About

Jeffrey Gale Williamson is the Laird Bell Professor of Economics, Emeritus, and an Honorary Fellow in the Department of Economics at the University of Wisconsin (Madison). He served as Chairman of the Economics Department from 1997 to 2000 and as the department's Director of Undergraduate Studies during 2001-2002 and 2004-2005. He was also Master of Harvard's Mather House from 1986 to 1993 and has received the Galbraith Prize for the best teacher in Harvard's graduate economics program twice, as well as the Hughes Prize for outstanding teaching from the Economic History Association in 2000. Since retiring from Harvard in July 2008, he continues to conduct research on economic history and the contemporary Third World. His recent research topics include the growth and distributional implications of demographic transitions in Asia, the Atlantic economy from 1820 to 1940, the impact of international migration, capital flows, and trade on factor price convergence since 1830, and the causes and effects of globalization backlash before World War I. He has also explored the sources and consequences of mass migrations prior to the 1920s and after the 1950s, as well as the economic implications of 1492. His current projects involve establishing a database and analyzing the evolution of world factor prices and living standards since 1820, and examining economic change in the Third World since 1750, including debates over terms of trade, tariff policy, de-industrialization, re-industrialization, South-South migration, and the fundamental economic-demographic drivers of growth. Born and raised in New England, Professor Williamson is married to Nancy, has four children, and five grandchildren. He returned to Madison upon retirement, where he previously taught at the University of Wisconsin from 1963 to 1983 before moving to Harvard in 1983. His leisure activities include chopping firewood, swimming, sailing, and building woodland trails at his Maine cottage.

Research topics

• Biology
• Horticulture
• Mathematics
• Agronomy
• Botany
• Surgery
• Ecology
• Animal science
• Medicine

Selected publications

• Postharvest Quality and Shelf Life of Three Thornless Blackberry Cultivars over Two Seasons

  Horticulturae · 2025-09-05 · 1 citations

  articleOpen access

  Postharvest deterioration remains a major challenge for blackberries, particularly in warm climates where shelf life is limited. This study evaluated the postharvest performance of three thornless cultivars grown under subtropical conditions: ‘Prime-Ark® Freedom’, ‘Osage’, and ‘Sweet-Ark™ Ponca’ using a two-phase cold storage regime (0 °C for 7 days, then 5 °C for 9 days). Over two seasons (2023–2024), fruit quality was assessed at days 0, 7, 12, and 16, focusing on weight loss, leakiness, red drupelet reversion (RDR), soluble solids content (SSC), titratable acidity (TTA), SSC/TTA ratio, and ascorbic acid. Cultivar responses varied: ‘Prime-Ark® Freedom’ showed strong storage resilience with minimal weight loss and fewer disorders, although SSC and ascorbic acid levels were lower. ‘Osage’ maintained high SSC, SSC/TTA, and ascorbic acid, favoring shorter storage for fresh markets. ‘Sweet-Ark™ Ponca’ had high SSC/TTA ratios but was prone to leakiness and RDR. Ascorbic acid declined during storage in 2023 but was better preserved in 2024, especially with ‘Prime-Ark® Freedom’. Our results provide actionable insights for cultivar selection in postharvest strategies that are critical to preserving fruit quality and extending shelf life in blackberries.

  PublisherOA PDFDOI

• Adaptation and Early Establishment of Olive Trees (Olea europaea L.) under the Humid Subtropical Climate of the Southeastern United States

  HortScience · 2025-07-21

  articleOpen access

  Olive cultivation in the southeastern United States is challenging due to the warm and humid subtropical climate of the region. This study examined the impact of cultivar selection, transplant strategy, and environmental conditions on the adaptability and early establishment of olive trees in Florida. Two research orchards were established at two different locations (Citra and Jay), featuring three cultivars (Arbequina, Arbosana, and Koroneiki) transplanted at two sizes (large and small). Shoot and root growth were monitored over 2 years (Jul 2017 to May 2019) to assess transplant stress, tree establishment, and environmental adaptation. Small transplants exhibited higher growth rates than large ones, with differences in tree height and trunk cross-sectional area diminishing over time. Large transplants experienced greater transplant stress, as evidenced by a significant reduction in number of primary branches. Severe winter temperatures at Jay caused damage to ‘Arbosana’ and ‘Koroneiki’ trees, leading to high mortality rates and poor post-winter recovery growth. In contrast, ‘Arbequina’ demonstrated greater tolerance to both transplant stress and cold damage, maintaining stable vegetative growth. Root growth was primarily influenced by environmental factors rather than cultivar selection or transplant size. Total root length declined from 4 to 9 months after transplant (MAP), but it remained stable from 9 to 20 MAP. Most roots were concentrated within 20- to 40-cm soil depth, likely due to irrigation. These findings highlight the complex interactions among cultivar, transplant size, and environmental conditions. In addition, our results suggest ‘Arbequina’ has potential for commercial cultivation in the region. Further research is needed to assess long-term effects on productivity and resilience.

