scholarly journals Tree Mortality following Thinning and Prescribed Burning in Eastern Oregon, U.S.

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1677
Author(s):  
Christopher J. Fettig ◽  
Leif A. Mortenson ◽  
Jackson P. Audley

We examined causes and levels of tree mortality one year after thinning and prescribed burning was completed in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) forests at Pringle Falls Experimental Forest, Oregon, U.S. Four blocks of five experimental units (N = 20) were established. One of each of five treatments was assigned to each experimental unit in each block. Treatments included thinning from below to the upper management zone (UMZ) for the dominant plant association based on stand density index values for ponderosa pine followed by mastication and prescribed burning: (1) 50% UMZ (low density stand), (2) 75% UMZ (medium density stand), (3) 75% UMZ Gap, which involved a regeneration cut, (4) 100% UMZ (high density stand), and (5) an untreated control (high density stand). Experimental units were thinned in 2011 (block 4), 2012 (block 2), and 2013 (blocks 1 and 3); masticated within one year; and prescribed burned two years after thinning (2013–2015). A total of 395,053 trees was inventoried, of which 1.1% (4436) died. Significantly higher levels of tree mortality occurred on 100 UMZ (3.1%) than the untreated control (0.05%). Mortality was attributed to prescribed fire (2706), several species of bark beetles (Coleoptera: Curculionidae) (1592), unknown factors (136), windfall (1 tree), and western gall rust (1 tree). Among bark beetles, tree mortality was attributed to western pine beetle (Dendroctonus brevicomis LeConte) (881 trees), pine engraver (Ips pini (Say)) (385 trees), fir engraver (Scolytus ventralis LeConte) (304 trees), mountain pine beetle (D. ponderosae Hopkins) (20 trees), Ips emarginatus (LeConte) (1 tree), and Pityogenes spp. (1 tree).

2010 ◽  
Vol 25 (4) ◽  
pp. 181-185 ◽  
Author(s):  
Donald M. Grosman ◽  
Christopher J. Fettig ◽  
Carl L. Jorgensen ◽  
A. Steven Munson

Abstract Bark beetles (Coleoptera: Curculionidae, Scolytinae) are important tree mortality agents in western coniferous forests. Protection of individual trees from bark beetle attack has historically involved applications of liquid formulations of contact insecticides to the tree bole using hydraulic sprayers. More recently, researchers looking for more portable and environmentally safe alternatives have examined the effectiveness of injecting small quantities of systemic insecticides directly into trees. In this study, we evaluated trunk injections of experimental formulations of emamectin benzoate and fipronil for preventing tree mortality due to attack by western pine beetle (Dendroctonus brevicomis LeConte) on ponderosa pine (Pinus ponderosa Dougl. ex Laws.) in California, mountain pine beetle (Dendroctonus ponderosae Hopkins) on lodgepole pine (Pinus contorta Dougl. ex Loud.) in Idaho, and spruce beetle (D. rufipennis [Kirby]) on Engelmann spruce (Picea engelmannii Parry ex Engelm.) in Utah. Fipronil appeared ineffective for protecting P. ponderosa from mortality due to D. brevicomis over the 3 years in California because of insufficient mortality of untreated, baited control trees the first 2 years and high mortality of the fipronil-treated trees in the third year. Emamectin benzoate was effective in providing protection of P. ponderosa from D. brevicomis during the third year following a single application. To our knowledge, this is the first demonstration of the successful application of a systemic insecticide for protecting individual conifers from mortality due to bark beetle attack in the western United States. Estimates of efficacy could not be made during both field seasons in P. contorta because of insufficient mortality in control trees. Both emamectin benzoate and fipronil were ineffective for protecting P. engelmannii from D. rufipennis. Lower ambient and soil temperatures and soil moisture may have limited chemical movement and thus efficacy at the Idaho and Utah sites.


2008 ◽  
Vol 38 (5) ◽  
pp. 924-935 ◽  
Author(s):  
Christopher J. Fettig ◽  
Robert R. Borys ◽  
Stephen R. McKelvey ◽  
Christopher P. Dabney

Mechanical thinning and the application of prescribed fire are commonly used tools in the restoration of fire-adapted forest ecosystems. However, few studies have explored their effects on subsequent amounts of bark beetle caused tree mortality in interior ponderosa pine, Pinus ponderosa Dougl. ex P. & C. Laws. var. ponderosa. In this study, we examined bark beetle responses to creation of midseral (low diversity) and late-seral stages (high diversity) and the application of prescribed fire on 12 experimental units ranging in size from 76 to 136 ha. A total of 9500 (5.0% of all trees) Pinus and Abies trees died 2 years after treatment of which 28.8% (2733 trees) was attributed to bark beetle colonization. No significant difference in the mean percentage of trees colonized by bark beetles was found between low diversity and high diversity. The application of prescribed fire resulted in significant increases in bark beetle caused tree mortality (all species) and for western pine beetle, Dendroctonus brevicomis LeConte, mountain pine beetle, Dendroctonus ponderosae Hopkins, Ips spp., and fir engraver, Scolytus ventralis LeConte, individually. Approximately 85.6% (2339 trees) of all bark beetle caused tree mortality occurred on burned split plots. The implications of these and other results to sustainable forest management are discussed.


