Natural Resources & Environmental Sciences
Non Technical Summary
Harvesting of southern pine forests often results in large quantities of slash that can be challenging to manage. As is true of most aspects of forest operations, there is no one-size-fits-all approach for dealing with slash. In fact, there are several options commonly used in southeastern forests, each with its own advantages and disadvantages. It is important for land managers to understand the long-term implications of slash removal methods on ecosystem processes. However, most of the research concerning slash/biomass removal has been conducted in the Western United States to promote residue reduction as a means of influencing subsequent fire regimes and forest fire risks following timber harvest. This study will investigate non-burning techniques of managing slash, as well as the ecological, logistical and economical implication of each of the methods. Leaving untreated logging slash on site could be either detrimental or beneficial, depending on the variables of interest. Leaving logging slash on site can increase wildfire risk. Heavy loads of logging slash form a physical barrier making planting, natural seeding, and subsequent forest management activities difficult. Benefits of the presence of logging residues, on the other hand, include protection of seedlings from exposure to heat and drought which can negatively impact survival rates, especially on water limited sites. Slash material can protect forest soils from erosion, protect the root systems of new seedlings, provide habitat for wildlife, and act as a slow release source of nutrients such as nitrogen and phosphorus into the ecosystem. Also, while harvesting machine traffic may cause increased soil disturbance and compaction, the presence of surface organic matter helps to reduce the potential for erosion. Potential fire hazards of residual slash and the increased difficulty for planting or other post-harvest management activities must be weighed against potential benefits of slash to soil, advance regeneration, and wildlife habitat. In general, forest managers must balance fire risk and planting hindrance with the ecological benefits of leaving some slash in place. They also must assess what is logistically and financially feasible. Each slash management method has its advantages and disadvantages. A potential economic benefit of slash removal would be its use as biomass for energy by chipping and transporting it to an energy producing plant. This project considers each of the above aspects to allow the development of guidelines and management practices for sustainable forest logging residue removal operations in the southern United States. This research will benefit public and private landowners who manage pine forests in the South and optimize logging slash removal to allow improved site preparation operations while maintaining site productivity.
Animal Health Component
Research Effort Categories
Goals / Objectives
The objectives of this proposal are to (1) examine the impacts of The objectives of this proposal are to (1) examine the impacts of logging residue amount on regeneration survival and growth and (2) compare the productivity and cost-effectiveness of different harvesting/regeneration systems which produce different quality, quantity, and spatial distribution of slash. We will examine how operational treatments affect forest regeneration through the following sequence of factors and effects: operational treatments -> amount of slash -> regeneration technique and microclimate -> forest regeneration. Expected outputs include: prepare and train two Master of Science level graduate students in the field of forest operation research; introduce undergraduate students to forest operation research techniques; undertake outreach and extension for the purpose of disseminating the results of the study.
The proposed study will be located in Northern Alabama on xeric to xeric-mesic southern pine forest, either natural or planted and will include four years of field measurements. The experiment will be organized as a randomized complete block with three replicate blocks--one replication per site with each treatment replicate adjacent to others. The measurement area of each treatment plot will about 0.4 hectare (1 acre). Sites will be selected to minimize soil and climate differences without restricting the study to a very particular location. Three harvest treatments representing different quality, quantity, and spatial distribution of slash will be compared: 1. Two-pass timber and biomass harvesting (whole-tree harvesting) 2. Cut-to-length harvesting (well distributed slash) 3. Tree-length harvesting (control) 4. Reference (no harvesting) The harvesting/regeneration method will be clearcutting in accordance with the existing management plan. In case of difficulties with the logistics of real life tree harvesting, some operations may need to be simulated manually within the research plots in the treatment area. In such cases we will use cost estimate data from our two recent projects for conducting cut-to-length harvesting and tree-length harvesting (Tenyah 2009) and two-pass timber and biomass harvesting (Ndona-Makusa 2009). Two-pass timber and biomass harvesting can be considered a variant of whole-tree harvesting, in which roundwood and biomass are removed separately. After trees are felled with a feller buncher in the first pass, the skidder drags whole trees to the landing area, where they are delimbed and topped, and logs are loaded in a truck. In the second pass, tree limbs and tops are piled near a second loader, which pushes them into a chipper. Cut-to-length harvesting includes a harvester and a forwarder. The trees are felled, delimbed and bucked to desired log sizes directly at the stump. The products are then loaded into the forwarder and taken to the landing. As a result, residual slash is well distributed over the site. Tree-length harvesting is the conventional harvesting method in the South. The most commonly used system involves the use of a feller-buncher and grapple-skidder. Trees are delimbed, tops are cut, and boles are taken out. Typically, the residual slash remains in the vicinity of the landing area. This treatment will serve as a control. We will include also a reference site that will not be harvested to ensure that differences of variables between the first and the fourth year after harvest are not due to differences in environmental conditions. After harvesting, the sites will be planted with loblolly pines, using seedlings from the same seed source and nursery. Sites will be planted using the same planting method preferably by the same crew to reduce variability. The survival and growth rates of the seedlings will be assessed to evaluate the effect of the treatments on stand regeneration.