2015 Insect and Disease Update for Rocky Mountain. Region

Transcription

1 2015 Insect and Disease Update for Rocky Mountain Bob Cain USDA Forest Service State and Private Forestry and Tribal Relations Forest Health Protection Region

2 Mountain Pine Beetle Spruce beetle Douglas-fir Beetle Western Balsam Bark Beetle Western Pine Beetle Fir Engraver Beetle Rogues' Gallery Beetles behaving badly in the Region Pine and other Engraver Beetles Pinyon Ips

3 Bark beetles mass attack trees and feed under the bark

4 Mountain Pine Beetle Life Stages

5 Spruce beetle usually has a two year life cycle

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8 Favorable conditions for the Mountain Pine Beetle (MPB) and Spruce Beetle (SB) Epidemics included An abundance of older, dense, large diameter lodgepole pine stands (MPB)or Spruce stands (SB). MPB or SB increasing in nearby forested areas. Windthrown spruce (SB) is present. Suitable climate. Absence of severe cold winter temperatures capable of killing beetle larvae under the bark Prolonged, severe drought and extended summer drought conditions that reduced tree defenses when the beetles attack trees. 29 September 2015

9 U.S. Drought Index

10 Annual acres affected by mountain pine beetle in Colorado

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22 4.3 million acres affected in CO and Southern WY. 3.4 million acres affected in just CO

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24 Aggregating and anti-aggregating pheromones

25 Photo by William Ciesla Mountain Pine Beetle/Ponderosa Pine 29 September 2015 Larimer County, CO

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27 The State of Colorado has about 3.4 million acres (1.4 million ha) of spruce-fir sawtimber on commercial forests (Alexander 1974), most of which is old-growth and 75% of which is in either road less or reserved categories (Cahill 1976). Schmid and Frye Spruce beetle in the Rockies. General Technical Report RM-49, 38 pp.

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29 Annual acres affected by spruce beetle in Colorado.

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36 Scattered, shaded windthrown trees create the ideal habitat for spruce beetle populations to build up and move into standing spruce forest

37 Spruce Beetle- Rio Grande NF, CO Like fire and wind, the spruce beetle is a natural though destructive means for liquidating overmature forests and making way for the new Furniss and Carolin, Western Forest Insects Howell 2014

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39 Bark Beetles and Fire Snow Mountain Ranch, 2007

40 (Theoretical not based on fuel hazard research studies) Fuel Profile Hazard Associated with MPB Mortality Greatest Tree Crown in Red and Dead Stage Surface Fuel Loadings Increase with Tree Fall Hazard Needle Fall Leading to Snag Condition Lowest Snag Stage Years Since Beetle Attack (Approximate)

41 Fuel Profile Hazard Red and Dead Stage Bark beetle epidemics impact landscapes over 6 15 year time interval leading to mixed snag ages within impacted stands.

42 Fuel Profile Hazard Snag Stage At the snag stage, impacted forests are thought to be of reduced fire hazard due to the limited amount of fine fuels and decreased fuel continuity in the canopy. This may be less true in the spruce beetle killed forests, which are denser and hold more small twigs after needle drop.

43 Fuel Profile Hazard Surface Fuel Loading Stage Photo: Ashley National Forest MPB epidemic 1970 s early 1980 s As beetle-killed trees fall to the ground, fuels accumulate in jackstraw heaps, making fire fighting problematic and fire impacts on soils more significant. Photo: Utah State University

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45 High Park Fire Mountain pine beetles and fire overlapped

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48 West Fork Fire Rio Grande and San Juan National Forests

49 Fire Injury and Implications for Bark Beetles Douglas-fir beetle, spruce beetle, and pine engraver beetle populations may build up in fireinjured trees following fire. Mountain pine beetle outbreaks do not appear to be associated with fire-injured lodgepole pine. In general, trees severely burned and killed by wildfire do not provide suitable habitat for bark beetles. 29 September 2015 Photo: Dwight Scarbrough

