Fuel treatment effects on stand-level carbon pools, treatment-related emissions, and fire risk in a Sierra Nevada mixed-conifer forestPublication No. 143 of the National Fire and Fire Surrogate Project.

2009 ◽  
Vol 39 (8) ◽  
pp. 1538-1547 ◽  
Author(s):  
Scott L. Stephens ◽  
Jason J. Moghaddas ◽  
Bruce R. Hartsough ◽  
Emily E.Y. Moghaddas ◽  
Nicholas E. Clinton
Keyword(s):  
Sierra Nevada ◽  
Prescribed Fire ◽  
Fire Risk ◽  
C Sequestration ◽  
Mixed Conifer ◽  
Management Actions ◽  
C Stocks ◽  
Significant Difference ◽  
Live Tree ◽  
And Control

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 aboveground 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.

Pyrosilviculture: Combining prescribed fire with gap-based silviculture in mixed-conifer forests of the Sierra Nevada

2020 ◽  
Author(s):  
Robert A. York ◽  
Hunter Noble ◽  
Lenya Quinn-Davidson ◽  
John J. Battles
Keyword(s):  
Sierra Nevada ◽  
Prescribed Fire ◽  
Fire Hazard ◽  
Stand Age ◽  
Conifer Forests ◽  
Mixed Conifer ◽  
Commercial Thinning ◽  
Crown Scorch ◽  
Mixed Conifer Forests ◽  
Giant Sequoia

We used a prescribed fire study to demonstrate the concept of pyrosilviculture, defined here as a) using prescribed fire to meet management objectives or b) altering non-fire silvicultural treatments explicitly so that they can optimize the incorporation of prescribed fire in the future. The study included implementation of relatively hot prescribed burns in mixed-conifer forests that have been managed with gap-based silviculture. The fires burned through 12-, 22-, 32- and, 100-year old cohorts, thus enabling an analysis of stand age influences on fire effects. Mastication and pre-commercial thinning were assessed as pre-fire treatments in the 12-year-old stands. Post-burn mortality and crown scorch declined with stand age. There was a clear tradeoff between fuel consumption and high rates of tree damage and mortality in the 12-year-old stands. Masticated stands had higher levels of average crown scorch (78%) compared with pre-commercially thinned stands (52%). Mortality for all 12-year-old stands was high, as nearly half of the trees were dead one year after the fires. Giant sequoia and ponderosa pine had relatively high resistance to prescribed fire-related mortality. When applying the concept of pyrosilviculture, there could be opportunities to combine prescribed fire with regeneration harvests that create a variety of gap sizes in order to sustain both low fire hazard and to promote structural heterogeneity and sustainable age structures that may not be achieved with prescribed fires alone.

scholarly journals Effects of Thinning, Residue Mastication, and Prescribed Fire on Soil and Nutrient Budgets in a Sierra Nevada Mixed-Conifer Forest

2014 ◽  
Vol 60 (1) ◽  
pp. 170-179 ◽  
Author(s):  
Dale W. Johnson ◽  
Roger F. Walker ◽  
Dallas W. Glass ◽  
Chad M. Stein ◽  
James B. Murphy ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Prescribed Fire ◽  
Nutrient Budgets ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Mixed Conifer Forest

scholarly journals “Prescribed fire shrub consumption in a Sierra Nevada mixed-conifer forest

2021 ◽  
Author(s):  
Melissa R Jaffe ◽  
Brandon M. Collins ◽  
Jacob Levine ◽  
Hudson Northrop ◽  
Francesco Malandra ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Prescribed Fire ◽  
Additive Model ◽  
Tree Cover ◽  
Prescribed Fires ◽  
Percent Cover ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Mixed Conifer Forest ◽  
Coarse Woody Material

Live shrubs in forest understories pose a challenge for mitigating wildfire risk with prescribed fire. Factors driving shrub consumption in prescribed fires are variable and difficult to explain. This study investigated spatial patterns and drivers of Sierra Nevada mixed-conifer forest shrub consumption in prescribed fires through analysis of high-resolution imagery taken before and after prescribed fire. We applied a spatially explicit, generalized additive model to assess tree cover and coarse woody material as potential drivers of shrub consumption. Shrub cover in two experimental stands prior to burning was 38% and 59% and was 36% and 45% one-year post burn. In both stands shrub patch density increased, while area-weighted mean patch size and largest patch index decreased. Increased local percent cover of coarse woody material was associated with increased shrub consumption. These findings provide information for prescribed fire managers to help better anticipate shrub consumption and patchiness outcomes under similar conditions.

scholarly journals Effectiveness of Restoration Treatments for Reducing Fuels and Increasing Understory Diversity in Shrubby Mixed-Conifer Forests of the Southern Rocky Mountains, USA

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 508 ◽  
Author(s):  
Julie E. Korb ◽  
Michael T. Stoddard ◽  
David W. Huffman
Keyword(s):  
Prescribed Fire ◽  
Forest Restoration ◽  
Treatment Effectiveness ◽  
Conifer Forests ◽  
Mixed Conifer ◽  
Burn Treatment ◽  
Attack Tree ◽  
Natural Fire ◽  
Mixed Conifer Forests ◽  
And Control

