Treesearch

Aim: Tree size distributions are an emergent feature of forest dynamics across space and time. Theory suggests that undisturbed forests exhibit a size-abundance distribution captured by a power-law relationship with a near-2 slope. We aimed to quantify how disturbances systematically and predictably cause deviations from this expected pattern. Location: Contiguous United States. Time Period: 2001–2023. Major Taxa Studied: Diverse tree communities. Methods: We analysed size-abundance distributions in over 160,000 FIA plots for both disturbed and undisturbed forests, examining changes in...

Background: Remote sensing (RS) technologies provide unprecedented opportunities to assess forest structure at broad spatial scales. Light detection and ranging (LiDAR) is a powerful tool that offers detailed vertical information, but its consistent high-resolution coverage can be limited across vast areas and quantifying understory vegetation remains challenging due to occlusion. Conversely, while high-resolution RGB imagery is more accessible and valuable for large-scale analyses, it comes with higher uncertainty and only captures canopy-level information. Integrating RGB data with...

Aspen (Populus tremuloides) forests are generally thought to impede fire spread, yet the extent of this effect is not well quantified in relation to other vegetation types. We examined the influence of aspen cover on interpolated daily fire spread rates, the relative abundance of aspen at fire perimeters versus burn interiors, and whether these relationships shifted under more fire-conducive atmospheric conditions. Our study incorporated 314 fires occurring between 2001 and 2020 in the southwestern United States and a suite of gridded vegetation, topography, and fire weather predictor...

In recent years, the U.S. Federal government has advanced shared stewardship (see Study Background for definition) of Federal lands with American Indian Tribes across land management agencies. Yet little is understood about how these efforts are carried out in the context of Wild and Scenic Rivers (WSRs). The WSRs are managed across four Federal land management agencies: the Bureau of Land Management, the Forest Service, the National Park Service, and the U.S. Fish and Wildlife Service. Rivers designated under the WSR Act are managed to protect their free-flowing, undammed quality, along...

As the impacts of drought intensify with climate change, adaptation to drought is becoming an increasingly important consideration for tree breeding and forest management. This elevates the need to understand how breeding for faster growth affects drought tolerance and if breeding to improve drought tolerance could help mitigate the impacts of drought on forest health and productivity. To understand the implications for tree breeding in future climates, we studied how selective breeding of western larch (Larix occidentalis) for faster growth affects drought resistance (a component of...

Since the 1960s, there has been an increasing trend in oak (Quercus spp.) dominated forests exhibiting poor oak regeneration and recruitment, and associated hickories (Carya spp.) are likely undergoing a similar trend. Additionally, American chestnut (Castanea dentata) responses to management have been poorly studied. Silvicultural treatments to increase oak regeneration include prescribed fires and stand thinning, but often show mixed results. One potential issue is grouping oaks and hickories when analyzing treatment responses. This may obscure species- or genus-specific responses,...

Soils are a critical component of forest ecosystems and the global terrestrial carbon cycle. They regulate the resources that limit plant and microbial activity, support biodiversity, serve as reservoirs of carbon, and influence forest health. Systematic soil data can help fill key knowledge gaps, such as the sensitivity of forest health and functioning to disturbances and agents of change and the capacity of soils to help mitigate climate change through carbon storage. Since 2000, the Nationwide Forest Inventory (NFI) conducted by the Forest Inventory and Analysis (FIA) program has...

Establishing riparian zones to protect fish has been a standard forest management practice in western Oregon and Washington for decades. But to effectively place these zones, one needs to know where fish are living. Brooke Penaluna, a research fisheries biologist with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, has led the development of a new model that predicts the presence of fish more accurately than previous models or other methods, which relied heavily on electrofishing— a labor-intensive method of manually surveying streams. Her new model,...

Individual fire history studies paint a picture of how often and how severely fires burned on specific landscapes, providing valuable points of evidence for land management decisions. Syntheses of multiple fire history studies weave these individual pictures into a panoramic tapestry, providing a more complete understanding of historical fire regimes. For example, syntheses of fire history studies in ponderosa pine communities tell stories about precolonial historical fires frequently burning small areas and occasionally burning large areas, followed by a century with very few fires due to...

Healthy streams play a critical role in supporting plant, fish, and animal communities. However, stream degradation is a global problem that threatens the condition of these important ecosystems. Channel incision is one way that streams can change in response to natural or human processes. This process of degradation leads to lower water tables and a lost connection to the floodplain. As a result, water availability changes for the riparian plant communities, resulting in further degradation.