North American Forest
Genetics Society

F. Thomas Ledig, August 13 1938 – May 20 2015

IN MEMORIAM
 

Former F&ES Professor and Renowned Forest Geneticist

Dr. F. Thomas Ledig, a former professor at F&ES, died on May 20 in Vallejo, Calif., at the age of 76 from metastatic melanoma. He was a world-renowned research scientist in the fields of forest genetics and conservation biology, and he traveled the world consulting with government and scientific institutions. Tom was born in Dover, N.J. He earned a B.S. from Rutgers Univ. and an M.S. and Ph.D. from North Carolina State Univ. He was a member of the faculty of F&ES from 1967-1981, working his way up to becoming a full professor and member of the F&ES Board of Permanent Officers.

In 1979, Tom joined the U.S. Forest Service's Pacific Southwest Research Station in California as Director of the Institute of Forest Genetics. Tom retired from the Forest Service in 2008 as senior scientist and continued as an adjunct professor at the Univ. of California, Davis. He remained an active researcher, and his most recent work involved genetic diversity in conifers, evaluating experiments he established in 1973-1974 on the effects of climate change on pitch pine, and working on a National Geographic Society grant to study Coulter pine in Baja California. He produced over 135 publications in genetics and physiology. To the end, he maintained his interests in hiking the mountains and the Southwest desert, photog- raphy, SCUBA diving, and collecting fine and folk art.

Major recognition of his life's work includes the Society of American Foresters Barrington Moore Memorial Award for outstanding achievement in biological research; Fellowship in the American Association for the Advancement of Science; a special award from the Universidad Autónoma Agraria Antonio Narro, Saltillo, Mexico; and two North American Forest Commission awards. His service as secretary of the U.N./FAO/North American Forest Commission's Forest Genetic Resources Working Group was one of the most rewarding experiences of his career.

Yet, his most treasured honor was a 1997 letter, signed by former colleagues at Yale that reads, in part, "We miss the joie de vivre that left when you left." "Tom was an important factor in the transition of the program from traditional forestry to a broader emphasis on ecosystems," noted F&ES Professor Emeritus Bill Burch. "He played a significant part in our debates, where he was always sensitive to the need for keeping the old to bolster the new bold shift. It was not about dominance of a par- ticular discipline, but rather about the need for continuity and a constructive base of traditional practices."

F&ES Professor Graeme Berlyn remembered Tom as a "seminal faculty member here in forest genetics who rose through the ranks to full professor. Tom Ledig, Tom Siccama, and I shared an interest in pitch pine. Tom Ledig had long-term study sites in Connecticut and New Jersey.”

"It seems only yesterday (though it was this past February) he had called me for information about native pitch pine on Canaan Mountain to support his continuing research here," remarked Star Childs '76 B.S., '80 M.F.S. "He had such a calm and soothing voice and wonderful sense of joyful curiosity in this world and everyone in it. I am glad he was my teacher and life-long friend, even though the merid- ians of longitude between us were many."

Tom was beloved by his family and a host of friends from all over the world. He is survived by his wife, Linda Marie Lux; three children from a former marriage: Colleen Stanton Cassidy, Sean Cormac Ledig, and Brendan Owen Ledig; his grandson, Nicholaus Vitaly Ledig; brother Alan Lloyd Ledig; and father-in-law Raymond Clyde Lux.
 

Tom's Obituary

Written by Tom's dear friend and colleague Bohun B. Kinloch, Jr., for submittal to professional journals, December 2015 After overcoming two separate assaults of cancer over a span of 20 years, Tom succumbed to metastatic melanoma at his home in Vallejo, CA. He will be missed sorely by his family, former students, and many personal friends -- from home, office, and around the world. The collegium of forest geneticists and evolutionary biologists will miss his keen insights into population biology that he described in his papers with such clarity and cogency. These intellectual contributions were translated into practical strategies, policies, and action for conservation of forest genetic resources, including genes, populations, and threatened species.

Tom was a luminary in all of his professional undertakings. A cum laude graduate from Rutgers, he went on to get his MS and Ph. D degrees from North Carolina State University, supported in part by a National Science Foundation Fellowship. His first major job was as Assistant Professor at Yale, where he rose to Full Professor and Member of the Board of Permanent Officers, before leaving in 1979 to become Director of the Institute of Forest Genetics at the U.S. Forest Service’s Pacific Southwest Experiment Station in Berkeley, California. While there, he was also appointed Adjunct Professor at the University of California, Davis, where courses he taught in plant conservation genetics were often oversubscribed. Professional recognition was accorded him by several Universities, governments, and professional organizations. Especially notable were Fellowship in the AAAS, and the Society of American Foresters prestigious Barrington Moore Memorial Award for “outstanding achievement in biological research leading to the advancement of forestry”. But the tribute he cherished most personally was a remark in a letter signed by former colleagues at Yale: “We miss the joie de vivre that left when you left.”

