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Celebrate Juneteenth 2026 in Nature!

Join FOPOS’s Stewardship Team on June 19 for a special Juneteenth Nature Walk as we celebrate freedom, culture, community, and outdoor wellness in the Preserve. This guided walk offers an opportunity to honor the legacy of Juneteenth while connecting with the natural world and reflecting on the importance of access to green spaces, stewardship, and community.

Led by our summer stewardship interns, the walk will also recognize National Pollinator Month as we explore the fascinating role of native pollinators in sustaining healthy ecosystems. Along the trails, we’ll discover pollinator hotspots, learn about the wildflowers, shrubs, and trees that depend on them, and observe bees, butterflies, and other pollinating species in action.

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, June 13. There will be two volunteer sessions; the morning session is from 9 a.m. to 11 a.m., and the afternoon session is from 12 p.m. to 2 p.m. Come to one or both. Bring a friend and groups are welcome!

Join us at Mountain Lakes House to discuss "North Woods" by Daniel Mason.

This series is presented in partnership with the Princeton Public Library and the Princeton Environmental Film Festival, and is dedicated to readings about conservation, stewardship, and our relationship with nature.

Sign up for this session via Princeton Public Library. You do not need to be a library cardholder to register.

REGISTER FOR NATURE JOURNALING MEETUP

We'll meet at Mountain Lakes House to draw from nature in a playful and non-judgmental setting. This meetup is FREE, although registration is required. The program is designed for adults and older teens. Younger participants (under 16) are welcome to join if accompanied by an adult.

What is a meetup and how is it different from a class? While a class is a structured learning environment with a defined curriculum, schedule, projects, and goals, a meetup is a gathering of people with shared interests who get together, often with a facilitator (in this case Eleni Litt).

Meetup Location: Mountain Lakes House

Join the Friends of Princeton Open Space (FOPOS) and local foraging experts for a Mugwort Foraging Event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton.

In this hands-on event, participants will delve into the world of the invasive plant, Mugwort. Under the guidance of our stewardship team and local foraging experts Matt and Shannon, participants will learn how to properly identify mugwort, sample a recipe, and safely remove it from designated restoration areas at the preserve. From teas to donuts to savory dishes, discover how mugwort can enhance your kitchen creations.

Sign up for this session via Eventbrite.

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Join the Friends of Princeton Open Space (FOPOS) and expert birder Winnie Hughes Spar for a guided bird walk through the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ. Together, we will observe Princeton's birds and learn about their fascinating habits!

Space is limited to 20 participants; be sure to sign up in advance. Please note that this event is geared towards adults.

Photo Credit: Xintong “Equinox” Si

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, May 30th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m., and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend and groups are welcome!

Join us for our May Nature Walk through the trails of the Billy Johnson Mountain Lakes Nature Preserve.

Led by the Friends of Princeton Open Space stewardship team, this guided walk will offer a chance to explore lush trails, vibrant spring blooms, and the sights and sounds of nature as the season comes alive. Whether you’re a seasoned hiker or a first-time visitor, it's the perfect way to enjoy the outdoors and reconnect with nature. Our stewardship team will also share insights into the history of the preserve and the ongoing land stewardship efforts that help protect this special place for future generations.

Be sure to wear sturdy, weather-appropriate footwear. Feel free to bring a camera or binoculars along to help you spot and capture the beauty of wildlife as we explore.

Sign up for our May Nature Walk on Eventbrite

REGISTER TO VOLUNTEER

Join FOPOS for a community volunteer event at the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ.

Volunteers will work with the stewardship team at forest or riparian restoration project sites on critical tasks such as invasive species removal, native planting, and installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, May 16th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m., and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend and groups are welcome!

RESERVE YOUR SPOT

Join the Friends of Princeton Open Space (FOPOS) and eco-artist Susan Hoenig on Monday, May 11th at 11:00 AM for a guided nature walk and exhibition that brings together art, ecology, and conservation. Learn how we can all play a role in protecting American beech trees and the forest ecosystems that depend on them. Explore the beauty of American beech trees through a special indoor exhibition, then step outside for a guided nature walk to a beech grove in John Witherspoon Woods.

