Treesearch

Acorn woodpeckers are one of the most conspicuous and abundant birds in California oak forests due to their unique dependence on acorns, a food resource eaten directly and stored in specialized structures on their territories for later use when acorns are no longer present on trees. Parallel long-term studies of the demography and behavior of this species and of patterns of acorn production by oaks at Hastings Reservation in central coastal California have revealed many ways that acorn crops influence the ecology and behavior of acorn woodpeckers. We present results focusing on the...

Oak woodlands are a fixture of California geography, yet as recently as 10,000 years ago oaks were only a minor element in the landscape. The first fossil evidence for California's oaks is in the early Miocene (~20 million years ago) when oaks were present across the west, intermixed with deciduous trees typical of eastern North America. As climate became drier, species dependent upon summer precipitation went locally extinct and oaks retreated west of the Sierra Nevada. During the Pleistocene (the last 2 million years) oak abundance declined during cool glacial periods and expanded during...

The development of goals and policies for Californian oak woodlands is reviewed; then some important considerations for future policy development are highlighted. California and Spain share long and illuminating histories of human interaction with oak woodlands. The Integrated Hardwood Range Management Program, initiated about 1985, was a focal point for Californian research and policy, but also created connections among researchers, advisors, conservation organizations, and agencies. As the program's funding ran out, those constituencies continued to strengthen relationships through...

New research reveals how topography, soil temperature, and subtle shifts in soil drainage are key drivers in ecosystem function in the coastal temperate rain forests of southeast Alaska and British Columbia. These studies, by Dave D'Amore and his colleagues, provide a better understanding of the influence of soil hydrology on dissolved organic carbon export and the interplay between soil saturation and tree species' response to varying soil conditions. More refined techniques for identifying hydric soils are making wetland delineation in southeast Alaska quicker, easier, and more accurate....

The impact of mutualists on a partner’s demography depends on how they affect the partner’s multiple vital rates and how those vital rates, in turn, affect population growth. However, mutualism studies rarely measure effects on multiple vital rates or integrate them to assess the ultimate impact on population growth. We used vital rate data, population models and simulations of long-term population dynamics to quantify the demographic impact of a guild of ant species on the plant Ferocactus wislizeni. The ants feed at the plant’s extrafloral nectaries and attack herbivores attempting to...

This guide presents a classification of the Ecological Types of the eastern slope of the Wind River Range (WRR) on the Shoshone National Forest in west-central Wyoming. Ecological Types integrate vegetation and environmental characteristics, including climate, geology, landform, and soils, into a comprehensive ecosystem classification. The three objectives are: (1) complete field data collection, (2) simultaneously develop soil map unit components and Ecological Types, and (3) publish the ecological type classification such that it is compatible with the National Cooperative Soil Survey...

It is well known that the timing of growth and development influences critical life stages of all organisms. „The seasonal dynamics of ecosystems are usually well explained by photoperiod and temperature. However, phenological patterns in water-limited ecosystems are rarely studied and insufficiently explained by these two variables. We tested how onset (i.e., initiation of plant growth) and seasonality of plant growth are in‰fluenced by soil temperature and soil water. We collected seven years of daily measurements of near- surface re‰flected radiation, soil moisture, and soil temperature...

Piscivory by birds can be important, particularly on fish in small streams and during seasonal low flows when available cover from predators can be limited. We conducted an experiment at the Oregon Hatchery Research Center to evaluate size-selective survival of Coastal Cutthroat Trout (Figure 8; Oncorhynchus clarkii clarkii) in replicated semi-natural stream sections. Our findings, published in the Ecology of Freshwater Fish highlights that availability of instream cover and overhead shade from riparian vegetation can increase trout survival by reducing the effect of predation by Belted...

Urban tree planting initiatives aim to provide ecosystem services that materialize decades after planting, therefore understanding tree survival and growth is essential to evaluating planting program performance. Tree mortality is relatively high during the establishment phase, the first few years after planting. Qualitative assessments of programs with particularly high establishment survival can indicate best management practices for other programs to emulate. We present two case studies of high survival for young urban trees, from planting projects in East Palo Alto, CA and Philadelphia,...

As part of the Vermont Long-Term Soil Monitoring Project, five 50 x 50 m plots were established on protected forestland across Vermont. In 2002, ten randomly selected subplots at each monitoring plot were sampled. The 10 pedons sampled at the high-elevation spruce-fir “Forehead” plot on Mount Mansfield were found to include soils of four taxonomic Orders: Entisols, Histosols, Inceptisols, and Spodosols. Soil forming factors such as climate, vegetation, and time are uniform, and podzolization is the major soil forming process, but small variations in parent material thickness and microtopogr...