Long-term monitoring of fire and other disturbance effects in chaparral forests

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
122	0630	1060	15%
122	0630	1070	15%
122	0630	2050	35%
122	0630	2061	35%

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: None reported by cooperators. PARTICIPANTS: George Vourlitis - California State University - San Marcos, Michael Caterino - Santa Barbara Museum of Natural History, California Polytechnic University-Pomona, Pomona College, and California State University-Long Beach, University of California - Riverside, Northern Arizona University, Forest Service - Rocky Mountain Research Station, Pennsylvania State University TARGET AUDIENCES: Scientists and land managers. PROJECT MODIFICATIONS: None to report.

Impacts
Work performed by cooperators at SDEF and on the AZ long-term prescribed fire study produced information about ecosystem responses in the chaparral and ponderosa pine ecosystems that would not have been studied by FS scientists. These studies, too numerous to describe here, provide a more holistic understanding of these ecosystems and how they respond to fire.

Publications

Pasquini, S.C.; Vourlitis, G.L. 2010. Post-fire primary production and plant community dynamics in chaparral stands exposed to varying levels of nitrogen deposition. J. of Arid Environments 74:310-314.
Short, A.E.Z.; Caterino, M.S. 2009. On the validity of habitat as a predictor of genetic structure in aquatic systems: a comparative study using California water beetles. Molecular Ecology 18, 403-414.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Haase completed annual data collection and prescribed fire treatment application on the Arizona long term prescribed fire study on Coconino National Forest. A thesis describing the effects of 30 years of rotational burning on the Coconino NF on understory species was completed. The Angeles National Forest removed the last cabins which were part of the recreational tract predating the establishment of the San Dimas Experimental Forest. Installation of several instruments at SDEF as part of the establishment of the EFR Network. Paper chart records were sent to the University of Georgia for conversion to digital data. Weekly samples for the NADP monitoring activiity were collected and sent.

Impacts
Work performed by cooperators at SDEF and on the AZ long-term prescribed fire study produced information about ecosystem responses in the chaparral and ponderosa pine ecosystems that would not have been studied by FS scientists. These studies, too numerous to describe here, provide a more holistic understanding of these ecosystems and how they respond to fire.

Publications

Johnson, S.L.; Adams, M.B.; Amatya, D.M.; Bailey, S.W.; Rhoades, C.C.; Jones, J.B.; Knoepp, J.D.; McCaughey, W; McDowell, W.H.; McGuire, K.J.; Sebestyen, S.D.; Wohlgemuth, P.M. 2009. Stream nutrient responses to forest harvest and disturbance: lessons from long-term research at USFS Experimental Forests. [Abstract] In: Seventh North American Forest Ecology Workshop. [Logan, Utah]: Utah State University:
Scudieri, C. A. 2009. Understory Vegetation Response to 30 Years of Interval Prescribed Burning in Two Ponderosa Pine Sites. Flagstaff, AZ: Northern Arizona University. 115 p. Thesis.
Wohlgemuth, P. M. 2009. San Dimas Experimental Forest, California⿿a giant outdoor hydrologic lab. In: Wells, G. Experimental Forests and Ranges--100 Years of Research Success Stories. Gen. Tech. Rep. FPL-GTR-182, Madison, WI: Forest Products Laboratory, Forest Service, U.S. Department of Agriculture; 20-21.

Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Haase completed annual data collection and prescribed fire treatment application on the Arizona long term prescribed fire study on Coconino National Forest. Haase and Sackett prepared a manuscript about fire and fuels research as part of the centennial celebration of Ft. Valley Experimental Forest. Sackett and Haase conducted 2 tours of the long-term burning site on the Ft. Valley EF as part of the centennial symposium. The manuscript included a listing of theses and dissertations that have been completed using various data collected from the long term sites. The Angeles National Forest removed the last cabins which were part of the recreational tract predating the establishment of the San Dimas Experimental Forest. Oxford and Wohlgemuth installed several instruments at SDEF as part of the establishment of the EFR Network. Paper chart records were sent to the University of Georgia for conversion to digital data. Discussions to transfer complete control of SDEF to the PSW Director with the removal of the cabins occurred. Bridge construction and road repair occurred at SDEF. Weekly samples for the NADP monitoring activity were collected and sent. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Work performed by cooperators at SDEF and on the AZ long-term prescribed fire study produced information about ecosystem responses in the chaparral and ponderosa pine ecosystems that would not have been studied by FS scientists. These studies, too numerous to describe here, provide a more holistic understanding of these ecosystems and how they respond to fire.

Publications

Hamilton, C. E.; Faeth, S. H. 2007. Neotyphodium infection and hybridization as a function of environmental variation. In: Popay, A.; Thom, E. R., eds. Proceedings of the 6th International Symposium on Fungal Endophytes of Grasses. New Zealand Grassland Association, Dunedin, New Zealand: 215-217.
Jani, A. 2005. Association of Neotyphodium endophytes and alkaloids with community structure in native grass systems. M.S. thesis, Arizona State University, Tempe, AZ, 35 p.
Meyer, C. L.; Sisk, T. D. 2001. Butterfly response to microclimatic changes following ponderosa pine restoration. Restoration Ecology 9: 453-461.
Meyer, C. L.; Sisk. T. D.; Covington, W. W. 2001. Microclimatic changes induced by ecological restoration of ponderosa pine forest in northern Arizona. Restoration Ecology 9: 443-452.
Meyer, C. L. 2000. Microclimatic changes and biotic effects across forest structural gradients associated with ponderosa pine restoration. M.S. thesis, Northern Arizona University, Flagstaff, AZ, 74 p.
Rambo, J. 2006. The response of under story vegetation to prescribed fire in Northern Arizona Ponderosa pine forest. M.S. thesis, Arizona State University, Tempe, AZ, 26 p.
Sackett, S. S.; Haase, S. M. 2008. Fire and fuels research at Fort Valley and Long Valley Experimental Forests. In: Olberding, S. D.; Moore, M. M., tech coords. Fort Valley Experimental Forest-A Century of Research 1908-2008. August 7-9, 2008; Flagstaff, AZ. US Department of Agriculture, Forest Service, Rocky Mountain Research Station Proceedings RMRS-P-53CD. Fort Collins, CO: p. 54-67.