50 Fires can affect bark beetles as some species are attracted to scorched trees and cause additional tree losses in fire damaged areas or grow into epidemics. Mountain pine beetle Spruce Beetle NO probably? Douglas-fir beetle Yes! Can lead to epidemics Ips spp Yes MCH

51 Fire injured trees can lead to Douglas-fir beetle outbreaks. Shoshone National Forest, Park County, WY 29 September 2015

52 MCH (methylcyclohexenone), an anti-aggregation pheromone used on blowdown and standing Douglas-fir trees.

53 Illustration of the tree mortality as a result of Douglas-fir beetle within the 0.25 mile buffer around Eagle Creek Campground and the MCH treated area within the campground as of 2004, Shoshone NF.

54 Illustration of the tree mortality as a result of Douglas-fir beetle within the 0.25 mile buffer around Newton Creek Campground and the MCH treated area within the campground as of 2004, Shoshone NF.

55 Falling Tree Hazards Lodgepole pines killed by MPB begin to fall within 3 years after death in thinned stands, 5 years after death in unthinned stands. Thinned stands: 50% of trees fell within 8 years, 90% of trees fell within 12 years. Unthinned stands: 50% of trees fell within 9 years, 90% of trees fell within 14 years. (Mitchell and Preisler 1998)

56 Falling Tree Hazards On the Front Range, Colorado, ponderosa pines killed by MPB begin to fall within 3 years. On the Front Range, trees fall at the rate of 3-5% per year for 3-4 years after death. After that, the rate of tree fall increased substantially, such that most trees fell within 7-10 years of death. Trees broke off at ground level or within two feet of the ground. On the Black Hills, most beetle-killed trees broke off above ground but mostly below 25 feet, with most breaking off within 0-2 feet of the ground. (Schmid and others 1985 and 2009)

57 Falling-Tree Hazards and Public Safety Homes Roads Powerlines Campgrounds Trailheads

58 Falling-Tree Hazards in Bark Beetle-killed trees can: (1) fall at any time; (2) fall in any direction; and (3) fall without warning. Beetle Damaged Forests

59 411 developed administrative/ rec sites were treated on the three forests through Others remained closed until treated

60 Hazardous Trees Trails

61 . 442 miles of trails have been treated in the three Mountain pine beetle infested forests. 148 miles in Wilderness where hand crews are used. Another 1,435 miles still need work.

62 Forest roads through hazardous dead standing trees are a priority for treatment

63 Removal of hazardous trees along roadsides creates safer driving conditions. Bark beetle-killed trees along roadsides make driving conditions inherently hazardous falling trees may strike a vehicle, an individual, or block an exit.

64 Over 600 miles of roads were treated up to 2011 on the three MPB forests in Co and southern WY

65 Sanitation and salvage harvest of beetle infested and killed timber is being done on suitable sites

66 Timber sale conducted on Rio Grande NF before the spruce beetles. The area has established regeneration that survived the beetle epidemic

67 Where possible areas burned or salvaged can be replanted. Many areas will have natural regeneration that will include true firs and aspen.

68 Ips spp, Engraver Beetles

69 White fir mortality Sandia Ranger District. Cibola Natioanal Forest, NM

70 Ponderosa pine needle cast, Lincoln NF 2015 Wet Spring

71 Aspen Health Update

72 Aspen health appears to be improving with better precipitation in the last few years. There are still stands are declining from the severe drought in the early 2000 s but overall the conditions have improved. There is localized damage from leaf feeding insects and foliar fungal disease that do not generally kill trees. Western tent caterpillar defoliation >

73 Douglas-fir Tussock Moth localized outbreaks along the Front Range

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76 Natural Enemies include egg, larval and pupal parasites and predators and NPV (Nuclear polyhedrosis virus)

77 Western Spruce Budworm

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82 Western spruce budworm feeding damage

83 Tree mortality caused by bark beetles following years of heavy western spruce budworm defoliation

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