Along the way, learn how these remarkable trees support entire forest ecosystems and why they are increasingly at risk from Beech Leaf Disease (BLD), a fast-spreading threat that can weaken and kill infected trees. Hear directly from the FOPOS stewardship team about the work underway to protect these vital trees and forest ecosystem.

REGISTER FOR NATURE JOURNALING MEETUP

We'll meet at Mountain Lakes House to draw from nature in a playful and non-judgmental setting. This meetup is FREE, although registration is required. The program is designed for adults and older teens. Younger participants (under 16) are welcome to join if accompanied by an adult.

What is a meetup and how is it different from a class? While a class is a structured learning environment with a defined curriculum, schedule, projects, and goals, a meetup is a gathering of people with shared interests who get together, often with a facilitator (in this case Eleni Litt).

Meetup Location: Mountain Lakes House

RESERVE YOUR SPOT

Join the Friends of Princeton Open Space (FOPOS) and eco-artist Susan Hoenig on Saturday, May 9th at 12:30 PM for a guided nature walk and exhibition that brings together art, ecology, and conservation. Learn how we can all play a role in protecting American beech trees and the forest ecosystems that depend on them. Explore the beauty of American beech trees through a special indoor exhibition, then step outside for a guided nature walk to a beech grove in John Witherspoon Woods.

Along the way, learn how these remarkable trees support entire forest ecosystems and why they are increasingly at risk from Beech Leaf Disease (BLD), a fast-spreading threat that can weaken and kill infected trees. Hear directly from the FOPOS stewardship team about the work underway to protect these vital trees and forest ecosystem.

Join the Friends of Princeton Open Space (FOPOS) and local experts Matt and Shannon for a Dame's Rocket Forage Walk at the Billy Johnson Mountain Lakes Nature Preserve in Princeton.

In this engaging event, participants will delve into the world of the invasive plant, Dame's Rocket. Led by knowledgeable guides, you'll learn how to identify this invasive species and taste-test a recipe using this plant -- and then we will get harvesting! We will work to remove Dame's Rocket in our pollinator garden since it is out-competing our native plants and decreasing biodiversity.

Sign up online.

RESERVE YOUR SPOT

Join the Friends of Princeton Open Space (FOPOS) and expert birder Winnie Hughes Spar for a guided bird walk through the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ. Together, we will observe Princeton's birds and learn about their fascinating habits!

Space is limited to 20 participants; be sure to sign up in advance. Please note that this event is geared towards adults.

Canceled due to rain

This spring, we’re calling for volunteers to help plant over 400 native trees and shrubs. Be a part of a local effort to advance long-term goals for climate resilience and wildlife habitat restoration. This 45-acre forest restoration project in Community Park North is a joint initiative between the Municipality of Princeton and FOPOS, and it is funded in part by a Natural Climate Solutions grant from the NJDEP. From majestic canopy trees like white oak, red maple, and mockernut hickory to beautiful understory species such as redbud, flowering dogwood, and blackhaw viburnum, you’ll be helping rebuild a thriving, resilient ecosystem. No experience needed!

Volunteer with Friends of Princeton Open Space on Saturday, April 25th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m., and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend and groups are welcome!

RESERVE YOUR SPOT

Celebrate Arbor Day with Friends of Princeton Open Space (FOPOS) and eco-artist Susan Hoenig on Friday, April 24th at 10 AM for a unique experience that blends art, nature, and conservation. Explore the beauty of American beech trees through a special indoor exhibition, then step outside for a guided nature walk to a beech grove in John Witherspoon Woods.

Along the way, learn how these remarkable trees support entire forest ecosystems and why they are increasingly at risk from Beech Leaf Disease (BLD), a fast-spreading threat that can weaken and kill infected trees. Hear directly from the FOPOS stewardship team about the work underway to protect these vital trees and forest ecosystem.

