Navigation Links
Large trees declining in Yosemite

Large trees have declined in Yosemite National Park during the 20th century, and warmer climate conditions may play a role.

The number of large-diameter trees in the park declined 24 percent between the 1930s and 1990s. U.S. Geological Survey and University of Washington scientists compared the earliest records of large-diameter trees densities from 1932� to the most recent records from 1988�.

A decline in large trees means habitat loss and possible reduction in species such as spotted owls, mosses, orchids and fishers (a carnivore related to weasels). Fewer new trees will grow in the landscape because large trees are a seed source for the surrounding landscape. Large-diameter trees generally resist fire more than small-diameter trees, so fewer large trees could also slow forest regeneration after fires.

"Although this study did not investigate the causes of decline, climate change is a likely contributor to these events and should be taken into consideration," said USGS scientist emeritus Jan van Wagtendonk. "Warmer conditions increase the length of the summer dry season and decrease the snowpack that provides much of the water for the growing season. A longer summer dry season can also reduce tree growth and vigor, and can reduce trees' ability to resist insects and pathogens."

Scientists also found a shift to fire-intolerant trees in some forests that had not experienced fires for nearly a century. In these areas, trees changed from fire-tolerant ponderosa pines to fire-intolerant white fir and incense cedar. In burned areas, however, pines remained dominant.

"We should be aware that more frequent and severe wildfires are possible in Yosemite because of the recent shift to fire-intolerant trees in unburned areas and warmer climates bring drier conditions," said van Wagtendonk.


Contact: Jessica Robertson
United States Geological Survey

Page: 1

Related biology news :

1. Mixing large doses of both acetaminophen painkiller and caffeine may increase risk of liver damage
2. Microarray sequence capture speeds large-scale resequencing of targeted genomic regions
3. US fires release large amounts of carbon dioxide
4. Largest study to investigate risk factors of autism to begin enrolling families
5. Single-largest biodiversity survey says primary rainforest is irreplaceable
6. Technique controls nanoparticle size, makes large numbers
7. Texas Hospital nations first to use large-scale cocoon strategy against whooping cough
8. Worlds largest investor coalition seeks further disclosure on climate change and shareholder value
9. Worlds largest marine protected area created in Pacific Ocean
10. Airborne bacteria may play large role in precipitation
11. Are existing large-scale simulations of water dynamics wrong?
Post Your Comments:
(Date:11/18/2015)... 2015 --> ... market report titled  Gesture Recognition Market - Global Industry ... 2021. According to the report, the global gesture recognition market was valued ... reach US$29.1 bn by 2021, at a CAGR of ... America dominated the global gesture recognition market ...
(Date:11/17/2015)... , Nov. 17, 2015 Pressure BioSciences, Inc. ... the development and sale of broadly enabling, pressure cycling ... sciences industry, today announced it has received gross proceeds ... million Private Placement (the "Offering"), increasing the total amount ... or more additional closings are expected in the near ...
(Date:11/12/2015)... 2015   Growing need for low-cost, easy ... been paving the way for use of biochemical ... analytes in clinical, agricultural, environmental, food and defense ... in medical applications, however, their adoption is increasing ... continuous emphasis on improving product quality and growing ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... , November 26, 2015 ... Global Biobanking Market 2016 - 2020 report analyzes ... maintaining integrity and quality in long-term samples, minimizing ... long-term cost-effectiveness. Automation minimizes manual errors such as ... technical efficiency. Further, it plays a vital role ...
(Date:11/25/2015)... BRUSSELS , November 25, 2015 ... in cat and human plaque and pave the way for ... health problems in cats     ... the most commonly diagnosed health problems in cats, yet relatively ... until now. Two collaborative studies have been conducted by researchers ...
(Date:11/25/2015)... 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS; TSX: ... prospects remain fundamentally strong and highlights the following ... received DSMB recommendation to continue the ZoptEC Phase ... the final interim efficacy and safety data ... men with heavily pretreated castration- and Taxane-resistant prostate ...
(Date:11/25/2015)... November 25, 2015 The ... is a professional and in-depth study on the ...      (Logo: ) , ... industry including definitions, classifications, applications and industry chain ... the international markets including development trends, competitive landscape ...
Breaking Biology Technology: