Strengthening the Shortleaf Pine

Wurdack Research Center working to revive historic tree

This story also appears in our University of Missouri College of Agriculture, Food and Natural Resources’ Agricultural Research Center Magazine. Stop by your local Research Center to pick up a copy!

A variety of timber species inhabit the 260 acres at the University of Missouri College of Agriculture, Food and Natural Resources’ Wurdack Research Center.

Research at Wurdack on the shortleaf pine began with John Dwyer, an associate professor emeritus of forestry, in 2010. The United States Department of Agriculture Forest Service had done controlled cross pollinating with select shortleaf pine trees more than 30 years ago. The Forest Service categorized those trees in regards to timber production, choosing what they thought were the best trees. Those trees were then planted in Arkansas with further crossing done.
Research at Wurdack on the shortleaf pine began with John Dwyer, an associate professor emeritus of forestry, in 2010. The United States Department of Agriculture Forest Service had done controlled cross pollinating with select shortleaf pine trees more than 30 years ago. The Forest Service categorized those trees in regards to timber production, choosing what they thought were the best trees. Those trees were then planted in Arkansas with further crossing done.

The majority of the timber species at the Center are oak and other hardwoods. Wurdack is working hard to strengthen another species as well – the shortleaf pine. The only native pine tree that grows in Missouri, the shortleaf pine is a historic tree in the southern part of Missouri.

“We’re trying to recapture good genetics and put them back out into the landscape,” said Superintendent Dusty Walter. “We want to sustain these improved populations that are widely adapted and have the broadest range of the southern pine species.”

While most common in the southern United States, the shortleaf pine can be found as far north as New York. It’s an incredibly valuable tree to the wood industry.

“When we talk about shortleaf pine, it has a strong history of logging and wood utilization,” Walter said. “It’s one of the four primary southern pine species as well, along with loblolly, slash and longleaf. Those three species are more localized in their specific ecological range that they inhabit. The shortleaf pine is much more adaptable and can be found in a wide growing range.”

Research at Wurdack on the shortleaf pine began with John Dwyer, an associate professor emeritus of forestry, in 2010. The United States Department of Agriculture Forest Service had done controlled cross pollinating with select shortleaf pine trees more than 30 years ago. The Forest Service categorized those trees in regards to timber production, choosing what they thought were the best trees. Those trees were then planted in Arkansas with further crossing done.

From those controlled crossings, the Forest Service took numerous seeds and stored them in a cooler. With the viability of those seeds dropping after being stored for more than 30 years, some of those seeds were planted in the George O. White Nursery in Licking, Mo.

“John went down and did evaluations on the shortleaf offspring for a couple years in Licking,” Walter said. “Based on his assessments, they identified the 24 best families, where they knew the mom and dad. They went back to that cooler and picked those 24 families and planted them at Wurdack.

The majority of the timber species at the Center are oak and other hardwoods. Wurdack is working hard to strengthen another species as well – the shortleaf pine. The only native pine tree that grows in Missouri, the shortleaf pine is a historic tree in the southern part of Missouri.
The majority of the timber species at the Center are oak and other hardwoods. Wurdack is working hard to strengthen another species as well – the shortleaf pine. The only native pine tree that grows in Missouri, the shortleaf pine is a historic tree in the southern part of Missouri.

“It’s an offspring of what has already been done and a continuation of those improved selections that were made years ago.”

The Wurdack Research Center, located near Cook Station, is running two different trials on shortleaf pine trees. The first will follow a southern pine silvopasture model with the goal of growing strong trees and providing a grazing area for cattle. The trees are planted 10 feet apart in two rows. There is a 40-foot alleyway, then another two rows with trees planted 10 feet apart. This trial covers 10 to 12 acres.

“The goal is to provide an alleyway for cattle to graze on,” Walter said. “Down the road, when the trees are fully grown, they will provide good shade for the same cattle, giving us a strong silvopasture system.”

The second trial is purely a genetic study. They have planted shortleaf pine trees on five acres. Each tree is spaced 10 feet apart. It’s a randomized design that will look at the 24 families and monitor if their performance holds true.

“We have actually partnered with the Forest Service and used some of the Wurdack endowment money to cosponsor a graduate student,” Walter said. “They will measure the height and diameter of the tree, as well as update our maps on how well our trees are growing. When combined with the current research done by the Forest Service on other properties, the information will provide a detailed look at effectively establishing shortleaf pine. It’s all about gaining more knowledge.

“Anytime you can partner, it’s a win-win. We want to use our endowment dollars for projects like this.”

In total, Wurdack has planted just more than 3,000 shortleaf pine trees across its nearly 20 acres.

In total, Wurdack has planted just more than 3,000 shortleaf pine trees across its nearly 20 acres. The key to growing shortleaf pines is reducing the competition for light, moisture and nutrients.
In total, Wurdack has planted just more than 3,000 shortleaf pine trees across its nearly 20 acres. The key to growing shortleaf pines is reducing the competition for light, moisture and nutrients.

The key to growing shortleaf pines is reducing the competition for light, moisture and nutrients.

“Pines typically outgrow hardwoods if you put seedling next to seedling,” Walter said. “However, oftentimes when we clear a piece of ground there are leftover seedling sprouts. Those sprouts already have an existing root system, meaning those sprouts are already at a competitive advantage. You have to make sure that competition stays away, as those sprouts with a root system will outgrow newly-planted seedlings.”

Pines are adept at putting roots out in several soil types. Pines generally don’t want their roots too wet, so the site has to be well-drained. Pines can grow to be 120 feet tall.

“Growth is all site specific,” Walter said. “With our forests, the shortleaf pines probably won’t reach 120 feet.”

The shortleaf pine was one of the predominant trees cut in southern Missouri during the late 1800s and early 1900s. This was during a time when harvesting practices weren’t focused on the regrowth and regeneration of the tree. Once the shortleaf pines were harvested, hardwoods quickly moved in.

“Logging practices at that time were not done in a way that encouraged the renewal of shortleaf pines,” Walter said. “The follow-up practices weren’t focused on that, either. What we’re doing is more of a historic restoration of the tree.”

The shortleaf pine research at the Wurdack Research Center is part of a bigger forest management mission.

“It’s important for us to be proactive when it comes to our management practices,” Walter said. “It not only helps from a natural resources perspective, but it helps the landowners clarify their objectives.”

The shortleaf pines at Wurdack are adapted to certain site characteristics and their performance can help landowners envision their use on their private property.

“If there isn’t a plan in place, Mother Nature thins the forest out. She does that through wind storms, insects, disease and other processes. While Mother Nature does have the last say, proper forest management can help you be prepared for those events by managing for site appropriate trees and their health.”