Treesearch

We review past trading experiments and present 11 new experiments designed to show how the trading rate responds to alterations of the experimental procedure. In agreement with earlier studies, results show that if the trade decision is converted to one resembling a choice between goods the exchange asymmetry disappears, but otherwise the asymmetry is remarkably robust. Results also indicate that when trading is public herding can occur,which may have caused some of the more extreme examples of the exchange asymmetry,and that some of the lack of trade may result from preference indifference...

Phellinus noxius is an aggressive root rot pathogen affecting tropical and subtropical forests. Causing much damage in tropical Asia, Africa, Taiwan, Japan and the Pacific Islands, its wide host range encompasses more than 200 plant species representing 59 families (Ann et al. 2002). It can devastate agricultural plantations of tea, rubber, cocoa, avocados, and oil palm; tropical fruit trees such as longan, breadfruit, litchi, carambola, and loquat; timber trees including hoop pine (Araucaria), eucalypts, and mahogany (Swietenia); as well as many ornamental trees and woody shrubs. Also...

Armillaria species range from beneficial saprobes to damaging root pathogens, and their ecological roles and impacts vary with environment and host. Armillaria solidipes [pending vote to conserve A. ostoyae . (Redhead et al. 2011 )] is known as an aggressive pathogen of conifers and causes tree mortality and significant growth loss in Wyoming and throughout the world. Armillaria solidipes also seems to exist in a nonpathogenic state under certain conditions that vary depending on environment, host, and community (unpublished data). In this case, A. solidipes can be difficult to differentiat...

Corynespora cassiicola and Cercospora sp. have been identified as the most prevalent and destructive leaf-spot pathogens of garden hydrangea [Hydrangea macrophylla (Thunberg) Seringe] in the southeastern USA, but they are often difficult to accurately detect and distinguish because they often occur together in a disease complex with other pathogenic leaf-spot fungi and produce very similar symptoms. This study was conducted to provide diagnostic PCR primers for detecting and distinguishing Corynespora cassiicola and Cercospora sp. among other leaf-spot pathogens of garden hydrangea. Two...

Metagenomics has illuminated our understanding of how microbial communities influence health and disease. Researchers are beginning to characterize what constitutes healthy microbiota in terms of structure, function, and diversity in a variety of environments. Although investigation lags behind the more well-studied human microbiome, a growing body of research is using next-generation sequencing tools and advances in bioinformatics to explore how microbiota and constitutive microbiomes in soils, and plant tissues can affect crop and forest diseases (Damon et al. 2012, Bonito et al. 2014,...

Hawai'i is a biological hotspot with a variety of climates and habitats. While fungal species diversity has been more extensively studied in Hawai'i than other Pacific Islands (e.g. see Gilbertson et al. 2002), there remain many species unreported in the literature. This project attempted to capture a small portion of Hawai'i's fungal diversity in southeast O'ahu by identifying fruit bodies using molecular techniques. The efficacy of using the internal transcribed spacer (ITS) and large subunit (LSU) regions of the nuclear ribosomal DNA (rDNA) to identify Hawai'ian fungi is discussed.

Although the islands of the western Pacific comprise a hotspot of species, including fungi, a large number of these species have not been catalogued or documented in the scientific literature on an island to island basis. Butt- and root-rot fungi were collected from infected wood and fruiting bodies of diverse tropical trees from forest, agricultural, and urban sites during an outreach/survey trip to USA-affiliated islands in the western Pacific including Palau, Yap, Guam, Saipan, Pohnpei, and Kosrae (Figure 1). Collections focused on the aggressive brown root-rot pathogen, Phellinus...

European ash (Fraxinus excelsior) is an important tree species in most temperate forests in Europe. Its future is threatened however, especially by an invasive fungus, Hymenoscyphus fraxineus (Hymenoscyphus pseudoalbidus, Chalara fraxinea). The current study is focused on the health of ash in the Krkonoše Mountains National Park, Czech Republic. On permanent research plots containing mixtures of ash and other species, the stands’ health condition was evaluated annually in 2009-2015, by using radial increment and foliage of 350 trees as indicators, with emphasis on the cenotic arrangement...

Longleaf pine (Pinus palustris Mill.) forests are characterized by unusually high understory plant species diversity, but models describing understory ground cover biomass, and hence fuel load dynamics, are scarce for this fire-dependent ecosystem. Only coarse scale estimates, being restricted on accuracy and geographical extrapolation, are available. We analyzed the dynamics of ground cover biomass under different prescribed burning regimes in longleaf pine stands in the southeastern United States. We developed a set of functions to simulate ground cover biomass dynamics in stands of...

In Western North America, increasing wildfire and outbreaks of native bark beetles have been mediated by warming climate conditions. Bioclimatic models forecast the loss of key high elevation species throughout the region. This study uses retrospective vegetation and fire history data to reconstruct the drivers of past disturbance and environmental change. Understanding the relationship among climate, antecedent disturbances, and the legacy effects of settlement-era logging can help identify the patterns and processes that create landscapes susceptible to bark beetle epidemics.