Treesearch

Plant-carbon inputs to soils in the form of dissolved sugars, organic acids and amino acids fuel much of heterotrophic microbial activity belowground. Initial residence times of these compounds in the soil solution are on the order of hours, with microbial uptake a primary removal mechanism. Through microbial biosynthesis, the dissolved compounds become dominant precursors for formation of stable soil organic carbon. How the chemical class (e.g. sugar) of a dissolved compound influences stabilization in field soils is unknown and predictions from our understanding of microbial metabolism,...

The use of biomass as a source of energy has been identified as a viable option to diminish reliance on fossil fuels. We parameterized the effect of selected internal (e.g. coal-fire presence), external (e.g. price and renewable energy mandates) and location (e.g. biomass availability, infrastructure) variables on the likelihood of using biomass in cofiring with coal by building a two-stage econometric model. The first stage controlled for factors driving the spatial location of coal power plants and the second stage concentrated on factors influencing cofiring. The empirical model was...

Cronartium ribicola is one of the most destructive forest pathogens of North American white pines. The pathogen infects pine trees through their stomata, colonizes the stem, and produces stem cankers the following growing season. In this research, we collected samples from different white pine populations across Canada and the United States to develop an efficient ex vitro and in vitro screening method for phenotype expression of western white pine (Pinus monticola Douglas ex D. Don) following inoculation with C. ribicola. A major group of partial resistant plants in British Columbia,...

There is now a very long history of genetics/breeding for disease resistance in annual crops. These efforts have resulted in conceptual advances and frustrations, as well as practical successes and failures. This talk will review this history and its relevance to the genetics of resistance in forest species. All plant breeders and pathologists are familiar with boom-and-bust cycles of single major resistance genes. Though there may be occasional situations where a single-gene approach to resistance is reasonable, most interest is in finding alternatives to this approach. This is especially...

Quantitative resistance to white pine blister rust in 128 controlled- and open-pollinated sugar pine families was evaluated in a “disease garden”, where alternate host Ribes bushes were interplanted among test progenies. Overall infection was severe (88%), but with great variation among and within families: a 30-fold range in numbers of infections per tree, and a 10- fold range in trees with completely inactive, or aborted infections. Inheritance of these partial resistances was strong, with significant amounts of both additive and non-additive genetic variance evident. They will be most...

The Fourth International Workshop on the Genetics of Host-Parasite Interactions in Forestry (July 31-August 5, 2011) included a session on “Ecology and Evolutionary Biology of Resistance and Tolerance, Natural Systems.” Within this session, I gave a talk entitled “An overview of ecological and evolutionary research on disease in ‘natural’ systems” that reviewed research on disease that is primarily in ecology and evolutionary biology journals (as opposed to forestry and plant pathology journals). Several people requested that I provide details of the references listed in that talk, and...

The exotic fungus Cronartium ribicola causes the disease white pine blister rust on five-needled pines throughout North America. Although the effects of this disease are perhaps better known on pines in the western portion of the continent, the disease has also impacted regeneration and growth of eastern white pine (Pinus strobus L. ), especially in the upper Great Lakes region of Minnesota, Wisconsin, Michigan, and Ontario. This paper summarizes some of the early white pine blister rust research in Minnesota and Wisconsin, particularly the Moose Fence site near Tofte, Minnesota, the...

The weevil resistance breeding program against the white pine weevil, Pissodes strobi Peck (Coleoptera: Curculionidae), particularly for Sitka spruce (Picea sitchensis (Bong.) Carr), is arguably one of the most successful pest resistance breeding programs for plantation forest species, and it has done a lot to rehabilitate this important western conifer. Nearly all planting stock currently comes from this breeding program and so far the resistance seems effective, durable, and stable. We have used this program to also study causes behind this resistance, including: various hindrance...

Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murr.) Parl.) (POC) is a long-lived conifer native to northwestern California and southwestern Oregon. It has been widely used in horticulture in both western North America and elsewhere. The accidental introduction of the non-native pathogen Phytophthora lateralis into North America and Europe has raised concerns about the future viability of POC in some forest ecosystems, in managed forests, and in horticultural settings. Fortunately, some level of natural genetic resistance to P. lateralis exists in POC. Utilizing this genetic resistance...

Southern yellow pine (Pinus taeda) wood char powder was thermally treated at 1,000°:C in the presence of a 25-nm-size Fe nanoparticle catalyst. The thermally treated carbon materials were analyzed by Raman spectroscopy and high-resolution transmission electron microscopy. Well-aligned graphitic carbon structures with 15 to 17 layers on average were observed. These graphitic carbon structures were similar to those of graphite with an average interplanar distance of 0.34 nm. The Raman spectra results showed that the full-width half-maximum values of Raman G and D bands, and the peak...