardiness zones.

“The climate is warming fast enough to change the hardiness zones within the lifespan of trees planted today, so this tool is even helpful now as homeowners look to plant trees in their yards that will thrive in our changing environment,” said Dan Herms, vice president of research and development for The Davey Tree Expert Company.

Hardiness zones divide the United States into areas based on a 10-degree Fahrenheit difference in the average annual minimum temperature. The zones help inform what trees, shrubs, and plants can survive and thrive in that zone.

The Davey Institute created the new interactive website based on data and maps compiled by the USDA Forest Service. Its projections help demonstrate how a warming climate will change hardiness zones by the middle and end of this century. Users can search for specific zip codes throughout the United States to learn what changes are forecasted to take place in their region.

The website also forecasts the change in plant hardiness zones based on both low and high emissions scenarios. Currently, global patterns of greenhouse gas emissions correspond most closely with the high emissions scenario. Realizing the lower emissions scenario will require significant mitigation measures that are yet to be implemented, but still within reach.

To learn more about forecasted zone changes in your region, visit hardinesszones.daveyinstitute.com

Tree Cities of the World

Now more than ever, trees and forests are a vital component of healthy, livable, and sustainable communities around the globe. As cities continue to expand their commitment to trees, the Arbor Day Foundation’s Tree Cities of the World program is here to support them. Hundreds of cities of all sizes have come together to form a worldwide network leading the way in urban and community forestry.

Gisseli Giraldelli, biologist and superintendent of surveillance and environmental management of Campo Grande, shares some thoughts on why his city is actively involved in this program. Campo Grande is a recognized Tree City through the Arbor Day Foundation’s Tree Cities of the World program.

What is the value of being part of the Tree Cities of the World network?

Being part of the Tree Cities of the World network is a very important achievement for Campo Grande and our city’s community as a whole. Campo Grande’s primacy is to be a biophilic city that values its biodiversity. In this regard, being part of the network helps us to keep motivated and working endlessly

to maintain that status. The network provides us an opportunity to show to the world our case and all the benefits we got from those actions and, at the same time, to experience what other cities in the network do and, with that, optimize our actions.

What are you hoping to learn or gain from other cities that are recognized as Tree Cities of the World?

Being part of the network is a unique opportunity to learn other recognized cities’ projects or achievements to maintain or improve their afforestation and urban forests. The experience exchange can help us find solutions with more ease, thus making the other recognized Tree Cities an inspiration and reference for us.

What are your goals and objectives for your city’s trees?

We aim for a biophilic, biodiverse city that can work similarly to a biodiversity corridor. Thereby, the city will offer better life conditions to all its habitants, human or not. We see trees and urban forests as key elements, the most important in the process. We intend to recognize that with actions aimed at continuously protecting and recomposing our forest heritage.

Campo Grande, Brazil, is committed to a greener tomorrow.

How does your city celebrate its trees?

Annually we celebrate Tree Week, instituted by law in the year of 2005. In that week, several actions are developed to promote and engage the community, aiming to educate people about the importance of our trees. Lectures and forums are held; seedling plantings in schools, parks, and green areas are promoted; seedlings are donated for garden or farm planting; and celebrations are held in honor of notable trees, among other actions. Since its creation, this annual event has become a tradition, promoting society mobilization and wide exposure of local press (newspapers, radio, and TV channels).

What is the “tree culture” in your city? What do trees mean to you and your city?

In our city, the tree culture is something really important. We are proud to live in one of the more afforested cities in the country, we cherish our veteran trees, and we want to protect the existing forest, plant new ones, and also restore our permanent preservation areas. Moreover, we need to disseminate the tree culture even more because they are our biggest providers of environmental services. We need to be grateful to our giants; they work endlessly and voluntarily to improve city landscapes and are key elements for us to have a fresher, better life quality.

What do you want the world to know about your city’s trees and urban forestry program?

Campo Grande developed an Urban Forestry Program aimed at tree planting in order to protect watercourses and river sources; free areas, traffic islands, institutional areas and sidewalk afforesting; environmental education; protection for existing forests and seedlings productions.

Moreover, Campo Grande is a city full of wildlife, and was granted with the title of national capital of Birdwatching Tourism. Thus, maintaining the city as a biodiversity corridor is also a commitment for the Urban Forestry Program, otherwise, we understand the city could potentially work as a physical barrier to current gene flow.

In this way, the program aims to take advantage of beneficial environmental and landscape effects of afforestation, which contributes to the city’s atmospheric, noise, and visual pollution control, promoting a better life quality for its habitants and helping to maintain local biodiversity.

Campo Grande is one of hundreds of communities celebrating their Tree City status. As this network grows, so does the global commitment to a better future … one filled with trees. You can learn more about the Tree Cities of the World program at treecitiesoftheworld.org

Meet Our Team

Alana Tucker, Program Manager, Tree City Programs

What do you love about your work at the Arbor Day Foundation?

I get to meet like-minded people from all over the world! The world seems like a much smaller and better place when I am constantly surrounded by people making cities greener worldwide. It’s also so inspiring to learn the creative ways that Tree Cities are making the case to citizens and politicians about the importance of investing in urban forestry.

How did you develop a connection with trees?

My connection with trees began when I was a little girl. My dad built me a “tree house” in our backyard, which was essentially a bunch of spare two-by-fours wedged between branches so we could climb into the canopy. It was the best! However, I didn’t really discover my love for trees until I was on a spring break trip to Utah my junior year of college. So, my relationship with trees grew steadily over time.

What is your favorite tree?

My favorite tree is Populus tremuloides, also known as a quaking aspen. I love the way that you know you’re near water when you see them, because they’re a water-loving tree, and how their leaves shimmy in the wind.

A Global Effort

More than 50 countries benefit from Arbor Day Foundation support

Global planting projects have been a key part of our mission for many years. It all began in 2006, with just one country outside the United States. Today, the Arbor Day Foundation is proud to support planting projects in more than 50 countries.

Planting trees internationally has a myriad of benefits. Some of the world’s most diverse animal and plant species can be found overseas, and reforestation supports that rare biodiversity. Trees can also be an economic lifeline in developing countries, creating fertile soil for farmland and providing nutritious food for families.

It’s with your support that we’re able to make this global impact. Thank you for helping us create a greener future.

Stand-Out Projects

6 million+ trees since 2010

trees since 2010

1.6 million+ trees since 2010

4 million+ trees since 2010 (Senegal, Mali, and Chad)

GREAT GREEN WALL

n = Countries with Arbor Day Foundation projects

CANADIAN FORESTS