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Linda Joyce
Rocky Mountain Research Station
240 West Prospect
Fort Collins, CO 80526
Phone: 970-498-2560
 United States Department of Agriculture Forest Service.USDA logo which links to the department's national site.Forest Service logo which links to the agency's national site.
Development of Management Alternatives for Fire-prone and Fire-dependent ecosystems in Colorado and the Black Hills

Human influences have altered the way Rocky Mountain terrestrial ecosystems respond to fire, insects, disease, and other stressors. Throughout Colorado, fire suppression and exclusion has been implicated in the conversion of fire-dependent Ponderosa pine stands to fire-sensitive Douglas-fir stands, in the retrogression of pure aspen stands to mixed conifer-aspen or pure conifer stands, and the increasing incidence of insects and diseases. In the Black Hills, the ponderosa pine ecosystems have been intensively managed for many years.

Fire suppression and exclusion throughout the Central Rocky Mountain ecosystems has resulted in conditions that are poorly understood in terms of their ecology. In many of these western ecosystems, risk of catastrophic natural disturbances has become probable.

Knowledge is, therefore, needed on the ecological and environmental consequences of management alternatives for treating the current high fuel levels in these fire-prone ecosystems, on the climate-vegetation conditions under which these management alternatives would be effective, and on the interaction of fire and fuel treatment management with other disturbance processes such as insects and disease. Knowledge gained under this research is fundamental in the development of guidelines for sustainable land management of Western fire-prone and fire-dependent ecosystems.

Research Focus Areas

Research Focus Areas Navigation: Fire-suppressed & Disturbances | Vegetation Manipulation | Fire as Resource Management

Role of natural disturbances and forest management in maintaining healthy forest ecosystems in the West

Insects and disease

Insects and disease are an integral part of the western forest dynamics. Endemic levels of both insects and disease can be found throughout the West, subtly altering forest structure and composition. For more information on this research see:
Forest Insects
Landscape Pathology, Disease Economics and Impact Assessment

Forest Dynamics

Silviculture research provides the scientific basis for land management decisions, synthesizing knowledge from many disciplines to develop, test, and quantify management prescriptions that produce a variety of forest conditions. Specific objectives of silvicultural research include determining the patterns of mortality and recruitment in natural and old-growth Engelmann spruce, lodgepole pine, ponderosa pine, aspen, and mixed conifer forests, identifying long-term climatic patterns and disturbance events in these forests, improving the ability to model regeneration and early stand dynamics in managed unmanaged stands, and devising and testing new silviculture techniques to manage these forests. Additionally we are exploring the quality of and management for small-diameter material in the Front Range of Colorado. For more information, see:
Silviculture and Mensuration Research in the Central Rockies
Bio-based Products and Bio-Energy Program

Ecological response of fire-suppressed ecosystems to natural disturbances of insects, disease and forest management treatments

Fuel Loadings associated with roundheaded pine beetle infestations

The roundheaded pine beetle (RPB), Dendroctonus adjunctus, is one of the most important bark beetles associated with ponderosa pine, Pinus ponderosa, in the Southwest. Outbreaks of this insect have caused extensive mortality in the Lincoln National Forest, NM, in the 1970s and in the 1990s. During the mid-1990s a network of plots was established in infested and uninfested stands to develop models to estimate the probability of infestation by the RPB. These plots were re-visited in 2001 to quantify the fuel loadings that resulted from the beetle outbreak. No differences in coarse woody debris (cwd) in the 0 - ¼ inch or the ¼ to 1.0 inch size classes were observed between the infested and the uninfested stands. However, significantly higher cwd levels were observed in the 1.0 to 3.0 inch class; in the > 3.0 inch sound and rotten size classes; and in total cwd in the infested stands. BehavePlus (USDA Forest Service) was used to simulate spread and flame length using default values for the timber with litter and understory fuel model but adjusting the 1 -, 10 -, and 100-hour fuels to the levels observed. Increases in flame length and rate of spread with corresponding increases in 100-hr fuels were obtained. The largest increase in fuel loads are associated with cwd > 3.0 inches. These increases will likely result in increased fire severity. These findings suggest that bark beetle outbreaks can cause significant increases in fuel loads, influence fire behavior, and perhaps increase the severity of the fires. These findings can have profound implications for managing dead trees resulting from extensive bark beetle outbreaks.

