Treesearch

In dry, open coniferous forests of the montane West, stand-replacing wildfires and land use activities alter the composition and abundance of native grasses and forbs by degrading the habitat and accelerating the invasion of exotic annuals. On these lands, native forbs and grasses delayed or prevented from recovery by natural processes may require intervention through supplementary seeding. However, effective seeding of native plants requires that their seed traits and the potential outcome of the seeding be better understood.

Sustaining farm and forest land has been an important goal in the United States because of the role these lands play in the livelihoods of rural residents while also providing desired open space benefits. However, land use policies to protect rural lands often involve a tension between balancing public interests regarding economic and open space goals with the private interests and property rights of farm and forest land owners. This tension is especially prevalent when policies involve the regulation of private land such as through land use planning. In the Pacific Northwest, where...

Developing sustainable energy from forest biomass presents both opportunities and challenges for the future generations of Moldova. Located in the southeastern part of Europe between Ukraine and Romania, Moldova is a relatively poor country with limited natural resources compared with other developing European countries such as Albania or Bosnia. This lack of fossil fuels (natural gas, oil and coal) has resulted in a strong economical and political dependence on large neighboring countries including Russia and Ukraine. Historically, agriculture has been the dominant land use; however, poor...

Global environmental changes have direct effects on aquatic ecosystems, as well as indirect effects through alterations of adjacent terrestrial ecosystem structure and functioning. For example, shifts in terrestrial vegetation communities resulting from global changes can affect the quantity and quality of water, organic matter, and nutrient inputs to aquatic ecosystems. The relative importance of these direct and terrestrial-vegetation mediated effects is largely unknown, but understanding them is essential to our ability to predict the consequences of global changes for aquatic ecosystems...

There is still much uncertainty as to how wildfire affects the accumulation of burn residues (such as black carbon [BC]) in the soil, and the corresponding changes in soil organic carbon (SOC) composition in boreal forests. We investigated SOC and BC composition in black spruce forests on different landscape positions in Alaska, USA. Mean BC stocks in surface mineral soils (0.34 ± 0.09 kg C m-2) were higher than in organic soils (0.1 7 ± 0.07 kg C m-2), as determined at four sites by three different l3C Nuclear Magnetic Resonance Spectroscopy-based techniques. Aromatic carbon, protein, BC,...

Climate warming and permafrost degradation at high latitudes will likely impact watershed hydrology, and consequently, alter the concentration and character of dissolved organic carbon (DOC) in northern rivers. We examined seasonal variation of DOC chemistry in 16 streams of the Yukon River basin, Alaska. Our primary objective was to evaluate DOC chemical composition. Using base cation chemistry and principal component analysis, we observed high contributions of deep groundwater to glacial and clearwater streams, whereas blackwater streams received larger contributions from shallow...

Biomass burning in the Alaskan interior is already a major disturbance and source of carbon emissions, and is likely to increase in response to the warming and drying predicted for the future climate. In addition to quantifying changes to the spatial and temporal patterns of burned areas, observing variations in severity is the key to studying the impact of changes to the fire regime on carbon cycling, energy budgets, and post-fire succession. Remote sensing indices of fire severity have not consistently been well-correlated with in situ observations of important severity characteristics...

Following the European Union strategy concerning renewable energy (RE), Portugal established in their national policy programmes that the production of electrical energy from RE should reach 45% of the total supply by 2010. Since Portugal has large forest biomass resources, a significant part of this energy will be obtained from this source. In addition to the two existing electric power plants, with 22 MW of power capacity, 13 new power plants having a total of 86.4 MW capacity are in construction. Together these could generate a combination of electrical and thermal energy, known as...

As global climate changes over the next century, forest productivity is expected to change as well. Using PRISM climate and productivity data measured on a grid of 3356 plots, we developed a simultaneous autoregressive model to estimate the impacts of climate change on potential productivity of Pacific Northwest forests of the United States. The model, coupled with climate change output from four generalized circulation models, was used to predict the productivity impacts of four different scenarios derived from the fourth Intergovernmental Panel on Climate Change special report on...

Seven truffle species are reported from the Australian Outback-six Ascomycota (Elderia arenivaga, Mattirolomyces mulpu sp. nov., Mycoclelandia arenacea, M. bulundari, Reddelomyces westraliensis, Ulurua nonparaphysata gen. & sp. nov.) and one Basidiomycota (Horakiella watarrkana sp. nov.) Three Ascomycota species are redescribed from the African Kalahari (Eremiomyces echinulatus, Kalaharituber pfeilii and Mattirolomyces austroafricanus comb. nov.). The phylogenetic analyses of nrDNA of the Australian Ascomycota provided strong support for placement of all but one in the Pezizaceae (Reddellom...