1 Overview of UAA-ENRI’s Studies of the Spruce Bark Beetle Epidemic, Kenai Peninsula, Alaska by Vernon J. LaBau, Univ. of AK., ENRI

2 Forest Inventory and Assessment University of Alaska, 1997 & 1998 Two concurrent studies by UAA, ENRI oriented to determine: Two concurrent studies by UAA, ENRI oriented to determine:  Magnitude of spruce bark beetle kill  Phytomass present by vegetation class  Natural regeneration situation  Health of residual trees-post beetle attack  Mortality sampling plot efficacy  Criteria for modeling forest fires  Result- Six papers, summarized herein

3 Background --A major Outbreak During the mid to late 1990s, one of the largest forest bark beetle outbreaks ever experienced anywhere in the world occurred in Alaska. During the mid to late 1990s, one of the largest forest bark beetle outbreaks ever experienced anywhere in the world occurred in Alaska. More than 1 million acres were attacked in 1996 alone, primarily on the Kenai Peninsula south of Anchorage. More than 1 million acres were attacked in 1996 alone, primarily on the Kenai Peninsula south of Anchorage.

4

5 Cumulative Beetle Impact to 1998

6 Background-- Species Involved Attacker-- Attacker--spruce bark beetle (Dendroctonus rufipennis (Kirby)) Affected tree species white spruce ((Picea glauca (Moench) Voss) and Lutz spruce (Picea Xlutzii Little)

7 Background --Funding Source Funding came from: Funding came from:   The UAA Natural Resources Fund   $27,000 for the 1997 Study   $25,000 for the 1998 Study

8 Background Objectives   Determine the area of High, Moderate and Low intensity bark beetle impact strata.   Determine the extent the bark beetle has impacted growing stock, especially for white and Lutz spruce. What size trees were being attacked? What percent of the trees were being impacted?   Determine the level of regeneration in the above impact areas, especially for white and Lutz spruce. Is there any indication that grass is inhibiting regeneration of spruce where the spruce over-story has been killed by beetle attack.

9 Background Objectives   Expand on the 1997 study, primarily to collect data to develop a forest fire fuels model, as well as collect additional data on mortality, total vegetation phytomass and down wood biomass.   Expand the study sample size and ground plot configuration to evaluated the efficacy of sampling plot designs in capturing mortality information.

10 Methodology--The Study Design Two-Phase, Double Sampling Two-Phase, Double Sampling  Phase 1, Photo Stratification (2600 Points)  Forest type  Beetle attack intensity (from S&PF/ADNR Aerial Survey maps) (from S&PF/ADNR Aerial Survey maps)  Ownership

11 Methodology-- Study Design Establishing Study Impact Intensity Strata Establishing Study Impact Intensity Strata   High Impact: Photo point falling inside a Survey mapped insect attack polygon.   Moderate Impact: Photo point falling within one mile of a Survey map attack polygon.   Low Impact: Photo point beyond one mile of a polygon, but within one mile of a “dot” on the Aerial Survey maps, indicating an area of isolated attacks.   No Impact: Photo point beyond one mile of a polygon or “dot” from Aerial Survey maps.

12 Methodology-- Study Design  Phase 2 Data Collection (40 Ground Plots)  Standard Forest Inventory Data Species, diameter, height, crown dataSpecies, diameter, height, crown data  Specialized Mortality Tally (.6 hectare)  Forest Health Damage Assessment  Horizontal-Vertical Profile of Vegetation  Regeneration Assessment  Downed Wood Assessment  Fuels Assessment (laddering, etc.)

Million Acres in the Study Area

14 One Hectare Ground Plots

15 Establishing Tree Health Criteria

16 Taking the Ground Plots

17 Photos of Beetle Kill Near Homer

18 Results: Magnitude of spruce bark beetle kill By 1998, 58% of forests were under high or moderate impact and 78% of all forest land (conifer, mixed, and hardwood) was impacted by the bark beetle. By 1998, 58% of forests were under high or moderate impact and 78% of all forest land (conifer, mixed, and hardwood) was impacted by the bark beetle. The stratification system used in this study worked well, yielding a sampling error of only 5.3% for the 1.2 million acres of Kenai area forest under study. The stratification system used in this study worked well, yielding a sampling error of only 5.3% for the 1.2 million acres of Kenai area forest under study. 41% of all spruce alive in 1992 were dead in % of all spruce alive in 1992 were dead in On some plots, virtually 100% of all spruce killed. On some plots, virtually 100% of all spruce killed.

19 Chart of Beetle Impacts

20 Results: Health of residual spruce trees  Only 4.9% of the residual spruce were judged to have health at risk. 56% were in good health.  About 25% of the residual spruce were under attack by bark beetles in 1998.

21 Results: Health of residual birch trees Almost 75% of the residual birch exhibited risky or moderately risky tree health. Almost 75% of the residual birch exhibited risky or moderately risky tree health. The paper birch was found to have almost four times as much basal area in the “at risk” tree health class as the spruce. The paper birch was found to have almost four times as much basal area in the “at risk” tree health class as the spruce. The primary vectors of “Risk” for the paper birch were conks on the roots or lower boles and crown dieback exceeding 33% of the crown. The primary vectors of “Risk” for the paper birch were conks on the roots or lower boles and crown dieback exceeding 33% of the crown. About 2/3rds of the birch regeneration exhibited heavy moose browsing in About 2/3rds of the birch regeneration exhibited heavy moose browsing in 1998.

22 Result: Natural regeneration findings: Regeneration of the spruce was marginal, from 130 to 400 trees per acre, but nearly absent in some areas due to grass invasion and competition. Regeneration of the spruce was marginal, from 130 to 400 trees per acre, but nearly absent in some areas due to grass invasion and competition. Regeneration of birch was quite good, in many places over 1000 trees per acre. However, as noted before, 67% of the birch seedlings had been heavily browsed by moose. Regeneration of birch was quite good, in many places over 1000 trees per acre. However, as noted before, 67% of the birch seedlings had been heavily browsed by moose. Grass phytomass in High and Moderate “Impact” strata was up to four times greater than in the Low and No “Impact” strata, supporting the theory that grass invades as overstory is killed.

23 Example of Grass Invasion after Tree Kill

24 Chart of Phytomass Distribution

25 Result: Other interesting findings: Understory phytomass was only about 2% of that found in the overstory. Almost half of the understory phytomass occurred in shrub vegetation. There was evidence of a decrease in moss phytomass as the crown cover disappeared due to the bark beetles killing the spruce overstory. I.e. Less moss in the “High” impact stands, and more moss in the “Low” and “No” Impact stands, the latter having more closed canopy.

26 Chart of Under-story Phytomass

27 Result: Down Wood findings: The bark beetle killed trees were just beginning to fall down in Fall-down was more in evidence in the High “Impact” strata. The down wood component should see significant increase in phytomass in the near future as more beetle killed spruce fall.

28 A Textbook Condition for Ecological Studies The bark beetle epidemic in south-central Alaska during the 1990s provided plethora of unique ecological information on forest dynamics and vegetative succession, some of which we were fortunate to capture in these studies. The bark beetle epidemic in south-central Alaska during the 1990s provided plethora of unique ecological information on forest dynamics and vegetative succession, some of which we were fortunate to capture in these studies. There is certainly even more information to be mined from this event in various other disciplines of nature and sociology. There is certainly even more information to be mined from this event in various other disciplines of nature and sociology.

29 A Closing Thought to Remember Crunch, crunch, crunch, listen to 'em munch, it's always time for lunch, in the deep, dark, forest. Courtesy of Al Harris