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Book Douglas fir Beetle Mediated Changes to Fuel Complexes Foliar Moisture Content and Terpenes in Interior Douglas fir Forests of the Central Rocky Mountains

Download or read book Douglas fir Beetle Mediated Changes to Fuel Complexes Foliar Moisture Content and Terpenes in Interior Douglas fir Forests of the Central Rocky Mountains written by Andrew D. Giunta and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent bark beetle outbreaks have caused extensive tree mortality in conifer forests across western Northern America, which has altered forest fuels. These changes have raised concerns about forest health and wildfire risk. Studies focused on interactions between bark beetles, forests fuels, and changes in fire behavior have been primarily led in upper elevation forests characterized by high-severity fire regimes, principally in lodgepole pine (pinus contorta Douglas ex Loudon) and Engelmann spruce (Picea engelmannii Parry ex Engelm) forests. Few studies to date have addressed bark beetle fuel interactions in lower to middle montane forest characterized by a mixed-severity fire regime, with available research focused strictly on assessing fuel load conditions or stand structural changes. The goal of this research was to quantify and characterize surface and canopy fuel changes in middle montane interior Douglas-Fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.)) forest infested by Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins), while also measuring physical and chemical changes to foliage in terms of moisture content and terpenes, which are known to play important roles in foliage flammability. Our results revealed few changes in surface fuels following Douglas-fir beetle infestations aside from a significant increase in litter depth and loading in red stage sample plots. Substantial changes to canopy fuels were detected in the red stage of an outbreak with a significant reduction in foliar moisture content measured as tree crowns faded from a healthy green phase to red. During this period, volatile emissions and within-needle concentrations of terpenes increased, including some terpenes previously associated with increased foliage flammability in other tree species. Furthermore, aerial fuel parameters that estimate the likelihood of crown fire initiation, including canopy bulk density and canopy base height, showed a substantial reduction in gray stage sample plots. Based on our findings we judge the influence of Douglas-fir beetle activity on altering fuels is most pronounced in the aerial fuels complex. Our results suggest bark beetle affected interior Douglas-fir stands with a high percentage of trees in yellow and red crown phases could have an increased threshold for crown fire initiation based on higher levels of flammable monoterpenes and lower foliar moisture content.

Book Fire Regimes Spatial and Temporal Variability and Their Effects on Forests

Download or read book Fire Regimes Spatial and Temporal Variability and Their Effects on Forests written by Yves Bergeron and published by MDPI. This book was released on 2018-04-13 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Fire Regimes: Spatial and Temporal Variability and Their Effects on Forests" that was published in Forests

Book Notes on the Biology of the Douglas Fir Beetle in the Central Rocky Mountain Region

Download or read book Notes on the Biology of the Douglas Fir Beetle in the Central Rocky Mountain Region written by Donald De Leon and published by . This book was released on 1940 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Bark Beetle Effects on Fuel Profiles Across a Range of Stand Structures in Douglas fir Forests of Greater Yellowstone

Download or read book Bark Beetle Effects on Fuel Profiles Across a Range of Stand Structures in Douglas fir Forests of Greater Yellowstone written by Daniel C. Donato and published by . This book was released on 2013 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt: Consequences of bark beetle outbreaks for forest wildfire potential are receiving heightened attention, but little research has considered ecosystems with mixed-severity fire regimes. Such forests are widespread, variable in stand structure, and often fuel limited, suggesting that beetle outbreaks could substantially alter fire potentials. We studied canopy and surface fuels in interior Douglas-fir (Pseudotsuga menziesii v. glauca) forests in Greater Yellowstone, Wyoming, USA, to determine how fuel characteristics varied with time since outbreak of the Douglas-fir beetle (Dendroctonus pseudotsugae). We sampled five stands in each of four outbreak stages, validated for pre-outbreak similarity: green (undisturbed), red (1?3 yr), gray (4?14 yr), and silver (25?30 yr). General linear models were used to compare variation in fuel profiles associated with outbreak to variation associated with the range of stand structures (dense mesic forest to open xeric parkland) characteristic of interior Douglas-fir forest. Beetle outbreak killed 38?83% of basal area within stands, generating a mix of live trees and snags over several years. Canopy fuel load and bulk density began declining in the red stage via needle drop and decreased by 50% by the silver stage. The dead portion of available canopy fuels peaked in the red stage at 41%. After accounting for background variation, there was little effect of beetle outbreak on surface fuels, with differences mainly in herbaceous biomass (50% greater in red stands) and coarse woody fuels (doubled in silver stands). Within-stand spatial heterogeneity of fuels increased with time since outbreak, and surface-to-crown continuity decreased and remained low because of slow/sparse regeneration. Collectively, results suggest reduced fire potentials in post-outbreak stands, particularly for crown fire after the red stage, although abundant coarse fuels in silver stands may increase burn residence time and heat release. Outbreak effects on fuels were comparable to background variation in stand structure. The net effect of beetle outbreak was to shift the structure of mesic closed-canopy stands toward that of parklands, and to shift xeric parklands toward very sparse woodlands. This study highlights the importance of evaluating outbreak effects in the context of the wide structural variation inherent to many forest types in the absence of beetle disturbance.