Sayeeduzzaman, M. 2004. Development of a java-based distributed-parameter hydrological model for modeling runoff in fire-impacted mountain watersheds. Ph. D. dissertation, University of Iowa, Iowa City, IA. 185 p.
Sayeeduzzaman, M. 1995. The application of answers for modeling runoff and sediment yield in a high-energy mountain watershed. M.A. thesis, University of Iowa, Iowa City, IA, 147 p.
Trumbore, S. E. 1989. Carbon cycling and gas exchange in soils. Ph. D. dissertation, Columbia University, New York, NY. 194 p.
Trumbore, S. E.; Vogel, J.S.; Southon, J.R. 1989. AMS 14C measurements of fractionated soil organic matter: an approach to deciphering the soil carbon cycle. Radiocarbon 31: 644-654
Hamilton, C. E.; Faeth, S. H. 2005. Asexual, systemic endophytes in grasses: a test of the seed germination and pathogen resistance hypothesis. Symbiosis. 38: 69-86.
Vourlitis, G. L.; Pasquini, S. C. 2008. Carbon and nitrogen dynamics of pre- and post-fire chaparral exposed to varying atmospheric N deposition. Journal of Arid Environments 72: 1448-1463.
Schulthess, F. 1997. Endophytes of Festuca arizonica: Distribution and effects of the host. M.S. thesis, Arizona State University, Tempe, AZ, 33 p.
Schulthess, F. M.; Faeth, S. H. 1998. Distribution, abundances, and associations of the endophytic fungal community of Arizona fescue (Festuca arizonica). Mycologia 90(4): 569-578.
Sullivan, T. J. 2003. Geographic and genetic variation in the Neotyphodium/Festuca arizonica interaction. Ph.D. dissertation, Arizona State University, Tempe, AZ, 140 p.
Sullivan, T. J.; Faeth, S. H. 2004. Gene flow in the endophyte Neotyphodium and implications for coevolution with Festuca arizonica. Molecular Ecology. 13: 649-656.
Sullivan, T. J.; Faeth, S. H. 2008. Local adaptation in Festuca arizonica infected by hybrid and non-hybrid Neotyphodium endophytes. Microbial Ecology 55: 697-704.
Caterino, M. S.; Chatzimanolis, S. 2008. Conservation genetics of three flightless beetle species in southern California. Conservation Genetics DOI 10.1007/s10592-008-9548-7. 14 p.
Faeth S. H.; Saikkonen, K. 2007. Variability is the nature of the endophyte-grass interaction. In: Popay, A.; Thom, E. R., eds. Proceedings of the 6th International Symposium on Fungal Endophytes of Grasses. New Zealand Grassland Association, Dunedin, New Zealand: 37-48.
Graham, R. C.; Akers, S. C.; Meixner, T.; Wechsler, S. P. 2004. Fire and terrain controls on soil carbon in chaparral watersheds. Kearney Foundation of Soil Science: Soil Carbon and California's Terrestrial Ecosystems, Final Report: 2002019. 18 p. http://kearney.ucdavis.edu/OLD%20MISSION/2002%20Final%20Reports/20020 19Graham_FINALkms.pdf
Graham, R. C.; Egerton-Warburton, L. M.; Hendrix, P. F.; Shouse, P. J.; Johnson-Maynard, J. L.; Quideau, S. A.; Sternberg, P. D.; Jobes, J. A.; Breiner, J. M. 2006. Post-fire pedogenic response: wildfire effects on the soil environment in a 60-Year-old biosequence. Abstract P17368. The 18th World Congress of Soil Science (July 9-15, 2006). http://a-c-s.confex.com/crops/wc2006/techprogram/P17368.HTM