REGISTER TO VOLUNTEER

This spring, we’re calling for volunteers to help plant over 400 native trees and shrubs. Be a part of a local effort to advance long-term goals for climate resilience and wildlife habitat restoration. This 45-acre forest restoration project in Community Park North is a joint initiative between the Municipality of Princeton and FOPOS, and it is funded in part by a Natural Climate Solutions grant from the NJDEP. From majestic canopy trees like white oak, red maple, and mockernut hickory to beautiful understory species such as redbud, flowering dogwood, and blackhaw viburnum, you’ll be helping rebuild a thriving, resilient ecosystem. No experience needed!

Volunteer with Friends of Princeton Open Space on Tuesday, April 21st, from 1 p.m. to 3 p.m. Come to one or both. Bring a friend and groups are welcome!

RESERVE YOUR SPOT

A community hike to commemorate the induction of Witherspoon Woods and 153-Acre Wood Old-Growth Areas into the Old-Growth Forest Network.

Join us for a celebration of TWO Old-Growth Forests in Princeton. We will celebrate and initiate both forests and head on a hike into Witherspoon Woods to see the oldest and most enduring trees in the region.

We will walk through a portion of the 40-acre Witherspoon Woods, known for its stately red oak, tulip poplar, black cherry, red maple and white oak trees in a mixed hardwood forest. Taking the red trail requires sturdy shoes as the terrain is uneven with frequent rock outcrops along the natural surface path.

REGISTER FOR GARLIC MUSTARD FORAGING

Join the Friends of Princeton Open Space (FOPOS) and local experts Matt and Shannon for a garlic mustard foraging & land stewardship session at the Billy Johnson Mountain Lakes Nature Preserve in Princeton.

During this stewardship session, participants will learn about the origins of garlic mustard and how to identify this plant. We will spend some time removing this tasty, but invasive plant that threatens the biodiversity at the Preserve and crowds out native plants. Folks will be able to take their garlic mustard harvest home, as well as taste some homemade garlic mustard recipes (compliments of Matt and Shannon). Recipes will be shared with participants so that you too can make these unique and delicious recipes at home.

REGISTER TO VOLUNTEER

This spring, we’re calling for volunteers to help plant over 400 native trees and shrubs. Be a part of a local effort to advance long-term goals for climate resilience and wildlife habitat restoration. This 45-acre forest restoration project in Community Park North is a joint initiative between the Municipality of Princeton and FOPOS, and it is funded in part by a Natural Climate Solutions grant from the NJDEP. From majestic canopy trees like white oak, red maple, and mockernut hickory to beautiful understory species such as redbud, flowering dogwood, and blackhaw viburnum, you’ll be helping rebuild a thriving, resilient ecosystem. No experience needed!

Volunteer with Friends of Princeton Open Space on Saturday, April 18th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m., and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend and groups are welcome!

REGISTER FOR NATURE JOURNALING MEETUP

We'll meet at Mountain Lakes House to draw from nature in a playful and non-judgmental setting. This meetup is FREE, although registration is required. The program is designed for adults and older teens. Younger participants (under 16) are welcome to join if accompanied by an adult.

What is a meetup and how is it different from a class? While a class is a structured learning environment with a defined curriculum, schedule, projects, and goals, a meetup is a gathering of people with shared interests who get together, often with a facilitator (in this case Eleni Litt).

Meetup Location: Mountain Lakes House

REGISTER FOR GARLIC MUSTARD FORAGING

Join the Friends of Princeton Open Space (FOPOS) and local experts Matt and Shannon for a garlic mustard foraging & land stewardship session at the Billy Johnson Mountain Lakes Nature Preserve in Princeton.

During this stewardship session, participants will learn about the origins of garlic mustard and how to identify this plant. We will spend some time removing this tasty, but invasive plant that threatens the biodiversity at the Preserve and crowds out native plants. Folks will be able to take their garlic mustard harvest home, as well as taste some homemade garlic mustard recipes (compliments of Matt and Shannon). Recipes will be shared with participants so that you too can make these unique and delicious recipes at home.

