Arbor Day

Arbor Day is a time to encourage people to plant and protect trees. Many communities traditionally take the opportunity to organize tree-planting and litter-collecting events on or around the holiday. The first modern Arbor Day dates all the way back to 1805. The first Arbor Day in the United States was held in 1872 when an estimated one million trees were planted in Nebraska. Trees provide the very necessities of life itself. They clean our air, protect our drinking water, create healthy communities, and feed the human soul. But these life necessities are threatened around the globe. 

Arbor Day Foundation: The Time for Trees

Trees are an important part of the solution to many critical issues facing the planet. Trees purify our air, filter our water, and cool the earth. But our trees are at risk.

The Arbor Day Foundation has launched an initiative — Time for Trees — to plant trees at an unprecedented scale: they want to plant 100 million trees and engage five million tree planters by 2022. With their networks of members and partners, as well as access to both public and private land for tree planting, they are uniquely positioned to lead this undertaking.

Arbor Day 2021: What and When is Arbor Day?

Arbor Day is always observed on the last Friday in April. This year, it’s Friday, April 30, 2021. Arbor Day is a national holiday created to recognize the importance of trees. The most common way people celebrate Arbor Day is to get together in groups to plant trees.

The day was the brainchild of Julius Sterling Morton, a Nebraskan journalist who later became the U.S. Agriculture Secretary under President Grover Cleveland. Morton was an enthusiastic promoter of tree planting, had long championed the idea of a day dedicated to planting trees. Learn more about Arbor Day from the Farmers’ Almanac.

Learn Why We Celebrate Arbor Day and Plant a Tree!

An historical image of Arbor Day

Arbor Day is celebrated on the last Friday in April, although some states observe it on dates that better coincide with the local area’s planting times. For instance, Hawaii celebrates Arbor Day on the first Friday of November, and Alaskans celebrate it on the third Monday in May. Find out when your state observes Arbor Day.

Arbor Day is meant to encourage people to plant trees, and many communities traditionally take the opportunity to organize tree-planting and litter-collecting events on or around the holiday. A popular Arbor Day tradition is to plant a tree in honor or memory of a loved one. Dedicate a tree to someone who is special to you, and check out these facts about Arbor Day and the man who founded it from the Old Farmer’s Almanac.

The History of Arbor Day

An historical image of Arbor Day.

Arbor Day — which literally translates to “tree” day from the Latin origin of the word arbor—is a holiday that celebrates the planting, upkeep and preservation of trees. For centuries, communities spanning the globe have found various ways to honor nature and the environment.

However, the appreciation of trees and forests in modern times can be largely attributed to Arbor Day. And although Arbor Day may not have the same clout as holidays like Valentine’s Day or St. Patrick’s Day (or even Earth Day), it has a history with strong roots that branched out across multiple nations. Arbor Day 2021 will occur on Friday, April 30, and is typically celebrated on the last Friday in April in the United States. Learn more about Arbor Day from the History Channel

The Power of One Tree - The Very Air We Breathe

Trees in the Ambler Arboretum.

Just as we humans are comprised of many parts functioning together allowing us to do wondrous things, the anatomy of a tree is just as wondrous, empowering them with super hero qualities. A tree has the ability to provide an essential of life for all living things on our planet – oxygen, and the power to remove harmful gases like carbon dioxide making the air we breathe healthier.

Here is how it works. A tree is comprised of its leaves, stems, trunk and its roots.  When you look at a tree, note that about five percent of the tree is comprised of its leaves, 15 percent its stems, 60 percent goes into its trunk and 20 percent is devoted to its roots. Through a process called photosynthesis, leaves pull in carbon dioxide and water and use the energy of the sun to convert this into chemical compounds such as sugars that feed the tree. But as a by-product of that chemical reaction oxygen is produced and released by the tree.  It is proposed that one large tree can provide a day’s supply of oxygen for up to four people. Read more in this article from the USDA.

The Importance of Forests

The importance of forests cannot be underestimated. We depend on forests for our survival, from the air we breathe to the water we drink. Forests provide habitats for animals and livelihoods for humans, prevent soil erosion and mitigate climate change. But deforestation rates across the planet are putting our forests under threat. From the bushfires in Australia to the slow destruction of the Amazon forest. Now more than ever, the world's forests need our attention.

How to Save Our Planet and Rewild Our Planet

After centuries of clearing forest find out from Sir David Attenborough why we could soon have more forest than any of us have ever known in this video from the World Wildlife Federation International.

Replanting Our Forests

Replanting forests.

