Andrew J. Larson
A5014738523- Fire effects on ecosystems
- Ecology and Vegetation Dynamics Studies
- Forest ecology and management
- Rangeland and Wildlife Management
- Forest Ecology and Biodiversity Studies
- Plant Water Relations and Carbon Dynamics
- Forest Management and Policy
- Remote Sensing and LiDAR Applications
- Plant and animal studies
- Species Distribution and Climate Change
- Tree-ring climate responses
- Landslides and related hazards
- Forest Insect Ecology and Management
- Fire dynamics and safety research
- Mycorrhizal Fungi and Plant Interactions
- Archaeology and Natural History
- Animal Ecology and Behavior Studies
- Lung Cancer Diagnosis and Treatment
- Remote Sensing in Agriculture
- Atmospheric and Environmental Gas Dynamics
- Electric Vehicles and Infrastructure
- Cryospheric studies and observations
- Recreation, Leisure, Wilderness Management
- Marine and Offshore Engineering Studies
- Climate Change Policy and Economics
University of Montana
2016-2025
University of Louisville
2023
Rocky Mountain Research Station
2009-2021
Rocky Mountain Research (United States)
2021
National Museum of Natural History
2020
ForestGEO
2020
Universiti Brunei Darussalam
2020
The University of Texas MD Anderson Cancer Center
2011-2020
National Renewable Energy Laboratory
2018
University of Washington
1997-2017
Persistent changes in tree mortality rates can alter forest structure, composition, and ecosystem services such as carbon sequestration. Our analyses of longitudinal data from unmanaged old forests the western United States showed that background (noncatastrophic) have increased rapidly recent decades, with doubling periods ranging 17 to 29 years among regions. Increases were also pervasive across elevations, sizes, dominant genera, past fire histories. Forest density basal area declined...
Abstract Aim To examine the contribution of large‐diameter trees to biomass, stand structure, and species richness across forest biomes. Location Global. Time period Early 21st century. Major taxa studied Woody plants. Methods We examined large density, biomass using a global network 48 (from 2 60 ha) plots representing 5,601,473 stems 9,298 210 plant families. This was assessed three metrics: largest 1% ≥ 1 cm diameter at breast height (DBH), all DBH, those rank‐ordered that cumulatively...
Summary The relationship between species richness and ecosystem function, as measured by productivity or biomass, is of long‐standing theoretical practical interest in ecology. This especially true for forests, which represent a majority global biodiversity. Here, we conduct an analysis relationships tree richness, biomass 25 forest plots area 8–50 ha from across the world. data were collected using standardized protocols, obviating need to correct methodological differences that plague many...
Maintaining tree diversity Negative interaction among plant species is known as conspecific negative density dependence (CNDD). This ecological pattern thought to maintain higher in the tropics. LaManna et al. tested this hypothesis by comparing how changes with intensity of local biotic interactions tropical and temperate latitudes (see Perspective Comita). Stronger specialized seem prevent erosion biodiversity forests, not only limiting populations common species, but also strongly...
Resilience and resistance concepts have broad application to ecology society. is an emergent property that reflects the amount of disruption a system can withstand before its structure or organization uncharacteristically shift. Resistance component resilience. Before advent intensive forest management fire suppression, western North American forests exhibited naturally occurring resilience wildfires other disturbances. Using evidence from ten ecoregions, spanning Canada Mexico, we review...
More than a century of forest and fire management Inland Pacific landscapes has transformed their successional disturbance dynamics. Regional connectivity many terrestrial aquatic habitats is fragmented, flows some ecological physical processes have been altered in space time, the frequency, size intensity disturbances that configure these altered. Current efforts to address impacts yield small footprint comparison wildfires insect outbreaks. Moreover, current projects emphasize thinning...
Large-diameter trees dominate the structure, dynamics and function of many temperate tropical forests. Although both scaling theory competition make predictions about relative composition spatial patterns large-diameter compared to smaller diameter trees, these are rarely tested. We established a 25.6 ha permanent plot within which we tagged mapped all ≥1 cm dbh, snags ≥10 shrub patches ≥2 m2. sampled downed woody debris, litter, duff with line intercept transects. Aboveground live biomass...
