Timber harvest opens second chapter in forest research saga

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ELLINGTON–In the next few months, contractors working with the Missouri Department of Conservation will begin writing the second chapter in a century-long saga. Their theme is the quest to understand forest ecology. Their pages are rugged Ozarks hills, and their writing tools are chainsaws and skidders.

At its meeting Dec. 17 in Jefferson City, the Missouri Conservation Commission will consider seeking bids from professional loggers to harvest trees on 2,344 acres in Current River Conservation Area (CA) in Reynolds and Shannon counties and at Peck Ranch CA in Carter County. Altogether, the timber sales are expected to produce a little more than 7 million board feet of forest products, mostly oak.

The timber harvests are part of a carefully designed scientific experiment with breathtaking size and duration. The experiment, known as the Missouri Ozark Forest Ecosystem Project, or MOFEP, was launched in 1990. It is designed to measure the effects of different management practices on various elements of the forest ecosystem. The study area covers 9,381 acres of forest and will span 100 years. Researchers who participate in its early phases will not live to see its conclusion.

MOFEP seeks answers to several questions, including:

• How much carbon do Ozark forests sequester and how will climate change or different management scenarios affect carbon stocks?

• How do different forest management practices influence abundance and reproductive success of birds?

• How do different forest management practices affect tree growth, species composition and regeneration?

Preparations for MOFEP involved measuring a host of ecological factors on all 9,000-plus acres of MOFEP. Field workers documented existing populations of trees, wildflowers, fungi, insects, amphibians, reptiles, birds and mammals on MOFEP land. They studied soil and other physical components of the forest. Once these baseline data were assembled, MOFEP moved into its active phase – timber harvests – in 1996.

MOFEP methodically subjects small tracts of forest to different types of timber harvests and then measures the resulting changes. Timber harvests occur every 15 years.

On one-third of the MOFEP land, the Conservation Department conducts even-aged forest management. This involves cutting all trees within small tracts. The forest that re-grows on these tracts consists of trees of the same age – hence the name.

On another one-third of MOFEP land, contract loggers harvest individual trees and groups of trees selectively in what is known as uneven-aged management. This produces timber stands containing trees of different ages.

The remaining one-third of the study area is a scientific control, where no trees are harvested. The lack of timber harvests does not mean this forest is frozen in time, however. Trees die of natural causes, such as old age, disease and tornadoes, and they fall and decay. Field crews record these changes, too.

The 1996 timber harvests and subsequent measurements were Chapter 1 of MOFEP. Now, 15 years later, Chapter 2 is about to begin, as contract loggers return to harvest timber on different portions of MOFEP land.

On land under even-age management, they will thin 415 acres of forest and clear-cut another 488 acres. A total of 1,467 acres will be thinned under uneven-aged management, and 124 acres will have woodland/glade restoration work done.

Another 4,001 acres within the actively managed portions of MOFEP do not need treatment, according to standards MDC followed on all conservation areas. These acres will be reevaluated for possible timber harvests during the next MOFEP management cycle in 2026.

As always, the one-third of MOFEP land set aside as a control will receive no timber harvest, but monitoring of forest changes will continue there, as on the actively managed land.

As the forest changes under the three different management regimes, scientists collect and analyze data for insights about how different management strategies affect the forest ecosystem. Such insights already are accumulating and are being used by the Conservation Department to manage Missouri’s forests better.

One such insight is the observation that the first small-scale even-age timber harvests did not seem to hurt local populations of many forest bird species.

“For years, the Conservation Department has been concerned that logging in the Ozarks might contribute to the decline of migratory songbirds,” said MOFEP Coordinator David Gwaze. “This was based on the belief that logging could decrease available habitat or make songbirds more vulnerable to brown-headed cowbirds, which lay their eggs in other birds’ nests. But, study results so far show no increase in nest parasitism on MOFEP timber-harvest sites.”

According to Gwaze, early study results also indicate that logging – when performed according to MDC’s high standards – does not decrease the variety of bird species present in a forest tract. He said some birds that prefer mature forests, such as the ovenbird, may be less numerous around timber harvest sites. However, numbers of other forest-dwelling birds, including the wood thrush and Kentucky warbler, actually increase around harvest sites. So do numbers of birds, such as indigo buntings, yellow-breasted chats and prairie warblers, that prefer more open areas.

Similarly, the number and diversity of reptiles, amphibians and small mammals did not decline in areas with timber harvests.

Fieldwork during MOFEP’s first cycle shows the mix of tree species changing rapidly in control areas where no logging occurs. Gwaze said scarlet and black oaks are dying faster and not replacing themselves as rapidly as white oaks. The proportion of scarlet and black oaks also is declining in areas under uneven-age management. Where managers want to maintain the original mix of scarlet, black and white oaks, even-age management appears to be the best strategy.

The diversity of plant species growing on the forest floor is greater in areas where timber harvests have occurred than in unlogged areas, probably due to greater availability of light. For the same reason, berries and other wildlife food collectively called “soft mast” are more abundant in harvested areas.

Researchers also are discovering that even-age management is more efficient than uneven-age management in regenerating oak trees. Stump sprouting is the most common and efficient way to regenerate oak forests. So far, trees produce more, faster-growing sprouts after even-age harvests. As information continues to accumulate, managers will be able to use MOFEP data to refine regeneration practices and other management techniques.

Other MOFEP data suggest that root injuries caused by logging might contribute to harmful fungal infections, decreasing tree vigor and inhibiting stump sprouting. This indicates a need to find the exact causes of the injuries and educate loggers about how to avoid them.

So far, MOFEP results do not show that either even-aged or uneven-aged management is more profitable. The effects of each approach on other values, such as recreation, could be a significant factor in deciding which system to use.

“We are still very early in the study,” said Gwaze. “Some of these initial results might not hold true over the long term. We will adapt management as our knowledge and understanding of forests increases. MOFEP will have far-reaching effects on how we manage forests, but no one living now can say exactly what those effects will be. Today’s research is for future generations.”

MOFEP had to be designed as a long-term research project because the oak and hickory trees that make up the bulk of Missouri’s forests take 80 to 100 years to mature. The immediate goal is to track forest changes through one tree life cycle.

“Forests operate on a different time scale than people,” said Gwaze. “To understand them, you have to work on their time scale. Individuals don’t live long enough to do that, so several generations of workers will contribute to MOFEP. The longer we stay with it, the better we will understand how to manage the Ozarks forests for wildlife and plants sustainably.”

To learn more about the Missouri Ozarks Forest Ecosystem Project visit its official website at mofep.mdc.mo.gov/.

-Jim Low-