Treesearch

Biological invasions by insects that vector plant pathogens have altered the composition of natural and urban forests. Thousand cankers disease is a new, recent example and is caused by the complex of walnut twig beetle, Pityophthorus juglandis, and the fungus, Geosmithia morbida, on susceptible hosts, notably some Juglans spp. and Pterocarya spp. Host colonization by P. juglandis may be particularly important for disease development, but the beetle's host range is not known. In the United States and Italy, this insect has expanded its geographic range by colonizing naïve hosts. The...

Flame and mass loss data for chaparral, a mixture of shrub plants from the Mediterranean climate zone of southwestern North America, from five previously reported experiments were used to evaluate several published models relating flame characteristics to mass loss and heat release rates. These data are unique with fuel moisture content ranging from 0.36 to 0.94 (dry basis); the study used mass loss rates which included water loss. Fit of the data to Froude number correlations developed by Albini, Byram, Nelson and Thomas and heat release rate—flame length correlations by Heskestad,...

A study of commercial timber-harvesting activities in Montana was conducted during 2011 to 2016 to estimate growing-stock removals, characterize current tree utilization and logging operations, and assist with estimating the amount of woody biomass left onsite after harvesting. Sample logging sites were selected within major geographic regions proportional to 5-year timber harvest volumes. A two-stage sampling method was used to compute State-level logging utilization factors. Results of the study indicated that in Montana, for every 1,000 cubic feet (CF) delivered to the mill, harvesting...

On a warm July day in 2014, our group headed out to a field tour on the Mark Twain National Forest. The purpose of the trip was to learn firsthand what stakeholders thought of the Missouri Pine-Oak Woodlands Restoration Project. As wildlife ecologists and foresters, we were well aware of the conservation issues for this ecosystem and the ecological benefits of restoring open forests. On this visit we heard conservation agencies, an NGO, and even a local landowner voice their support for the project. It soon became clear, however, that not everyone agreed with the goals or the management...

Conserving multiple facets of biodiversity is important for sustaining ecosystems. However, understanding relationships between faunal diversity and measurable ecosystem quantities, such as heterogeneity and productivity, across continental scales can be complicated by disparate methods. We developed standardized approaches using lidar data and spectral greenness data (via NDVI; Normalized Difference Vegetation Index) from 637 sampling plots across four sites in North America, Europe, and Asia to test the local effects of habitat heterogeneity and productivity on taxonomic, functional, and...

Emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), an invasive beetle from Asia, spreads through human-mediated movement and active flight. The effects of adult feeding and overwintering conditions on A. planipennis energy reserves (e.g., lipid, glycogen, and sugars) and flight are poorly understood. We conjectured that the potential energetic demands associated with the production of cryoprotectants might affect dispersal capacity and partially explain slower spread of A. planipennis in Minnesota than in the other states. Two studies sought to measure the effects...

The emerald ash borer, Agrilus planipennis Fairmaire, is invading North America and Europe but has not yet reached its ultimate distribution. Geographic differences in host availability and winter temperatures might affect where this species will occur. In central North America, black ash (Fraxinus nigra) is more abundant than green ash (F. pennsylvanica) at northern latitudes, but much of our current understanding of A. planipennis cold tolerance is based on observations of overwintering larvae from green ash. The effects of black and green ash on the cold hardiness of A. planipennis...

The walnut twig beetle (Pityophthorus juglandis Blackman) (Coleoptera: Curculionidae) is a regulated pest in the United States due to its causal role in thousand cankers disease of walnut trees, including the commercially valuable eastern black walnut (Juglans nigra L.). Several state quarantines designed to limit spread of P. juglandis regulate movement of kiln-dried walnut lumber that contains bark. Previous research demonstrated that P. juglandis will enter and re-emerge from bark of kiln-dried, J. nigra slabs subjected to extreme beetle pressure (baited with a pheromone lure and hung...

The South’s production of pulpwood decreased from 61.8 million cords in 2014 to 60.6 million cords in 2015. Roundwood production decreased by 260 thousand cords to 49.5 million cords and accounted for 82 percent of the South’s total pulpwood production. The use of wood residue dropped 8 percent to 11.2 million cords in 2015. Georgia and Alabama led the South in total production, with 10.1 and 9.6 million cords, respectively. In 2015, 79 mills were operating and drawing wood from the 13 Southern States.

The statistical properties of candidate methods to adjust for the bias in growth estimates obtained from observations on increasing interval lengths are compared and contrasted against a standard set of estimands. This standard set of estimands is offered here as a solution to a varying set of user expectations that can arise from the jargon surrounding a particular data aggregation procedure developed within the USDA’s Forest Inventory and Analysis Program, specifically the term “average annual” growth. The definition of a standard set of estimands also allows estimators to be defined and...