Role of Woodboring Insects in Ponderosa Pine Forests in the Black Hills

Little is known about these insects. The objective of this study is to increase our understanding of the biology and ecology of woodboring insects and improve our ability to sample populations dynamics.

Environmental Influences on Regeneration of Ponderosa Pine after Fire and in Competition with Herbaceous Species

Successful establishment of ponderosa pine seedlings after fire depends on the multiple environmental conditions that the fire created. Some biotic and abiotic factors, such as canopy cover, ground cover, soil moisture and temperature or nutrient levels, may vary greatly within the same burned area. Directly or through the competition for nutrients and water with other plant species, these factors and environmental gradients may affect the Ponderosa pine regeneration. This study is part of the overall effort to monitor recovery processes after the Jasper fire event (August 24th to September 25th 2000), which was the largest fire recorded in the Black Hills (South Dakota). The fire occurred in the limestone plateau region and spread over 83,508 acres across Ponderosa pine forests. Due to the widespread distribution of this fire, a mosaic of different burned severities and intensities patches was created. The overall program objectives are to monitor the recovery processes with respect to the different burned severities and different burn patch sizes (See Monitoring Fire Effects on the Jasper Fire). The focus of this study is to address the effects of fire on Ponderosa pine regeneration and on the role of early-established plant competitors within a spatial context of different fire intensities and/or environmental conditions.

Development of effective and cost-efficient vegetation manipulation techniques to mimic the fire disturbances when fire is not a viable alternative in the Front Range of Colorado and the Black Hills of South Dakota

Fuel loads within the Urban-Wildland Interface Forests

Recent large fires in the Colorado Front Range and concern about the volatility of forest conditions in Ponderosa pine and mixed conifer ecosystems have prompted renewed interest in the need for treating these forests to reduce fuels risk. With this interest comes the need to obtain quantitative data on the fuels that exist under Front Range Forests and to understand how ground fuels vary across differing site and stocking conditions in Front Range landscapes. This study quantified fuel loadings within existing Ponderosa pine and Mixed-conifer forests on the 16,700 ac Manitou Experimental Forest west of Colorado Springs, CO. The forest contains a variety of stocking and physiographic conditions in ponderosa pine and mixed conifer forest types typical of the Southern Front Range. Although average fuel loadings in the Manitou Experimental Forest are low, there are pockets of high fuel loadings. Fuel loadings in areas dominated by ponderosa pine were much lower than those found in mixed conifer, spruce, and aspen stands. The diverse distribution and types of fuels across this landscape will likely influence fire behavior in different ways. Click here for more information (link to a new page with the poster VARIATION IN FUEL LOADINGS WITHIN EXISTING PONDEROSA PINE AND MIXED CONIFER Battaglia, W.D. Shepperd, and M.J. Platten)

Contribution of Seedling Regeneration to Ladder Fuels Loads in Treated Uneven-aged Ponderosa Pine Forests

A major limitation is the ability to estimate how rapidly new and existing seedlings will grow into a forest canopy, creating the ladder fuel conditions that lead to catastrophic wildfire. One of the principle goals of vegetation treatments to restore ponderosa pine ecosystems to conditions that likely existed under natural fire regimes is lower the density of smaller trees in the forest. Dense understories of smaller trees act as ladder fuels, allowing cool slow-burning ground fires to climb into the forest canopy and consume the entire forest. Lowering the density of small trees reduces the likelihood of crownfire and allows the re-introduction of periodic prescribed burns to mimic past natural fires that kept ponderosa pine forests in an open, irregularly stocked condition. However, reducing the number of trees in most forests will stimulate the establishment of new seedlings. Knowing how many new seedlings will appear and how rapidly they will grow is crucial in maintaining low crownfire risk.

In 1993, an uneven-aged management prescription was imposed on ponderosa pine stands on the North Kaibab National Forest. The position of all existing trees mapped. This detailed mapping in 1993 provided a baseline on which to revisit the site in 2001 and identify the conditions that favor the establishment of new trees and to hopefully, predict their rates of growth. Such information is needed for growth and yield models such as FVS to predict the growth of remaining trees and schedule future management activities.

