Oak decline-induced mortality and failure of oak regeneration have become a concern in upland oak forests in the Missouri Ozarks. This project investigated the effects of timber harvesting on both oak regeneration and mortality of oak residuals following a suite of harvesting treatments in the Missouri Ozarks based on the sixteen-year monitoring data from the Missouri Ozark Forest Ecosystem Project (MOFEP). On dry sites by year 10, clearcutting improved the density of oak reproduction the most, and that intermediate cutting and clearcutting increased the proportion of black oak reproduction with 2% and 3%, respectively in the composition of the forests in the study area. Single-tree selection exacerbated the mortality of oak residuals, group selection and no harvesting had a similar effect on oak residuals. Intermediate cutting improved the survival of residuals the most. This project suggested well-designed silvicultural practices would likely reduce oak mortality and increase understory oak reproduction.

Sediment is a leading contributor to nonpoint source (NPS) pollution in streams and rivers. Sources and sinks of sediment movement were identified for a 121-hectare watershed located in Webster County, Mississippi in order to evaluate the impact of forest harvesting on water quality and sedimentation rates. In a completely randomized design containing three replications of two treatments (unharvested vs. harvested) and two slopes (≤9% vs. >9%), twelve sub-watersheds were randomly selected for intensive measurement of the sources and sinks of sediment after precipitation events. In-stream, bank and forest road sediment movement were also monitored pre- and post-harvest. Total suspended sediment (TSS) in runoff from forest roads ranged from 36-188 g/L with a consistent trend of decreasing sediment concentrations with increasing distance from the road. Within the watershed, erosional processes dominated however there was little net change in soil elevation one year post-harvest.

No description available.

A group of 22 independent southeastern U.S. logging contractors provided 44 contractor-years of detailed cost and production information. Information was collected on demographics, operational characteristics, and business strategies for the participants. Precipitation was statistically proven to not be a good predictor of production, accounting for 2% of the weekly variation. High production through periods of favorable harvesting did not occur. Loggers contracting for the same mill in the same general area had higher than average production in the winter months and lower than average production in the summer months. Summary analyses for the entire population found that the cost of producing an additional ton dropped in 1997 by $0.90, but fixed annual costs rose. Predicting costs on the basis of production for the population was misleading. A comparison of total costs for individual firms with the population average (regression equation) found that the equation underestimated costs by as much as $408,000 and overestimated costs by as much as $528,000. Contracted services expenditures increased in 1997, as expenditures for equipment, consumables, and labor decreased. Over the study period, total costs per ton increased by 3.7%, but total production increased by 3.9%. The relationship between key cost components revealed strong evidence to disprove previously held theories. A major portion of the population increased production but experienced increased costs per ton. Replacement purchases of equipment tended to be of similar capabilities and technology and did not reduce labor costs. Trends in supply and equipment costs per-unit were not found in the expected fashion. / Master of Science

Two computer simulation models were developed to address harvest system - stand assignment and wood flow variability problems in the southeast United States. The Harvest System Assignment (HSA) model is used to evaluate the impact of a particular stand assignment on harvest system effectiveness and is designed to assist with harvest system assignment decisions. Four general harvesting systems: manual, mechanized, shovel and cut-to-length can be modeled to harvest timber, from standing trees to processed logs loaded on to trucks. Model testing showed that as terrain, tract and system characteristics changed, the effectiveness of each of the four systems varied. The most effective system can be determined for any combination of terrain, tract and system characteristics. The model output shows production potential as well as cost per unit, and identifies the causes and magnitude of inefficiency. The Machine Allocation (MA) model is used to evaluate the potential of a given machine combination and is designed as a research tool to investigate the cause and impact of machine interactions. This model has a defined system structure and can incorporate up to five machines for each of three phases in the harvesting operation: felling, skidding and processing. Particular system configurations can be evaluated and possible improvements to machine combination determined. The HSA model is a widely applicable tool that will be available for industry in the southeastern United States. It has utility for training of personnel and for operational use. The MA model is a detailed tool that will be used in a research capacity to advance harvesting system management. / Master of Science

Timber harvesting is an important activity in the state of Kentucky; however, there is still a lack of information about the procedure used by the local loggers. The stump to landing transport of logs with skidders is often the most expensive and time-consuming task in timber harvesting operations. This thesis evaluated the feasibility of using a multi-camera system for time and motion studies of timber harvesting operations. It was installed in 5 skidders in 3 different harvesting sites in Kentucky. The time stamped video provided accurate time consumption data for each work phase of the skidders, which was used to fit linear regressions and find the influence of skidding distance, skid-trail gradient, and load size on skidding time. The multi-camera systems were found to be a reliable tool for time and motion studies in timber harvesting sites. Six different time equations and two speed equations were fitted for skidding cycles and sections of skid-trails, for skidders that are both loaded and unloaded. Skid-trail gradient and load size did not have an influence on skidding time. There is a need for future studies of different variables that could affect skidding time and, consequently, cost.