Our forests. They provide wildlife habitat, natural beauty and recreational opportunities. They filter our air and our water. They are vital to life as we know it. And they need our help. Learn about critical efforts to revitalize forests across the country — and around the globe — that are underway to ensure that they live on for future generations from the Arbor Day Foundation. You can support this important work!

Wild For Life Journeys – Forests

Nature sustains all life on earth, but nature is under threat. One million wild plant and animal species are facing extinction – many within decades. Three-quarters of the land-based environment, eighty-five per cent of wetlands, and two-thirds of oceans have been significantly and negatively altered by human activity.

The UN Environment Programme has created immersive digital experiences for its #WildforLife​ campaign. These four ecosystem-based “journeys” show the magic of interconnected natural systems and inspire people to take action to protect these distinct ecosystems.

What Would Happen If We All Helped Plant Trees?

Large scale global ecosystem restoration and reforestation is possible and can be done when millions of people contribute to tree planting. The Trillion Trees Campaign offers a simple way to get involved by helping to plant trees for as little as 10 cents per tree – micro-crowd funding our way to a thriving future. Visit​ to learn more.

How Trees Clean the Air

Trees and forests are constantly cleaning our air and improving our air quality. They exhale the oxygen we need to breathe, while absorbing carbon dioxide and other air pollution. Here are four things that trees do for our atmosphere that are essential for our health and our quality of life: trees create oxygen;  trees reduce air pollution; trees remove humid hazes air; and Trees Prevent Dust Storms. Visit​ to learn more.

Jane Goodall on the Importance of Planting Trees

Jane Goodall started her career studying chimps in Gombe, Tanzania. Her work changed the way we see chimps forever, but when she returned to Gombe 30 years after her first visit, she was shocked to see it had been stripped of most of its trees — an island of forest surrounded by completely bare hills, with people struggling to survive.

Thanks to Goodall’s innovative Roots & Shoots program, thousands of kids around the world are planting trees, encouraging children to volunteer in nature. Now, Goodall’s taking her reforesting mission to the next level, joining the global movement to plant and protect one trillion trees.

The Canopy Project

A canopy of trees

The Canopy Project improves our shared environment by planting trees across the globe. Since 2010, has planted tens of millions of trees with The Canopy Project, working worldwide to strengthen communities. works with global partners to reforest areas in dire need of rehabilitation, including areas with some of the world’s communities most at-risk from climate change and environmental degradation. They have also conducted broad tree planting in the wake of environmental disasters.

What if Everyone Planted a Tree?

Around 30 percent of our planet is covered in trees — that's approximately three trillion trees, according to this video from BBC Ideas. As well as helping with biodiversity, they can also help combat climate change. But we're cutting our trees down at an alarming rate — 4.1 million a day. So, what would happen if everyone on the planet — all 7.7 billion of us — planted a tree?

What Are Urban Forests?

An urban forest.

Over 141 million acres of America’s forests are located right in our cities and towns. Urban forests come in many different shapes and sizes. They include urban parks, street trees, landscaped boulevards, gardens, river and coastal promenades, greenways, river corridors, wetlands, nature preserves, shelter belts of trees, and working trees at former industrial sites. Urban forests, through planned connections of green spaces, form the green infrastructure on which communities depend. Green infrastructure works at multiple scales from the neighborhood to the metro area to the regional landscape. Learn more from the U.S. Forest Service.

Healthy Trees, Healthy Cities

The Nature Conservancy's Healthy Trees, Healthy Cities (HTHC) will help you take actions to improve the quality of life in your community through the planting, care, and stewardship of trees in your yard, neighborhood, and community. This easy to use app will cover the necessary steps to properly plant and care for trees, both new and mature.

Healthy trees mean healthy communities. Learn how you can support trees where you live, work, and play using the Healthy Tress, Healthy Cities Mobile app. The U.S. Forest Service provides an 8-part training video series on their YouTube channel to help you get started in using this innovative tool to support tree health. 

#FranklinOutside​: How to Sharpen Your Tree ID Skills

Dr. Rachel Valletta is heading back into the woods! Join her and Franklin Institute colleague Joy Montefusco, Director of Digital Editorial and former professional landscape designer, to sharpen up on your tree identification skills.

Tips for Caring for Your Trees

Stephen Goin and John Studdy from Bartlett Tree Experts offer some helpful tips on how to care for your trees and shrubs.

Habitat and the Scientist Gardener

Jared and Laura talk gardens and science. Additional resources meeting Next Generation Science Standards for elementary through high school can be found at our website: This video is used with permission from the College of Science and TechnologyTuTeach and the incredible FunScienceDemos team.

