ABSTRACT The use of pheromone trap catches to reliably predict damage by the Nantucket pine tip m... more ABSTRACT The use of pheromone trap catches to reliably predict damage by the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), in loblolly pine (Pinus taeda L.) plantations would provide forest managers with a valuable integrated pest management tool. At 17 sites throughout four states in the southern United States, in areas where R. frustrana has four annual generations, adult moths were monitored throughout the year (2002) using two types of pheromone traps, and subsequent infestation levels were determined for each tip moth generation. Cumulative wing trap catch tallies up to published spray dates for three of four adult emergence periods were highly predictive of top whorl damage during the subsequent generation using linear regression models. Multiple linear regression that included initial average tree height as a covariate did not significantly improve model efficacy. Cumulative delta trap catch tallies up to the spray date were not predictive of subsequent damage levels for any tip moth generation using linear regression models. Although multiple linear regression incorporating tree height as a covariate did greatly improve delta trap model efficacy, the power and significance of these models remained insufficient. Wing traps seem to be much more sensitive to tip moth population change than delta traps; however, both are useful for monitoring seasonal activity and initiation of spray timing models.
Loblolly pine (Pinus taeda L.) is the most important commercial tree species in the southeastern ... more Loblolly pine (Pinus taeda L.) is the most important commercial tree species in the southeastern United States. Since the 1950s, there have been reports of loblolly pines showing reduced growth and increased mortality, particularly in central Alabama and western Georgia, United States; the phenomenon is termed as southern pine decline (SPD). Recently, the role of rhizophagous (root-feeding) insects in loblolly pine health within the context of SPD has come under greater scrutiny. We investigated the impacts of subcortical insects, particularly rhizophagous weevils (Coleoptera: Curculionidae), on loblolly pine health in northeastern Georgia. We created plots-representing a gradient of increased relative tree stress-from ungirdled trees, ungirdled trees baited with ethanol and turpentine (ungirdled-baited), and girdled trees. In total, 10,795 subcortical insects from four families (Buprestidae, Cerambycidae, Curculionidae, and Siricidae) and >82 species were trapped in two years. Almost half of the insects trapped (46% of individuals and 11% of species) were nonnative to North America. Insect captures in plots with girdled trees were 61 and 187% greater than those with ungirdled-baited and ungirdled trees, respectively. Tree treatment impacted captures of native, but not nonnative insects. Relative feeding area by the rhizophagous weevils Hylobius pales (Herbst) and Pachylobius picivorus (Germar) on pine twigs placed in pitfall traps was 1, 17, and 82% in plots with ungirdled, ungirdled-baited, and girdled trees, respectively. Hence, there was a strong association of native subcortical insects, especially rhizophagous weevils, with relatively highly stressed trees, confirming that they are secondary instead of primary pine colonizers.
Intensive forest management practices have been shown to increase tree growth and shorten rotatio... more Intensive forest management practices have been shown to increase tree growth and shorten rotation time. However, they may also lead to an increased need for insect pest management because of higher infestation levels and lower action thresholds. To investigate the relationship between intensive management practices and insect infestation, maximum growth potential studies of loblolly pine, Pinus taeda L., were conducted over 4 yr using a hierarchy of cultural treatments. The treatments were herbaceous weed control (H), H + irrigation (I), H + I + fertilizer (F), and H + I + F + pest control (P). These treatments were monitored for differences in growth and insect infestation levels related to the increasing management intensities. The Nantucket pine tip moth, Rhyacionia frustrana (Comstock), was consistently found infesting study trees. In the third field season, the H + I + F + P treatment had significantly more southern pine coneworm, Dioryctria amatella (Hulst), attacks than the H and H + I treatments. There were significant differences in volume index (D2H) among all treatments after each of the four growing seasons. This study indicated that tree fertilization can increase coneworm infestation and demonstrated that tip moth management can improve tree growth initially. Future measurements will determine if the growth gains from tip moth management are transitory or sustainable.