Book Douglas fir Beetle Project

    Douglas fir Beetle Project

    Book Details:
  • Author : Idaho Panhandle National Forests. Colville National Forest (Wash.).
  • Publisher :
  • Release : 1999
  • ISBN :
  • Pages : pages

Download or read book Douglas fir Beetle Project written by Idaho Panhandle National Forests. Colville National Forest (Wash.). and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book User s Guide to the Douglas fir Beetle Impact Model

Download or read book User s Guide to the Douglas fir Beetle Impact Model written by Michael A. Marsden and published by . This book was released on 1994 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book On Certain Factors Influencing Douglas fir Beetle Populations

Download or read book On Certain Factors Influencing Douglas fir Beetle Populations written by M. D. Atkins and published by . This book was released on 1960 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Douglas fir Beetle Project

Download or read book Douglas fir Beetle Project written by Colville National Forest (Wash.) and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Certain Biotic Factors Influencing the Invasion and Survival of the Douglas fir Beetle Dendroctonus Pseudotsugae Hopkins Coleoptera

Download or read book Certain Biotic Factors Influencing the Invasion and Survival of the Douglas fir Beetle Dendroctonus Pseudotsugae Hopkins Coleoptera written by William Henry Hendrickson and published by . This book was released on 1965 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Factors considered were phloem moisture, sour-phloem (which may be furthered by the presence of ample phloem moisture), oleoresin of the host, and the presence of unmated female beetles in suitable host material. Levels of phloem moisture present in variously prepared logs in the field ranged from about 100 to upwards of 250 percent of dry weight. Observation of such host material during the main season of beetle flight supported the conclusion that the Douglas-fir beetle attack volume was not related to moisture level. Experimentation with short logs which had either been soaked or not soaked verified this conclusion; at the same time it was demonstrated that Gnatho-trichus sp., Dryocetes autographus (Ratzeburg), and Hylastes nigrinus (Mannerheim) were attracted to the logs which had been made wetter, Within the range observed in the field, moisture level did not influence brood success. The case where moisture implements an air-tight seal, its effectiveness being indicated by sour-phloem development, is an exception. Sour-phloem is a decay condition which develops under anerobic circumstances. Moisture is viewed as an accessory to its formation in that it implements an air-tight seal of intact bark. At the time of attack only incipient sour-phloem was present in various of the pieces of host material in this study and in this stage of development did not influence attack by the Douglas-fir beetle. Sour-phloem, however, was associated with restricted brood development, more likely as an indicator of low oxygen levels rather than as a detrimental habitat factor in itself. Minimal oleoresin exudation pressures (1 to 17 pounds per square inch) were measured in fallen Douglas-firs which, observed through the attack season and later analyzed, were seen to have an appreciable number of incidences where oleoresin was judged to have interfered with beetle entry. Similarly, brood size and success was determined to have been limited by oleoresin. The introduction of unmated female beetles was seen to so strongly prompt other females to attack a log that it not only affords an explanation of how beetles are attracted en masse but also explains why there can be beetle indifference to otherwise suitable host material which happens to lack prior entered females. MaIe beetles are also attracted by the unmated females. Beetle response is to odor; air blown over a properly treated and hidden log attracted beetles. The intensity of mass attack relates to the intensity of the earliest attack. The species demonstrates a gregarious habit which, it is argued, would facilitate mating, shatter the tree's defensive oleoresin exudation, enable mass tunneling of the inner bark so that adequate ventilation would be afforded the brood, and serve to insure that it will place economic demand on the population of its host. The strong displacement effect of logs having female beetles warrants strong consideration when studies are made seeking to identify attractive factors that belong to the host per se. When forced entry of females was made into irregular host material, it received subsequent attack. Intensity of attack, as judged from the experiment of one season, is independent of host felling dates when the range of these is less than a year. Air temperature observation in connection with the studies provided insight with regard to the predicability of attack in suitable host material as spring warming continued.

Book The Photoload Sampling Technique

Download or read book The Photoload Sampling Technique written by Robert E. Keane and published by . This book was released on 2007 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fire managers need better estimates of fuel loading so they can more accurately predict the potential fire behavior and effects of alternative fuel and ecosystem restoration treatments. This report presents a new fuel sampling method, called the photoload sampling technique, to quickly and accurately estimate loadings for six common surface fuel components (1 hr, 10 hr, 100 hr, and 1000 hr downed dead woody, shrub, and herbaceous fuels). This technique involves visually comparing fuel conditions in the field with photoload sequences to estimate fuel loadings. Photoload sequences are a series of downward-looking and close-up oblique photographs depicting a sequence of graduated fuel loadings of synthetic fuelbeds for each of the six fuel components. This report contains a set of photoload sequences that describe the range of fuel component loadings for common forest conditions in the northern Rocky Mountains of Montana, USA to estimate fuel loading in the field. A companion publication (RMRS-RP-61CD) details the methods used to create the photoload sequences and presents a comprehensive evaluation of the technique.