Treesearch

A randomized sample of 250 loblolly (Pinus taeda L.) and shortleaf (Pinus echinata Mill.) pine ring counts was collected from the Good and Poor Farm Forestry compartments on the Crossett Experimental Forest. These mature, pine-dominated stands have been managed using uneven-aged silviculture since 1937. Our sample shows that both of these compartments have many different age classes although few distinct cohorts. Over the decades, pine recruitment followed the dozens of timber harvests and occasional natural mortality events (e.g., lightning strikes, ice storms, windthrow, insects, and...

The northern hardwood research program at the Dukes Experimental Forest in Michigan and Argonne Experimental Forest in Wisconsin has been adapting to changing management and social objectives for more than 80 years. In 1926, the first northern hardwood silviculture study was established in old-growth stands at the Dukes Experimental Forest. In response to social demands for more "natural" forestry, the study included then-contemporary practices (e.g., liquidation of oldgrowth forest) and new approaches (e.g., partial cuttings). By 1953, the partial cutting treatments were deemed most...

Potential shifts in rainfall driven by climate change are anticipated to affect watershed processes (e.g., soil moisture, runoff, stream flow), yet few model systems exist in the tropics to test hypotheses about how these processes may respond to these shifts. We used a sequence of nine watersheds on Hawaii Island spanning 3000 mm (7500–4500 mm) of mean annual rainfall (MAR) to investigate the effects of short-term (24-h) and long-term (MAR) rainfall on three fecal indicator bacteria (FIB) (enterococci, total coliforms, and Escherichia coli). All sample sites were in native Ohia dominated...

Dissolved organic matter (DOM) source and composition are critical drivers of its reactivity, impact microbial food webs and influence ecosystem functions. It is believed that DOM composition and abundance represent an integrated signal derived from the surrounding watershed. Recent studies have shown that land-use may have a long-term effect on DOM composition. Methods for characterizing DOM, such as those that measure the optical properties and size of the molecules, are increasingly recognized as valuable tools for assessing DOM sources, cycling, and reactivity. In this study we...

Large fallen wood can have a significant impact on channel form and process in forested mountain streams. In this study, four small channels on the Fraser Experimental Forest near Fraser, Colorado, USA, were surveyed for channel geometries and large wood loading, including the size, source, and characteristics of individual pieces. The study is part of a larger effort to understand the impact of mountain pine beetle infestation on a suite of watershed properties. Here, we present baseline data collected at the onset of widespread tree mortality. Channels range from 1.5 to 2 m in width,...

Disturbances are increasing globally due to anthropogenic changes in land use and climate. This study determines whether a disturbance that affects the physiology of individual trees can be used to predict the response of the ecosystem by weighing two competing hypothesis at annual time scales: (a) changes in ecosystem fluxes are proportional to observable patterns of mortality or (b) to explain ecosystem fluxes the physiology of dying trees must also be incorporated. We evaluate these hypotheses by analyzing 6 years of eddy covariance flux data collected throughout the progression of a...

The link between healthy forests and watersheds and healthy streamflow and quality water is universally recognized. The major rivers of the USA originate in the forested mountains of the western and eastern USA and the glaciated regions of the Lake States and Great Plains and produce almost two-thirds of the nation’s clean water supply. Original logging and mismanagement of upstream forested watersheds often resulted in degradation of land and water resources and adversely impacted aquatic and human populations. During the 30-year period, between the 1930s and 1960s, experimental forests,...

The transfer of energy and nutrients largely depends on the role of animals in the movement of biomass between trophic levels and ecosystems. Despite the historical recognition that amphibians could play an important role in the movement of biomass and nutrients, very few studies have provided reliable estimates of abundance and density of amphibians to reveal their true importance. Here, we provide robust estimates of abundance and density of a dominant species, the Southern Redback Salamander (Plethodon serratus Grobman, 1944), in the oak forest ecosystem of the Ozark Highlands in...

Despite decades of measurements, the nitrogen balance of temperate forest catchments remains poorly understood. Atmospheric nitrogen deposition often greatly exceeds streamwater nitrogen losses; the fate of the remaining nitrogen is highly uncertain. Gaseous losses of nitrogen to denitrification are especially poorly documented and are often ignored. Here, we provide isotopic evidence (δ15NNO3 and δ18ONO3) from shallow groundwater at the Hubbard Brook Experimental Forest indicating extensive denitrification during midsummer, when transient, perched patches of saturation developed in...

A network of shallow groundwater wells in a headwater catchment at the Hubbard Brook Experimental Forest in New Hampshire, U.S. was used to investigate the hydrologic behavior of five distinct soil morphological units. The soil morphological units were hypothesized to be indicative of distinct water table regimes. Water table fluctuations in the wells were characterized by their median and interquartile range of depth, proportion of time water table was present in the solum, and storage-discharge behavior of subsurface flow. Statistically significant differences in median, interquartile...