At least 200,000 m3 of timber are harvested annually using semi-mechanised harvesting systems (SMS) on the Viphya forest plantations in Malawi. Although these systems have long been used on the Viphya, no investigation on their productivity has so far been reported. The absence of local productivity models created uncertainty about the importance of sitebased factors that influence timber harvesting productivity of these systems on the Viphya. Secondly, there is paucity of information regarding the appropriate timber harvesting systems for production maximisation and cost minimisation. This study aimed to develop prediction models for estimating the productivity and costs of semi-mechanised and simulated mechanised timber harvesting systems on the Viphya forest plantations. The study was conducted in Pinus kesiya stands at Kalungulu and Champhoyo forest stations of the Viphya forest plantations. A work study approach was followed to capture harvesting time and volume data. Stepwise multiple regressions were used to develop felling time models for a chainsaw over tree size, inter-tree distance, slope, ground condition, brush density, and ground roughness; and skidding time models over distance, slope, ground condition, ground roughness and volume skidded per cycle for a grapple skidder. Models were statistically validated. Secondary work study data for semi-mechanised systems were simulated for mechanised productivity based on local site factors. The study had shown that diameter at breast height and inter-tree distance were important factors that best explained felling time prediction models in Pinus kesiya stands on the Viphya forest plantations. Similarly, distance from stump to the roadside landing was the most important factor in addition to volume load, slope and ground conditions that determined grapple skidding time. Mechanised systems appear to be more advantageous than semi-mechanised systems. The former are associated with lower operating costs and inventories with relatively high production rates. Therefore, mechanised systems could help to optimise timber harvesting productivity on the Viphya. Further studies should be conducted to determine the effect of different ground conditions and roughness on skidding productivity. / Dissertation (MSc)--University of Pretoria, 2012. / Plant Production and Soil Science / MSc / Unrestricted

Headwater streams are considered to be the greatest contributor to nonpoint source and are a crucial part of overall watershed dynamics because they comprise more than 50-80% of stream networks and watershed land areas. This study addressed the influence of headwater areas (ephemeral and intermittent) on downstream hydrology and water quality following harvest as well as characteristics of vegetation communities within three first-order catchments in the Upper Gulf Coastal Plain of Mississippi. Four treatments representing a range of potential Best Management Practices (BMPs) for ephemeral drains were used: BMP1 - removal of all merchantable stems while leaving understory intact with minimum surface soil disturbance; BMP2 - same as BMP1 with the addition of logging debris to the drainage channel; No harvest - left uncut as a reference; Clearcut - total harvest with no BMPs applied. Harvested treatments caused the height of water table to increase up to 55 cm; however impacts of timber harvesting on peak discharge, storm discharge, and time of concentration were not consistent with water table response. Response time to stormflow was reduced significantly in harvested treatments (BMP2 and unrestricted harvest) as a result of decreased evapotranspiration and increased soil disturbance. Forest clearcutting in ephemeral drains caused intensive surface soil disturbance that resulted in substantial impacts to net soil erosion/deposition in both channel and hillslope positions and significantly increased total suspend sediment (TSS). There were no significant differences between two BMP and reference treatments in net soil erosion/deposition and TSS. Distinct vegetation communities between channel and hillslope positions in ephemeral-intermittent drains corresponded to water table gradients. Timber harvesting affected vegetation communities through direct and indirect disturbances. Four indicator species (V. blanda, L. glandulosa, A. gigantean, and P. acrostichoides) were identified as having a strong response to hydrologic gradients in ephemeral-intermittent drains.

