Treesearch

During biological invasions, the initial arrival and establishment of invading populations often go unnoticed for many years yet information on early invasion dynamics is key to understanding and managing invasions. We used the presence of ring discoloration, "rotholz", in tree cores to date historical Adelges piceae outbreaks and reconstruct its invasion history in 14 Abies balsamea subsp. phanerolepis stands in West Virginia. In 2018, we collected and cross-dated tree ring samples from 676 cores. We measured ring width increments and recorded the presence of rotholz in each annually...

Although spatial variation in climate can directly affect the survival and reproduction of forest insects and the tree species compositions of forests, little is known about the indirect effects of climate on outbreaks of forest insects through its effects on forest composition. In this study, we use structural equation modeling to examine the direct and indirect effects of climate, water capacity of the soil, host tree density, and non-host density on the spatial extent of Lymantria dispar outbreaks in the Eastern USA over a period of 44 years (1975–2018). Host species were subdivided...

Forest covers about one-third of the land area of the conterminous United States (CONUS) and plays an important role in offsetting carbon emissions and supporting local economies. Growing interest in forests as relatively cost-effective nature-based climate solutions, particularly restoration and reforestation activities has increased the demand for information on forest regrowth and recovery following natural and anthropogenic disturbances (e.g. fire, harvest, or thinning). However, a wall-to-wall mapping of the CONUS tree regrowth duration at an annual time interval and 30-m resolution...

On June 7, 2021, staff at the Maine Department of Agriculture, Conservation and Forestry (DACF), received reports of a black substance deposited on Wells Beach in Maine that was staining the bare feet of beachgoers over the previous two days (Edward Smith, personal communication, 2021). Similar reports also came from York, Kennebunk, and Ogunquit Beaches in Maine, Great Island Common beach in New Hampshire, and an unspecified beach in Gloucester, Massachusetts (Figure 1). Numerous news outlets reported on this phenomenon and on the concern from beachgoers about whether this substance could...

Carbon (C)-informed forest management requires understanding how disturbance and management influence soil organic carbon (SOC) stocks at scales relevant to landowners and forest policy and management professionals. The continued growth of data sets and publications allows powerful synthesis approaches to be applied to such questions at increasingly fine scales. Here, we report results from a synthesis that used meta-analysis of published studies and two large observational databases to quantify disturbance and management impacts on SOC stocks. We conducted this, the third in a series of...

Woody tissue carbon (C) concentration is a key wood trait necessary for accurately estimating forest C stocks and fluxes, which also varies widely across species and biomes. However, coarse approximations of woody tissue C (e.g., 50%) remain commonplace in forest C estimation and reporting protocols, despite leading to substantial errors in forest C estimates. Here, we describe the Global Woody Tissue Carbon Concentration Database (GLOWCAD): a database containing 3,676 individual records of woody tissue C concentrations from 864 tree species. Woody tissue C concentration data—i.e., the...

Wildfires devastated communities in Oregon and Washington in September 2020, burning almost as much forest west of the Cascade Mountain crest (“the westside”) in 2 weeks (~340,000 ha) as in the previous five decades (~406,00 ha). Unlike dry forests of the interior western United States, temperate rain forests of the Pacific Northwest have experienced limited recent fire activity, and debates surrounding what drove the 2020 fires, and management strategies to adapt to similar future events, necessitate a scientific evaluation of the fires. We evaluate five questions regarding the 2020 Labor...

No common global definition exists of urban populations, resulting in a lack of shared standards across countries for equivalent comparisons. Therefore, I used global population models of Landscan, Worldpop, and Gridded Population of the World to generate a provisional classification of population density classes to define urban and rural by human population densities, which is an enduring attribute to differentiate urban lands from rural lands. I calibrated 2015 population density models to the United Nations 2015 global urban population estimate of 53.9% and then balanced among the...

White pines (Pinus, subgenus Strobus) in North America are highly vulnerable to the native mountain pine beetle (Dendroctonus ponderosae), invasive white pine blister rust (Cronartium ribicola), and consequences of altered disturbance regimes, with sugar pine (Pinus lambertiana) being among the most in peril. Radial thinning treatments reflect an effort to balance the needs of late seral, high forest cover for some wildlife species with the desire to also promote habitat for species requiring higher light and lower competition, as well as to create heterogenous forest structure that can be...

Forest and nonforest ecosystems of the western United States are experiencing major transformations in response to land-use change, climate warming, and their interactive effects with wildland fire. Some ecosystems are transitioning to persistent alternative types, hereafter called “vegetation type conversion” (VTC). VTC is one of the most pressing management issues in the southwestern US, yet current strategies to intervene and address change often use trial-and-error approaches devised after the fact. To better understand how to manage VTC, we gathered managers, scientists, and practition...