2012 ◽  
Vol 42 (12) ◽  
pp. 2022-2036 ◽  
Author(s):  
Ryan S. Davis ◽  
Sharon Hood ◽  
Barbara J. Bentz

Bark beetles can cause substantial mortality of trees that would otherwise survive fire injuries. Resin response of fire-injured northern Rocky Mountain ponderosa pine ( Pinus ponderosa Douglas ex P. Lawson & C. Lawson) and specific injuries that contribute to increased bark beetle attack susceptibility and brood production are unknown. We monitored ponderosa pine mortality and resin flow and bark beetle colonization and reproduction following a prescribed fire in Idaho and a wildfire in Montana. The level of fire-caused tree injury differed between the two sites, and the level of tree injury most susceptible to bark beetle attack and colonization also differed. Strip-attacked trees alive 3 years post-fire had lower levels of bole and crown injury than trees mass attacked and killed by bark beetles, suggesting that fire-injured trees were less well defended. Brood production of western pine beetle ( Dendroctonus brevicomis LeConte) did not differ between fire-injured and uninjured trees, although mountain pine beetle ( Dendroctonus ponderosae Hopkins) brood production was low in both tree types, potentially due to competition with faster developing bark beetle species that also colonized trees. Despite a large number of live trees remaining at both sites, bark beetle response to fire-injured trees pulsed and receded within 2 years post-fire, potentially due to a limited number of trees that could be easily colonized.


1986 ◽  
Vol 64 (7) ◽  
pp. 1507-1509 ◽  
Author(s):  
Thomas M. Pettey ◽  
Charles Gardner Shaw

Isolations of Hymenomycetes on a preferential medium were attempted from preflight pine engraver beetles, Ips pini, and the following in-flight bark beetles: pine engraver beetle, I. pini; western pine beetle, Dendroctonus brevicomis; mountain pine beetle, Dendroctonus ponderosae; and red turpentine beetle, Dendroctonus valens. Thirty pine engraver beetles removed from ponderosa pine slash (preflight) yielded no hymenomycete. However, Hymenomycetes were isolated from 50 of 114 beetles (all species) trapped in flight; Fomitopsis pinicola from 44, and other unidentified suspected Hymenomycetes, from 6. Cryptoporus volvatus was not isolated from any of the in-flight beetles. Since most of these isolates were without clamps (monokaryotic), the beetles may acquire basidiospores after emergence from beetle galleries in coniferous trees as hypothesized previously for the Douglas-fir beetle, Dendroctonus pseudotsugae. The isolation of F. pinicola from all species of in-flight bark beetles indicates that these beetles may be important in the dissemination of this hymenomycete.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michael J. Koontz ◽  
Andrew M. Latimer ◽  
Leif A. Mortenson ◽  
Christopher J. Fettig ◽  
Malcolm P. North

AbstractThe recent Californian hot drought (2012–2016) precipitated unprecedented ponderosa pine (Pinus ponderosa) mortality, largely attributable to the western pine beetle (Dendroctonus brevicomis; WPB). Broad-scale climate conditions can directly shape tree mortality patterns, but mortality rates respond non-linearly to climate when local-scale forest characteristics influence the behavior of tree-killing bark beetles (e.g., WPB). To test for these cross-scale interactions, we conduct aerial drone surveys at 32 sites along a gradient of climatic water deficit (CWD) spanning 350 km of latitude and 1000 m of elevation in WPB-impacted Sierra Nevada forests. We map, measure, and classify over 450,000 trees within 9 km2, validating measurements with coincident field plots. We find greater size, proportion, and density of ponderosa pine (the WPB host) increase host mortality rates, as does greater CWD. Critically, we find a CWD/host size interaction such that larger trees amplify host mortality rates in hot/dry sites. Management strategies for climate change adaptation should consider how bark beetle disturbances can depend on cross-scale interactions, which challenge our ability to predict and understand patterns of tree mortality.


