scholarly journals Predicting postfire Douglas-fir beetle attacks and tree mortality in the northern Rocky Mountains

2007 ◽  
Vol 37 (6) ◽  
pp. 1058-1069 ◽  
Author(s):  
Sharon Hood ◽  
Barbara Bentz

Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) were monitored for 4 years following three wildfires. Logistic regression analyses were used to develop models predicting the probability of attack by Douglas-fir beetle ( Dendroctonus pseudotsugae Hopkins, 1905) and the probability of Douglas-fir mortality within 4 years following fire. Percent crown volume scorched (crown scorch), cambium injury, diameter at breast height (DBH), and stand density index for Douglas-fir were most important for predicting Douglas-fir beetle attacks. A nonlinear relationship between crown scorch and cambium injury was observed, suggesting that beetles did not preferentially attack trees with both maximum crown scorch and cambium injury, but rather at some intermediate level. Beetles were attracted to trees with high levels of crown scorch, but not cambium injury, 1 and 2 years following fire. Crown scorch, cambium injury, DBH, and presence/absence of beetle attack were the most important variables for predicting postfire Douglas-fir mortality. As DBH increased, the predicted probability of mortality decreased for unattacked trees but increased for attacked trees. Field sampling suggested that ocular estimates of bark char may not be a reliable predictor of cambium injury. Our results emphasize the important role of Douglas-fir beetle in tree mortality patterns following fire, and the models offer improved prediction of Douglas-fir mortality for use in areas with or without Douglas-fir beetle populations.

2013 ◽  
Vol 22 (6) ◽  
pp. 810 ◽  
Author(s):  
Maria M. Godoy ◽  
Guillermo E. Defossé ◽  
Lucas O. Bianchi ◽  
Miguel M. Davel ◽  
Tomás E. Withington

In 2003 in a municipal park near Esquel, Patagonia, Argentina, plots within a 21-year-old Douglas-fir (Pseudotsuga menziesii) afforested area were subjected to three silvicultural treatments (thinning to Reineke’s Stand Density Index (SDI) of 900, 700, 500). In March 2007 all plots were burned by a wildfire that presented extreme fire behaviour. Three weeks after the wildfire we assessed mortality, height of scorch and percentage of crown scorch, and during three subsequent growing seasons we measured mortality and growth parameters. At the end of the study, mortality differed significantly among treatments and an untreated control, and ranged from 100% in the untreated control to 25, 10 and 5% in the SDI 900, 700 and 500 treatments. The highest growth parameters and lower mortality rates were achieved at SDI indices of 700 or 500 (i.e. in the least dense plots). Trees thinned to these densities not only appear to withstand extreme fires, at least under the conditions presented, but also to achieve the highest growth rates.


1999 ◽  
Vol 14 (3) ◽  
pp. 121-127 ◽  
Author(s):  
Jose F. Negron ◽  
Willis C. Schaupp ◽  
Kenneth E. Gibson ◽  
John Anhold ◽  
Dawn Hansen ◽  
...  

Abstract Data collected from Douglas-fir (Pseudotsuga menziesii) stands infested by the Douglas-fir beetle (Dendroctonus pseudotsugae) in Wyoming, Montana, Idaho, and Utah, were used to develop models to estimate amount of mortality in terms of basal area killed. Models were built using stepwise linear regression and regression tree approaches. Linear regression models using initial Douglas-fir basal area were built for all study sites but produce low precision estimates. Regression tree models using initial Douglas-fir basal area or stand density index or both were also built for all sites. Regression tree models provide a more realistic approach to estimate potential mortality by creating more homogenous mortality classes with reduced variance. The models developed provide land managers with a basis for determining the potential mortality should a Douglas-fir beetle outbreak develop. West. J. Appl. For. 14(3):121-127.


2020 ◽  
Vol 113 (4) ◽  
pp. 1858-1863 ◽  
Author(s):  
Gabriel G Foote ◽  
Christopher J Fettig ◽  
Darrell W Ross ◽  
Justin B Runyon ◽  
Tom W Coleman ◽  
...  

Abstract Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, trees and stands can be protected from Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (DFB)-caused mortality by application of synthetic formulations of the beetle’s antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH). A biodegradable formulation of MCH, SPLAT MCH, was developed and evaluated for protecting individual Douglas-fir trees and small stands from colonization and mortality by DFB. In an individual-tree experiment in Idaho, both MCH bubble capsules and SPLAT MCH significantly reduced the proportion of treated trees colonized and killed by DFB compared to untreated controls. SPLAT MCH was as effective as MCH bubble capsules for protecting individual trees. Both MCH bubble capsules and SPLAT MCH significantly reduced the proportion of trees colonized and killed by DFB within 0.04-ha circular plots surrounding each treated tree compared to untreated controls. In 0.41 ha stands in New Mexico, both MCH bubble capsules and SPLAT MCH significantly reduced the proportion of trees colonized and killed by DFB compared to untreated controls, again with no differences observed between MCH treatments. In a similar stand level trial in Idaho, neither MCH treatment significantly reduced the proportion of trees colonized by DFB, and only MCH bubble capsules significantly reduced levels of tree mortality compared to untreated controls, but no significant difference was observed between SPLAT MCH and MCH bubble capsules. Overall, the results indicate that SPLAT MCH is as effective as MCH bubble capsules for protecting individual trees and small stands of Douglas-fir from DFB-caused mortality.