Small Diameter Trees and Fuels Reduction Treatments

Forests overstocked with large amounts of small-diameter trees heighten fire danger, threatened biodiversity, and are more costly in terms of management. However, there are currently limited options for small-diameter material. Research within this project is also exploring innovative methods to harvest small diameter material, the management necessary to produce a long-term biomass supply for energy production, wood consumption in Colorado, opportunities for making wood products from small diameter trees, and the wood quality of small-diameter material as influenced by growing conditions. For more information: Bio-Based Products and Bio-Energy Program

Development and testing of management techniques that make fire a viable option for resource management.

Front Range Demonstration Study

Many western forests are at risk to forest health problems and catastrophic fire. Forest areas at high risk to catastrophic fire, commonly referred to as Red Zones, contain 2.4 million acres in the Colorado Front Range and 6.3 million acres statewide. The increasing frequency, size and intensity of recent forest fires have prompted new research on ways to reduce fire risk, improve fire protection, explore appropriate vegetation management treatments in the urban-wildland interface, and to enhance the harvest and production of bio-based products. A demonstration project of management techniques applicable in Front Range Urban-Interface Ponderosa pine forests has been initiated at the Manitou Experimental Forest to test the applicability of several vegetation manipulation techniques that could be used to maintain the health and vigor of forested ecosystems within the urban-wildland interface. The 25 ha forested site near the MEF headquarters is readily accessible for public tours. A no treatment control will be compared with a prescribed fire treatment, an uneven-aged silvicultural treatment, and a combination of silvicultural treatments followed by fire. The silvicultural treatments were imposed in FY00 and the prescribed fire is scheduled for FY04.

Prescribed Fire and Slash Burning Treatment Effects on Soils and Soil Ecology

Forest areas at high risk to catastrophic fire, commonly referred to as Red Zones, contain 2.4 million acres in the Colorado Front Range and 6.3 million acres statewide. Silvicultural treatments on these areas could involve some type of slash burning or lop and scatter followed by a prescribed fire treatment. Fire influences soil temperatures and water relations, plant root and microbial activity, soil nutrients, soil carbon, and ultimately the rate of forest regeneration. The aim of 3-year research study is to improve our understanding of soil microbial responses to and recovery from fire and to describe the microbes’ ambient environment before, during and after a fire, which means measuring the influence fire has on the soil physical properties and the movement of thermal energy through the soil.

A prototype experiment was conducted after snowmelt in FY01 to investigate how different fuel loadings and geometrical arrangements for controlled burns may influence the soil’s physical and biological environment. Soil temperature and heat flux measurements were taken during three controlled burns with different amounts of slash on the surface and in a meadow and in a forested area at the Manitou Experimental Forest in southern Colorado, USA. Although there has been a long history of in situ soil temperature measurements during controlled fires, there are virtually no corresponding soil heat flux data. Fuel loading was found to impact fire intensity and duration, the depth of the thermal pulse into the soil and the magnitude of the soil temperatures caused by the fire. At a meadow site with relatively little slash, the thermal pulse penetrated only the upper few centimeters of soil, however the maximum temperatures were over 200 degrees C. At a much more heavily fueled slash pile site soil temperatures exceeded 400 degrees C. Duration of the soil thermal pulse varied from a couple of hours at the lowest fuel site to two weeks at the slash burn site. However, the distribution of soil carbon appears to have been significantly impacted only at the slash pile burn. These additional heat flux data are important for modeling the penetration of heat into soils and for assessing whether roots and microbes are influenced more by soil temperature or by the rate energy is added to the soil. We intend to expand our study to include soil carbon dioxide, other important soil chemical species, and microbial ecology. This information could inform forest management on maximizing ecosystem benefits of a prescribed fire while minimizing the potential for harm.

Massman, W.J.; Frank, J.M.; Shepperd, W.D.; Platten M.J. (In press) In situ soil temperature and heat flux measurements during controlled surface burns at a southern Colorado forest site. In: Omi, P.; Joyce, L.A., tech. eds. Fire, fuel treatments, and ecological restoration: Conference proceedings; 2002 16-18 April; Fort Collins, CO. Proc. RMRS-P-29. Fort Collins, CO: USDA Forest Service, Rocky Mountain Research Station.




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