Dana Mitchell

Forest Operations and Woody Biomass Logistics to Improve Efficiency, Value, and Sustainability

This paper reviews the most recent work conducted by scientists and engineers of the Forest Service of the US Department of Agriculture (USDA) in the areas of forest operations and woody biomass logistics, with an emphasis on feedstock supply for emerging bioenergy, biofuels, and bioproducts applications. This work is presented in the context of previous research in this field by the agency and is measured against the goals and objectives provided by several important national-level initiatives, including the USDA Regional Biomass Research Centers. Research conducted over the past 5xa0years in cooperation with a diverse group of research partners is organized in four topic sections: innovative practices, innovative machines, sustainability, and integration. A wide range of studies in operations and logistics address advances in harvest and processing technology, transportation systems, scheduling and planning, feedstock quality, biomass conversion processes, and environmental impacts, including greenhouse gas emissions. We also discuss potential future research to address persistent knowledge gaps, especially those in fire and fuel management. Overall, the research reviewed here aligns well with broad national goals of providing the USA with sustainable and efficient forest biomass management and production systems, specifically including: (1) improved harvest, collection, handling, and transportation systems for woody biomass; (2) cost and equipment information and options for field processing biomass to improve efficiency and mitigate impacts; and (3) forest biomass management systems and technologies to offset impacts and enhance environmental outcomes. However, as needs evolve, professionals in this field must strive to adapt research, development, and dissemination to address relevant future challenges and strengthen capabilities to solve critical problems in the forest sector.

Application of a Small-Scale Equipment System for Biomass Harvesting

The small-scale harvesting equipment system has been and continues to grow in use in forestry operations in some regions in the world. This harvest system can include a range of equipment types, such as feller-bunchers or chainsaws, skidders or farm tractors, and chippers. These machines are generally smaller, lower cost and less productive than larger, more advanced forestry machines. The objective of this project was to investigate the feasibility of a small scale harvesting system that would produce feedstock for a biomass power plant. The system had to be cost competitive. A boom-type feller-buncher, a small grapple skidder and a chipper were tested as a small-scale system. In this study, feller-buncher and skidder productivity was determined to be 10.5xa0m3 per productive machine hour, and production for the chipper was determined to be 18xa0m3 per productive machine hour. Production from the system did not reach the desired levels of 4 loads/day (25xa0m3/load); however, the system was able to produce about 3 loads/day. The results showed that the system currently could fill a roadside van for

Determining the effects of felling method and season of year on the regeneration of short rotation coppice

16.90/m3, but suggested machine modifications could potentially reduce the system cost to

High tonnage harvesting and skidding for loblolly pine energy plantations

12.73/m3. Residual stand damage was minimal, especially on flatter ground and not operating on a slash layer. Soil disturbance from the harvesting system was predominantly undisturbed or classified as a shallow disturbance.

A new slash bundling concept for use in a southern US logging system.

There is increasing interest in plantations with the objective of producing biomass for energy and fuel. These types of plantations are called Short Rotation Woody Crops (SRWC). Popular SRWC species are Eucalypt (Eucalyptus spp.), Cottonwood (Populus deltoides) and Willow (Salix spp.). These species have in common strong growth rates, the ability to coppice, and rotations of 2–10 years. SRWC have generated interest for many forest products’ companies (seeking for diversification or energy self-sufficiency) and private landowners, and although they might help with the supply for the expected growth on the bioenergy and biofuels market, there are still several concerns about how and when to harvest SRWC to maximize their ability to coppice. SRWC have elevated establishment and maintenance costs if compared to other type of plantations, but due to the coppicing ability, the same plantation may be harvested up to 5 times without the need of establishing a new one. Study plots were installed at six locations in Florida, Mississippi and Arkansas, and were cut with a chainsaw and a shear head during summer and winter, to determine the effects of felling method and season on coppice regeneration. Thus, plots were divided into areas of four different treatments: shear-winter, saw-winter, shear-summer, saw-summer. Harvesting eucalypt and cottonwood trees during winter resulted in better survival rates than harvesting during summer; however, there was no effect of felling method on coppice regeneration. Finally, no statistically significant difference was found on coppice regeneration of black willow when harvested during winter or summer with a chainsaw or a shear head.

