1. Fire History and Age Structure Analyses of Kipuka Forests in El Malpais National Monument, New Mexico D aniel B. Lewis Henri D. Grissino-Mayer Laboratory of Tree-Ring Science Department of Geography University of Tennessee Knoxville, Tennessee 37996

2. About El Malpais “el malpais” is Spanish for “badlands” or “bad country” Established December 31, 1987 to protect a unique lava flow environment Located in NW New Mexico A patchwork of lava flows ranging from ca. 110,000-ca. 3200yrs > 30 cinder cones found in and around the area

4. Research Questions How interrelated are the fire regimes of the kipukas and the Hoya Flow? Does the age structure of the kipukas indicate that forest composition has been altered due changes in their fire regimes? What can the agencies managing the monument do to preserve these relict areas and reduce the impacts of human disturbances?

7. Fire History Methods

8. Age Structure Methods

10. Fire History Results Fire frequency increased in the mid-late 1700s, followed by a long, fire-free interval from 1782- 1806. Most fire-free intervals were between 2-10yrs, and more widespread fire-free intervals were between 3-16yrs (all sites combined). Maximum hazard intervals were 20yrs (all scarred) and 93yrs (10% scarred) (all sites). The seasonality of fire events changed ca. 1800 from predominantly late season occurrences to predominantly early season occurrences.

12. Age Structure Results 64 trees were found on the lower slopes of Hidden Kipuka, 53 occurred as seedlings 180yrs old. Seedling density was higher on the western side of Hidden Kipuka due to the more dense ponderosa pine forests on the Hoya Flow. Lower slopes of Mesita Blanca dominated by trees <40yrs old. Majority of trees in excess of 100yrs were located on the upper slopes. Tree density on Mesita Blanca was not noticeably different from the eastern side to the western side.

14. Conclusions From 1600-1799, 31% of all fires recorded on the Hoya Flow were synchronous with the kipukas. From 1800-2000, 47% of all fires were synchronous. When analyzing widespread fire events (10% scarred), only 15% of the fires were synchronous from 1600-1799. From 1800- 2000, 61% of the fires in this class were synchronous. Fires became scarce on the Hoya Flow after 1933. Subsequently, fire frequency declined on the kipukas after 1933.

15. Conclusions Inordinate numbers of ponderosa pine seedlings were found on the lower slopes of Hidden Kipuka. Large numbers of trees <40yrs were found growing on the lower slopes of Mesita Blanca. The lack of mature ponderosa pines on these lower kipuka slopes indicates these areas were not formerly in the natural range of ponderosa pine in the malpais area.

16. Recommendations Allowing fires to burn as they once did prior to Euro-American settlement is problematic due to the proximity of human development. Before these can be implemented, many areas of the monument will have to be thinned. The trees growing on the lower slopes of the kipukas should be considered for removal (preferably by methods with low environmental impact).

17. Acknowledgements Joint Fire Science Program El Malpais National Monument Laboratory of Tree-Ring Science Committee members: Dr. Henri D. Grissino- Mayer, Dr. Sally P. Horn, Dr. Ken H. Orvis Department of Geography Beth Atchley, Michael Armbrister, David Mann, Jake Cseke, Kevin Anchukaitis, Damian Kolbay