Treesearch

Yosemite Valley is a narrow, steep-walled canyon with fantastic natural areas, and its scenic and ecological wonders inspired the National Park concept and preservation ethic. But the Merced River through Yosemite Valley is one of the most heavily used non-urban riparian areas in the world. Over 4 million people visit each year, and 90 percent go to the box canyon where towering granite summits rise over 4,000 feet above the meandering river. About 8 miles long and less than one mile wide, the valley has a mix of riparian vegetation, open meadows, and forests. There are also roads,...

Many of the same features that are good for riparian ecology are good for people. Varying flow regimes, diversity of plants and animals, dynamic geomorphology that produces open beaches and shaded/sheltered areas, and most importantly, the presence of water - all are attractive for recreation, so human use can be an explicit part of the restoration equation.

Presence of the introduced genus Tamarix has been a perplexing problem for decades along rivers of the southwestern States. It is clearly an invasive species occurring along most perennial, ephemeral, and intermittent drainages of the Southwest including rivers, small streams, and normally dry washes. It seems to reach highest densities and form monocultures along waterways with altered flow regimes, but it can also invade unaltered streams and small springs, where it may become the dominant or exclusive woody species. Approximately 150 years after Tamarix was first introduced into the...

The “mesquite bosque” (Spanish for “forest” or “woodland”), one of the most unique and productive southwestern riparian habitat types, was once far more abundant than it is today. Twenty-five years ago, Stromberg (1993), with a focus on Arizona, provided an excellent review on the ecology, decline, existing threats, and potential for recovery of these mesquite forests. By 1993 the iconic mesquite bosque riparian habitat was in serious decline, due primarily to anthropogenic activities. Stromberg (1993) observed that previous attempts at habitat restoration were of limited success and...

One of the most wide-ranging scientific treatments of riparian vegetation of the American Southwest (exclusive of New Mexico and southwestern Colorado) can be found in the 2007 book, The Ribbon of Green by Robert Webb, Stanley Leake, and Raymond Turner (Webb et al. hereafter). In The Ribbon of Green, the authors use sets of matched photographs to evaluate and interpret historical changes in riparian vegetation along southwestern streams that have taken place since the late 19th century. As stated in the book’s preface, the authors “concentrate on the question of long-term changes, addressin...

In the Preface to volume 1, we discuss the development of riparian ecology as one of the newest of ecological fields that gained significant momentum in the 1950s and 1960s as part of the general “riparian movement” in the United States. The field expanded rapidly throughout the latter half of the 1900s. Volume 2 involves more than two dozen authors - most with decades of experience - who expand upon riparian and other topics introduced in volume 1. Two important recent developments are global climate change and impacts of introduced tamarisk leaf beetles (Diorhabda spp.) in the American...

Fuels reduction treatments to mitigate fire behavior are common in ponderosa pine ecosystems of the western United States. While initial impacts of fuel treatments have been reported, less is known about treatment longevity as live and dead fuels change with time. We analyzed fuel dynamics in ponderosa pine-Douglas-fir forests 21-23 years following experimental fuel reduction designed as two independent studies of cutting combined with burning: one tested a commercial thinning strategy, while a second tested a retention shelterwood strategy to reduce fuels while also restoring ponderosa...

Fire refugia-locations that burn less severely or less frequently than surrounding areas - support late-successional and old-growth forest structure and function. This study investigates the influence of topography and fuels on the probability of forest fire refugia under varying fire weather conditions. We focused on recent large fires in Oregon and Washington, United States (n = 39 fires > 400 ha, 2004-2014). Our objectives were to (1) map fire refugia as a component of the burn severity gradient, (2) quantify the predictability of fire refugia as a function of prefire fuels and topograph...

Thermal regimes of rivers and streams profoundly affect aquatic ecosystems, but are poorly described and classified in many areas due to the limited availability of annual datasets from extensive and representative monitoring networks. By mining a new temperature database composed of >23,000 site records that spans the western United States (U.S.), we extract annual monitoring records at 578 sites on perennial streams to describe regimes in this diverse region. Records were summarized using 34 metrics that described regime aspects related to magnitude, variation, frequency, duration, and...

Adding biochar to soil can change soil properties and subsequently affect plant growth, but this effect can vary because of different feedstocks and methods (e.g., pyrolysis or gasification) used to create the biochar. Growth and biological nitrogen fixation (BNF) of leguminous plants can be improved with rhizobia inoculation that fosters nodule development. Thus, this factorial greenhouse study examined the effects of two types of biochar (i.e., pyrolysis and gasification) added at a rate of 5% (v:v) to a peat-based growth substrate and rhizobia inoculation (yes or no) on Robinia pseudoaca...