[MCN] Tree seedlings don't always thrive next to parents

[Lance Olsen]

Soil fungi help tree seedlings survive, influence forest diversity
THE UNIVERSITY OF MONTANA PUBLIC RELEASE: 13-JAN-2017

MISSOULA - A new paper published Jan. 13 in Science reveals that the 
relationship between soil fungi and tree seedlings is more 
complicated than previously known. The paper was co-written by Ylva 
Lekberg, an assistant professor of soil community ecology at the 
University of Montana.

The paper is online at http://science.sciencemag.org/content/355/6321/181.

Lekberg and her collaborators studied 55 species and 550 populations 
of North American trees. Scientists have long known that plants and 
soil biota can regulate one another, but the new findings highlight 
the complexity of the feedback loop.

"Fungi differ in their ability to protect tree seedlings from 
pathogens, and this has implications for seedling recruitment and 
therefore forest community patterns," Lekberg said.

Most plant roots are colonized by mycorrhizal fungi, but tree species 
associate with different fungal groups. The researchers showed that 
ectomycorrhizal fungi that form a thick sheet around root tips are 
better able to protect trees from pathogens than arbuscular 
mycorrhizal fungi.

Thus, while ectomycorrhizal tree seedlings actually prefer growing 
next to parent trees, arbuscular mycorrhizal tree seedlings can only 
establish outside the control of parents' enemies. This can have 
consequences for how temperate forests are structured and their 
overall diversity.

"Our findings show that to appreciate the complexity in nature, we 
need to better understand and consider interactions between plants 
and soil biota," said Lekberg, who works in UM's Department of 
Ecosystem and Conservation Sciences in the W.A. Franke College of 
Forestry & Conservation. She also works with the MPG Ranch, a 
research and conservation organization in Montana's Bitterroot Valley.

###

Jonathan Bennett, lead author of the paper, is at the University of 
British Columbia. Other co-authors include Hafiz Maherali from 
University of Guelph, Kurt Reinhart at the U.S. Department of 
Agriculture Fort Keogh Livestock and Range Research Laboratory, and 
Miranda Hart and John Klironomos from University of British Columbia.

The paper is online at http://science.sciencemag.org/content/355/6321/181.


-- 
=--------------------------------------------------------------------------------------------------------=
"Oxygen in the atmosphere might be reduced several percent below the 
present level without adverse effects."

"Free oxygen not only supports life; it arises from life. The oxygen 
now in the atmosphere is probably mainly, if not wholly, of 
biological origin."

Preston Cloud and Aharon Gibor. The Oxygen Cycle.
Scientific American, September 1970
=--------------------------------------------------------------------------------------------------------=
"We found that tree mortality rates increased by an overall average 
of 4.7%yr from 1963 to 2008, with higher mortality rate increases in 
western regions than in eastern regions (about 4.9 and 1.9% yr , 
respectively). The water stress created by regional drought may be 
the dominant contributor to these widespread increases in tree 
mortality rates across tree species, sizes, elevations, longitudes 
and latitudes. Western Canada seems to have been more sensitive to 
drought than eastern Canada" (Peng et al 2011).
************************************************************************
"We contend that traditional approaches to forest conservation and 
management will be inadequate given the predicted scale of 
social-economic and biophysical changes in the 21st century."

Forest Ecology and Management Accepted 7 October 2015
Review and synthesis
Achievable future conditions as a framework for guiding forest 
conservation and management
S.W. Golladay, K.L. Martin, J.M. Vose, D.N. Wear, A.P. Covich, R.J. 
Hobbs, K.D. Klepzig, G.E. Likens, R.J. Naiman, A.W. Shearer