Treesearch

Paired aerial photographs were interpreted to assess recent changes (c. 2009–2014) in tree, impervious and other cover types within urban/community and urban land in all 50 United States and the District of Columbia. National results indicate that tree cover in urban/community areas of the United States is on the decline at a rate of about 175,000 acres per year, which corresponds to approximately 36 million trees per year. Estimated loss of benefits from trees in urban areas is conservatively valued at $96 million per year. Overall, for both urban and the broader urban/community areas, 23...

Consumers can alter decomposition rates through both feces and selective feeding in many ecosystems, but these combined effects have seldom been examined in tropical ecosystems. Members of the detrital food web (litter-feeders or microbivores) should presumably have greater effects on decomposition than herbivores, members of the green food web. Using litterbag experiments within a field enclosure experiment, we determined the relative effects of common litter snails (Megalomastoma croceum) and herbivorous walking sticks (Lamponius portoricensis) on litter composition, decomposition rates,...

Evaluating the causes of spatial synchrony in population dynamics in nature is notoriously difficult due to a lack of data and appropriate statistical methods. Here, we use a recently developed method, a multivariate extension of the local indicators of spatial autocorrelation statistic, to map geographic variation in the synchrony of gypsy moth outbreaks. Regression analyses indicated that local synchrony of gypsy moth defoliation increased with the local synchrony of precipitation and the proportion of host tree density composed of oaks, especially those in the Lobatae (red oak) section....

The spread of the invasive emerald ash borer (EAB) across North America has had enormous impacts on temperate forest ecosystems. The selective removal of ash trees (Fraxinus spp.) has resulted in abnormally large inputs of coarse woody debris and altered forest tree community composition, ultimately affecting a variety of ecosystem processes. The goal of this study was to determine if the presence of ash trees influences soil bacterial communities and/or functions to better understand the impacts of EAB on forest successional dynamics and biogeochemical cycling. Using 16S rRNA amplicon...

DNA markers can provide valuable genetic information for forest tree research, breeding, conservation, and restoration programs. When properly evaluated, selected sets of DNA markers can be used to efficiently get information about genetic diversity in regions, forests, or stands, or in seed lots and orchards. Selected markers also can be used to determine parentage or verify clonal identity of individual trees in tree improvement programs and seed production orchards. With these purposes in mind, we developed sets of informative markers for four species of southern pines: shortleaf pine...

Although it is well established that the availability of upstream flow (AUF) affects downstream water supply, its significance has not been rigorously categorized and quantified at fine resolutions. This study aims to fill this gap by providing a nationwide inventory of AUF and local water resource, and assessing their roles in securing water supply across the 2,099 8-digit hydrologic unit code watersheds in the conterminous United States (CONUS). We investigated the effects of river hydraulic connectivity, climate variability, and water withdrawal, and consumption on water availability...

The desired future conditions of longleaf pine (Pinus palustris) can be described by ecosystem structural characteristics as well as by the provision of ecosystem services. Although the desired structural characteristics of restored longleaf pine ecosystems have been described at length, these characteristics deserve a brief review here because ecosystem structure directly contributes to the provision of key ecosystem services and helps differentiate these forests from other land uses in the southeastern United States. Briefly, upland longleaf pine stands managed with frequent fire are...

Trail-based recreation is a popular use of public forests in the United States, and four types are common: allterrain vehicle (ATV) riding, mountain biking, hiking, and horseback riding. Effects on wildlife, however, are controversial and often a topic of land use debates. Accordingly, we studied trail-based recreation effects on elk (Cervus canadensis), a wide-ranging North American ungulate highly sought for hunting and viewing on public forests, but that is sensitive to human activities, particularly to motorized traffic on forest roads. We hypothesized that elk would respond to...

To see a frequent-fire forest burn for the first time is to experience a remarkable treat of nature. Most people are accustomed to the slow change of forests with the seasons, not the instantaneous conversion of green and brown plant mass to smoke and char. Yet to visit such a forest a week after it burns is to see bright green shoots emerging, highlighted against a background of charcoal. Frequent-fire forests, or forests that regularly experience low-intensity/low-severity fires, although surprisingly common, challenge commonly held notions about what forests are and how they function....

Through contracting and timber sales, the private sector is engaged in management of national forest lands and local community economies in the United States. But there is little recent research about current relationships between these lands and timber purchasers that could better inform future timber and biomass sale and business assistance policies and programs. We conducted a survey of timber-purchasing businesses active in six USDA Forest Service regions where ecosystem restoration and wildfire risk reduction policies have been prevalent to examine their characteristics, reliance on...