An early and leading apostle conservation of forest genetic resources, Tom gave abundantly of his time and energy to many institutions and organizations. He served over two decades as Secretary of FAO’s North American Forest Commission’s Forest Genetics Working Group. Under his leadership the Commission was active in habitat protection and seed collection of fast growing and stress-adapted populations of tree species important to world forestry. His service was recognized with two awards for “significant and long-standing contribution” to the Commission. Because of his familiarity with forest conditions on every continent and broad perspective on conservation issues, he was able to contribute to many national programs, and was often invited as a keynote speaker for symposia and Distinguished Professorships at several universities at home and abroad. He wrote extensively and poignantly of the depredations humankind has caused to biodiversity historically, while proposing strategies for mitigation and remedy. Above all, perhaps, were his deep feelings for the spiritual and ethical dimensions of conservation: “Esthetic reasons are the hardest to pin down, but I believe that diversity is necessary to the health of humanity. Some sense of diversity seems necessary for sanity.”

Tom’s research spanned an unusually broad area of forest genetics, from the physiological genetics of photosynthesis and growth, to practical tree improvement, population genetics and taxonomy. Tree species he investigated were equally diverse, including pines, spruce, oak, and eucalyptus. But his main focus was on the genetic structure of tree populations: their diversity, origins, adaptations, mating systems, and migration patterns, especially as these properties might be affected by climate change.

His research often took him to isolated and relict populations in remote, almost inaccessible locations, such as the Sierra Oriental and Sierra Occidental for the rare Mexican pines and spruces; Brewer spruce in the Klamath Mountains of northern California; Engelmann and blue spruce from the mountains and sky islands of the Rockies; and Torrey pine from the Channel Islands of California. Some of Tom’s colleagues, of a more timber-beast persuasion, needled him for his seeming preoccupation with non-commercial “trash trees” (as they called them). But Tom’s vision was strategic: he chose subjects most likely to lead to insights into the evolutionary dynamics of populations, that would in turn inform policy guidelines for conservation. (Of course, he also loved the excitement of the chase, and its physical challenges; one time, during a field trip to the parched and rugged Ventana Wilderness of California, he alarmed staff when he failed to show up for a meeting he had scheduled. But a day later, exhausted, hungry, scratched and bleeding -- but smiling defiantly – he and crew stumbled out of the tall brush, holding the bagged quarry in hand: cones of the rare Santa Lucia fir from the high peaks. Even Indiana Jones might have been envious).

A main concern was about how population fragmentation, whether through climate change, habitat loss, or logging might affect genetic diversity and integrity of tree populations, and their ability to continue to evolve and adapt.

The rare and endangered Mexican spruces and pines were thus of special interest, because they represented natural experiments of populations under severe disruption and selection pressure. Paleontological evidence had shown spruce to be much more widespread in Mexico during the Pleistocene, extending down into the lowlands. Tom and coworkers showed how climate warming in the Holocene caused wholesale retreat of spruce populations northward and higher in elevation. As they migrated, individual populations became highly disjunct and often decimated. Some of the genetic consequences documented were overall loss of diversity through genetic drift; the positive association of heterozygosity with population census; highly increased homozygosity in some populations, leading to inbreeding depression severe enough to threaten the continued existence of populations; and in an extreme case, evidence that Maxipinion, a species with only a single existing population, also had a maximum of two alleles per locus, most at intermediate frequencies -- suggesting its possible origin from a single seed! A major accomplishment, coincident with these individual investigations, was bringing taxonomic coherence, using molecular markers, to the complex and long-unresolved relationships among the six species of western and southwestern spruces of North America. In both pines and spruces, his work showed that migration patterns could be tracked with molecular genetic data: populations migrating north from different glacial refugia after the last ice age lost diversity as a result of founder effects and genetic drift; this of course had important consequences for identifying contemporary centers of diversity for conservation purposes. He provided empirical evidence that heterozygosity was positively related to fitness, and the negative effects of inbreeding on reproductive health of populations.

His research ended where it began as an Assistant Professor at Yale, over 40 years earlier, on the Pine plains and Pine Barrens of New Jersey, in a common garden of rangewide provenance sources of pitch pine (Pinus rigida). One of the most variable of eastern conifers, pitch pine had long intrigued forest ecologists ever since Gifford Pinchot first described the strange pygmy forest (Pine Plains) embedded within the tall forest (Pine Barrens) of New Jersey. For it’s innovative design and far reaching objectives, his study proposal was awarded a National Science Foundation grant for its implementation, and several other grants over the years for its continuation and completion. Numerous publications were forthcoming, some still in press. Some outstanding insights from this study included demonstration of the positive relationship between the degree of heterozygosity and fitness; evidence from genetic data of the origin of pitch pine from at least three widely spread refugia following the last glacial maximum, including one on the exposed continental shelf; and, most interestingly, a remarkable example of natural selection: that in spite of potentially massive gene flow from the surrounding forest, the dwarf form of pitch pine derived from a suite of heritable traits associated with reproduction, culminating in the evolution of a distinct fire ecotype.

Not a bad legacy for trash trees.

Vale, Tom