Featured Research

from universities, journals, and other organizations

Lowering stand density reduces mortality of ponderosa pine stands

Date:
November 26, 2013
Source:
USDA Forest Service - Pacific Southwest Research Station
Summary:
As trees grow larger in even-aged stands, competition develops among them. Competition weakens trees, as they contend for soil moisture, nutrients, and sunlight. Competition also increases trees' risk to bark beetles and diseases, and subsequently leads to a buildup of dead fuels. A recent study considered if the onset of this risk could be determined.

As trees grow larger in even-aged stands, competition develops among them. Competition weakens trees, as they contend for soil moisture, nutrients, and sunlight. Competition also increases trees' risk to bark beetles and diseases, and subsequently leads to a buildup of dead fuels. A recent study, led by Dr. Jianwei Zhang, research forester at the U.S. Forest Service's Pacific Southwest Research Station, considered if the onset of this risk could be determined. The study, which appears in the Canadian Journal of Forest Research, also considered if the relationship between density and mortality varies with site quality as ponderosa pine stands developed.

Based on the analysis of 109 long-term research plots established on even-aged natural stands and plantations from 1944 to 1988, and 59 additional ponderosa pine plots measured by the Forest Service's Forest Inventory and Analysis group, these researchers found that site quality affected the relationship between density and mortality.

"Any silvicultural treatments that enhances growth will reduce mortality rate for a given stand density." Dr. Zhang said. "By establishing the self-thinning boundary lines from the size-density trajectories, the onset of mortality risk can be determined for ponderosa pine stands."

The research also confirmed the added value of such long-term study sites which allow new questions to be addressed that were not included in the original studies. Other recently published research from this group of scientists demonstrated thinning forest stands to a lower density reduces fuel buildup significantly, and enhances its economic value by increasing growth of residual trees. Specifically, stand basal area, which is the cross sectional area of all trees in a stand measured at breast height, is not affected by thinning ponderosa pine stands to half the normal basal area of a specific site quality. If the stand has experienced high mortality caused by bark beetles, it can be thinned more heavily without sacrificing timber, biomass, or volume increment and plant diversity.

In addition, results from these long-term studies show that early shrub removal and tree density control are the most effective and efficient ways to reduce fuel buildup. Under Mediterranean climatic conditions, shrubs reduce overstory tree growth and keep tree crowns in contact with the shrub canopy. In turn, this growing fuel ladder can carry a ground fire into the crowns of the overstory trees. Although carbon stocks may be the same with or without understory vegetation, by controlling competing vegetation, carbon is reallocated into the trees instead of shrubs; and carbon loss to wildfire is reduced.

These findings provide useful information for managers in their stand treatment projects within National Forest and private forestlands.

To read the full article, go to http://treesearch.fs.fed.us/pubs/45108; or http://www.fs.fed.us/psw/programs/efh/staff/jzhang/ for other articles.


Story Source:

The above story is based on materials provided by USDA Forest Service - Pacific Southwest Research Station. Note: Materials may be edited for content and length.


Cite This Page:

USDA Forest Service - Pacific Southwest Research Station. "Lowering stand density reduces mortality of ponderosa pine stands." ScienceDaily. ScienceDaily, 26 November 2013. <www.sciencedaily.com/releases/2013/11/131126092704.htm>.
USDA Forest Service - Pacific Southwest Research Station. (2013, November 26). Lowering stand density reduces mortality of ponderosa pine stands. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2013/11/131126092704.htm
USDA Forest Service - Pacific Southwest Research Station. "Lowering stand density reduces mortality of ponderosa pine stands." ScienceDaily. www.sciencedaily.com/releases/2013/11/131126092704.htm (accessed July 23, 2014).

Share This




More Plants & Animals News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Stone Fruit Listeria Scare Causes Sweeping Recall

Stone Fruit Listeria Scare Causes Sweeping Recall

Newsy (July 22, 2014) The Wawona Packing Company has issued a voluntary recall on the stone fruit it distributes due to a possible Listeria outbreak. Video provided by Newsy
Powered by NewsLook.com
Michigan Plant's Goal: Flower and Die

Michigan Plant's Goal: Flower and Die

AP (July 22, 2014) An 80-year-old agave plant, which is blooming for the first and only time at a University of Michigan conservatory, will die when it's done (July 22) Video provided by AP
Powered by NewsLook.com
Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Huge Schizophrenia Study Finds Dozens Of New Genetic Causes

Newsy (July 22, 2014) The 83 new genetic markers could open dozens of new avenues for schizophrenia treatment research. Video provided by Newsy
Powered by NewsLook.com
CDC Head Concerned About a Post-Antibiotic Era

CDC Head Concerned About a Post-Antibiotic Era

AP (July 22, 2014) Sounding alarms about the growing threat of antibiotic resistance, CDC Director Tom Frieden warned Tuesday if the global community does not confront the problem soon, the world will be living in a devastating post-antibiotic era. (July 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins