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The Natural State of the Forest By: Andrea Muffuletto The Natural State of the Forest Arkansas is home to 18.8 billion acres of forest, including the Ozark, the Ouachita, and the St. Francis National Forests. Woodlands account for over 56% of Arkansas’ total land base and are vital to the state’s economy, national image, and most importantly the ecosystem (Gary, 2006). Because of the integral role of the forest here in Arkansas, it is critical to recognize one of the most pressing issues regarding its condition- the issue of overcrowding. Overcrowding refers to the overabundance of vegetation in an ecosystem, which leads to increased competition for resources such as light, water, and nutrients. This problem is the result of the elimination of natural fire regimes. It has compromised the natural integrity of the woods by promoting the growth of non-native species and has led to increased susceptibility of vegetation to drought, disease, and pests. Few solutions have been posed to address the issue of forest overcrowding, most of which are widely controversial, such as prescribed burning and sustainable timber management. Population Ecology and the Historic Role of Fire Overcrowding is a concept often associated with population ecology, which is the study of how species interact with their environment. The overcrowding of Arkansas’ forest directly correlates with the spread and additional growth of non-native species, which have resulted from accidental introduction and prior management techniques. Effects associated with this include wildlife habitat degradation, displacement of native species, altered soil, and hydrological conditions, as well as decreased biodiversity. In relation to overcrowding, population ecologists state “a population can decline because it lacks resources or it can decline because it is prey to another species that is increasing in numbers” (Colyvan 2008). Both of these explanations appropriately model the current conditions found in Arkansas forests. The native hardwood population is slowly diminishing as a result of increased competition for resources, specifically Page 2 of 8 The Natural State of the Forest competition with shade tolerant trees such as maple, ash, and gum trees. Further evidence suggests that with the elimination of natural fire practices, non-native species have been able to thrive and out-compete the already stressed hardwood populations. Fire has played a fundamental role in the history of forest ecology and is useful in identifying the origins of forest overcrowding. Prior to human inhabitation, lightning ignited wildfires progressed unimpeded across the landscapes, limited only by physical factors such as topography, bodies of water, and weather patterns. Dendrochronological studies have indicated that most forests were exposed to fire on a time interval of every five to ten years. Exposure to recurrent wildfires led to the adaption of native species, forming a fragile ecosystem dependent on frequent burnings. When Native Americans inhabited the land it was a common practice to utilize fire to maintain ecosystems. This can be seen by the increased rate of charcoal deposits in dendrochronological studies, which essentially are marks in the rings of trees illustrating at what points in time the tree was exposed to fire. Historical records documenting early European migration to the Ozark Mountains cite firsthand accounts of these Indian practices. Within the next few centuries, consistent European settlement in the area led to modified practices in regards to natural fire, focusing primarily on fire suppression as a means to control what was viewed as a destructive force. Unfortunately, this mindset has carried into the twentieth-century and it has only been within the past 75 years that ecologists have recognized “that fire was a primary agent of change in many ecosystems” (National Park Service n.d), and by suppressing these natural phenomena settlers unintentionally altered the natural state of the Arkansas woodlands. Page 3 of 8 The Natural State of the Forest Appearances may be Deceiving Oak-hickory forests have been the dominant ecosystem present in the Ozarks for over 4,000 years. Upon initial observation, Arkansas forests may appear to be healthy and highly productive, but in reality they are an unhealthy ecosystem dominated by non-native species that are able to thrive in the densely populated environment. The forests we see today starkly contrasts accounts recorded from the 1800s by men such as Henry Rowe Schoolcraft. Known to have traveled widely throughout the Ozark Mountains, he is quoted as saying they were “covered chiefly by oaks without underbrush. A tall thick, and rank growth of wild grass covers the whole country, in which the oaks are standing interspersed, like fruit trees in some well-cultivated orchard” (Purcell, 2004). The picturesque appearance described by Schoolcraft can no longer be found in the Arkansas woodlands due to an increase in shade-tolerant vegetation. This results in the inhibition of small oak tree regeneration, which has led to the overabundance of other tree species and the emergence of closed canopy stands. The understory of the forest is dominated by shrubs, poison ivy, and Virginia creeper, which in conjunction with a high stem density of 300 to 1000 stems per acre (as opposed to 38-76 stems per acre recorded in the 1800s), excludes the growth of native warm season grasses and wildflowers that once flourished on the forest floor (Ozark St. Francias National Forest, n.d). This decrease in forest floor growth negatively impacts animal species that utilize the vegetation for habitat or as a food source. Native species such as white-tailed deer, rabbits, quail, and turkey all benefit from an open understory, which allows them to easily find food and shelter. In addition, studies have shown that migratory birds benefit from an open understory because it is better suited for the foraging of seeds and provides optimal conditions for nesting. Page 4 of 8 The Natural State of the Forest Susceptibility The oak and hickory trees native to Arkansas are considered highly susceptible to drought, disease, and pests as a result of the already stressed ecosystem. Historically, competition for essential resources such as light, water, and nutrients was uncommon, but with the increasing diversity of the understory and the added