Leader Bios

When you join a Yosemite Conservancy Outdoor Adventures program, you will have quality time in the field with some of the most knowledgeable and talented naturalists, historians and artists in Yosemite. Collectively, they’ve hiked tens of thousands of miles in the park, won numerous awards, authored dozens of books, and had their art or photographs published around the world. Our guides are excited to share their passion for Yosemite with you.

John Ricca

John Ricca is a San Francisco Bay Area professional fine art photographer who uses the camera to capture moods and visual experiences usually associated with other visual art forms. He focus on natural and close-up images that emphasize shapes, textures, and patterns. He tutors individuals and small groups in photography workshops and field trips on how to improve their photographic techniques. He has exhibited in numerous group and solo exhibitions throughout the Bay Area.

Heather Sullivan

Heather Sullivan co-founded and served as the first Executive Director of Balanced Rock and is now the Program Director. Heather is both a yoga instructor and an accomplished backcountry guide with Yosemite destinations and trips in the Himalayas. She has been a NatureBridge (formerly Yosemite Institute) field instructor, a Volunteer Mountaineering Ranger in Denali National Park in Alaska, and Naturalists at Large instructor. Her yoga classes blend Ashtanga flow, Iyengar alignment, a strong connection to the rhythms of the natural world.

Kylie Chappell

Kylie Chappell grew up in the Yosemite gateway, Mariposa. She has always enjoyed a love for the outdoors including rock climbing, backpacking, skiing and swimming. After traveling abroad to New Zealand, Australia and China she couldn’t wait to return to her roots and settle in Yosemite. She has worked as a horseback riding guide and packer in Yosemite for three years. As the Outdoor Adventure Coordinator for Yosemite Conservancy, Kylie is able to share her love and knowledge of Yosemite with visitors from all over the world.

Glen Young

Glen Young was born in the flatlands of Michigan. After completing a Master’s in Park, Recreation, and Tourism Management in New Zealand, Glen worked as an alpine guide, and in the fields of international, environmental, and outdoor education throughout the United States (including Alaska and Hawaii). He also worked abroad in Canada, Thailand, Laos, Cambodia, Vietnam, Burma, Malaysia, Singapore, Nepal, Australia, New Zealand, Ecuador, and Peru where he led study abroad programs and adventure education activities.

Allison Baggett

Allison Baggett grew up in a small town at the entrance to Yosemite. She has backpacked from Mr. Whitney to Canada on the Pacific Crest Trail and from Portland, Oregon, to Missoula, Montana, following the route of Lewis and Clark. Allison has worked as a teacher, naturalist, mountain guide and artist since graduating from The Evergreen State College in Olympia, Washington. She has been trained as a Wilderness Emergency Medical Technician and currently holds a Wilderness First Responder certificate.

Julia Parker

Julia Parker has lived and worked in Yosemite for over fifty years where she is the park’s longest-tenured employee. As a “living legend”, Julia has dedicated her life to preserving and communicating traditional American Indian cultural history, inspiring visitors to be responsible environmental stewards. She has studied under master weavers and currently demonstrates basket weaving techniques at the Yosemite Museum. Her handiwork is highly sought after and several of her baskets are displayed in prominent museums and collections all over the world.

Peter Hemming

Peter Hemming grew up in Los Angeles and now lives on the Monterey Peninsula. He is a featured Nikon photographer who has been published in hundreds of periodicals and websites around the world. He is a member of the Explorers Club and has extensive experience traveling in the High Sierra, with a particular focus on the Tuolumne Meadows area.

Gus Smith

Gus Smith has worked in Yosemite National Park as the Fire Ecologist for the last three years. Prior to working in Yosemite, he was an associate professor of Biology and Natural Resources at Northland College in northern Wisconsin for ten years. Gus developed a research interest and passion for wildland fire while working in the pine barrens of Wisconsin. Gus enjoys hiking in the Sierra forests and foothills and identifying the patterns that fires have left for us to discover. Sequoia trees are a favorite.

