Treesearch

Tropical forests represent < 15% of Earth's terrestrial surface yet support > 50% of the planet's species and play a disproportionately large role in determining climate due to the vast amounts of carbon they store and exchange with the atmosphere. Currently, disturbance patterns in tropical ecosystems are changing due to factors such as increased land use pressure and altered patterns in hurricanes. At the same time, these regions are expected to experience unprecedented warming before 2100. Despite the importance of these ecosystems for forecasting the global consequences of multiple...

Prescribed fire escapes continue to challenge most fire and land management agencies and many communities. This article considers the issue from knowledge management (KM) and organizational learning (OL) perspectives. We review organizational initiatives and the literature that have developed over the last 10 years to support learning from escaped prescribed fires, then use this to evaluate current learning practices and identify potential next frontiers for improving performance. Due to the difficulty obtaining statistics for non-federal entities, this review focuses primarily on developme...

Changes in individual climate variables have been widely documented over the past century. However, assessments that consider changes in the collective interaction amongst multiple climate variables are relevant for understanding climate impacts on ecological and human systems yet are less well documented than univariate changes. We calculate annual multivariate climate departures during 1958-2017 relative to a baseline 1958-1987 period that account for covariance among four variables important to Earth’s biota and associated systems: annual climatic water deficit, annual evapotranspiration...

Climate connectivity, the ability of a landscape to promote or hinder the movement of organisms in response to a changing climate, is contingent on multiple factors including the distance organisms need to move to track suitable climate over time (i.e. climate velocity) and the resistance they experience along such routes. An additional consideration which has received less attention is that human land uses increase resistance to movement or alter movement routes and thus influence climate connectivity. Here we evaluate the influence of human land uses on climate connectivity across North...

In this issue, we include topics from the importance of biocrusts on invasive versus native plant establishment, effects of dryland restoration on invasive plants, using native seed mixes (rather than nonnative grass mixes) to inhibit cheatgrass invasion after fire, and exploring volatiles of high-elevation pines to better understand resistance to insects and pathogens. As always, we welcome feedback on ways to improve the ISWG and this newsletter.

This paper describes our initial evaluation of survival and performance of 14 species of trees being tested in Southern California's Inland and Coastal communities as part of the statewide Climate-Ready Trees study. Overall, 88% of all trees survived the first three years and survival rates for trees in reference sites (95%) were greater than for trees in parks (84%). Survival rates were higher in the Inland parks where growing conditions more closely matched the arid environments from which many of these species originated. Differences in species' survival rates and performance are...

The balance of production activities at the landing is pivotal to the success of any forest harvesting operation and has a direct impact on the cost and effciency of the enterprise. The primary objective of this study was to understand the operational characteristics of the loader in a hot operation (handling both sawlog and biomass components concurrently) and cold operation (handling biomass and sawlogs separately) for harvesting sawlogs and biomass. Systematic work sampling techniques were employed to obtain “snapshots” of the loader activities for a cable logging operation, including...

Ecologists routinely fit complex models with multiple parameters of interest, where hundreds or more competing models are plausible. To limit the number of fitted models, ecologists often define a model selection strategy composed of a series of stages in which certain features of a model are compared while other features are held constant. Defining these multi-stage strategies requires making a series of decisions, which may potentially impact inferences, but have not been critically evaluated. We begin by identifying key features of strategies, introducing descriptive terms when they did...

Leptographium terebrantis S. J. Barras and T. J. Perry is an opportunistic root pathogen that compromises the xylem function of infected trees and is commonly associated with Pinus taeda L. stands that experience an unexplained loss of vigor in the southeastern U.S. To understand the relationship between L. terebrantis inoculation density, sapwood occlusion, and sapwood function characterized by hydraulic conductivity and moisture content, an artificial inoculation study was conducted in young P. taeda trees in a naturally regenerated stand over a 24-week period in south central Alabama....

The 2004 detection of the nonnative woodwasp Sirex noctilio F. (Hymenoptera: Siricidae) in New York (Hoebeke et al. 2005, Newsl. Mich. Entomol. Soc. 50: 24– 25) raised concerns of potential tree mortality in North America because S. noctilio has caused extensive mortality of pine trees in the Southern Hemisphere (Ciesla 2003, J. For. 101: 18–23). Unlike in the Southern Hemisphere, pine woodwasps and associated parasitoids are native to North America (Schiff et al. 2012, Can. J. Arthr. Ident. No. 21). Determining the phenology of native woodwasps in the United States should help to determine...