Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

To Thin or Not to Thin

21.11.2002


USGS-funded research weighs benefits of forest thinning on plants and animals


Wilson’s warbler, a songbird common in many Pacific Northwest forests; photo credit Joan Hagar


Caterpillar form of a moth found in Pacific Northwest forests; photo credit Jeff Miller



Recent studies show that thinning of young forests can benefit the development of old-growth characteristics and the diversity of plants and animals, but only if methods are used that protect and promote the development of shrubs, hardwoods, and large or old trees.

The findings, which were made by researchers from the U.S. Geological Survey (USGS) and Oregon State University (OSU), hold special significance for the management of many young forests, with trees less than about 60 years old, which cover vast portions of the Pacific Northwest.


The conclusions are based on a number of related studies funded in recent years by the USGS.

According to John Tappeiner, a professor at OSU and retired USGS forest scientist, the forests in the Pacific Northwest that were clearcut in past decades were densely replanted with uniformly spaced tree seedlings. The original management goal of most plantations was to produce high yields of timber and associated wood products.

This management goal dramatically shifted for millions of acres of young forests on federal lands with the adoption of the Northwest Forest Plan in 1994. Many dense, young forests were incorporated into a network of large conservation reserves intended to provide habitat for plants and animals typically associated with older forests.

Although researchers and land managers had assumed that these dense, young forests would, in time, grow to resemble the old-growth forests they replaced, a group of researchers have accumulated a wide range of evidence suggesting that this may not occur unless the young forests are selectively thinned to allow the remaining, uncut trees to grow under less-dense conditions.

Crowded young trees develop differently from more open-grown individuals, the scientists found. Widely spaced trees have larger crowns and diameters than closely spaced trees of the same species and age. Dense young forests typically have over 200 trees per acre at 50 years of age, but studies of 90 old-growth forests revealed an average of just 6-8 large trees (over 40 inches in diameter) per acre.

Other findings of the research include:

Studies of the relationship between a tree’s diameter at age 200 years and its diameter and growth at age 50 show that trees that were large at age 200 years were generally large and fast growing when young.

Studies of lichens and mosses, which are collectively known as epiphytes, showed that thinning of dense, young-growth stands may increase the diversity and abundance of some lichens, particularly those that are important as forage for wildlife.

Thinning may lead to increased similarity of some lichen communities on shrubs between young and old-growth stands. But in some cases, thinning apparently led to the loss of old shrub stems, resulting in these thinned stands supporting fewer shrub epiphytes than did comparable unthinned stands.

Hardwood trees and old remnant conifers in young stands hosted diverse and abundant epiphyte communities and are likely to provide refuges for epiphytes if they are retained in stands during thinning.

The abundance of forest songbirds was greater in thinned young stands and old-growth stands than in young unthinned stands, and the number of different species of birds was positively linked with the presence of hardwood trees.

There are more caterpillars and other insects, which are important foods for several types of birds living in the forest understory, in thinned stands that encourage more hardwood shrubs.

There were few differences in the number of species of moths, including their caterpillar stage, in thinned stands compared to unthinned stands, but the hardwoods more prevalent in thinned stands contributed to a greater richness of moth populations.
"Taken together, these studies suggest that thinning may have positive results for plants and animals if the methods used protect shrubs, hardwoods, large trees, and old trees," Tappeiner said.

Pat Muir, a professor of botany at OSU, said it also important to consider that the sites studied were thinned only 15 to 20 years ago, with a primary objective of commercial tree harvest.

"As a group we found indications of positive benefits for some plants and animals less than two decades after thinning, even though the thinning was conducted without bearing in mind the effect on these organisms, and some benefits of thinning may not be seen for many decades," Muir said. "I suspect even greater benefits would be evident if thinning were conducted with a long-term goal of enhancing forest biodiversity."

In these research projects, the USGS and OSU scientists contrasted the responses of plants and animals in three types of forest stands in Western Oregon: young stands thinned by commercial techniques 15-20 years ago, young unthinned stands, and old-growth stands.

The organisms selected for study have complex interdependencies that are only partially understood, the scientists say, such as providing food, nesting material, habitat, or pollination.

Other contributors to this research included Joan Hagar, a doctoral candidate at OSU who studied forest songbirds; Bruce McCune, an OSU professor of botany and plant pathology; Nathan Poage, previously a doctoral candidate at OSU and currently a contractor for the USGS who studied tree growth; Jeff Miller, an OSU professor of entomology, and Eric Peterson, previously a doctoral candidate at OSU who studied lichens and mosses.

The USGS serves the nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life.


###
This press release and in-depth information about USGS programs may be found on the USGS home page: http://www.usgs.gov. To receive the latest USGS news releases automatically by email, send a request to listproc@listserver.usgs.gov. Specify the listserver(s) of interest from the following names: water-pr: geologic-hazards-pr; geological-pr; biological-pr; mapping-pr; products-pr; lecture-pr. In the body of the message write: subscribe (name of listserver) (your name). Example: subscribe water-pr joe smith.

Ruth Jacobs | EurekAlert!

More articles from Agricultural and Forestry Science:

nachricht Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli
26.04.2017 | University of the Basque Country

nachricht New data unearths pesticide peril in beehives
21.04.2017 | Cornell University

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>