  PublisherDOI

• Preparing a Southern Highbush Blueberry Field for Machine Harvesting

  EDIS · 2024-05-01

  articleOpen access1st authorCorresponding

  Blueberries are grown commercially in Florida for the early-season fresh fruit market. The majority of Florida’s blueberry crop is currently harvested by hand to ensure high quality standards for fresh fruit production. However, hand harvesting is the single greatest annual production cost for Florida blueberry growers, and mechanization of berry harvests could greatly reduce production costs. This is particularly important when considering the volume of fruit imported into the United States from countries where labor rates are significantly lower. Also, at times the availability of harvest labor when needed may be an issue for Florida growers; mechanization could help address that issue. This publication provides information for commercial blueberry growers interested in adopting machine harvesting.

  PublisherOA PDFDOI

• Principles and Significance of Nitrogen Management for Blackberry Production

  Agriculture · 2024-08-24 · 2 citations

  articleOpen access

  Blackberry cultivation presents significant opportunities for fruit growers in subtropical regions, where nitrogen (N) is identified as a crucial macronutrient for optimal production. Given the variability in climate and soil conditions, determining the ideal N fertilizer amount can be complex. Effective blackberry cultivation requires careful attention to the principles of nutrient stewardship, including the selection of appropriate N sources, application rates, timing, and placement. Recommended N rates generally range from 25–45 kg/ha in the first year and 45–70 kg/ha in subsequent years, with adjustments based on plant type and regional conditions. The choice of fertilizer, particularly NH4+, is beneficial for blackberry plants, which thrive in acidic soils and show improved biomass and chlorophyll levels with this form of N. Research on N-cycling reveals its importance in supporting new plant growth, such as primocane development. However, improper N management, either excessive or insufficient, can negatively impact flower bud production and, consequently, fruit setting and yield. By using databases such as Google Scholar, Scopus, and Web of Science, this review synthesizes existing research on the role of N in blackberry cultivation, emphasizing the importance of precise fertilization practices tailored to regional climate and soil conditions. By highlighting variations in recommended N amounts and underscoring the principles of nutrient stewardship, this review aims to guide growers in achieving sustainable and high-quality blackberry production.

  PublisherOA PDFDOI

• Transitioning Away from Fossil Fuels Will Drive Repositioning of Horticulture

  HortScience · 2024-03-26 · 3 citations

  articleOpen access

  Like everything for the past 2 centuries, agriculture has depended increasingly on fossil fuel energy. Pressures to shift to renewable energy and changes in the fossil fuel industry are set to massively alter the energy landscape over the next 30 years. Two near-certainties are increased overall prices and/or decreased stability of energy supplies. The impacts of these upheavals on specialty crop production and consumption are unknowable in detail but the grand lines of what will likely change can be foreseen. This foresight can guide the research, extension, and teaching needed to successfully navigate a future very unlike the recent past. Major variables that will influence outcomes include energy use in fertilizer manufacture, in farm operations, and in haulage to centers of consumption. Taking six increasingly popular fruit and vegetable crops and the top two horticultural production states as examples, here we use simple proxies for the energy requirements (in gigajoules per ton of produce) of fertilizer, farm operations, and truck transport from Florida or California to New York to compare the relative sizes of these requirements. Trucking from California is the largest energy requirement in all cases, and three times larger than from Florida. As these energy requirements themselves are all fairly fixed, but in future will likely rise in price and/or be subject to interruptions and shortages, this pilot study points to two commonsense inferences: First, that fruit and vegetable production and consumption are set to reposition to more local/regional and seasonal patterns due to increasing expenses associated with fuel, and second, that coast-to-coast produce shipment by truck will become increasingly expensive and difficult.

