Fuel loadings 5 years after a bark beetle outbreak in south-western USA ponderosa pine forests

Landscape-level bark beetle (Coleoptera: Curculionidae, Scolytinae) outbreaks occurred in Arizona ponderosa pine (Pinus ponderosa Dougl. ex Law.) forests from 2001 to 2003 in response to severe drought and suitable forest conditions. We quantified surface fuel loadings and depths, and calculated canopy fuels based on forest structure attributes in 60 plots established 5 years previously on five national forests. Half of the plots we sampled in 2007 had bark beetle-caused pine mortality and half did not have mortality. Adjusting for differences in pre-outbreak stand density, plots with mortality had higher surface fuel and lower canopy fuel loadings 5 years after the outbreak compared with plots without mortality. Total surface fuels averaged 2.5 times higher and calculated canopy fuels 2 times lower in plots with mortality. Nearly half of the trees killed in the bark beetle outbreak had fallen within 5 years, resulting in loadings of 1000-h woody fuels above recommended ranges for dry coniferous forests in 20% of the mortality plots. We expect 1000-h fuel loadings in other mortality plots to exceed recommended ranges as remaining snags fall to the ground. This study adds to previous work that documents the highly variable and complex effects of bark beetle outbreaks on fuel complexes.

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Relative and Seasonal Abundance of Three Bark Beetle Predators (Coleoptera: Trogositidae, Cleridae) Across an Elevation Gradient in Ponderosa Pine Forests of North Central Arizona

Western North American Naturalist ◽

10.3398/064.069.0309 ◽

2009 ◽

Vol 69 (3) ◽

pp. 351-363 ◽

Cited By ~ 6

Author(s):

Kelly K. Williams ◽

Joel D. McMillin ◽

Tom E. DeGomez

Keyword(s):

Bark Beetle ◽

Ponderosa Pine ◽

Elevation Gradient ◽

Pine Forests ◽

Seasonal Abundance ◽

North Central ◽

Ponderosa Pine Forests ◽

Central Arizona

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Historical (1860) forest structure in ponderosa pine forests of the northern Front Range, Colorado

Canadian Journal of Forest Research ◽

10.1139/cjfr-2014-0387 ◽

2015 ◽

Vol 45 (11) ◽

pp. 1462-1473 ◽

Cited By ~ 28

Author(s):

Peter M. Brown ◽

Michael A. Battaglia ◽

Paula J. Fornwalt ◽

Benjamin Gannon ◽

Laurie S. Huckaby ◽

...

Keyword(s):

Pinus Ponderosa ◽

Forest Structure ◽

Ponderosa Pine ◽

Rocky Mountain ◽

Structural Data ◽

Pine Forests ◽

Land Use Impacts ◽

Quadratic Mean ◽

Ponderosa Pine Forests ◽

Northern Colorado

Management of many dry conifer forests in western North America is focused on promoting resilience to future wildfires, climate change, and land use impacts through restoration of historical patterns of forest structure and disturbance processes. Historical structural data provide models for past resilient conditions that inform the design of silvicultural treatments and help to assess the success of treatments at achieving desired conditions. We used dendrochronological data to reconstruct nonspatial and spatial forest structure at 1860 in fourteen 0.5 ha plots in lower elevation (∼1900–2100 m) ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) forests across two study areas in northern Colorado. Fires recorded by trees in two or more plots from 1667 to 1859 occurred, on average, every 8–15 years depending on scale of analysis. The last fire recorded in two or more plots occurred in 1859. Reconstructed 1860 stand structures were very diverse, with tree densities ranging from 0 to 320 trees·ha−1, basal areas ranging from 0.0 to 17.1 m2·ha−1, and quadratic mean diameters ranging from 0.0 to 57.5 cm. All trees in 1860 were ponderosa pine. Trees were significantly aggregated in 62% of plots in which spatial patterns could be estimated, with 10% to 90% of trees mainly occurring in groups of two to eight (maximum, 26). Current stands based on living trees with a diameter at breast height of ≥4 cm are more dense (range, 175–1010 trees·ha−1) with generally increased basal areas (4.4 to 23.1 m2·ha−1) and smaller trees (quadratic mean diameters ranging from 15.7 to 28.2 cm) and contain greater proportions of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and Rocky Mountain juniper (Juniperus scopulorum Sarg.). This is the first study to provide detailed quantitative metrics to guide restoration prescription development, implementation, and evaluation in these and similar ponderosa pine forests in northern Colorado.

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Trends in Snag Populations in Drought-Stressed Mixed-Conifer and Ponderosa Pine Forests (1997–2007)

International Journal of Forestry Research ◽

10.1155/2012/529197 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 4

Author(s):

Joseph L. Ganey ◽

Scott C. Vojta

Keyword(s):

Pinus Ponderosa ◽

Ponderosa Pine ◽

Tree Mortality ◽

Management Practices ◽

Pine Forests ◽

Conifer Forest ◽

Mixed Conifer ◽

Ecological Processes ◽

Ponderosa Pine Forests ◽

Class Composition

Snags provide important biological legacies, resources for numerous species of native wildlife, and contribute to decay dynamics and ecological processes in forested ecosystems. We monitored trends in snag populations from 1997 to 2007 in drought-stressed mixed-conifer and ponderosa pine (Pinus ponderosaDougl.exLaws) forests, northern Arizona. Median snag density increased by 75 and 90% in mixed-conifer and ponderosa pine forests, respectively, over this time period. Increased snag density was driven primarily by a large pulse in drought-mediated tree mortality from 2002 to 2007, following a smaller pulse from 1997 to 2002. Decay-class composition and size-class composition of snag populations changed in both forest types, and species composition changed in mixed-conifer forest. Increases in snag abundance may benefit some species of native wildlife in the short-term by providing increased foraging and nesting resources, but these increases may be unsustainable in the long term. Observed changes in snag recruitment and fall rates during the study illustrate the difficulty involved in modeling dynamics of those populations in an era of climate change and changing land management practices.