Progress 10/01/06 to 09/30/07

Outputs
San Dimas Experimental Forest (SDEF) continues to provide an environment where university scientists can conduct research of various types. SDEF was selected to be one of eleven experimental forests and ranges to become part of continental-scale observing network. As a result, $96,000 in funding to add high-speed communications capability, convert paper records to digital form, and add significant instrumentation to monitor water and air quality was received. A portion of the instrumentation is necessary in order for the U.S. to establish sites to participate in the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests operates under the UNECE Convention on Long-range Transboundary Air Pollution. Several publications and presentations relative to nitrogen pollution effects on carbon and nitrogen cycling in chaparral were produced by cooperators. Additional work on soil development in the type-converted watersheds also occurred and was reported by university cooperators. SDEF served as one of several sites used in the Cal State Long Beach Geosciences Diversity Enhancement Program to introduce high school and community college minority students to the geosciences. SDEF is the only experimental forest located adjacent to a large, diverse urban populace.

Impacts
These long-term research sites provide locations where the long-term ecosystem responses to both human and natural activities can be studied by several generations of scientists. This long-term view can then be incorporated into management plans for similar public lands that take into account ecosystem resiliency or sensitivity.

Publications

Ambos, E. L.; Behl, R.; Francis, R. D.; Larson, D. O.; Ramirez, M.; Rodrigue, C.; Sample, J.; Wechsler, S.; Whitney, D.; Hazen, C. 2002. The Geoscience Diversity Enhancement Program (GDEP): building an earth system science centered research, education, and outreach effort in urban Long Beach, California. Eos, Transactions, American Geophysical Union, 83(47) Supplement: F339.
Ambos, E. L; Sample, J. C; Behl, R.; Francis, R. D.; Larson, D. O; Ramirez, M.-T.; Rodrigue, C.; Wechsler, S.; Whitney, D.; Hazen, C. 2002. GDEP (Geoscience Diversity Enhancement Program): creating a community-based summer geoscience research program. Abstracts with Programs - Geological Society of America 34(6): 524.
Ambos, E.; Rodrigue, C.; Behl, R.; Lee, C.; Wechsler, S.; Holk, G.; Larson, D.; Francis, R.; Whitney, D. 2005. Geoscience field studies at California State University Long Beach: urban applied research with a community focus. CUR Quarterly 26(2): 56-61.
Behl, R. J; Ambos, E. L.; Francis, R. D.; Holk, G. J.; Larson, D. O.; Lee, C. T.; Rodrigue, C. M.; Wechsler, S. P.; Whitney, D. J. 2004. Hunting for students; outreach and retention strategies in a competitive urban market. Abstracts with Programs - Geological Society of America 36(5): 353.
Davis, K.; Vourlitis, G. 2005. The effects of anthropogenic nitrogen deposition on the gas exchange of native southern California chaparral and coastal sage scrub species. Ecological Society of America, August 7-12, 2005, Montreal, Quebec, Canada.
Pasquini, S. C.; Vourlitis, G. 2005. Effects of nitrogen deposition on coastal sage scrub and chaparral growth responses in southern California. Ecological Society of America, August 7-12, 2005, Montreal, Quebec, Canada.
Pasquini, S. C.; Vourlitis, G. L. 2007. Nitrogen deposition alters ecosystem fire recovery in semi-arid chaparral ecosystems of southern California. Abstract COS 86-2. Ecological Society of America, 5-10 August 2007, San Jose, CA.
Strand, J. 2006. Impact of wildfires on historical and modern analysis of baseflow recession in the San Dimas watershed. Pomona: Geological Sciences Department, Cal Poly Pomona; CA; 28 p. Senior thesis.
Vourlitis, G. L.; Zorba, G. 2005. Soil N and P storage and cycling in semi-arid shrublands exposed to high atmospheric N deposition. Ecological Society of America, 7-12 August 2005, Montreal, Quebec, Canada. Page numbers unknown.
Vourlitis, G. L.; Zorba, G. 2007. Nitrogen and carbon mineralization of semi-arid shrubland soil exposed to long-term atmospheric nitrogen deposition. Biology and Fertility of Soils 43: 611-615.
Vourlitis, G. L.; Zorba, G.; Pasquini, S. C.; Mustard, R. 2007. Carbon and nitrogen storage in soil and litter of southern Californian semi-arid shrublands. Journal of Arid Environments 70: 164-173.
Vourlitis, G. L.; Zorba, G.; Pasquini, S. C.; Mustard, R. 2007. Chronic nitrogen deposition enhances nitrogen mineralization potential of semiarid shrubland soils. Soil Science Society of America Journal 71: 836-842.
Vourlitis, G.; Zorba, G. 2006. Nitrogen and carbon mineralization of semi-arid shrubland soil exposed to long-term atmospheric nitrogen deposition. Ecological Society of America, 6-11 August 2006, Memphis, TN. Page numbers unknown.
Wechsler, S. 2004. Assessment of interpolated elevation accuracy in steep terrain of the San Dimas Experimental Forest (SDEF). SCAC report of work accomplished; Long Beach: California State University; 5 p. http://www.csulb.edu/divisions/aa/research/our/internal_funding/intaw ard/documents/WechslerSCAC03_ReportofWorkAccomplished.doc
Wechsler, S.; Whitney, D.; Ambos, E.; Rodrigue, C.; Lee, C.; Behl, R.; Larson, D.; Francis, D.; Holk, G. 2005. Enhancing diversity in the geosciences. Journal of Geography 104(4):141-149.
Whitney, D.; Behl, R.; Ambos, E.; Francis, D.; Holk, G.; Larson, D.; Lee,C.; Rodrigue, C.; Wechsler, S. 2005. Ethnic differences in geoscience attitudes of college students. Eos, Transactions, American Geophysical Union 86(30): 277-279.
Williamson, T. N.; Gessler, P. E.; Shouse, P. J.; Graham, R. C. 2006. Pedogenesis-terrain links in zero-order watersheds after chaparral to grass vegetation conversion. Soil Science Society of America Journal. 70: 2065-2074.
Zorba-Denison, G. 2006. Soil nutrient cycling and storage in semi-arid shrubland ecosystems exposed to high N deposition in Southern California. San Marcos: Department of Biological Sciences, California State University, San Marcos; 45 p. M.S. thesis.