Christine White Loberg

Christine White Loberg has lived and worked in Yosemite for many years and has devoted herself to a photographic exploration of the park. She attended Cal State Fullerton and the Brooks Institute of Photography in Santa Barbara. She’s worked as a photographer for The Ansel Adams Gallery and has had her work published in books, calendars, magazines, etc. The thousands of Yosemite visitors she’s met in her years as an interpretive ranger will attest to her great enthusiasm for the park.

Wayne Christensen

Wayne Christensen is a local astronomer with a passion for the clear skies of the Sierra. He grew up in Los Angeles but was mesmerized by the stars on family trips to Pinecrest. Wayne lived in Hawaii for many years, where he was president of the Hawaii Astronomical Society. He lives near Sonora, just north of Yosemite, where he has instructed astronomy programs for Columbia College. He looks forward to carrying his Dobsonian telescope to where ever he can find dark skies and open space.

Jon Byers

Jon Byers did his first backpack trip in Canyonlands at age four and has always loved wild country. He’s been a member of the NatureBridge (Yosemite Institute) faculty for the last few years and has taught programs for the Conservancy since last summer. Originally from Colorado, Jon studied geology and ecology and has recently been learning HD videography. He is a co-founder of the Alpine Americas Project, a citizen effort to survey climate changes in the Sierra and the Andes.

Ken Rockwell

Ken Rockwell is a talented photographer and host of a popular website for essays, photo galleries, lessons and equipment reviews. Having fully the embraced digital age, Ken is equally adept with traditional 35mm, panoramic, medium and large format photography. An engineer by training, Ken has an artistic eye and is excited to share his knowledge and opinions about photography.

Dave Wyman

Dave Wyman is an accomplished photographer and author of three pictorial guidebooks (“Backroads of Northern California”, “Backroads of Southern California”, and “Yosemite in Photographs”). His photographs and articles have appeared in Outdoor Photographer, Outside, Backpacker, Sky and Telescope, and many other publications. He is an experienced guide, leading tours for environmental organizations and museums, in addition to photography tours and workshops through his company, Image Quest. He enjoys sharing his passion for photography and the outdoors.

Dick Ewart

Dick Ewart, a veteran hiker and winter enthusiast, has been a park ranger in Yosemite for over thirty years. He has a Bachelor’s degree in biology from the University of New Hampshire and has hiked and snowshoed most of the park’s 800 miles of trails. Dick spends his summers presenting naturalist programs at Glacier Point while during the winter he enjoys leading snowshoe hikes at the Badger Pass Ski Area.

John Senser

John Senser is an accomplished landscape and wildlife photographer/writer. His images have appeared in Sierra Club calendars and National Geographic publications and he is regularly featured in Central Sierra Seasons Magazine. He has conducted numerous courses and workshops for organizations including the University of California and Columbia College. As the owner of Yosemite Light Photography, he produces finely crafted photographic prints and notecards that are sold at art shows and galleries around California.

Greg Stock

Greg Stock is Yosemite’s first park geologist. He has a Ph.D. in Earth Sciences from the University of California, Santa Cruz where his research focused on dating the uplift rate of the Sierra Nevada. Since arriving in Yosemite he has been researching geologic hazards such as rock falls and debris flows, and piecing together Yosemite’s glacial history. Greg enjoys sharing the story of Yosemite’s geology and makes it sound as fascinating as it really is.

Shirley Spencer

Shirley Spencer is a renowned artist, musician/singer, athlete and educator. She is also the author/illustrator of Yosemite Conservancy’s “Flowering Shrubs of Yosemite and the Sierra Nevada” and co-author (with her husband Mark) of “Southern Yosemite Rock Climbs”. Since the 1980s, thousands have been lucky enough to explore Yosemite with Shirley and share her infectious affinity for the outdoors.

Robert Hanna

Robert Hanna, a descendent of John Muir, has a special life-long connection to Yosemite. After starting his career in financial services, Robert now runs an outdoor clothing company (Range of Light) and is deeply involved with environmental causes. He has inherited John Muir’s love for the Sierra and his passion for advocating wilderness preservation.

Scott Borden

Scott Borden was a faculty member for two years at NatureBridge (formerly Yosemite Institute) before becoming the Mentor Teacher overseeing science and service-learning projects. He is a rockclimber and naturalist with a love of the outdoors.

