Bruce R. Hartsough

The Effects of Forest Fuel-Reduction Treatments in the United States

The current conditions of many seasonally dry forests in the western and southern United States, especially those that once experienced low- to moderate-intensity fire regimes, leave them uncharacteristically susceptible to high-severity wildfire. Both prescribed fire and its mechanical surrogates are generally successful in meeting short-term fuel-reduction objectives such that treated stands are more resilient to high-intensity wildfire. Most available evidence suggests that these objectives are typically accomplished with few unintended consequences, since most ecosystem components (vegetation, soils, wildlife, bark beetles, carbon sequestration) exhibit very subtle effects or no measurable effects at all. Although mechanical treatments do not serve as complete surrogates for fire, their application can help mitigate costs and liability in some areas. Desired treatment effects on fire hazards are transient, which indicates that after fuel-reduction management starts, managers need to be persistent with repeated treatment, especially in the faster-growing forests in the southern United States.

A survey of Italian chipping operations

Abstract We observed over 100 wood chipping operations, using time-and-motion methods to quantify their productivities, and interviews and observations to subjectively evaluate the factors that affect their existence and character. Productive time per green tonne decreased with increases in both chipper power and piece size. In Italy, chipping has evolved from a primary business for contractors who processed whole trees, to a secondary activity for loggers who dispose of residues by chipping them for particleboard. In recent years, biomass-fueled district heating plants in northern Italy have been added to the mix of users, and larger electric power plants may expand the chipping industry in the near future. Operators who heavily utilize chippers prefer self-propelled machines. Tractor-powered and towed chippers are used in a wide range of conditions, but the latter are restricted to landings while the former are employed at landings and within stands. Disc chippers have dominated the industry, but drum chippers are making inroads, especially in fuel supply operations. Chips are transported by farm tractors and powered trailers when distances are short (up to 3– 4 km ), by high-speed tractors for intermediate distances, and by trucks for distances over 30 km .

Fuel treatment effects on stand-level carbon pools, treatment-related emissions, and fire risk in a Sierra Nevada mixed-conifer forest

Policies have been enacted to encourage carbon (C) sequestration through afforestation, reforestation, and other silvicultural practices; however, the effects of wildfires on forest C stocks are poorly understood. We present information from Sierran mixed-conifer forests regarding how control, mechanical, prescribed-fire, and mechanical followed by prescribed-fire treatments affected C pools. Secondly, we report CO2 emissions from machinery and burning associated with the treatments. Lastly, the effects of treatments on the potential for C loss to wildfire are presented. The amount of above- ground C in live trees was significantly reduced in mechanical-only and mechanical plus fire treatments; C contained in dead trees was not significantly different. There was no significant difference in aboveground live and dead tree C between the fire-only and control treatments. Fire-only and mechanical plus fire treatments emitted significantly more CO2 than the mechanical treatment and control. Modeling results for the control demonstrated 90% of the live tree C had a high (>75%) chance of being killed in a wildfire; in contrast, all three active treatments had low vulnerabilities to C loss. With wildfire severity increasing in most Sierran forests, management actions designed to increase fire resistance are justified for long- term C sequestration.

Testing Mobile Chippers for Chip Size Distribution

Abstract Nine chippers were tested for particle size distribution, in order to a) see how chips produced with these machines matched the quality specifications set by the district heating plants of Northeastern Italy and b) detect significant differences between machines. The benchmark was set by collecting chip samples from fourteen district heating plants in the region of interest. The effect of operator skill was minimized and all machines were fed with the same assortment: logs, supplied in lengths varying between 2.4 and 6 m. All logs had similar moisture contents, which typically ranged between 33 and 37 % on a fresh weight base. Mobile in-woods chippers fed with limb-free logs produce high-quality chips, whose particle size distribution matches that of the best chips normally fed to the Italian district heating plants. Indeed, all the tested machines produced chip samples containing almost no oversize particles, very little fines (0.5 to 1 %), and a large majority of chips within the 3–45mm range (95 to 99 %), except the auger-equipped Laimet, which is designed to produce larger chips. There were statistically significant differences between machines and machine types, which were not affected by possible variations of the tree species processed.

Productivity Standards for Harvesters and Processors in Italy

The authors developed a general productivity model for the harvesters and processors currently used in Italy. The model consists of a set of mathematical relationships that can estimate the product...