Exclusion of natural surface fires in warm/dry mixed-conifer forests of the western U.S. has increased potential for stand-replacing crown fires and reduced resilience of these systems to other disturbances, such as drought and insect attack. Tree thinning and the application of prescribed fire are commonly used to restore more resilient ecological conditions, but currently, there is a lack of long-term data with which to evaluate restoration treatment effectiveness in forest types where resprouting shrubs dominate understory communities. At a mixed-conifer site in southwestern Colorado, we compared forest structure and understory vegetation responses to three restoration treatments (thin/burn, burn, and control) over 10 years in a completely randomized and replicated experiment. Forest density, canopy cover, and crown fuel loads were consistently lower, and crown base height was higher, in thin/burn than burn or controls, but the effects diminished over time. Ten years following treatment, >99% of all plant species within both treatments and the control were native in origin. There were no differences between treatments in understory richness, diversity, cover, or surface fuels, but graminoid cover more than doubled in all treatments over the 15-year monitoring period. Similarly, there was more than a 250% increase post-treatment in shrub density, with the greatest increases in the thin/burn treatment. In addition, we saw an increase in the average shrub height for both treatments and the control, with shrub stems >80 cm becoming the dominant size class in the thin/burn treatment. Conifer seedling density was significantly lower in thin/burn compared with burn and control treatments after 10 years. Taken together, these conditions create challenges for managers aiming to reestablish natural fire patterns and sustain mixed-conifer forests. To limit the dominance of resprouting shrubs and facilitate conifer regeneration after overstory thinning and prescribed fire, managers may need to consider new or more intensive approaches to forest restoration, particularly given current and projected climate change.

Long-term effects of prescribed fire on mixed conifer forest structure in the Sierra Nevada, California

2011 ◽  
Vol 261 (6) ◽  
pp. 989-994 ◽  
Author(s):  
Phillip J. van Mantgem ◽  
Nathan L. Stephenson ◽  
Eric Knapp ◽  
John Battles ◽  
Jon E. Keeley
Keyword(s):  
Sierra Nevada ◽  
Prescribed Fire ◽  
Forest Structure ◽  
Conifer Forest ◽  
Long Term Effects ◽  
Mixed Conifer ◽  
Mixed Conifer Forest

scholarly journals Non-Native Earthworms Invade Forest Soils in Northern Maine, USA

Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 80
Author(s):  
Joshua J. Puhlick ◽  
Ivan J. Fernandez ◽  
Jay W. Wason
Keyword(s):  
Forest Ecosystems ◽  
C Sequestration ◽  
Mechanical Mixing ◽  
Soil C ◽  
Management Actions ◽  
C Stocks ◽  
Winter Temperatures ◽  
Abrupt Changes ◽  
C Stock ◽  
Earthworm Populations

Non-native earthworms can cause abrupt changes in forest ecosystems by altering soil properties and depleting or redistributing soil carbon (C) stocks. The forests of Northern Maine are often perceived as having winters that are too harsh to support earthworm populations and that earthworms are restricted to more southerly regions. In this study, we report the discovery of European earthworms at two research sites in Northern Maine. At one site, earthworms were only found across a portion of the forest, and the median organic (O) horizon C stock in the area with earthworms was 34% less than that of areas without earthworms. At a second site, earthworms were found across the entire 60-ha forest and the median O horizon C stock was 39% less than that of a similar forest without earthworms. Consistent with reports from other regions, areas with earthworms had no or minimal eluvial (E) horizons, while earthworm-free locations always had E horizons. Earthworm presence was always associated with a topsoil (A) horizon, reflecting mechanical mixing and organic matter processing by earthworms. This is one of the first reports of non-native earthworm presence in Northern Maine forests and monitoring changes in soil C will be important for determining rates of C sequestration in these forests. Warmer winter temperatures, particularly winter minimums, and greater annual precipitation will likely increase the success of new earthworm introductions across Northern Maine forests. Management actions that limit the transport of earthworms into earthworm-free areas should be carefully evaluated to minimize the potential for new introductions.

A Comparison of Chain Saws, Brushcutters, and Machetes in Thinning a Young Conifer Plantation in the Sierra Nevada

1989 ◽  
Vol 4 (2) ◽  
pp. 60-62
Author(s):  
Mark S. Jamnick
Keyword(s):  
Sierra Nevada ◽  
Tree Size ◽  
The Other ◽  
Mixed Conifer ◽  
Production Rates ◽  
Conifer Plantation ◽  
Significant Difference ◽  
Conifer Plantations

Abstract Chain saws, power brushcutters, and machetes were used in thinning an 8-year-old, 14.5 ac mixed conifer plantation in the Sierra Nevada. A comparison of production rates indicated no significant difference between chainsaws and machetes, with brushcutter production rates significantly lower than the other two tools. Differences in production rates were not attributable to tree size or number of trees per acre. Inefficiency of brushcutters was attributable to greater maintenance and downtime as compared to the other two tools. Further comparisons of these tools could be useful in determining the least expensive method of conducting precommercial thinnings in young mixed conifer plantations. West. J. Appl. For. 4(2):60-62, April 1989.

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