Progress 10/01/05 to 09/30/06

Outputs
Measurement of sediment and vegetation recovery in several small watersheds following a prescribed burn at San Dimas Experimental Forest continued. Data previously collected by cooperators in the lysimeters prior to the 2003 Williams Fire continue to provide new information about soil processes in chaparral systems. A limited number of archival soil samples from the lysimeters have been found at U.C. Berkeley. These samples will supplement the few remaining samples following the destruction of the soil samples in the Williams Fire. An annual survey of migratory birds was conducted in the spring and information on threatened, endangered, and sensitive birds sited on the experimental forest was shared with the Angeles National Forest. Weather data collected at SDEF were used by electrical engineers in the development of a photovoltaic system. The Joint Fire Science program provided funding for the 30th anniversary sampling of the two long term burn rotation study sites located in Arizona on the Coconino National Forest. Fuel loading, understory composition, overstory stand characteristics, and soil nutrient levels are components of the long-term study that will be measured with this funding in 2007 and 2008. Work was initiated on the USDA NRI study with Penn State University to study carbon storage resulting from various forest management activities. Activities included the relocation of the growth release sample trees previously utilized by Petersen and others for sampling and the collection of forest floor material on the 6-year and control plots.

Impacts
These 2 long-term study sites provide a unique opportunity to study ecosystem dynamics over a long period of time. The San Dimas Experimental Forest is uniquely situated adjacent to the second largest metropolitan area in the United States. The pressures placed on the chaparral ecosystem by an urban populace can be measured here and used to manage chaparral elsewhere in California. Significant long-term effects of prescribed fire reintroduction into ponderosa pine forests in the southwestern United States have influenced local management practices.

