My work assesses sustainability of afforestation and plantation forestry as part of the Jackson lab. I am interested in the interactions of plants, soils, and people, and in answering ecological questions to understand how humans can participate in and contribute to healthy ecosystems.

Current Research and Scholarly Interests

I am interested in human land use and its interactions with soils and vegetation. My general research goal is to address ecological questions related to land use to help humans participate in healthy ecosystems. Currently, I study the long-term effects of tree-planting and plantation forestry on soil nutrients and plant productivity. My research focuses on the extreme case of eucalyptus plantations in Southeastern Brazil, where rapid tree growth yields efficient pulp and paper production and potential bioenergy feedstock, as well as concerns about depletion of water and nutrients from the soil. I combine remote sensing, soil chemistry, and statistical techniques to address these concerns at large spatial and temporal scales, as well as at the plot level.

Lab Affiliations

All Publications

  • A global meta-analysis of soil phosphorus dynamics after afforestation NEW PHYTOLOGIST Deng, Q., McMahon, D. E., Xiang, Y., Yu, C., Jackson, R. B., Hui, D. 2017; 213 (1): 181-192


    Afforestation significantly affects soil chemistry and biota, but its effects on the potentially growth-limiting nutrient phosphorus (P) had not to our knowledge been analyzed globally. We conducted a comprehensive meta-analysis of 220 independent sampling sites from 108 articles to evaluate global patterns and controls of soil P change following afforestation. Overall, total P concentration decreased by 11% and total P stock by 12% in the top 20 cm of mineral soil following afforestation, with no change in available P. Time since afforestation had no consistent effect on total P, while available P tended to increase with time. Prior land cover was the most influential factor for soil P change after afforestation, with available P increasing on native vegetation but decreasing on cropland. Afforestation increased available P by 22% without decreasing total P on formerly 'degraded' land, but depleted total P by 15% at nondegraded sites. Climate also influenced soil P response to afforestation, with larger P loss in the tropics. Afforestation did not appear to directly induce P limitation, as available P only decreased on cropland. However, substantial declines in total P may drive tropical plantations toward greater P limitation as the capacity to replenish available P decreases.

    View details for DOI 10.1111/nph.14119

    View details for Web of Science ID 000389184600020

    View details for PubMedID 27477387

  • Tree community shifts and Acorn Woodpecker population increases over three decades in a Californian oak woodland CANADIAN JOURNAL OF FOREST RESEARCH McMahon, D. E., Pearse, I. S., Koenig, W. D., Walters, E. L. 2015; 45 (8): 1113-1120