Carl N. Skinner Research Geographer USDA Forest Service Pacific Southwest Research Station Redding, CA

Transcription

1 Fire & Healthy Forests Carl N. Skinner Research Geographer USDA Forest Service Pacific Southwest Research Station Redding, CA

2 Our general view of forest fires. Fountain Fire ,000 acres 300 homes

3 Annual Area Burned Western States Calif. Alone Before 1900 Arno & Allison-Bunnell 2002 (1915 to 2000) & National Interagency Fire Center

4 The most potent factor in shaping the forest of the region has been, and still is, fire. The general character of the forest,... in fact almost every phase of its condition has been determined by... fire. J. B. Leiberg 1902 Forest conditions in the northern Sierra Nevada, California. Professional Paper 8, Series H, Forestry, 5. US Geological Survey, GPO, Washington, D.C.

5 Forest health? Concept is subjective and adaptive. Usually related to a condition of a forest based on ecological indicators and collective value judgments of stakeholders. From Online PowerPoint: Forest Health Definitions, Concept, Perceptions. R.W. Hofstetter, NAU.

6 Fire Climate - Precipitation Patterns YELLOWSTONE LAKE, WY REDDING, CA Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec NORTH PLATTE, NE FLAGSTAFF, AZ Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

7 Red dots = Lightning Caused Fires Blue dots = Human Caused Fires

8

9 June 2008 Lightning Fires Modis Image from NASA World Wind overlayed on Google Earth

10 33 Fire Scars

11 Blacks Mt. Experimental Forest

12 Historical, Frequent, Low-intensity fires Created forests of open structure with low fuels.

13 Stand Structure & Species Composition Changes over 20th Century Fire exclusion has helped lead to increasing stand density. Original Stand Structure

14 Fire Occurrence & Tree Establishment Blacks Mountain Experimental Forest Number of Trees Established Yellow Number of Sites w/scars Green Year

15 Resilience the capacity of a system to absorb disturbance while undergoing change so as to retain essentially the same function, structure, identity, and feedbacks Folke, C. and others Regime shifts, resilience, and biodiversity in ecosystem management. Annual Review of Ecology, Evolution, and Systematics 35:

16 Resilience Forested systems characterized by fire regimes of frequent, mostly lowmoderate intensity fires, dominated by large, long-lived trees, are considered resilient if the forested landscape exhibits a generally forested condition, including larger trees, shortly following a disturbing event such as fire.

17 Resilient? Fountain Fire 1992 Campbell Fire 1990 Barkley Fire 1994

18 The virgin forest is uneven-aged, or at best even-aged by small groups, and is patchy and broken; hence it is fairly immune from extensive devastating crown fires. fire creates a patchy scattered distribution of reproduction (Show and Kotok 1924) Stanislaus NF Knapp et al. 2013

19

20

21

22 Topography Fire Severity Patterns Greater % High Severity Mid Slope Intermediate Taylor & Skinner 1998 Greater % Low Severity

23 Topography & Fire Regimes Fires were limited by topographic features (ridgetops, streams, aspect changes, etc.) Taylor & Skinner 2003 Skinner, Taylor, Agee 2006

24 Much information about the effectiveness of fuel treatments is anecdotal. We are often unable to draw statistical inference from these case studies. However, the preponderance of the information supports effectiveness of managing fuels.

25 Wind Direction Origin No Burn Split Rx Burn Split Cone Fire September 2002 Blacks Mountain Experimental Forest

26 Unthinned Unit 46 LoD Thinned + Prescribe Burn Unthinned Cone Fire - Sept Blacks Mountain Experimental Forest Thinned Early 1980s

27 Thinned with no prescribed burn Unthinned No fuels treatment Back-to-back photos Across treatment boundary

28 Thinned & Prescribe Burned Unthinned No fuels treatment Back-to-back photos Across treatment boundary

29 Thinned & Prescribe Burned Unthinned No fuels treatment Back-to-back photos Across treatment boundary

30 Priorities for Fuels Assessments Stand Scale Surface Fuels Ladder Fuels Crown Fuels Maintain Large Fire Resistant Trees Agee & Skinner 2005 Basic principles of forest fuel reduction treatments. Forest Ecology & Management 211: 83-96

31 Cone Fire Effects A. No Treatment B. Thinned No RxBurn C. Thinned with RxBurn A. B. C. Ritchie et al. 2007

32 Climate Change Where are we headed? Fire season getting longer. Fuels keep growing. Greater probability of intense fires. Fire Triangle Fuel

33 Options?

34 Thank You!