The wood supply system is a dynamic and complex structure. Traditionally, key components of the system have been treated as stand-alone entities with very little regard to the performance of the overall system. The central component, the logging contractor, is usually viewed as a service provider and largely ignored. A value chain approach is an excellent tool to examine the primary stakeholders’ contributions to the wood supply system. The value chain for forestry usually extends completely across the physical and political landscape, reaching into the most geographically and economically remote locations. A conceptual model was developed depicting the wood supply system value chain and the socioeconomic impacts of a logging firm’s cash flow contributions. Financial and production data were obtained from 93 independent logging firms from 18 Eastern US States. This analysis provided 690 business years of data, beginning with the 1988 financial year and concluding in 2005. In addition, three impact scenarios were modeled using Impact Analysis for Planning (IMPLAN) software to understand the effects of Hurricane Katrina. The first model addressed the economic impacts of a timber deficit from the landowner’s perspective, the second introduced a disruption in the wood supply system from a logger’s position in the value chain, and the third attempted to analyze the impacts of a mill closure. Data analysis showed that operating costs have increased drastically during the study period with payment for services failing to provide adequate compensation to contractors. Furthermore, no significant per unit cost incentive was found to justify expanding the scale of operation. Smaller-volume producers appeared to have more ability to generate a profit on operations than their larger-volume counterparts. Cash flow analyses revealed much of the economic activity generated by the wood supply system remained in the local community. Some deficiencies of IMPLAN appeared upon examining the models introduced in this research. Many rural communities across the Southeastern US are heavily dependent on production forestry. When the logging industry suffers, so does the entire economy of these regions. It is important to ensure that the socioeconomic impacts of the wood supply value chain for such communities remains intact.

The Lower Coastal Plain of the southeastern United States is a major wood producing region. The region is characterized by a combination of nearly-level topography, poorly-drained soils, and high rainfall, which results in a perched water table in some soils that inundates the surface several times each year. Harvesting timber under wet site conditions often results in extensive soil compaction, rutting, soil displacement, and waterlogging. Forest managers are concerned that these visually-displeasing soil disturbances may cause site damage and reduced productivity. These concerns were addressed in an operational-scale field experiment conducted in South Carolina. The objectives of this experiment were to determine: (i) if soil disturbance changes key soil properties and processes; (ii) if soil disturbance reduces loblolly pine productivity; and, (iii) if disturbance can be mitigated with site preparation practices? Three 20-ha, 20-yr-old loblolly pine (Pinus taeda L.) plantations were harvested under wet and dry conditions to create a broad gradient in soil disturbance. Within each harvested plantation, a subset of 3-ha plots were site prepared by either bedding, or mole-plowing plus bedding, then all sites were established as 3rd -rotation pine plantations. Prior to site preparation, each plot was classified and mapped using a 5 by 5 soil disturbance (none to churned) by organic debris (none to slash piles) classification matrix. Within each plot, data were collected on several soil physical, chemical, and biological properties over a 2-yr period following site preparation. Key soil properties were integrated into a Soil Quality Index (SQI) and compared to aboveground productivity of 2-yr-old loblolly pine trees growing on closely-spaced (30 by 30 cm) bioassay plots planted across the gradient of soil disturbance. The soil physical properties were used to determine the least limiting water range (LLWR), the range in soil water content within which root growth is not limited. Soil compaction and deep rutting reduced the LLWR. Retention of logging slash improved the LLWR for compacted and rutted soils. Site preparation improved the quality of the soil physical environment across all levels of soil disturbance. Soil disturbance had no effect on soil chemical or biological properties as evidenced by no change in soil pH, ECEC, base saturation, available P, or net N mineralization with disturbance. The base saturation exceeded 80 % on all sites, with Ca saturation controlling soil pH. The high base saturation buffered any redox-induced changes in soil chemistry that would have resulted from disturbance. The results showed that high fertility is an important mechanism for buffering the potentially-negative effects of soil disturbance on the soil nutritional environment. Site preparation changed soil chemical properties, but the changes were probably associated with tillage effects on organic matter and clay content, not redox processes. The SQI showed that surface soil compaction and deep rutting reduced soil quality, mainly by decreasing the LLWR and aeration depth. Site preparation mitigated the effects of most disturbances on soil quality, evidenced by similar aboveground biomass production among soil disturbance classes after bedding. A regression model was developed for predicting aboveground biomass production as a function of SQI. SQI explained 73 % of the variation in aboveground biomass production. The regression model showed that compression tracks and rutting decreased aboveground biomass production compared to undisturbed soils. The long-term effect of these disturbances on productivity will depend on natural soil recovery processes. However, these early results suggest that compaction and rutting should be minimized on similar sites, especially if sites will not be bedded before reforestation. The mole-plow / bedding treatment increased aboveground biomass production, indicating that this experimental treatment may be a viable practice for enhancing productivity. / Ph. D.