Photochemical processing of anthropogenic emissions from the west coast of the continental US was... more Photochemical processing of anthropogenic emissions from the west coast of the continental US was examined from the NOAA WP-3 aircraft on several flights during the Intercontinental Transport and Chemical Transformation (ITCT) experiment in May 2002. Airborne measurements of fine particle (< 1 micron diameter) composition, fine particle volume, trace gases, and gas-phase particle precursors are used to describe gas-to-particle conversion observed within the planetary boundary layer over Los Angeles, San Francisco, and the neighboring valleys. Correlations of fast response (1 s) measurements of nitric acid, carbon monoxide, and particle volume are used to identify the sources of the measured ammonium nitrate particles. Conversion of gas-phase nitric acid to ammonium nitrate particles was observed both in regions characterized by high ammonia emissions from livestock sources and in the Los Angeles urban plume upwind of agricultural emissions of ammonia. In an air mass that was tran...
Each spring, state and federal agencies monitor southern pine beetle (SPB) populations by baiting... more Each spring, state and federal agencies monitor southern pine beetle (SPB) populations by baiting funnel traps with frontalin (an SPB aggregate lure) and α-pinene (a host monoterpene) to collect SPB and their primary predator, a clerid beetle, Thanasimus dubius. The ratio of the average number of collected SPB to T. dubius acts as a predictive model; forecasting SPB population levels and trends for the current year. Previous studies suggest that both SPB and T. dubius do not differentiate between frontalin enantiomers. However, it is unknown whether SPB or T. dubius differentiate between α-pinene enantiomers, and the chirality of α-pinene is (host) species dependent. The objective of this study was to determine whether SPB or T. dubius differentiate between α-pinene enantiomers. In 2011, we conducted field trials using (+) α-pinene, (-) α-pinene, (+/-) α-pinene, (+/-) α-pinene of double volume, and an unbaited control. To ensure SPB and clerid captures, frontalin and endo-brevicomin...
The southern pine beetle (SPB) is the most destructive forest pest in the South. After a recent S... more The southern pine beetle (SPB) is the most destructive forest pest in the South. After a recent SPB outbreak, the US Forest Service (Forest Health Protection and Southern Research Station [SRS]) received SPB Initiative (SPBI) funding to focus more resources on proactive SPB prevention work. This funding is being used for on-the-ground accomplishments, landowner education, and research and development. Since 2003, on-the-ground accomplishments have totaled over 500,000 ac of thinning and restoration work on state, private, and national forestland. The SRS (SRS Research Work Unit 4552) has worked, internally and externally, on projects addressing (1) the risks and costs of SPB, (2) preventing and controlling SPB outbreaks, and (3) recovery from SPB outbreaks. Much work has been accomplished through the SPBI and will hopefully have a long-lasting impact. This article describes the history, current practices, and the accomplishments for the first 6 years of the SPBI.
Activity based costing (ABC) has revolutionized product costing, planning, and forecasting in the... more Activity based costing (ABC) has revolutionized product costing, planning, and forecasting in the last decade. It is based on a philosophy of estimation that: "it is better to be approximately right, than precisely wrong." The philosophy of discrete-event simulation modeling follows a similar tack, where statistical inference and the stochastic nature of processes are used to replicate the behavior of a physical syster In this work, ABC and discrete-event simulation are linked to provide an improved costing, planning, and forecasting tool. Numerous point cost estimates are generated by the ABC model, using driver values obtained from a discrete-event simulation of the process. The various cost estimates can be used to produce confidence interval estimates of both the physical system and underlying cost structure. Rather than having a single point estimate of a product's cost, it is now possible to produce the range of costs to be expected as process conditions vary. T...
Gas-phase low volatility organic compounds (LVOC), produced during an experiment studying the oxi... more Gas-phase low volatility organic compounds (LVOC), produced during an experiment studying the oxidation of isoprene 4-hydroxy-3-hydroperoxide (4,3-ISOPOOH) under low-NO conditions, were observed during the FIXCIT chamber study. Decreases in LVOC concentrations directly correspond to the appearance and growth in secondary organic aerosol (SOA) of consistent elemental composition, indicating that LVOC condense (at OA levels below 1 µg m-3). This represents the first simultaneous measurement of condensing low volatility species from isoprene oxidation in both the gas and particle phases. The experimental conditions and aerosol composition indicate that SOA formation observed in this study is separate from previously described isoprene epoxydiol (IEPOX) uptake. Comparison with a kinetic model suggests that these LVOC arise as first generation products from the reaction of OH with ISOPOOH and associated species in the experiment. Assigning all condensing LVOC signals to 4,3-ISOPOOH oxida...