pressure of competition, these native species have become extremely vulnerable to insects such as the Red Oak Borer and diseases such as Hypoxylon canker. The red oak borer is a small insect whose larvae bore tunnels into live oak trees, damaging the trees and providing access for other dangerous pests such as carpenter worms, timber worms, and carpenter ants. Because of the densely populated forests and overabundance of understory, these borers are able to reproduce and migrate rapidly, severely damaging large quantities of native oak trees and thus promoting additional growth of shade-tolerant vegetation. The insect is particularly destructive due to the fact that the forest is already in a weakened state, and has recently caused large scale devastation in the Boston Mountain Range. In 1999, following a two year drought, 1.6 million acres of red oak were infested by the borer in Northwest Arkansas, killing 30-40% of the red oak trees. In the event of a wildfire, these standing dead trees act as a chimney and draw flames to the level of the tree tops, resulting in high vegetative mortality rates (Starkey 2004). Hypoxlon canker is a fungal infection which attacks weakened red and black oak trees. Its ability to colonize is contingent upon the health of the tree. The opportunistic fungi are unable to infect healthy trees, but will rapidly kill damaged ones by entering the tree and causing decay. Similar to the red oak borer, overcrowded conditions are favorable for the spread of this fungus. Page 5 of 8 The Natural State of the Forest New infections can be caused by aerial migration from one tree to another, promoting additional decay as the fungus moves through the forest. In addition to these problems, overcrowding in the forest can result in devastating droughts. The densely populated ecosystem requires a greater amount of water than previously needed in order to sustain the growth of the nearly 300-1000 stems per acre. The increased demand for water has become one of the primary factors influencing competition. Prescribed Burning and Sustainable Timber Harvesting Overcrowding in the Arkansas woodlands is due to the elimination of natural fire regimes in the twentieth-century. Long viewed as a destructive force, fire is now considered by many ecologists to be a natural remedy for this issue. Employed by many state and government agencies, prescribed burning utilizes low-intensity fires in an attempt to restore the forest to its natural state. Because many of the shade tolerant species have only been present for the last two hundred years, and have never been exposed to fire, they are easily killed by exposure to the flames of a prescribed burn. In addition to restoring the native forest, this solution also reduces hazardous fuels which can lead to destructive wildfires. This particular method of conservation is considered controversial by many because of the perceived dangers surrounding the use of fire and the high costs associated with it. This results in many individuals viewing prescribed burning as being an ineffective and an unnecessary solution to the problem. A second solution to this problem is mechanical thinning through the use of sustainable timber harvesting. Small, family-owned sawmill operations have been sustainably logging in the Ozark Mountains for hundreds of years. Sustainable logging involves the removal of a portion of the timber in a forest stand, leaving enough for re-growth. Two of the major benefits of this method are eliminating wastefulness and the methods ability to affect the diversity of tree Page 6 of 8 The Natural State of the Forest species. Unfortunately, a stigma associated with this solution is that it is often thought to be synonymous with the large-scale, clear-cutting practices of major timber companies. Practices of logging companies are not the solution to the problem of overcrowding, as they often clear cut old growth hardwoods and replant pine. This process is even more detrimental to the native ecosystem than the overpopulation problems. It is imperative that a distinction is made between the timber management practices utilized by small sustainable sawmills and the large timber harvesting companies. “Before our eyes, many areas of the Ozarks are shifting from majestic oak woodlands to overstocked stands of maples, ashes, and other tree species” (Purcell 2004). With the extinction of fire practices that were once used to control undergrowth in the forest, issues of overcrowding have threatened the expected lifespan of the oak-hickory forests. Competition for resources has led to a dramatically weakened oak-hickory population in the state of Arkansas, making these native trees more susceptible to disease and pests. Sustainable timber harvesting as well as prescribed burning are two of the primary means of combatting forest overcrowding, but controversy surrounds both of these practices. This environmental issue is pressing because the oak-hickory forests present in Arkansas are among the very few in the entire world. Because these forests cover such a large portion of Arkansas they are crucial to the historic meaning of the natural state. The Arkansas Heritage Commission is quoted in saying “oak-hickory forests are fairly common, but high quality examples of them have become so rare that each deserves special attention. Thus the opportunity to preserve the best example of a type can be as important as a chance to preserve the only example.” Page 7 of 8 The Natural State of the Forest References Arkansas Natural Heritage Commision. (2011). Endangered, Threatened, and Rare Species. Little Rock. Colyvan, M. (2008). Chapter 17. Population Ecology. In A Companion to the Philosophy of Biology. Gray, J. (2006). Forestry. University of Arkansas Division of Agriculture . Lamar, J. (2001, April 13). Forester says disease killing Arkansas oak trees. Delta Farm Press , p. 1. Laurel, J, Haavik, L, & Joshua, M. J. (2011). Oak decline and red oak borer outbreak: impact in upland oak-hickory forests of Arkansas, USA. Institute of Chartered Forests. Ozark St. Francias National Forest. Ozark Highlands Ecosystem Restoration Proposal. Russellville: USDA. Purcell, L. (2004, March). Resotring the Health of our Forests. Hector, Arkansas. Starkey, D, Oliveria, F, Mangini, A, & Mielke, M. (2004). Oak Decline and Red Oak Borer in the Interior Highlands of Arkansas an Missouri: Natural Phenomena, Severe Occurrences. Gen. Tech. Rep. Page 8 of 8