Treesearch

Arginine (Arg) and ornithine (Orn), both derived from glutamate (Glu), are the primary substrates for polyamine (PA) biosynthesis, and also play important roles as substrates and intermediates of overall N metabolism in plants. Their cellular homeostasis is subject to multiple levels of regulation. Using reverse transcription quantitative PCR (RT-qPCR), we studied changes in the expression of all genes of the Orn/Arg biosynthetic pathway in response to upregulation [via transgenic expression of mouse Orn decarboxylase (mODC)] of PA biosynthesis in poplar (Populus nigra x maximowiczii)...

The Luquillo Mountains are affected by a wide array of environmental processes and distnrbances. Events that concurrently alter the environmental space of several different areas of the Luquillo Mountains occur every 2 to 5 years. Events such as hurricanes that cause widespread environmental modification occur once every 20 to 60 years. The most common disturbance-generating weather systems that affect the Luquillo Mountains are (1) cyclonic systems, (2) noncyclonic intertropical systems, (3) extratropical frontal systems, and ( 4) large-scale coupled oceanatmospheric events (e.g., North...

Destruction of homes and businesses from Wildland Urban Interface (WUI) fires have been steadily escalating as have the fire suppression costs associated with them. Since 2000, in the U.S. over 3,000 homes per year are lost to WUI fires, compared to about 900 homes in the 1990s, and 400 homes in the 1970s. In 2011, in Texas alone, over 2,000 homes were destroyed during WUI fires. The WUI fire problem affects both existing communities and new construction. In the U.S, the problem is most acute in the western and southern states; however, WUI fires have also recently destroyed homes in the...

Anomalous dark growth rings have been observed in black cherry (Prunus serotina) sawlogs from northwestern Pennsylvania making the logs unsuitable for veneer products. Thirty-six cross sections with dark rings, each traceable to one of ten stands, were obtained from a local mill and sections were dated and annual ring widths were measured. One or more dark rings were found in 30 of the 36 cross sections. The most frequent years in which dark rings formed were 1994, on 55% of cross sections, and 1995, on 72% of cross sections. Both years were coincident with widespread cherry scallop shell...

Soil Ca depletion because of acidic deposition-related soil chemistry changes has led to the decline of forest productivity and carbon sequestration in the northeastern USA. In 1999, acidic watershed (WS) 1 at the Hubbard Brook Experimental Forest (HBEF), NH, USA was amended with Ca silicate to restore soil Ca pools. In 2006, soil samples were collected from the Ca-amended (WS1) and reference watershed (WS3) for comparison of bacterial community composition between the two watersheds. The sites were about 125 m apart and were known to have similar stream chemistry and tree populations...

Population declines of early successional forest-associated wildlife species have been linked to declines in habitat abundance. Forest Inventory and Analysis (FIA) data can be used to estimate composition and change in 'young' forest, but such information typically lacks spatial specificity for determining landscape patterns that also affect habitat suitability. We developed a satellite remote sensing approach for making spatially explicit maps of young forest, using Landsat time series stacks and a vegetation change tracker (VCT) algorithm to identify forest disturbances occurring since...

This publication provides an overview of forest resource attributes for Delaware based on an annual inventory conducted by the Forest Inventory and Analysis (FIA) program at the Northern Research Station of the U.S. Forest Service. These estimates, along with web-posted core tables, will be updated annually. For more information please refer to page 4 of this report.

Ozone is a highly toxic air contaminant that has been shown to decrease tree growth and cause significant disturbance to forested ecosystems. Ozone also causes distinct foliar injury symptoms to certain species (bioindicator plants) that can be used to detect and monitor ozone stress (biomonitoring) in the forest environment. In the early 1990s, the U.S. Forest Service, in partnership with the U.S. Environmental Protection Agency, developed and implemented a suite of forest health indicators to respond to emerging demands for a comprehensive assessment of the health of U.S. forests. This...