Assessment of Current Technologies for Communition of Forest Residues

Abstract The southeastern United States has a promising source for renewable energy in the form of woody biomass. To meet the energy needs, energy plantations will likely be utilized. These plantations will contain a high density of small-stem pine trees. Since the stems are relatively small when compared with traditional product removal, the harvesting costs will increase. The purpose of this research was to evaluate specialized harvesting and skidding equipment that would harvest these small stems cost efficiently. The feller-buncher utilized was a Tigercat 845D with a specialized biomass shear head. The skidder was a Tigercat 630D equipped with an oversized grapple. This equipment was evaluated in a 4-hectare stand with characteristics of a southern pine energy plantation. During the study, the feller-buncher achieved an average production rate of 47 green tonnes/productive machine hour (gt/PMH) and the skidder had an average production rate of 112 gt/PMH. A before-tax cash-flow model was used to deter...

Changing Times: Altering Establishment Spacing, Harvesting Frequency, and Harvesting Machines to Promote Increased Sawtimber Volumes

John Deeres biomass bundler unit is an effective machine for harvesting forest residues, which can be used as a source of fuelwood and/or a feedstock for biofuel production. This project explored an avenue that could supply a promising source of readily available energy in southeastern forested lands. Typical southern harvesting operations consist of whole-tree harvesting in which trees are felled and then skidded to a landing. Limbs and tops are usually either deposited over the landscape or piled in windrows. The biomass bundler captures the otherwise nonmerchantable material and maximizes the marketability of the entire tree. In order to reduce costs, maximize efficiency, and implement the bundler in a tree-length harvesting operation, this project tested a prototype harvesting system. This venture (1) adapted the John Deere B380 bundler unit to a motorized trailer, (2) designed an optimum landing configuration, and (3) conducted a productivity study of the bundler unit. The unit produced 13.2 tonnes ...

Chipping whole trees for fuel chips: a production study

Recent legislation and energy prices have led to an increased need for alternative energy sources. Biomass, including forest residues, is expected to replace a part of the nations reliance on petroleum consumption. This paper provides an overview of existing literature related to the harvest, communition and transport of forest residues. Past studies have investigated the systems associated with biomass harvesting. Researchers have explored whether to incorporate the biomass component with other forest product removals, or to harvest it in a separate entry. Land managers do not have the tools to adequately assess the cost of biomass processing prior to treatments. Handling residue can be awkward due to the size and arrangement of the material. Dirt and rocks can contaminate residues and cause equipment repair problems or reduced utilization of the resource. These issues coupled with the problems of comparing existing production studies lead to some of the reasons why land managers have difficulty in assessing communition processing costs. Logging residue and unmerchantable stems are expensive to transport without some sort of communition prior to transport. There are few studies available today that investigate some of the newer technology, such as horizontal grinders and slash bundling machines. Forest professionals could benefit from further research in this area to provide a means of more adequately determining production and costs of biomass harvesting.

Determining the Impact of Felling Method and Season of Year on Coppice Regeneration

Today’s landowners are faced with important decisions when establishing loblolly pine plantations in the Southeastern part of the United States with regards to planting dimensions and forest management techniques. Although recent studies are beginning to demonstrate the need for change from the old practices, suppressed biomass markets and prices are hindering the transition. This paper provided readers with an informational overview of the benefits of: incorporating an additional thinning regime for biomass, using alternate spacing methods such as FlexstandsTM and rectangularity, and using small-scale harvesting machines for conducting initial thinning’s. The overview was supported with both a field study as well as a modeling tool which verified using one or all of the above-mentioned techniques to increase total harvest volumes while minimizing residual stand damage. The modeling tool determined that final sawtimber volumes were increased by a minimum of 15 tons per acre using one or more of the above techniques. When expanding this volume out to 20 acres, the minimum tract size harvested in the southeast using convention equipment, landowners could easily recover any losses incurred from the suppressed biomass markets minimizing overall risk and promoting the use of these alternative techniques.