Fuel treatment impacts on estimated wildfire carbon loss from forests in Montana, Oregon, California, and Arizona

Using forests to sequester carbon in response to anthropogenically induced climate change is being considered across the globe. A recent U.S. executive order mandated that all federal agencies account for sequestration and emissions of greenhouse gases, highlighting the importance of understanding how forest carbon stocks are influenced by wildfire. This paper reports the effects of the most common forest fuel reduction treatments on carbon pools composed of live and dead biomass as well as potential wildfire emissions from six different sites in four western U.S. states. Additionally, we predict the median forest product life spans and uses of materials removed during mechanical treatments. Carbon loss from modeled wildfire-induced tree mortality was lowest in the mechanical plus prescribed fire treatments, followed by the prescribed fire-only treatments. Wildfire emissions varied from 10–80 Mg/ha and were lowest in the prescribed fire and mechanical followed by prescribed fire treatments at most sites. Mean biomass removals per site ranged from approximately 30–60 dry Mg/ha; the median lives of products in first use varied considerably (from 50 years). Our research suggests most of the benefits of increased fire resistance can be achieved with relatively small reductions in current carbon stocks. Retaining or growing larger trees also reduced the vulnerability of carbon loss from wildfire. In addition, modeled vulnerabilities to carbon losses and median forest product life spans varied considerably across our study sites, which could be used to help prioritize treatment implementation.

Drying Characteristics and Quality of Rough Rice under Infrared Radiation Heating

Infrared (IR) radiation heating could provide a high heating rate and rapid moisture removal for rough rice drying. The objective of this research was to investigate the effect of the drying bed thickness on drying characteristics and quality of rough rice subjected to IR heating. Samples of freshly harvested medium grain rice (M202 variety) with 20.5% and 23.8% (w.b.) moisture contents were used for this study. They were dried with two different radiation intensities (4685 and 5348 W m-2) and exposure times of 15, 30, 40, 60, 90, and 120 s for each drying bed thickness. The three tested drying bed thicknesses were single layer, 5 mm, and 10 mm. After IR drying, the samples were tempered for 4 h followed by natural cooling. The drying rate, moisture removal, and temperature of the rice were determined. The rice temperatures after the IR heating were in the range of 35.9°C to 71.4°C. The heating and drying rates decreased with the increase of bed thickness. Up to 2.2% of moisture was removed during natural cooling after tempering, without additional energy input. IR heating under tested conditions did not have adverse effects on rice sensory and milling quality, including total rice yield, head rice yield, and degree of milling of the dried rice. We concluded that a high heating rate, fast drying, and good rice quality can be achieved by IR heating of rough rice to about 60°C followed by tempering and natural cooling with a tested bed thickness up to 10 mm.

Operational Trials of Cut-To-Length Harvesting of Poplar in a Mixed Wood Stand

Abstract Cut-to-length harvesting systems offer an alternative to conventional mechanical systems for thinning mixedwood stands. We evaluated the performance of a single-grip harvester and forwarder in a poplar-dominated mixedwood stand in Southern Ontario to quantify the effect of tree size and tree form on harvester productivity and harvesting cost, and to assess the damage caused by the harvesting operation to advance regeneration and residual trees. A single-tree selection silvicultural system was used. Individual trees were assigned a form index based on their visual estimates of limb size and stem form. The cut-to-length harvester produced 23.1 m3 per productive machine hour (PMH). Forwarder productivity was 17.2 m3/PMH. The results indicate a significant and positive relationship between harvester productivity and tree size (dbh) and tree form. Tree size (dbh) has the greatest influence on the unit cost of harvesting. At an average 27 cm dbh and extraction distance of 200 m, the stump-to-landing cost was approximately 10 US

Users Guide for STHARVEST: Software to Estimate the Cost of Harvesting Small Timber

/m3 As tree size increased, the unit cost of wood produced decreased. Damage to residual trees and advance regeneration was minimal. The results suggest that single-grip cut-to-length harvesting systems can be effective in managing poplar-dominated mixedwood stands.

Productivity and Cost of Mechanized Whole-Tree Harvesting of Fast-Growing Eucalypt Stands

Fight, Roger D.; Zhang, Xiaoshan; Hartsough, Bruce R. 2003. Users guide for STHARVEST: software to estimate the cost of harvesting small timber. Gen. Tech. Rep. PNW-GTR-582. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p. The STHARVEST computer application is Windows-based, public-domain software used to estimate costs for harvesting small-diameter stands or the small-diameter component of a mixed-sized stand. The equipment production rates were developed from existing studies. Equipment operating cost rates were based on November 1998 prices for new equipment and wage rates for the Pacific Northwest. There are four ground-based and two cable harvesting systems. Harvesting costs can be estimated for both clearcutting and partial cutting for an average tree size ranging from 1 to 80 or 150 cubic feet depending on the system selected. Cost estimates are in U.S. dollars per 100 cubic feet or per green ton.