ABSTRACT The use of pheromone trap catches to reliably predict damage by the Nantucket pine tip m... more ABSTRACT The use of pheromone trap catches to reliably predict damage by the Nantucket pine tip moth, Rhyacionia frustrana (Comstock), in loblolly pine (Pinus taeda L.) plantations would provide forest managers with a valuable integrated pest management tool. At 17 sites throughout four states in the southern United States, in areas where R. frustrana has four annual generations, adult moths were monitored throughout the year (2002) using two types of pheromone traps, and subsequent infestation levels were determined for each tip moth generation. Cumulative wing trap catch tallies up to published spray dates for three of four adult emergence periods were highly predictive of top whorl damage during the subsequent generation using linear regression models. Multiple linear regression that included initial average tree height as a covariate did not significantly improve model efficacy. Cumulative delta trap catch tallies up to the spray date were not predictive of subsequent damage levels for any tip moth generation using linear regression models. Although multiple linear regression incorporating tree height as a covariate did greatly improve delta trap model efficacy, the power and significance of these models remained insufficient. Wing traps seem to be much more sensitive to tip moth population change than delta traps; however, both are useful for monitoring seasonal activity and initiation of spray timing models.
Loblolly pine (Pinus taeda L.) is the most important commercial tree species in the southeastern ... more Loblolly pine (Pinus taeda L.) is the most important commercial tree species in the southeastern United States. Since the 1950s, there have been reports of loblolly pines showing reduced growth and increased mortality, particularly in central Alabama and western Georgia, United States; the phenomenon is termed as southern pine decline (SPD). Recently, the role of rhizophagous (root-feeding) insects in loblolly pine health within the context of SPD has come under greater scrutiny. We investigated the impacts of subcortical insects, particularly rhizophagous weevils (Coleoptera: Curculionidae), on loblolly pine health in northeastern Georgia. We created plots-representing a gradient of increased relative tree stress-from ungirdled trees, ungirdled trees baited with ethanol and turpentine (ungirdled-baited), and girdled trees. In total, 10,795 subcortical insects from four families (Buprestidae, Cerambycidae, Curculionidae, and Siricidae) and &amp;amp;gt;82 species were trapped in two years. Almost half of the insects trapped (46% of individuals and 11% of species) were nonnative to North America. Insect captures in plots with girdled trees were 61 and 187% greater than those with ungirdled-baited and ungirdled trees, respectively. Tree treatment impacted captures of native, but not nonnative insects. Relative feeding area by the rhizophagous weevils Hylobius pales (Herbst) and Pachylobius picivorus (Germar) on pine twigs placed in pitfall traps was 1, 17, and 82% in plots with ungirdled, ungirdled-baited, and girdled trees, respectively. Hence, there was a strong association of native subcortical insects, especially rhizophagous weevils, with relatively highly stressed trees, confirming that they are secondary instead of primary pine colonizers.
Intensive forest management practices have been shown to increase tree growth and shorten rotatio... more Intensive forest management practices have been shown to increase tree growth and shorten rotation time. However, they may also lead to an increased need for insect pest management because of higher infestation levels and lower action thresholds. To investigate the relationship between intensive management practices and insect infestation, maximum growth potential studies of loblolly pine, Pinus taeda L., were conducted over 4 yr using a hierarchy of cultural treatments. The treatments were herbaceous weed control (H), H + irrigation (I), H + I + fertilizer (F), and H + I + F + pest control (P). These treatments were monitored for differences in growth and insect infestation levels related to the increasing management intensities. The Nantucket pine tip moth, Rhyacionia frustrana (Comstock), was consistently found infesting study trees. In the third field season, the H + I + F + P treatment had significantly more southern pine coneworm, Dioryctria amatella (Hulst), attacks than the H and H + I treatments. There were significant differences in volume index (D2H) among all treatments after each of the four growing seasons. This study indicated that tree fertilization can increase coneworm infestation and demonstrated that tip moth management can improve tree growth initially. Future measurements will determine if the growth gains from tip moth management are transitory or sustainable.