Karen Amstutz

Karen Amstutz is a California native with a Masters in Environmental Education who has over 15 years of experience working in Yosemite. She has taught for NatureBridge and has worked as a National Park Service ranger in Tuolumne Meadows, where she is well-known for her campfire programs. Karen lives with her family in El Portal and loves to share her extensive knowledge about the natural world.

Chris Van Winkle

Chris Van Winkle is an award-winning California artist who has served as president of the National Watercolor Society. He was also selected as one of the “top twenty” art instructors by Watercolor Magazine. For the past 30 years, Chris has taught watercolor at Citrus College in Southern California.

Charles Waldman

Charles Waldman started pursuing a career as a full-time fine art painter in 1999 after practicing Family Medicine in Sonora, Calif. for 22 years. He was selected as an Artist Member of the California Art Club, The Laguna Plein Air Painters and “The Sea-to-Shining-Sea” Exhibition. He shows in galleries throughout the country, attends plein air events, and teaches numerous workshops. Chuck loves to paint outdoors in the Sierras and enjoys sharing his artistic vision and philosophy with others.

Suzanne Swedo

Suzanne Swedo is the director of W.I.L.D. and has backpacked the mountains of every continent. She has led groups into the backcountry for over 30 years and teaches wilderness survival and natural science for individuals, schools, universities, museums and organizations, including Yosemite Conservancy and the Sierra Club. She has authored numerous books and has appeared on radio and television to share her knowledge of backpacking, botany and wilderness survival.

Lucy Parker

Lucy Parker is descended from a long line of Yosemite cultural interpreters. Brought up in a traditional cradle basket, Lucy worked in the park as an Indian cultural demonstrator for many seasons. She has also performed living history at Bodie State Park, and demonstrated traditions of the Paiute people at the Lee Vining Visitor Center.

Mike Osborne

Mike Osborne recently retired after a 30 year career as a ranger in Yosemite, including eight seasons as a wilderness ranger. Mike has actively photographed nature for over thirty-five years. His images have been used in promotional programs and literature supporting the Yosemite Fund and the Yosemite Association. He is also the author of the book Granite, Water & Light, an interpretive and photographic paean to the waterfalls of Yosemite Valley.

David Lukas

David Lukas is a popular and knowledgeable naturalist who has been leading programs in the Sierra Nevada and writing natural history books for over 20 years. He is the author of the revised guidebook “Sierra Nevada Natural History” and the new comprehensive guidebook, “Sierra Nevada Birds” in addition to contributing to 40 additional books. David lives in Groveland, Calif. and delights in leading visitors on hikes in Yosemite.

Michael Elsohn Ross

Michael Elsohn Ross has led Outdoor and Custom Adventures for Yosemite Conservancy since 1977. He is the award-winning author of 42 books for young people including “Baby Bear Isn't Hungry”, “The Happy Camper Handbook”, “The World of Small”, and “Snug as a Bug”. He teaches children’s book writing workshops and is a popular speaker at schools and conferences around the world. Michael is passionate about sharing Yosemite’s diversity to newcomers and long-time park enthusiasts. He lives with his family near the park in a home overlooking the Merced River.

Moira Donohue

Moira Donohue was born and raised in Yosemite, California, was lucky to be in daily contact with grandparents who were also born and raised there in the 1880s. Their influence, and freedom to roam the woods and mountains, shaped and continue to inform her identity. Says Moira, “I paint my experience of the landscape - time, emotion, the bugs, the breeze, the colors, and me. I love being out in the elements.

Pete Devine

Pete Devine has taught outdoors in Yosemite for 30 years and is the now the Yosemite Conservancy’s Resident Naturalist. Originally from New England, Pete has worked in the West as a park ranger, archeologist, river guide, naturalist and teacher. He has hiked the Alps, Andes, Himalaya, Min Shan and Southern Alps, and has a bird list that includes motmots, minivets, drongos and the plain-mantled tit spinetail. Pete has been studying the recession of Yosemite’s Lyell Glacier since 1998.