  PublisherDOI

• Government Agency Resources for Florida Blueberry Growers

  EDIS · 2024-06-04 · 1 citations

  articleOpen accessSenior author

  Several federal, state, and local government offices and agencies offer assistance and resources to Florida blueberry growers. These include the University of Florida and IFAS Extension, the U.S. Department of Agriculture (USDA), the Florida Department of Agriculture and Consumer Services (FDACS), and various Florida water management districts. This publication summarizes some of the resources and assistance available from each of these agencies, along with website links as a starting point for growers to use in learning more about and accessing that assistance.

  PublisherOA PDFDOI

• Radioluminescence Dosimetry in Modern Radiation Therapy

  Advanced Photonics Research · 2024-07-15 · 12 citations

  articleOpen access

  Accurate and precise measurement of radiation energy delivered to and absorbed by the patient's tissue is of great importance in radiation therapy (RT) quality assurance. Radioluminescence (RL) dosimetry has shown great potential for high spatiotemporal resolution dose measurement of RT fields. Implementation of efficient RL dosimetry in RT requires multidisciplinary effort and skills in optics, medical physics, radiation physics, electronics, and imaging science. In this review, a wide overview of fundamentals and applications of RL properties of media for RT dosimetry with emphasis on their potential use for multidimensional, small‐field, and ultra‐high dose rate RT dosimetry is provided.

  PublisherOA PDFDOI

• The Senator’s Son

  Digital Commons-Sarah Lawrence (Sarah Lawrence College) · 2023-05-01

  article1st authorCorresponding
  Publisher

• Hydrogen Cyanamide Application Accelerates Vegetative Bud Break and Causes Earlier Yield in ‘Optimus’ and ‘Colossus’ Southern Highbush Blueberry

  HortScience · 2023-08-18

  articleOpen accessSenior author

  Southern highbush blueberry ( Vaccinium corymbosum interspecific hybrid) cultivation is a major industry in subtropical regions where low winter temperatures are infrequent and inconsistent. In Florida and other subtropical areas, growers use hydrogen cyanamide (HC) applications during endodormancy to mitigate the negative effects of low chill accumulation. Hydrogen cyanamide is a synthetic plant growth regulator that increases and expediates dormancy release and budbreak. However, southern highbush blueberry cultivars differ in their sensitivity to HC. Optimus and Colossus are two recently released cultivars from the University of Florida blueberry breeding program. The effects of HC in these cultivars are unknown. This research aimed to describe responses to HC applications at different rates for these new varieties. Experiments took place in a commercial farm in Waldo, FL, on 3- to 4-year-old deciduous blueberry bushes. HC was applied at rates of 3.8 g·L −1 (0.38%), 5.1 g·L −1 (0.50%), and 6.4 g g·L −1 (0.63%) in ‘Optimus’ and 3.8 g·L −1 (0.38%), 5.1 g·L −1 (0.50%), 6.4 g·L −1 (0.63%), and 7.7 g·L −1 (0.75%) in ‘Colossus’. In both cultivars, the control treatment was not sprayed. Vegetative bud count, and flower bud development, flower bud mortality, and yield were determined. HC application thinned reproductive buds and increased vegetative budbreak. Although seasonal yield was not increased, HC advanced fruit ripening early in the season.

  PublisherOA PDFDOI

• Irrigation Practices for Southern Highbush Blueberry in Florida

  EDIS · 2022-01-04

  articleOpen accessSenior author

  This new 4-page publication of the UF/IFAS Horticultural Sciences Department provides guidance on irrigation requirements and practices to Florida Southern highbush blueberry growers. Written by Douglas A. Phillips and Jeffrey G. Williamson.https://edis.ifas.ufl.edu/hs1432

  PublisherOA PDFDOI

Recent grants

• Coping With City Growth: Urban Labor, Land and Housing Markets

  NSF · $161k · 1984–1990

Frequent coauthors

• Richmond Williams

  222 shared

• Peter H. Lindert

  University of California, Davis

  199 shared

• Carol Petraitis

  196 shared

• C Knick

  Queens University of Charlotte

  180 shared

• Timothy J. Hatton

  167 shared

• Hugh Rockoff

  145 shared

• Stefano Fenoaltea

  University of Massachusetts Boston

  144 shared

• William Lazonick

  Research Network (United States)

  143 shared

Education

• Ph.D., Economics

  University of California, Berkeley

  1976

• B.A., Economics

  Harvard University

  1971

Awards & honors

• Galbraith Prize for the best teacher in Harvard's graduate e…
• Hughes Prize for outstanding teaching in the Economic Histor…