In the archives of the Chestnut Hill Conservancy, there’s a photograph of a towering tree in the snow, its branching trunk as thick and menacing as thunder. The photo, taken on the grounds of what would become the Morris Arboretum in about 1910, has a tragic air – but not because of the tree’s gesture. It’s because of what was lost.

The tree in the photo is a glorious specimen of the American chestnut, Castanea dentata, a species that once dominated Eastern forests from Maine to Georgia and from the prairies to the Piedmont, providing timber for our growing nation’s telegraph poles and railroad ties, and food for wildlife and humans alike. 

A few years before the photo was taken, a fungal blight from Asia was discovered in American chestnuts in New York City. The disease spread quickly among these stately, native trees, which had no natural resistance, and within four decades, all of the nation’s mature American chestnuts were dead above the roots. “Functional extinction” is the term scientists use to describe the state of the species, meaning it hasn’t died out, but shoots can’t grow old and large enough to produce nuts and reproduce before the fungus stunts or kills the tree.

For most organisms, reaching the point of functional extinction would be the end of the line, but some species grab hold of the human imagination and won’t let go. 

Across the country, and here in the Philadelphia region, a growing number of people are joining efforts to develop disease-resistant chestnuts that could eventually repopulate Eastern forests. 

Early demonstrations of those efforts are increasingly visible around the region – especially here in Chestnut Hill, the neighborhood named for this majestic tree. And if you’re a homeowner, and you want to experience the magic of chestnuts in a deeper, more personal way, you also can plant your own.

The most visible “wild” American chestnuts newly planted in the area are in Chestnut Hill’s Pastorius Park, put there in 2021 by a group of volunteers led by arborist and passionate chestnut advocate Erik Werner, proprietor of Hedgerows Tree Service of Mt. Airy. You can find the small grove of these tiny, young trees – each in its own small wire enclosure to prevent damage and grazing – in a clearing on the north side of the park. 

Because they have no natural disease resistance, these trees are highly unlikely to survive very long after reaching sexual maturity. But volunteers are hoping that one of the disease-resistant transgenic American chestnuts currently being developed by researchers at the SUNY College of Environmental Science and Forestry in Syracuse, New York, will be approved by the U.S. Department of Agriculture in time to be planted amidst these “wild” youngsters in Pastorius Park and pollinate them, conferring its genetically engineered immunity to the nuts they produce.

Genetic engineering isn’t the only pathway to a disease-resistant chestnut. On a parallel track, a nonprofit organization called the American Chestnut Foundation (ACF) is using a more old-fashioned horticultural tool: cross-breeding. The goal in that project is to create a hybrid that’s as genetically close to the American chestnut as possible, but with disease resistance conferred by a Chinese chestnut (Castanea mollissima), a species that isn’t susceptible to fungal blight. 

They start by crossing an American chestnut with a Chinese chestnut, then take the hybrid offspring, select for disease resistance, and cross it back with “wild” American chestnuts for multiple generations. In this effort, the hope is to gradually reduce the Chinese chestnut portion of the hybrid offspring’s genetic material while maintaining its disease resistance. 

Northwest Philadelphia now has several examples of these American-Chinese hybrids, including on the grounds of Springside Chestnut Hill Academy. Students planted dozens in a teaching grove on campus in 2019, as part of a partnership with the ACF. Hybrid chestnuts also can be found in the public collection of the Morris Arboretum.

For some tree lovers, short visits with small trees won’t be enough. Fortunately, there are other options for enthusiasts who are looking for a more immersive experience. For example, people who support the ACF’s mission at the “Seed Level” of membership may be eligible to receive seeds harvested from select parent trees with elevated blight resistance. 

If you want to grow a chestnut and see it reach maturity and produce gorgeous and tasty nuts, try planting a Chinese chestnut. 

Somewhat shorter than their enormous American cousins, Chinese chestnuts often branch lower to the ground and form a broadly spreading crown, eventually reaching heights of 40 to 60 feet. Their prolific, sweet-scented flowers emerge in late June, and their nuts follow in the fall. Just watch out for the spiny, green burs that surround them – those burs bite. But it’s worth it to get at these beautiful nuts and their crisp, slightly sweet nutmeat. 

For now, until the hard work of innumerable researchers, volunteers and supporters turns the dream of restored American chestnut forests into a reality, savoring the beauty of a Chinese chestnut and the bounty it creates is as close as we can get to the glory of that massive tree in that haunting old photo.

Paul Meyer is the retired F. Otto Haas Executive Director of the Morris Arboretum of the University of Pennsylvania and a board member of the Chestnut Hill Conservancy and the Chestnut Hill Garden District Fund.