Emerald Ash Borer: Background & Overview of the Green Menace NATHAN W. SIEGERT, PH.D. FOREST ENTOMOLOGIST

Transcription

1 Emerald Ash Borer: Background & Overview of the Green Menace NATHAN W. SIEGERT, PH.D. FOREST ENTOMOLOGIST US FOREST SERVICE NORTHEASTERN AREA STATE & PRIVATE FORESTRY FOREST HEALTH PROTECTION

2 Number of Non-Native Forest Pests History of industrialization Host tree diversity Forest fragmentation Promote pest arrival & establishment LIEBHOLD ET AL. (2013) A HIGHLY AGGREGATED GEOGRAPHICAL DISTRIBUTION OF FOREST PEST INVASIONS IN THE USA. DIVERSITY & DISTRIBUTIONS, 19:

3 Cumulative pest detections in US Non-Native Forest Insect Establishment 2.5 species per year All non-native forest insects 0.43 species per year Economically damaging forest pests Year AUKEMA ET AL. (2010) HISTORICAL ACCUMULATION OFNONINDIGENOUS FOREST PESTS IN THE CONTINENTAL UNITED STATES. BIOSCIENCE, 60:

4 Frequency of establishment Establishment of Phloem & Wood Borers Phloem and wood borers AUKEMA ET AL. (2010) HISTORICAL ACCUMULATION OFNONINDIGENOUS FOREST PESTS IN THE CONTINENTAL UNITED STATES. BIOSCIENCE, 60:

5 Agrilus planipennis Emerald Ash Borer

6 First Detected in Detroit EAB was first detected in the US in Detroit, MI in Many thousands of ash trees were already dying. The Port of Detroit receives significant international shipping.

7 EAB is the most destructive forest insect in North America EAB has killed millions of ash trees in North America. Transported to new areas in infested firewood, timber and nursery stock.

8 Native Range of EAB EAB is a destructive wood-boring beetle introduced from Asia. It is rare in its native range with little known about EAB globally at the time of its detection in the US.

9 Host Susceptibility Average survivorship of EAB is greater on North American ash species (63.3 ± 7.2%) compared to ash species with European (51.4 ± 17.0%) or Asian (26.6 ± 10.5%) origins. SIEGERT ET AL. (2014) SUSCEPTIBILITY OFSELECTED ASIAN, EUROPEAN, & NORTH AMERICAN ASH SPECIES TO EMERALD ASH BORER: PRELIMINARY RESULTS OF NO-CHOICE BIOASSAYS. NATIONAL EAB RESEARCH & TECHNOLOGY DEVELOPMENT MEETING.

10 EAB Biology & Life Cycle Adults are roughly a half inch long and dark metallic green. Life cycle generally takes one year to complete. 2-yr development typical at newly established sites. More rapid development at high EAB densities and/or in stressed trees.

11 EAB Biology & Life Cycle Larvae begin feeding in July and most finish by Oct-Nov.

12 EAB Biology & Life Cycle Extensive galleries under the bark disrupt translocation of water and nutrients in the tree.

13 Tree Decline & Mortality Foliage becomes thin, ragged and yellow. Canopy dieback progresses through the summer. North American ash of all sizes typically die in 3-5 years.

14

15

16 Tools for Detection Employing multiple trapping options improves the intensity and distribution of monitoring resources Increases the likelihood of early detection of EAB infestations in new areas

17 Short- & Long-Distance Dispersal Satellite populations of EAB increase the rate of spread.

18 Short- & Long-Distance Dispersal Radial distance (km) <3.2 km (2 mi) per yr ~13 km (8 mi) per yr Year Natural spread via adult flight is <3.2 km (2 mi) per yr. Human-assisted spread results in disjunct satellite infestations. Quarantines, outreach, and BMPs all help to reduce the frequency of long-distance dispersal events. SIEGERT ET AL. (2014) DENDROCHRONOLOGICAL RECONSTRUCTION OF THE EPICENTRE & EARLY SPREAD OF EMERALD ASH BORER IN NORTH AMERICA. DIVERSITY & DISTRIBUTIONS, 20:

19 Integrating Tactics to Slow Ash Mortality Integrate available tools & strategies appropriate for specific sites Slow EAB population growth & spread Delay onset & advance of ash mortality

20 Targeted Ash Biological Girdled Ash Insecticide Removal Control Trees Treatment Oobius Tetrastichus Woodpeckers

21 Emphasis on the Urban Forest EAB management in rural forests & woodlands will remain an important interest in many areas, especially those with a significant ash component.

22

23 Emphasis on the Urban Forest EAB management in rural forests & woodlands will remain an important interest in many areas, especially those with a significant ash component. The national focus of EAB management, however, is rapidly shifting to the urban forests of our local municipalities & communities as the range of EAB expands to the southern & western states.