Photochemical processing of anthropogenic emissions from the west coast of the continental US was... more Photochemical processing of anthropogenic emissions from the west coast of the continental US was examined from the NOAA WP-3 aircraft on several flights during the Intercontinental Transport and Chemical Transformation (ITCT) experiment in May 2002. Airborne measurements of fine particle (< 1 micron diameter) composition, fine particle volume, trace gases, and gas-phase particle precursors are used to describe gas-to-particle conversion observed within the planetary boundary layer over Los Angeles, San Francisco, and the neighboring valleys. Correlations of fast response (1 s) measurements of nitric acid, carbon monoxide, and particle volume are used to identify the sources of the measured ammonium nitrate particles. Conversion of gas-phase nitric acid to ammonium nitrate particles was observed both in regions characterized by high ammonia emissions from livestock sources and in the Los Angeles urban plume upwind of agricultural emissions of ammonia. In an air mass that was tran...
Each spring, state and federal agencies monitor southern pine beetle (SPB) populations by baiting... more Each spring, state and federal agencies monitor southern pine beetle (SPB) populations by baiting funnel traps with frontalin (an SPB aggregate lure) and α-pinene (a host monoterpene) to collect SPB and their primary predator, a clerid beetle, Thanasimus dubius. The ratio of the average number of collected SPB to T. dubius acts as a predictive model; forecasting SPB population levels and trends for the current year. Previous studies suggest that both SPB and T. dubius do not differentiate between frontalin enantiomers. However, it is unknown whether SPB or T. dubius differentiate between α-pinene enantiomers, and the chirality of α-pinene is (host) species dependent. The objective of this study was to determine whether SPB or T. dubius differentiate between α-pinene enantiomers. In 2011, we conducted field trials using (+) α-pinene, (-) α-pinene, (+/-) α-pinene, (+/-) α-pinene of double volume, and an unbaited control. To ensure SPB and clerid captures, frontalin and endo-brevicomin...
The southern pine beetle (SPB) is the most destructive forest pest in the South. After a recent S... more The southern pine beetle (SPB) is the most destructive forest pest in the South. After a recent SPB outbreak, the US Forest Service (Forest Health Protection and Southern Research Station [SRS]) received SPB Initiative (SPBI) funding to focus more resources on proactive SPB prevention work. This funding is being used for on-the-ground accomplishments, landowner education, and research and development. Since 2003, on-the-ground accomplishments have totaled over 500,000 ac of thinning and restoration work on state, private, and national forestland. The SRS (SRS Research Work Unit 4552) has worked, internally and externally, on projects addressing (1) the risks and costs of SPB, (2) preventing and controlling SPB outbreaks, and (3) recovery from SPB outbreaks. Much work has been accomplished through the SPBI and will hopefully have a long-lasting impact. This article describes the history, current practices, and the accomplishments for the first 6 years of the SPBI.
Activity based costing (ABC) has revolutionized product costing, planning, and forecasting in the... more Activity based costing (ABC) has revolutionized product costing, planning, and forecasting in the last decade. It is based on a philosophy of estimation that: "it is better to be approximately right, than precisely wrong." The philosophy of discrete-event simulation modeling follows a similar tack, where statistical inference and the stochastic nature of processes are used to replicate the behavior of a physical syster In this work, ABC and discrete-event simulation are linked to provide an improved costing, planning, and forecasting tool. Numerous point cost estimates are generated by the ABC model, using driver values obtained from a discrete-event simulation of the process. The various cost estimates can be used to produce confidence interval estimates of both the physical system and underlying cost structure. Rather than having a single point estimate of a product's cost, it is now possible to produce the range of costs to be expected as process conditions vary. T...
Gas-phase low volatility organic compounds (LVOC), produced during an experiment studying the oxi... more Gas-phase low volatility organic compounds (LVOC), produced during an experiment studying the oxidation of isoprene 4-hydroxy-3-hydroperoxide (4,3-ISOPOOH) under low-NO conditions, were observed during the FIXCIT chamber study. Decreases in LVOC concentrations directly correspond to the appearance and growth in secondary organic aerosol (SOA) of consistent elemental composition, indicating that LVOC condense (at OA levels below 1 µg m-3). This represents the first simultaneous measurement of condensing low volatility species from isoprene oxidation in both the gas and particle phases. The experimental conditions and aerosol composition indicate that SOA formation observed in this study is separate from previously described isoprene epoxydiol (IEPOX) uptake. Comparison with a kinetic model suggests that these LVOC arise as first generation products from the reaction of OH with ISOPOOH and associated species in the experiment. Assigning all condensing LVOC signals to 4,3-ISOPOOH oxida...
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