Treesearch

The 2020 Resources Planning Act (RPA) Assessment explores the present condition and 50-year outlook for the Nation’s forest and rangeland resources. This chapter follows the organization of the resource-specific chapters (Chapters 4 through 11). Each section provides the key findings of the corresponding chapter, as well as the results that support those findings. Key findings apply to the conterminous United States unless otherwise specified.

The 2020 Resources Planning Act (RPA) Assessment summarizes findings about the status, trends, and projected future of the Nation's forests and rangelands and the renewable resources that they provide. The 2020 RPA Assessment specifically focuses on the effects of both socioeconomic and climatic change on the U.S. land base, disturbance, forests, forest product markets, rangelands, water, biodiversity, and outdoor recreation. Differing assumptions about population and economic growth, land use change, and global climate change from 2020 to 2070 largely influence the outlook for U.S....

Climate change is expected to lead to higher temperatures in the Mediterranean region of northern California in the Sierra Nevada. Dendroclimatic studies typically focus on large, old trees, but there relatively limited understanding on how climatic sensitivity can vary with trees of different size classes. We collected tree increment cores and compared radial growth responses of small (20.32 to ≤40.64 cm), medium (40.64 to ≤60.96 cm), and large (>60.96 cm) diameter mixed conifer species in the Sierra Nevada to different climate variables (temperature, precipitation, and climate moisture...

The eruption of Mount St. Helens in 1980 resulted in a cataclysmic restructuring of its surrounding landscapes. The Pumice Plain is one of these landscapes, where tree species such as Sitka willow (Salix sitchensis) and their dependent communities have been established along newly-formed streams. Thus, the study of these dependent communities provides a unique and rare opportunity to investigate factors influencing metacommunity assembly during true primary succession. We analyzed the influence of landscape connectivity on metacommunity assembly through a novel application of circuit...

Forest management affects conditions for both early- and late-seral organisms, and managers and conservationists require information for balancing the ostensibly opposing habitat needs of both these guilds. We conducted meta-analyses that examined silvicultural systems with a range of postharvest retention and their impacts on mature-forest and shrubland bird species densities in eastern North America during the breeding season. Densities of mature-forest bird species generally declined as canopy tree retention and basal area decreased, although some mature-forest species had similar...

Wildfire affects many types of communities and is a particular concern for communities in the wildland urban interface (WUI), such as those of Park County, Colorado. The core intent of this project was to provide evidence to support the Platte Canyon Fire Protection District (PCFPD) and Fire Adapted Bailey in their wildfire mitigation and education programming. This report describes wildfire risk data collected in fall 2020 and pairs it with social data collected in the fall and winter of 2020-2021, in order to better understand residents’ knowledge, experiences, and perceptions about...

Our understanding of how bees (Apoidea) use temperate forests is largely limited to sampling the understory and forest floor. Studies over the last decade have demonstrated that bee communities are vertically stratified within forests, yet the ecology of bee assemblages immediately above the canopy, the canopy-aerosphere interface, remains unexplored. We sampled and compared bee communities above the canopy of a temperate forest to the understory (1 m), midstory (10 m), and canopy (20 m) on the campus of the University of Massachusetts, in Amherst, Massachusetts, United States from April...

Climate change and land-use change are leading drivers of biodiversity decline, affecting demographic parameters that are important for population persistence. For example, scientists have speculated for decades that climate change may skew adult sex ratios in taxa that express temperature-dependent sex determination (TSD), but limited evidence exists that this phenomenon is occurring in natural settings. For species that are vulnerable to anthropogenic land-use practices, differential mortality among sexes may also skew sex ratios. We sampled the spotted turtle (Clemmys guttata), a...

Ecosystem services provided by the natural enemies of agricultural pests can increase crop yield in low intensity agricultural systems. However, these services are highly variable, and trade-offs may exist between harmful and beneficial species. An increasing proportion of New England farms have adopted farming practices that retain extensive native vegetation, and prior research has shown these practices support native bird populations. To determine the pest control services provided by birds on low-intensity New England farms, we compared pest populations and leaf damage on crops where...