24 Urban Centers on a Forested Landscape Large forested areas tend to be in very close proximity to densely populated areas, popular event destinations, and centers of manufacturing, trade, and commerce.

25 Emphasis on the Urban Forest EAB management in rural forests & woodlands will remain an important interest in many areas, especially those with a significant ash component. The national focus of EAB management, however, is rapidly shifting to the urban forests of our local municipalities & communities as the range of EAB expands to the southern & western states. Aesthetics, hazards, costs of treatment or removal/replacement, impacts on property values, & home heating/cooling costs are the most profound & affect the most people in our developed communities.

26 Emerald Ash Borer: Invasion Wave & Ash Dynamics in Aftermath Forests NATHAN W. SIEGERT US FOREST SERVICE, NA S&PF, FOREST HEALTH PROTECTION

27 EAB Invasion Wave Cusp Crest Post Crest

28 Aftermath Forest Dynamics Changes in ash inventory Timing of ash mortality Frequency of stump sprouting Ash regeneration Cusp Crest Post Crest

29 36-ha site 18-ha floodplain EAB in 2004 Aftermath Forest Study Site

30 Densities of EAB were at or near infestation levels capable of killing trees, averaging 36.3 ± 9.8 larvae per m 2.

31 Aftermath Forest Study Site Live ash inventoried by diameter class in winter prior to EAB-induced ash mortality.

32 Aftermath Forest Study Site In summer 2016, live ash was re-inventoried by diameter class 10+ years after EAB invasion.

33 Changes in Ash Density

34 Changes in Ash Density >60 Diameter size class (cm) Pre-EAB Ash Inventory >60 Diameter size class (cm) Post-EAB Ash Inventory

35 Changes in Ash Density While the number of stems per plot was reduced by an average of 50.9%, the amount of ash phloem per plot was reduced by an average of 87.7% following EAB invasion.

36 Post-EAB Ash Species

37

38 Ash Chronology & Mortality Increment cores were collected from 3 trees per plot (n = 72 trees). 36 black ash, 33 green ash Crossdated to live ash chronology developed in 2008.

39 Ash Chronology & Mortality Series intercorrelation = Average mean sensitivity = >70% of chronology developed from 20+ trees

40 Ash Chronology & Mortality

41

42 Post-EAB Stump Sprouting Stump sprouting has been suggested as a means to regenerate ash after EAB invasion. Plots were crisscrossed and 10 dead ash trees were evaluated for surviving stump sprouts (n = 240 trees). Green ash and black ash were assessed.

43 No Surviving Black Ash Stump Sprouts

44 Surviving Green Ash Stump Sprouts

45 Surviving Green Ash Stump Sprouts

46 Post-EAB Ash Regeneration Ash regeneration quantified in 4 subplots in each of the 0.25 ha plots. Saplings: <2.5 cm dbh, greater than 1 m in height. Seedlings: less than 1 m in height. Non-ash species also quantified in subplots.

47 Post-EAB Ash Regeneration Saplings (>1 m) Seedlings (<1 m)

48

49

50 Post-EAB Ash Regeneration

51 Summary of EAB Impacts

52 Inventory: drastically reduced; smallest diameter class present but about half of pre-eab inventory Timing: ash mortality advanced rapidly; mortality >90% about 8-10 years after EAB invasion Stump sprouting: approximately 30% of EAB-killed green ash had live stump sprouts 10+ years after EAB invasion; sprouting not related to tree dbh; EAB-killed black ash did not have surviving stump sprouts Ash regeneration: green ash, black ash, and white ash among top 5 seedling and sapling species present

53 Current Pressure on Ash Dynamics EAB pressure over time and effect on ash dynamics.

54 EAB Invasion Wave Cusp Crest Post Crest

55

56 Current Pressure on Ash Dynamics EAB pressure over time and effect on ash dynamics. Deer browse heavily impacts growth of ash seedlings, saplings, and stump sprouts.

57

58 Current Pressure on Ash Dynamics EAB pressure over time and effect on ash dynamics. Deer browse heavily impacts growth of ash seedlings, saplings, and stump sprouts. Loss of overstory ash may affect water table and establishment of invasive plants, which in turn affects residual trees and stress/survival of regeneration.

59

60 Current Pressure on Ash Dynamics EAB pressure over time and effect on ash dynamics. Deer browse heavily impacts growth of ash seedlings, saplings, and stump sprouts. Loss of overstory ash may affect water table and establishment of invasive plants, which in turn affects residual trees and stress/survival of regeneration. Loss of ash seed source.

61

62 Current Pressure on Ash Dynamics EAB pressure over time and effect on ash dynamics. Deer browse heavily impacts growth of ash seedlings, saplings, and stump sprouts. Loss of overstory ash may affect water table and establishment of invasive plants, which in turn affects residual trees and stress/survival of regeneration. Loss of ash seed source. Strategies for ash management in post-crest forests will need to be developed and evaluated.

63