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The Effects of Fire on Understory Vegetation in Ponderosa Pine Forests

The UW National Parks Service Research Station Annual Reports ◽

10.13001/uwnpsrc.1980.2229 ◽

1980 ◽

Vol 4 ◽

pp. 96-97

Author(s):

Jane Bock ◽

Carl Bock

Keyword(s):

Pinus Ponderosa ◽

Ponderosa Pine ◽

Prescribed Burning ◽

Fire Regime ◽

Management Plan ◽

Black Hills ◽

Pine Forests ◽

Natural Phenomenon ◽

Natural Fire ◽

Ponderosa Pine Forests

This was the second year of our study designed to evaluate the nature of vegetation occurring under Pinus ponderosa canopy in Wind Cave National Park and to define the relationship between this vegetation and fire. Fire is known to be a natural phenomenon in ponderosa pine forests (Wright 1978), and to play a major role in determining the position of the pine-grassland ecotone in the Black Hills (Gartner and Thompson 1973). Wind Cave personnel are developing a fire management plan allowing for prescribed burning, in hopes of bringing the park ecosystems back under a "natural" fire regime. Results of our study will help park management predict the effects of such prescribed burning on the ponderosa pine community.

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Phenology Patterns Indicate Recovery Trajectories of Ponderosa Pine Forests After High-Severity Fires

Remote Sensing ◽

10.3390/rs11232782 ◽

2019 ◽

Vol 11 (23) ◽

pp. 2782 ◽

Cited By ~ 2

Author(s):

Jessica J. Walker ◽

Christopher E. Soulard

Keyword(s):

Time Series ◽

Pinus Ponderosa ◽

Ponderosa Pine ◽

Google Earth ◽

Thematic Mapper ◽

Pine Forests ◽

Land Resource ◽

Ponderosa Pine Forests ◽

High Severity ◽

Peak Value

Post-fire recovery trajectories in ponderosa pine (Pinus ponderosa Laws.) forests of the southwestern United States are increasingly shifting away from pre-burn vegetation communities. This study investigated whether phenological metrics derived from a multi-decade remotely sensed imagery time-series could differentiate among grass, evergreen shrub, deciduous, or conifer-dominated replacement pathways. We focused on 10 fires that burned ponderosa pine forests in Arizona and New Mexico, USA before the year 2000. A total of 29 sites with discernable post-fire recovery signals were selected within high-severity burn areas. At each site, we used Google Earth Engine to derive time-series of normalized difference vegetation index (NDVI) signals from Landsat Thematic Mapper, Enhanced Thematic Mapper Plus, and Operational Land Imager data from 1984 to 2017. We aggregated values to 8- and 16-day intervals, fit Savitzky–Golay filters to each sequence, and extracted annual phenology metrics of amplitude, base value, peak value, and timing of peak value in the TIMESAT analysis package. Results showed that relative to post-fire conditions, pre-burn ponderosa pine forests exhibit significantly lower mean NDVI amplitude (0.14 vs. 0.21), higher mean base NDVI (0.47 vs. 0.22), higher mean peak NDVI (0.60 vs. 0.43), and later mean peak NDVI (day of year 277 vs. 237). Vegetation succession pathways exhibit distinct phenometric characteristics as early as year 5 (amplitude) and as late as year 20 (timing of peak NDVI). This study confirms the feasibility of leveraging phenology metrics derived from long-term imagery time-series to identify and monitor ecological outcomes. This information may be of benefit to land resource managers who seek indicators of future landscape compositions to inform management strategies.

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Double Sampling Increases the Efficiency of Forest Floor Inventories for Arizona Ponderosa Pine Forests

International Journal of Wildland Fire ◽

10.1071/wf9940003 ◽

1994 ◽

Vol 4 (1) ◽

pp. 3 ◽

Cited By ~ 6

Author(s):

PZ Fule ◽

WW Covington

Keyword(s):

Ponderosa Pine ◽

Basal Area ◽

Stand Density ◽

Cost Effective ◽

Pine Forests ◽

Double Sampling ◽

Fuel Loading ◽

Size Classes ◽

Ponderosa Pine Forests ◽

Stand Density Index

Stand and natural fuel conditions were sampled in ponderosa pine forests in northern and central Arizona to develop predictive fuel depth and loading equations. Litter and duff depths can be estimated from measurements of stand density (basal area, stand density index). Although woody fuel loading did not correlate well with stand variables, correlations were found among loadings of different woody fuel size classes, so that results from a planar intersect tally of certain single woody fuel size classes may be used to predict the loadings in certain other size classes. The relatively low precision of estimates from these predictive equations can be substantially increased by applying them in a double sampling scheme. Making use of these predictive relationships, managers can devise simple, rapid, arid cost-effective fuel inventories that focus on the fuel category of interest. Fuel loads can be estimated at a desired precision with reduced investment of time and funds compared to a more comprehensive direct fuel inventory.

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