Research Database
Displaying 1 - 5 of 5
Future climate risks from stress, insects and fire across US forests
Year: 2022
Forests are currently a substantial carbon sink globally. Many climate change mitigation strategies leverage forest preservation and expansion, but rely on forests storing carbon for decades to centuries. Yet climate-driven disturbances pose critical risks to the long-term stability of forest carbon. We quantify the climate drivers that influence wildfire and climate stress-driven tree mortality, including a separate insect-driven tree mortality, for the contiguous United States for current (1984–2018) and project these future disturbance risks over the 21st century. We find that current…
Publication Type: Journal Article
Rapid Growth of Large Forest Fires Drives the Exponential Response of Annual Forest-Fire Area to Aridity in the Western United States
Year: 2022
Annual forest area burned (AFAB) in the western United States (US) has increased as a positive exponential function of rising aridity in recent decades. This non-linear response has important implications for AFAB in a changing climate, yet the cause of the exponential AFAB-aridity relationship has not been given rigorous attention. We investigated the exponential AFAB-aridity relationship in western US forests using a new 1984–2019 database of fire events and 2001–2020 satellite-based records of daily fire growth. While forest-fire frequency and duration grow linearly with aridity, the…
Publication Type: Journal Article
Tree mortality response to drought-density interactions suggests opportunities to enhance drought resistance
Year: 2022
1. The future of dry forests around the world is uncertain given predictions that rising temperatures and enhanced aridity will increase drought-induced tree mortality. Using forest management and ecological restoration to reduce density and competition for water offers one of the few pathways that forests managers can potentially minimize drought-induced tree mortality. Competition for water during drought leads to elevated tree mortality in dense stands, although the influence of density on heat-induced stress and the durations of hot or dry conditions that most impact mortality remain…
Publication Type: Journal Article
Riparian and adjacent upland forests burned synchronously during dry years in eastern Oregon (1650-1900 CE), USA
Year: 2020
Riparian forests link terrestrial and freshwater communities and therefore understanding the landscape context of fire regimes in these forests is critical to fully understanding the landscape ecology. However, few direct studies of fire regimes exist for riparian forests, especially in the landscape context of adjacent upland forests or studies of long-term climate drivers of riparian forest fires. We reconstructed a low-severity fire history from tree rings in 38 1-ha riparian plots and combined them with existing fire histories from 104 adjacent upland plots to yield 2633 fire scars…
Publication Type: Journal Article
Crowded and Thirsty: Fire exclusion leads to greater drought sensitivity in mixed-conifer forests
Year: 2020
Wildfires were a frequent source of disturbance in forests of the Western United States prior to Euro-American settlement. Following a series of catastrophic wildfires in the Northern Rockies in 1910, the U.S. Forest Service adopted a broad wildfire suppression policy that has resulted in forests thick with small trees. These crowded trees compete for nutrients and water and experience increased drought stress in summer.In recent decades, many trees have died following drought, bark beetle outbreaks, and severe wildfire. A link between this mortality and increasing susceptibility to drought…
Publication Type: Report