Habitat of the Soil

Jared explores the habitat of soil in Pennsylvania. There is so much more to soil than just dirt. Try digging around in your backyard to explore the habitat where you live! This video is used with permission from the College of Science and TechnologyTuTeach and the incredible FunScienceDemos team.

Installing Cicada Netting to Protect Trees and Shrubs

Bartlett Tree Experts’s Dr. Kevin Chase, Entomological Researcher, demonstrates how to construct and place framing over trees and shrubs for protection against cicadas. This type of netting structure is only recommended for newly planted and small, high value trees or shrubs. This timely information is useful for the anticipated arrival of Brood X.

Spotted Lanternfly Basics from iEcoLab

According to the Pennsylvania Department of Agriculture, the Spotted Lanternfly is an invasive species native to China, Bangladesh, and Vietnam. In 2014 it was found in Pennsylvania, and has since spread to 26 counties which are now quarantined. If you see a Spotted Lanternfly, it's imperative to immediately report it online or via phone by calling 1-888-4BADFLY. This pest poses a significant threat to the state’s more than $28 million grape, $87 million apple, and more than $19 million peach industries, as well as the hardwood industry in Pennsylvania, which accounts for nearly $17 billion in sales.

In this video from Victoria Ramirez, Lab Manager at iEcoLab in Temple’s Department of Biology, learn the basics about the spotted lanternfly and how you can do your part to control them.

Viral Water Bottle Hack for Trapping Spotted Lanternfly

The Pennsylvania Department of Agriculture is not subtle about what you should do if you see a spotted lanternfly — "Kill it! Squash it! Smash it! Just get rid of it!" You get the idea. iEcoLab in Temple’s Department of Biology, however, has tested out the viral hack of catching spotted lanternfly (SLF) with an empty water bottle that requires a lot less messy squishing. SLF bottle trapping can be a safe and easy method to euthanize the pests humanely and sustainably.

  • Get a bottle.

  • Trap the hoppin' SLF.

  • Freeze the bottled SLF.

  • Compost the caught SLF.

  • Reduce, reuse, recycle bottles.

Images/video taken by Victoria Ramirez, Lab Manager, iEcoLab.

#FranklinOutside​: How to Hunt & Squash Spotted Lanternfly Eggs!

Why is now the perfect time of year to hunt the spotted lanternflyFranklin Institute Environmental Scientist Rachel “Dr. Don” Valletta weighs in on how we can put our limited time outside to good use! Learn where to look for spotted lanternfly egg masses, how to ID them, and how to SQUASH them. 

Learn About Emerald Ash Borer

Kathy Salisbury, Director of the Ambler Arboretum of Temple University, invites you to learn about the Emerald Ash Borer. Many natural spaces are experiencing a decline in the population of Ash Trees because of the Emerald Ash Borer. In this video, Kathy shows you what they look like and the damage they cause.

Keep An Eye Out for Invasive Vines!

When plants, trees and vines are not native to the area they are growing in, they are considered invasive. Invasive plants can cause harm to the ecosystems they encroach upon. They are particularly harmful to trees. In this video by the Upper Dublin Parks and Recreation Department, learn about several invasive species that may be commonly found in this area and steps for combatting them (no audio).

The Department of Conservation and Natural Resources also provides an informative “Invasive Plant Fact Sheet” to help with identification of invasive plants, treatment, and protection suggestions for your property.

Managing Forests and Wildlife: Spotted Owls and Fishers

Forests provide habitat for a wide variety of wildlife species. In this video from the U.S. Forest Service, researchers explain how variable forest conditions can help support species like the California spotted owl and fishers. Through forest management, we can help improve habitat for some of the species that are most threatened. Work being done in experimental forests is helping to advance our understanding of the effects of a variety of restoration treatments to forest structure and wildlife.

Smokey Bear: Campfire Safety Steps

In this video from the U.S. Forest Service, Smokey Bear spreads the message that "Only you can prevent wildfires", follow these important safety steps next time you have a campfire. Video by Charity Parks. Narrated by Harrison Ford.

Prevent Food Waste While Exploring Nature

U.S. Forest Service Field Ranger Darielle Rocca discusses issues with food waste at campgrounds and recreation areas. 

Books On Trees and the Environment: An Arbor Day Reading List

A forest in the Temple Ambler Field Station

If you're looking for something environmental to place on your bookshelf, Ambler Arboretum Director Kathy Salisbury has you covered! From Suburban Safari to Eating Dirt, from Farm City to Flower ConfidentialKathy provides a review of a diversity of books focusing on the environment and trees. 

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