2006 ◽  
Vol 36 (3) ◽  
pp. 768-782 ◽  
Author(s):  
Steven R Radosevich ◽  
David E Hibbs ◽  
Claudio M Ghersa

In the Pacific Northwest, a mixture of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and red alder (Alnus rubra Bong.) often results when red alder regenerates naturally in planted conifer stands. The relationships among stand structure, tree mortality, tree size, and understory development in the two species mixtures were explored at two sites for the first 16 years after planting. Treatments included a range of species proportions, and red alder was either planted simultaneously with Douglas-fir or planting was delayed for 5 years. Red alder was also removed from some simultaneously planted proportions. Both replacement effects (total stand density held constant) and additive effects (stand density doubled) of the interaction were considered. Red alder grew relatively better at Cascade Head Experimental Forest in the Coast Range, while Douglas-fir grew better at H.J. Andrews Experimental Forest in the less temperate Cascade Mountains. Possible production benefits from mixed plantings were examined using two methods of calculation. Potential production benefits from certain planted proportions of the two species occurred at H.J. Andrews Experimental Forest. No planting time or species proportion resulted in yield improvements over monoculture stands at Cascade Head Experimental Forest. Understory species also varied because of differences in site and stand characteristics that resulted from the differences in planting times and species proportions.


1993 ◽  
Vol 17 (6) ◽  
pp. 773-779 ◽  
Author(s):  
Robert J. Lilieholm ◽  
Winifred B. Kessler ◽  
Karren Merrill

1985 ◽  
Vol 15 (3) ◽  
pp. 596-598 ◽  
Author(s):  
David L. Peterson

In salvage operations after wildfire, timber managers need to identify those trees most likely to die. Crown scorch volume and scorch height are commonly used to estimate damage to conifers after fire. Calculated crown scorch volume based on scorch height and tree dimensions was compared with observed crown scorch volume for four common conifer species of the northern Rocky Mountains. Calculated crown scorch volume was significantly greater than observed crown scorch volume for all species. The overestimates are the result of differences among species and trees of varying crown shape. When postfire tree condition was evaluated from observed crown scorch volume rather than from measured scorch height, crown damage was estimated with greater accuracy. Functions that estimate postfire tree mortality based on crown damage should be based on observed crown scorch volume rather than scorch height.


2009 ◽  
Vol 24 (2) ◽  
pp. 88-94 ◽  
Author(s):  
Gregory M. Filip ◽  
Stephen A. Fitzgerald ◽  
Kristen L. Chadwick ◽  
Timothy A. Max

Abstract Portions of a 30-year-old stand of ponderosa pine were precommercially thinned in 1966 and commercially thinned in 2000 at age 64 years to determine the effects of thinning from below on tree growth and mortality caused by Armillaria root disease in central Oregon. Thirty years after precommercial thinning, leave-tree mortality was significantly less in thinned plots than in unthinned plots, but leave-treeߝdiameter growth was not significantly increased by thinning. Leave-tree basal area (BA) per acre growth, however, was significantly greater in thinned plots.In 2007 at age 71 years, 7 years after commercial thinning of the same plots that were precommercially thinned in 1966, leave-tree mortality was less in thinned plots than in unthinned plots, but more time probably is necessary to adequately assess Armillaria-caused mortality after commercial thinning. Both tree diameter and BA growth were significantly increased by commercial thinning. Hypotheses on fungal-host dynamics are discussed, and recommendations for multiple thinning based on stand density index are given.


1986 ◽  
Vol 16 (6) ◽  
pp. 1175-1179 ◽  
Author(s):  
David L. Peterson ◽  
Michael J. Arbaugh

Survival patterns after late summer wildfires were evaluated for Douglas-fir and lodgepole pine in the northern Rocky Mountains. Crown scorch was the most important variable for predicting postfire survival and variables representing bole damage improved the significance of logistic regression models for both species. Crown scorch and basal scorch were the best combination of variables for predicting survival in lodgepole pine. Crown scorch and insect damage were the best combination of variables for predicting survival in Douglas-fir. Postfire survival of lodgepole pine, which has relatively thin bark, was more sensitive than Douglas-fir to variables that quantified bole damage.


1991 ◽  
Vol 1 (1) ◽  
pp. 63 ◽  
Author(s):  
DL Peterson ◽  
MJ Arbaugh ◽  
GH Pollock ◽  
LJ Robinson

Dendroecological methods were used to study the effects of wildfire on radial growth of Pseudotsuga mniiesii (Douglas-fir) and Pinus contorta (lodgepole pine) in the northern Rocky Mountains. Mean basal area increment during a 4-year postfire period declined relative to prefire growth in 75% of burned P. menziesii trees and 70% of P. contorta trees. Percent of crown volume scorched was the most important variable related to postfire growth of P. menziesii, while basal scorch was slightly more important than crown scorch to postfire growth of P. contorta. Postfire growth always declined when crown scorch exceeded 50% in P. menziesii and 30% in P. contorta. None of the significant regression models had high predictive capability because of the large amount of variance in the data. It is clear, however, that crown injury is critical to postfire survival and growth of P. menziesii, while basal injury is critical for the thin-barked species P. contorta.


2020 ◽  
Vol 153 (1) ◽  
pp. 62-78
Author(s):  
Darrell W. Ross

AbstractThis paper reviews the literature on the identification of 3-methylcyclohex-2-en-1-one (MCH) as the antiaggregation pheromone of the Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) (Coleoptera: Curculionidae) and the development of successful management applications using the pheromone. Previously unpublished data from two studies on novel uses of MCH are included. The successful development of antiaggregation pheromone-based treatments for the Douglas-fir beetle is discussed in relation to efforts to develop similar treatments for other bark beetle species, and opportunities for future research on MCH and the Douglas-fir beetle are suggested.


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