(01/14/20) Homer, La. — Pine trees are an important natural resource in Louisiana. They fuel the state’s multibillion-dollar timber industry, provide habitat for wildlife and are a defining element of the landscape.
But drought is becoming a more common occurrence in Louisiana and throughout the southeastern United States — threatening pine forests and their many benefits.
“It’s not so much that the rain levels are lower than they have been historically,” said Michael Blazier, a forestry researcher at the LSU AgCenter Hill Farm Research Station in Homer. “It’s that we’re getting higher summertime temperatures. That’s cooking the water out of the soil more frequently.”
To learn more about how tree growth is affected when water is limited, Blazier is artificially imposing drought on some loblolly pines at the research station. He has covered their roots with plastic sheeting to keep moisture out and is using sensors to gather data on water and carbohydrate usage.
The U.S. Department of Agriculture National Institute of Food and Agriculture is funding the project, which is titled Thinning Integrated with Genotype Exclusion of Rainfall Study, or TIGERS.
Blazier hopes the study will shed light on physiological differences between the pine trees found in Louisiana versus other states.
“What we’re trying to understand is where these trees differ in their mechanisms for surviving drought,” he said. “Is there a difference between the local families and some from other parts of the Southeast? Can we find something that’s going to be the best combination to optimize how well our forests can ride out a drought?”
Drought affects different trees in different ways. Some simply become unable to pull up water. Others try to hold onto moisture by closing the pores on their leaves, which stops the process of photosynthesis and causes them to starve to death.
Blazier wants to find out which trees hold out the longest before displaying those kinds of reactions.
He also is studying how thinning out stands of trees can help them survive droughts.
“We can take some of the weaker individuals out so that the remaining trees have more moisture availability,” he said.
There is an oversupply of timber on the market, a lingering effect of the Great Recession that has caused some landowners to postpone cutting their trees, Blazier said. That means there is greater competition for scarce water and other resources, which stresses trees and makes them susceptible to beetles and raises the risk of forest fires.
Protecting tree health is important, Blazier said.
“Forestry and wildlife have a tremendous impact on the economy of Louisiana — about $10 billion of economic contribution from the forest industry and then another $2 billion from the wildlife industry,” he said.
A shelter made of plastic sheeting covers the roots of loblolly pine trees to keep out moisture at the LSU AgCenter Hill Farm Research Station in Homer. Forestry researcher Michael Blazier is artificially imposing drought on these trees to study how they respond to such conditions. Photo by Olivia McClure/LSU AgCenter
LSU AgCenter forestry researcher Michael Blazier stands in a forest area in the LSU AgCenter Hill Farm Research Station in Homer, Louisiana. Photo by Olivia McClure/LSU AgCenter