Forests in a Looking Glass
The Conservation Department and the University of Missouri are conducting a long-term study of the effects of timber cutting on Missouri forests. The Missouri Ozark Forest Ecosystem Project (MOFEP) began five years ago and will extend years into the future. It centers on over 9,000 acres of land in Shannon, Reynolds and Carter counties.
About one-third of the state of Missouri is covered with forests, some 14 million acres. These forests provide recreation in the form of hunting, hiking and camping, and they are important to the health of the streams that provide fishing. They also produce wood products, providing lumber, furniture and charcoal. The Conservation Department and the University want to know how cutting trees by different methods affects the health of the forest and the creatures, plants and soil nutrients that exist there.
Forests on the study lands will be treated three different ways. Some tracts will have no timber harvesting. Some will be lightly harvested every 10 years. A third group will have total harvesting in small, rotating stands. All of the components of a healthy forest will be studied in the presence of these timber cutting plans.
During the spring of 1991, 27 summer interns with maps and binoculars looked for birds and nests in the woods as part of the forest interior songbird study. The vegetation study began accumulating data on the types, sizes and condition of trees and determining what small plants were growing under the tree canopies. The reptile and amphibian study began in the fall by installing special traps to count toads, frogs, salamanders, lizards, snakes and turtles the following March.
As MOFEP matured, we realized that this was a unique opportunity to study how forest ecosystems respond to management. To make MOFEP even better, we recruited scientists and funding from other sources to broaden the study to other ecosystem components. Eighteen studies are active now on MOFEP.
To learn the effects of these practices on the forest and its inhabitants, we needed to measure the current condition of the forest to detect what changes occur. Many interesting questions will be answered after the actual tree harvesting takes place, but there is much to learn from the existing conditions before harvest.
On the vegetation study, we constructed 648 half-acre vegetation plots and measured more than 55,000 trees that were bigger than 4.5 inches in diameter and 70,000 smaller trees. Eight oak species make up 72 percent of the trees counted. Four hickories comprise 19 percent and shortleaf pine 9 percent. The other 50 species make up less than 1 percent of the trees surveyed. Black oak is the most common tree, and white oak, the second most common tree, is increasing because it can live under tree canopies with a little less light.
Wildlife dens are found in 31 percent of the trees that are larger than 19 inches in diameter but in only 2 percent of the trees less than 10 inches. Seventy percent of the blackgum of the larger size had dens but less than 1 percent of the pine did.
We are also monitoring dead trees and branches on the forest floor on these plots. We will find how fast they decay and how amphibians, reptiles and other animals use them.
We are aging and measuring more than 3,000 trees. We will plot their locations on detailed soil maps to detect how fast trees grow on specific soil types.
Most plant diversity is found beneath the canopy. These plants are often more sensitive to changes and react more quickly than trees, so they are good indicators of forest health. Many people may remember when they first saw a ladyslipper or recognized a patch of mayapples, but few would guess there are more than 500 species of small plants growing in the forest.
Each summer, botanists visit 16 small plots, 1 meter by 1 meter in size, on each of the larger 648 plots to find what is growing in each. As anyone who walks the woods in the fall might guess, beggars' ticks or tick trefoil is the most common plant in the understory. Flowering dogwood, Virginia creeper, hog peanut and sassafras follow. Tick trefoil occurs more frequently on north slopes than ridges. Virginia creeper does just the opposite.
The botany crew also determines how much area is covered by rock, bare ground, leaf litter and tree stumps, plus the canopy coverage above the vegetation plots. Canopy coverage is the ground area shadowed by leaves from trees growing overhead. Excluding glades, most plots range from 75-85 percent canopy coverage.
Information from the botany study is useful to forest managers. The botany sampling shows there are less than 100 pine seedlings per acre. There are more than 1,200 white oaks of this size alone. If black, scarlet and post oak are added, the quantity climbs to more than 2,700 per acre. This suggests that pine is having a hard time becoming established under a full canopy of trees.
The songbird study is tracking the kinds, numbers and reproductive success of migratory bird species that nest in lower Ozark forests. In the early morning during the first half of the summer, student interns map singing male bird territories on approximately 150-acre plots. On a good day, there can be as many as 70-100 birds on one area. Each area is spot-mapped 10 times during the summer, and a total of 630 spot maps are made over the entire MOFEP site.
The students also search for nests, and revisit "finds" every 3 to 5 days to detect their development and success. They usually find between 300 and 400 nests per summer.
During the latter part of the summer, the 27 birders switch gears and begin trapping birds in fine mesh nets. Birds are identified by species, sex and age; marked with a numbered metal band and released. They caught about 900 birds per summer during the first years of the study, but this increased to 1,400 birds in the summer of 1994, using a refinement in technique.