RESERVE YOUR SPOT

Join the Friends of Princeton Open Space (FOPOS) and expert birder Winnie Hughes Spar for a guided bird walk through the Billy Johnson Mountain Lakes Nature Preserve in Princeton, NJ. Together, we will observe Princeton's birds and learn about their fascinating habits!

Space is limited to 20 participants; be sure to sign up in advance. Please note that this event is geared towards adults.

REGISTER TO VOLUNTEER

Celebrate Earth Day all month long. Volunteer with Friends of Princeton Open Space at the Billy Johnson Mountain Lakes Nature Preserve. Join us as we work in our forest or riparian restoration project areas for critical tasks such as invasive species removal, spring planting, or installing cages around native plants to protect them from deer & beaver browse.

Volunteer with Friends of Princeton Open Space on Saturday, April 4th. There will be two volunteer sessions; the morning session is from 10 a.m. to 12 p.m., and the afternoon session is from 1 p.m. to 3 p.m. Come to one or both. Bring a friend and groups are welcome!

Join us at Mountain Lakes House to discuss "Walden" by Henry David Thoreau. The discussion will include an indoor study of plant pressings, with the opportunity to create one.

This series is presented in partnership with the Princeton Public Library and the Princeton Environmental Film Festival, and is dedicated to readings about conservation, stewardship, and our relationship with nature.

Sign up for this session via Princeton Public Library. You do not need to be a library cardholder to register.

RESERVE YOUR TICKET

Join the Friends of Princeton Open Space (FOPOS) and South Jersey Wildlife Tours for a guided Eastern Screech Owl Walk at dusk on Saturday, March 21st at 7:30pm.

Did you know that Eastern Screech Owls are one of the most common owl species in North America? Odds are you have one of these nocturnal neighbors mere miles (or less!) from your doorstep. During this experience, we will walk the trails at the Billy Johnson Mountain Lakes Nature Preserve in Princeton and listen and look for Eastern Screech Owls, learning much more about them along the way.

Space is limited to 20 participants; be sure to sign up in advance. Please note that this event is geared towards adults as it begins at 7:30 PM.

Please note that Screech Owl sightings are not guaranteed. We do have high owl activity at the preserve but you never know how the night will go.

REGISTER TO VOLUNTEER

Join FOPOS for a land stewardship volunteer session at the Billy Johnson Mountain Lakes Nature Preserve in Princeton on Saturday, March 21st. Volunteers will work under the guidance of the FOPOS stewardship staff to perform ecological restoration work and invasive plant removal.

We have two volunteer sessions: 10AM-12PM and 1PM-3PM. You are welcome to attend one or both sessions. Groups welcome!

REGISTER FOR THE MARCH NATURE WALK

Join us for our March Nature Walk through the trails of the Billy Johnson Mountain Lakes Nature Preserve. This guided walk offers a chance to explore the Preserve as spring emerges and the land wakes from its winter rest.

Meetup Location: Mountain Lakes House parking lot

REGISTER TO VOLUNTEER

Join FOPOS for a land stewardship volunteer session at the Billy Johnson Mountain Lakes Nature Preserve in Princeton on Wednesday, March 18th from 10AM-12PM. Volunteers will work under the guidance of the FOPOS stewardship staff to perform ecological restoration work and invasive plant removal.

REGISTER FOR NATURE JOURNALING MEETUP

We'll meet at Mountain Lakes House to draw from nature in a playful and non-judgmental setting. This meetup is FREE, although registration is required. The program is designed for adults and older teens. Younger participants (under 16) are welcome to join if accompanied by an adult.

What is a meetup and how is it different from a class? While a class is a structured learning environment with a defined curriculum, schedule, projects, and goals, a meetup is a gathering of people with shared interests who get together, often with a facilitator (in this case Eleni Litt).

Meetup Location: Mountain Lakes House