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Forest Recovery following Mountain Pine Beetle in Colorado

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Forest Recovery following Mountain Pine Beetle in Colorado

  1. 1. Initial and Future Stand Development following Mountain Pine Beetle in Harvested and Uncut Lodgepole Pine Stands<br />Byron Collins<br />Colorado State University<br />Forest, Rangeland & Watershed Stewardship<br />
  2. 2. Mountain Pine Beetle Outbreak<br />
  3. 3. Mountain Pine Beetle in North America<br />~450,000 Hectares in Colorado<br />~12 million ha in British Columbia<br /><ul><li>British Columbia: Sparse regeneration in uncut stands</li></ul>Raffa,K.F., Aukema, B.H., Bentz, B.J., Carroll, A.L., Hicke, J.A., Turner, M.G. and Romme, W.H. 2008. Cross-scale drivers of natural disturbances prone to anthropogenic amplification: the dynamics of bark beetle eruptions. BioScience 58:501-517. doi:10.1641/B580607.<br />
  4. 4. Management Response<br />Sulphur Ranger District – Arapaho-Roosevelt NF<br />• 3,700 ha since 2000<br />• 2.5x increase over ’90 -’99<br />• 40% potentially treatable (slope, access)<br />
  5. 5. Objectives<br />Characterize cut & uncut stands<br /> - quantify advance regeneration and recruitment<br />Pre-outbreak vs. outbreak<br /> - green vs. red<br />Growth<br />- advance regeneration and recruitment<br />• Future forests<br />- project stand growth, species composition<br />
  6. 6. Research Approach<br />Historic Data – Green vs. Red<br />- Seedling and stand survey data, Sulphur RD- <br /> Arapaho-Roosevelt NF <br />Current<br />- Operational scale study of management vs. no-<br /> action<br />
  7. 7. Management Research Areas<br />North Platte Basin<br /> - Colorado State Forest- Routt National Forest – Parks RD<br />Upper Colorado Basin<br /> - Arapaho-Roosevelt NF -Sulphur <br /> RD/ Fraser Experimental Forest<br /> - Routt NF – Yampa RD<br />
  8. 8. Fraser Experimental Forest<br />• 10 harvest units paired with <br /> 10 adjacent uncut stands<br />• Range of overstory removal <br /> (partial cut, clear cut)<br />• Range of slash management <br /> (lop and scatter, whole tree <br /> harvest)<br />
  9. 9. Harvest: Fall & Winter 2007-2008<br />
  10. 10. Methods<br />Seedling plots (1/100 acre, 114 plots)<br />Overstory transects (5 x 150 m, 69 transects)<br />Growth measurements (250 trees)<br />
  11. 11. Harvest 2007 - 2008<br />• 39% - 86% basal area removed<br />
  12. 12. Forest Composition – Uncut Stands<br />• Lodgepole makes up<br /> majority of basal area<br /> - 45% - 100% of total BA<br /> - 74% mortality (60% - 93%)<br />
  13. 13. Recruitment<br />• 3x more recruitment in harvested stands (aspen and lodgepole)<br />• Continued fir and pine recruitment in uncut stands beneath<br /> deteriorating canopy<br />
  14. 14. Effects of Canopy Condition at HarvestGreen vs. Red<br />Post-harvest seedling recruitment is similar during outbreak as prior to outbreak<br />
  15. 15. Frequency of Density:<br />Seedling Recruitment<br />Among all species:<br />• In uncut stands seedlings were found in 90% of plots (18% > 3000 trees ha-1)<br />• In harvested stands seedlings were found in 80% of plots (56% > 3000 trees ha-1)<br />
  16. 16. Advance Regeneration<br />• Density did not differ between harvested and uncut areas<br />• ~4000 stems/ha-1<br />all species in cut and uncut stands<br />•Subalpine fir half of all advance regeneration<br />• Species composition differs from overstory<br />
  17. 17. Frequency of Density:Advance Regeneration<br />Among all species:<br />• In uncut stands adv. regeneration was found in 97% of plots (49% > 3000 trees ha-1)<br />• In harvested stands adv. regeneration was found in 92% of plots (39% > 3000 trees ha-1)<br />
  18. 18. Growth Response to HarvestRecruitment<br />Lodgepole grew 30% more in cut stands compared to uncut<br />
  19. 19. Growth Response to Reduced CanopyAdvance Regeneration<br />Lodgepole Pine:<br /><ul><li> Responding to reduced canopy cover
  20. 20. Increased leader growth in 2009 in untreated and harvested stands (23%)</li></ul>Subalpine Fir:<br /><ul><li>Less leader growth in harvested stands
  21. 21. 2x more leader growth (2008 and 2009) in untreated stands
  22. 22. 23% of trees in harvested stands had no new leader growth in 2009</li></li></ul><li>Stand Growth Projections<br />Used initial findings and FIA data to predict changes in basal area and species composition over time<br />• Uncut Stands: Subalpine fir, lodgepole pine evenly mixed (50 to 100 yrs)<br />• Partial Cut: Aspen and subalpine fir dominant for 50 years then aspen becomes less important<br />• Clear cut: lodgepole pine is dominant<br />* Forest Vegetation Simulator, Forest Inventory and Analysis Data<br />
  23. 23. Summary of Results<br /> Seedling recruitment occurred in 90% of uncut and 80% of harvested stands<br /> Advance regeneration was found in > 90% of uncut and harvested stands<br /> Species composition of seedling recruitment and advance regeneration differed between cut and uncut stands <br /> Lodgepole increased height growth in cut and uncut stands<br /> Subalpine fir grew poorly in cut stands <br />
  24. 24. Summary of Results (cont.)<br />Cut and uncut stands will recover pre-outbreak basal area in 80 – 100 years<br /> Future species composition dependent on treatment<br />
  25. 25. Special Thanks<br />Graduate Committee<br /><ul><li>Chuck Rhoades - Rocky Mountain Research Station
  26. 26. Bill Romme - Forest Range & Watershed Stewardship
  27. 27. Rob Hubbard - Rocky Mountain Research Station
  28. 28. Patrick Martin - Horticulture & Landscape Architecture </li></ul>Funding Support<br /> • Tony Cheng - Colorado Forest Restoration Institute<br /> • Clint Kyhl- USFS Region 2, Bark Beetle Initiative<br />Technical Assistance<br />Mike Battaglia, Lance Asherin, Laurie Porth, David Turner<br />Field Assistance<br />Anna Johnson, Landon Gryzkowski, Tyson Wormus, Chad Kooistra, Jarrett Tishmack, Bryn Evans, Adam Heath, Brett Macalady, Amanda Morrison, Phil Bissell<br />
  29. 29. Questions?<br />

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