The bird study is an extension of work in Central Missouri, where forest songbird populations are depressed and nesting success is almost nonexistent because of predation and cowbird parasitism. Studies in fragmented forests in other midwestern states support the notion that edge and conversion to some other habitat is bad for migrant songbirds.
Data collected so far show that on MOFEP sites these problems are low. Overall, more than half the nests are successful for some species while others approach 90 percent. Now we are poised to learn if forest management in large contiguous forests affects these bird populations either positively or negatively.
Reptiles and Amphibians
Workers on the reptile and amphibian study use what they call "drift fences" to trap the objects of their study. The fences consist of three long lines of aluminum flashing buried vertically in the ground to form a "Y." They bury a five-gallon pail at the middle, and funnel traps made from window screens are placed on each side of the "Y." When viewed from afar, a person surely thinks a space alien has visited the woods. Nevertheless, it works!
Unsuspecting toads, frogs, salamanders, skinks, lizards and snakes bump into the aluminum walls. They may decide to go left and crawl into a funnel trap or they may follow the fence right and fall into the pail. Whichever happens, they are trapped, counted, measured and released. This last season 42 species of reptiles and amphibians made the charts, and the workers subsequently measured and released 5,700 individual specimens.
The workers on the reptile and amphibian study also trap small mammals using box traps. They captured 726 individuals representing 6 species, with deer mice and white-footed mice comprising more than 90 percent of the captures. By experimenting with trap design and season, they almost doubled their success rate from the previous year.
A soil scientist, on loan from the Department of Natural Resources, is compiling a detailed soil inventory of the MOFEP sites. He delineates areas of similar soil types based on the material in which the soil developed, the landform and its shape. These units have properties that lend themselves to similar use and management.
Aspect and vegetation types will be added to these units later to develop ecological land types (ELTs). ELTs will become the units for making management decisions and a basis for the analysis of data collected on other projects.
Several studies are concerned with other soil characteristics, such as water flow and nutrient cycling. Cooperators from the University of Missouri, the University of Tennessee at Chattanooga, the Natural Resources Conservation Service and Missouri Department of Natural Resources have all given help.
The creepy crawlers that eat oak leaves are the focus of the canopy insect study. So far, the scientist on this study has recorded 245 species, mostly moth larvae. By sampling four times per year, he has discovered that few species from one sample will be found in the next. Lab work in this study is determining what parasites of moths exist in the Ozarks that will be natural control agents for the gypsy moth, when it arrives.
Many species of wildlife depend on the annual production of soft mast (berries) and hard mast (acorns and nuts). Two studies in place are collecting data to determine annual production and how it varies by season or growing conditions.
In the hard mast study, 130 plots containing a total of 2,600 traps to catch acorns and nuts are checked weekly from August through January. Technicians identify each acorn by species, determine if it is sound, then weigh each sample. Preliminary analyses show extreme variability in acorn production both from location to location and from year to year.
The soft mast study works closely with the data from the vegetation study. Although many plants can produce soft mast in the forest, most often they do not. Dogwood and blackgum consistently produce fruit, but other species (such as blackberries, blueberries and raspberries) only will grow in open areas with sunlight. Both mast studies will determine how timber management practices affect fruit production.
One study is not field intensive but takes an enormous amount of laboratory time. The researcher in charge of this study is looking at invertebrate species living in the leaf litter on the forest floor. These species make up a large part of the diversity of the forest.
She has so far identified 700 different species on MOFEP sites, and she estimates that up to 250 million individuals occur per acre. Two species that are new to science already have been collected on this study.
Another scientist is measuring soil temperatures, air temperature, relative humidity, solar radiation and wind speed along a 10-mile transect to determine microclimate variability on the landscape. We hope to see if microclimate changes, whether natural or resulting from management, affect the vegetation types and growth.
Genetic diversity within a species is necessary for its long-term survival, allowing it to adapt to changing conditions. The woody plant genetics study will determine how genetic diversity changes in some species with the type of forest management.
Last but not least, a study is looking for different species of Armellaria and how they and the trees they affect respond to the management treatments. These fungi mostly hasten wood rot but may attack severely stressed living trees.
With all these studies in place, computers are bulging at the seams with information. Data management is critical to MOFEP to allow systematic storage and retrieval of data for use by all the scientists. An overall goal of MOFEP is to cross-reference findings from the many studies to be able to get the big picture, rather than individual frames.
The MOFEP project has many things that set it apart from most studies. We are looking at land management practices over large areas. We are also overlapping many different studies on the same sites to see how the pieces fit together. This huge, cooperative effort involves many scientists and technicians in many agencies, universities and colleges.
It may take 100 years before we see the full effects of management on the MOFEP sites, but we plan on learning and, in turn, teaching many things along the way. The scientists who created MOFEP will not live long enough to see the project's completion. Nevertheless, they know the information collected along the way will be as valuable as the end product. Sustainability of the forest is the goal of all forest managers, and the information generated by MOFEP will help us reach that goal.