Treesearch

Tree regeneration in northern temperate and southern boreal forests is threatened by multiple factors, including over-browsing by ungulates such as white-tailed deer (Odocoileus virginiana). However, characterizing the effects of deer browse on tree regeneration at regional scales has been challenging due to (a) the lack of reliable indicators of browsing intensity and (b) the fact that browsing impacts are likely to vary by seedling size yet coarse metrics are often used to capture this seedling attribute. To address these challenges, we modeled effects of white-tailed deer browse and...

Forest drought monitoring tools are crucial for managing tree water stress and enhancing ecosystem resilience. The Forest Drought Response Index (ForDRI) was developed to monitor drought conditions in forested areas across the contiguous United States (CONUS), integrating vegetation health, climate data, groundwater, and soil moisture content. This study evaluated ForDRI using Pearson correlations with the Bowen Ratio (BR) at 24 Ameri- Flux sites and Spearman correlations with the Tree-Ring Growth Index (TRSGI) at 135 sites, along with feedback from 58 stakeholders. CONUS was divided into...

Rapid ‘ōhiʻa death (ROD), caused by fungal pathogens Ceratocystis lukuohia and Ceratocystis huliohia, is devastating ʻōhiʻa (Metrosideros polymorpha), the keystone forest tree species of Hawaiʻi. Ceratocystidaceae fungi produce fruity volatile organic compounds (VOCs) and sticky sexual spores, suggesting they are adapted for insect dispersal. In this study, we explored chemical signaling of the causal agents of the ROD disease complex and how those VOCs mediate ambrosia beetle (Coleoptera: Curculiondiae: Scolytidae)-plant interactions. Four species of ambrosia beetles (Xyleborinus saxesenii...

In Michigan, United States of America, where Asian parasitoids were released to manage emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), we monitored four native parasitoids that also attack the invasive beetle – Atanycolus cappaerti Marsh and Strazanac, A. simplex (Cresson), and Spathius laflammei Provancher (all Hymenoptera: Braconidae), and Phasgonophora sulcata Westwood (Hymenoptera: Chalcididae) – using yellow pan traps and tree dissections. Adult A. cappaerti, followed by A. simplex, had the broadest seasonal activity, S. laflammei was captured primarily in...

In the United States, ecosystems regularly experience wildfires and as fire seasons lengthen, fires are becoming a more important disturbance. While all types of disturbance have impacts on the carbon cycle, fires result in immediate emissions into the atmosphere. To assist managers in assessing wildland fire impacts, particularly on federally managed land, we developed estimates of area burned and related emissions for a 21-year period. These estimates are based on wildland fires defined by the interagency Monitoring Trends in Burn Severity database; emissions are simulated through the...

The expansion of African mahogany (Khaya spp.) plantations in Brazil has led to an increase in the number of associated insect pests. Here we report the first instances of defoliating caterpillars [Glena bipennaria bipennaria (Guenée) (Geometridae) and Apatelodes pandara Druce (Apatelodidae)] on commercial stands of African mahogany in Brazil, specifically Khaya grandifoliola C. DC. and Khaya senegalensis (Desr.) A. Juss. Glena b. bipennaria was the dominant defoliator in all stands, with A. pandara only found in K. senegalensis stands. We provide data on seasonal development, defoliation...

The United States national forest inventory (NFI) serves as the foundation for forest aboveground biomass (AGB) and carbon accounting across the nation. These data enable design-based estimates of forest carbon stocks and stock-changes at state and regional levels, but also serve as inputs to model-based approaches for characterizing forest carbon stocks and stock-changes at finer spatial and temporal resolutions. Although NFI tree and plot-level data are often treated as truth in these models, they are in fact estimates based on regional species-group models and parameters known collective...

This document contains abstracts and papers of the oral and poster presentations offered at the 32nd USDA Interagency Research Forum on Invasive Species held in Annapolis, MD, in January 2024. The forum, sponsored by the Forest Service, Animal and Plant Health Inspection Service, National Institute of Food and Agriculture, and Agricultural Research Service, illustrates the depth and breadth of studies supported by the agencies and their cooperators.

The USDA Forest Service supports research to promote forest health and protect trees from damaging agents, such as insects and disease. The Northern Research Station of the Forest Service collaborates with many partners to conduct research at local to international scales that offers insights and solutions to challenging forest health issues and helps meet unmet forest health needs. In 2024, the Northern Research Station published 65 publications related to forest health. This document reprints the abstracts for each publication and the 2023 regional forest health goals, threats, and needs...

Areas with landform characteristics that lead to more rapid runoff may be more vulnerable to increases in flood flows from more intense rainfall in the future. Those characteristics include fine-grained soils, low storage in lakes and wetlands, steep slopes, and high drainage densities. Landform characteristics that attenuate runoff include coarse-grained soils, high storage, gentle terrain, and low drainage densities. Groundwater recharge tends to be a dominant hydrologic process in such areas. Landtype associations (LTAs) are ecological units that relate closely with characteristics...