1980 ◽  
Vol 112 (7) ◽  
pp. 725-730 ◽  
Author(s):  
D. J. Goheen ◽  
F. W. Cobb

AbstractThe relationship between bark beetle infestation of ponderosa pine and severity of infection by Ceratocystis wageneri was investigated by closely monitoring 256 trees (136 apparently healthy, 60 moderately diseased, and 60 severely diseased at initiation of study) for beetle infestation from summer 1972 to fall 1975. Disease ratings were updated by periodic examination, and some trees changed disease category during the study. Ninety trees were infested by Dendroctonus brevicomis, D. ponderosae, or both, five by buprestids alone, and one tree died from effects of the pathogen alone. Sixty-two of the beetle-infested trees were severely diseased at time of infestation, 25 were moderately diseased, and only three were apparently healthy. Thus, the results showed that bark beetles were much more likely to infest infected than healthy trees. Among diseased trees, those with advanced infections were most likely to be infested. There was evidence that buprestids (especially Melanophila spp.) and possibly Ips spp. attacked diseased trees prior to Dendroctonus spp. infestation.


2008 ◽  
Vol 23 (1) ◽  
pp. 40-45 ◽  
Author(s):  
Christopher J. Fettig ◽  
Christopher P. Dabney ◽  
Stephen R. McKelvey ◽  
Dezene P.W. Huber

Abstract Nonhost angiosperm volatiles (NAV) and verbenone were tested for their ability to protect individual ponderosa pines, Pinus ponderosa Dougl. ex. Laws., from attack by western pine beetle (WPB), Dendroctonus brevicomis LeConte, and red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Curculionidae, Scolytinae). A combination of (−)-verbenone and eight NAVs [benzyl alcohol, benzaldehyde, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol, and (Z)-2-hexen-1-ol] (NAVV) significantly reduced the density of WPB attacks and WPB successful attacks on attractant-baited trees. A significantly higher percentage of pitchouts (unsuccessful WPB attacks) occurred on NAVV-treated trees during two of three sample dates. In addition, significantly fewer RTB attacks were observed on NAVV-treated trees during all sampling dates. The application of NAVV to individual ponderosa pines significantly reduced tree mortality, with only 4 of 30 attractant-baited trees dying from bark beetle attack while 50% mortality (15/30) was observed in the untreated, baited control. To our knowledge, this is the first report establishing the effectiveness of NAVs and verbenone for protecting individual ponderosa pines from WPB attack.


2020 ◽  
Vol 46 (5) ◽  
pp. 333-346
Author(s):  
Joseph Doccola ◽  
Sheri Smith ◽  
Joseph Fischer ◽  
Brian Strom

The protection of high-value trees against bark beetles and the development of alternatives to bole sprays is a priority for the tree manager. The objective of this study was to evaluate stem-injected TREE-äge® (emamectin benzoate [EB]) as a protective treatment for western white pines (Pinus monticola Dougl. ex D. Don) against mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins). Treatment efficacy was based solely on tree mortality as per Shea protocols (i.e., ≥ 60% check vs. ≤ 20% treated tree mortality). Our first experiment was installed in 2007 and included trees stem-injected with TREE-äge and untreated controls. Bole application of S-(-)-verbenone and green leaf volatile (GLV) blend was included for observational comparison. Pressure from MPB was heavy, as indicated by the number and timing of control tree mortality (90%). Strip attacks by MPB in TREE-äge trees indicated that the impacts of EB, and by inference its distribution, were inconsistent. In 2009, the injection protocol was revised to improve EB distribution in the phloem via closer injection points. In the 2009 TREE-äge-treated trees, adult beetle mining stopped when they contacted phloem and was insufficient to cause tree death by girdling. Blue-stain fungi colonized the sapwood of trees in both studies. Isolates from autopsied trees treated with TREE-äge alone were subsequently identified as Grosmannia clavigera and Leptographium longiclavatum (Ophiostomatales: Ascomycota), species that can incite tree mortality. In 2013, we revised our protocol to include GLV plus verbenone or propiconazole with TREE-äge, wherein these treatments proved effective in protecting trees against MPB and their associated pathogenic fungi.


1958 ◽  
Vol 90 (10) ◽  
pp. 582-584 ◽  
Author(s):  
R. L. Lyon

The sex of the western pine beetle (Dendroctonus brevicomis Lec.) and the mountain pine beetle (Dendroctonus monticolae Hopk.) can be ascertained easily and with 100 percent accuracy by means of a secondary sex character on the seventh abdominal tergite of the male. This character can probably be used with equal accuracy to identify sex in all species of the genus Dendroctonus.The need to distinguish between the sexes of adult bark beetles often arises in studies of biology, behavior, or response. The sexing procedure is laborious when large numbers of beetles are involved and external markings of sex are not known. It is then necessary to dissect each beetle to check the genitalia. Dissection is impossible when iniury to the insect must be avoided.


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