Increasing fire severity and warmer, drier postfire conditions are making forests in the western United States (West) vulnerable to ecological transformation. Yet, relative importance of interactions between these drivers forest change remain unresolved, particularly over upcoming decades. Here, we assess how interactive impacts changing climate wildfire activity influenced conifer regeneration after 334 wildfires, using a dataset from 10,230 field plots. Our findings highlight declining...
Abstract Fire suppression is the primary management response to wildfires in many areas globally. By removing less-extreme wildfires, this approach ensures that remaining burn under more extreme conditions. Here, we term “suppression bias” and use a simulation model highlight how bias fundamentally impacts wildfire activity, independent of fuel accumulation climate change. We illustrate attempting suppress all necessarily means fires will with severe less diverse ecological impacts, burned...
Abstract Numerous studies have shown reduced performance in plants that are surrounded by neighbours of the same species 1,2 , a phenomenon known as conspecific negative density dependence (CNDD) 3 . A long-held ecological hypothesis posits CNDD is more pronounced tropical than temperate forests 4,5 which increases community stabilization, coexistence and diversity local tree 6,7 Previous analyses supporting such latitudinal gradient 8,9 suffered from methodological limitations related to...
Ecological systems often exhibit resilient states that are maintained through negative feedbacks. In ponderosa pine forests, fire historically represented the feedback mechanism ecosystem resilience; exclusion reduced resilience, predisposing transition to an alternative state upon reintroduction of fire. We evaluated effects reintroduced frequent wildfire in unlogged, fire‐excluded, forest Bob Marshall Wilderness, Montana, USA. Initial 2003 tree density and consumed surface fuels, but also...
Large-diameter trees dominate the structure, dynamics and function of many temperate tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged mapped all 30,973 woody stems ≥1 cm dbh, 1,966 snags ≥10 shrub patches ≥2 m2. Basal area 26 species was 62.18 m2/ha, 61.60 m2/ha 0.58 tall shrubs. (≥100 dbh) comprised 1.5% stems, 31.8% basal area, 17.6% with...
Abstract. Advances in forest carbon mapping have the potential to greatly reduce uncertainties global budget and facilitate effective emissions mitigation strategies such as REDD+ (Reducing Emissions from Deforestation Forest Degradation). Though broad-scale is based primarily on remote sensing data, accuracy of resulting stock estimates depends critically quality field measurements calibration procedures. The mismatch spatial scales between inventory plots larger pixels current planned...
Understanding how climate affects tree growth is essential for assessing change impacts on forests but can be confounded by effects of competition, which strongly influences responses to climate. We characterized the joint size, and diameter using hierarchical Bayesian methods applied permanent sample plot data from montane Mount Rainier National Park, Washington State, USA, are mostly comprised Abies amabilis Douglas ex Forbes, Tsuga heterophylla (Raf.) Sarg., Pseudotsuga menziesii (Mirb.)...
Rates and spatial patterns of tree mortality are predicted to change during forest structural development. In young forests, should be primarily density dependent due competition for light, leading an increasingly spatially uniform pattern surviving trees. contrast, in old‐growth forests caused by contagious autocorrelated agents (e.g., insects, wind), causing aggregation trees increase through time. We tested these predictions contrasting a three‐decade record from replicated mapped...
One mechanism proposed to explain high species diversity in tropical systems is strong negative conspecific density dependence (CDD), which reduces recruitment of juveniles proximity adult plants. Although evidence shows that plant-specific soil pathogens can drive CDD, trees also form key mutualisms with mycorrhizal fungi, may counteract these effects. Across 43 large-scale forest plots worldwide, we tested whether ectomycorrhizal tree exhibit weaker CDD than arbuscular species. We further...
Mortality processes in old‐growth forests are generally assumed to be driven by gap‐scale disturbance, with only a limited role ascribed density‐dependent mortality, but these assumptions rarely tested data sets incorporating repeated measurements. Using 12‐ha spatially explicit plot censused 13 years apart an approximately 500‐year‐old Pseudotsuga – Tsuga forest, we demonstrate significant mortality and aggregated tree recruitment. However, the combined effect of strongly nonrandom...
Forest dynamics plots, which now span longitudes, latitudes, and habitat types across the globe, offer unparalleled insights into ecological evolutionary processes that determine how species are assembled communities. Understanding phylogenetic relationships among in a community has become an important component of assessing assembly processes. However, application information to questions ecology been limited large part by lack accurate estimates individual found within communities, is...