Publications

Podolsky, R.H. 2001. Genetic variation for morphological and allozyme variation in relation to population size in Clarkia dudleyana, an endemic annual. Conservation Biology 15(2): 412-423.
Podolsky, R.H.; Shaw, R.G.; Shaw, R.H. 1997. Population structure of morphological traits in Clarkia dudleyana. II. Constancy of within-population genetic variance. Evolution 51(6):1785-1796.
Quideau, S.A.; Graham, R.C.; Oh, S-W.; Hendrix, P.F.; Wasylishen,R.E. 2005. Leaf litter decomposition in a chaparral ecosystem, southern California. Soil Biology and Biochemistry 37(11): 1988-1998.
Allen, M.F.; Swenson, W.; Querejeta, J.I.; Egerton-Warburton, L.M.; Treseder, K.K. 2003. Ecology of mycorrhizae: a conceptual framework for complex interactions among plants and fungi. Annual Review of Phytopathology 41:271-303. doi: 10.1146/annurev.phyto.41.052002.095518.
Williamson, T.N.; Newman, B.D.; Graham, R.C.; Shouse, P.J. 2004. Regolith water in zero-order chaparral and perennial grass watersheds four decades after vegetation conversion. Vadose Zone Journal 3(3): 1007-1016.
Kelly, E.F.; Chadwick, O.A.; Hilinski, T.E. 1998. The effect of plants on mineral weathering. Biogeochemistry 42(1-2): 21-53. doi:10.1023/A:1005919306687.
Feng, X. 2002. A theoretical analysis of carbon isotope evolution of decomposing plant litters and soil organic matter. Global Biogeochemical Cycles 16(4) 1119, doi:10.1029/2002GB001867
Platkick, N.I.; Ubick, D. 2005. A revision of the North American spider genus Anachemmis Chamberlin (Araneae, Tengellidae). American Museum Novitates, Number 3477. New York: The American Museum of Natural History: 20 p.
Liu, S.; Dougal, R.A; Solodovnik, E.E. 2004. VTB-based design of a standalone photovoltaic power system. International Journal of Green Energy 1(3): 279-300.
Liu, S.; Dougal, R.A.; Solodovnik, E.V. 2005. Design of autonomous photovoltaic power plant for telecommunication relay station. In: Proceedings on Generation, Transmission, and Distribution 152(6): 745-754. Edison, NJ: Institute of Electrical Engineers, doi:10.1049/ip-gtd:20045028.
Egerton-Warburton, L.; Graham, E.C.; Hendrix, P.F. 2005. Soil ecosystem indicators of post-fire recovery in the California chaparral. Final Report to the National Commission on Science for Sustainable Forestry, NCSSF Research Project C4.1. Chicago Botanic Garden, Chicago, IL. 36 p.
Egerton-Warburton, L.; Podbielski, J.; Sickel, J.; Hendrix, P.; Sternberg, P.; Graham, R. 2005. Mycorrhizal community dynamics following a high intensity wildfire in the California chaparral. Poster in: 90th Annual Meeting; 2005 August 7 - 12; Montreal, Canada: Ecological Society of America.
Shengyi L.; Solodovnik, E.; Dougal, R. 2005. Shunt regulation for continuous operation of solar array at maximum power. In: Conference Record of the 31st IEEE Photovoltaic Specialists Conference; 2005 January 3-7; Orlando, FL: Institute of Electronic and Electrical Engineers, p. 1597-1600.

Progress 10/01/04 to 09/30/05

Outputs
Hydrologic monitoring at San Dimas Experimental Forest was significantly affected by the near-record rainfall in the 2004 - 2005 winter period. Over 70 inches of precipitation were collected. Significant sediment movement filled up and overtopped the 3 dams which had been cleaned out following the 2002 Williams Fire. Measurement of sediment and vegetation recovery in several small watersheds following a prescribed burn continued. An annual survey of migratory birds was conducted in the spring. Due to a particularly wet fall, not all of the annual burning plots were successfully burned on the Arizona long-term fire study. Given that these plots have been burned repeatedly nearly 30 times, the impact of this missed treatment will probably be minimal.

Impacts
These two long-term study sites provide a unique opportunity to study ecosystem dynamics over a long period of time. The San Dimas Experimental Forest is uniquely situated adjacent to the second largest metropolitan area in the United States. The pressures placed on the chaparral ecosystem by an urban populace can be measured here and used to manage chaparral elsewhere in California.

Publications

Johnson-Maynard, J.L.; Graham, R.C.; Shouse, P.J.; Quideau, S.A. 2004. Base cation and silicon biogeochemistry under pine and scrub oak monocultures: Implications for weathering rates. Geoderma 126(3-4): 353-365, doi:10.1016/j.geoderma.2004.10.007
Williamson, T. N.; Graham, R. C.; Shouse, P. J. 2005. Effects of a chaparral-to-grass conversion on soil physical and hydrologic properties after four decades. Geoderma 123(1-2): 99-114. doi:10.1016/j.geoderma.2004.01.029.

Progress 10/01/03 to 09/30/04

Outputs
Studies were completed that determined the effects of individual species on soil microclimate and related properties, to quantify the influence of shrub live oak (quercus dumosa) and coulter pine (pinus Coulteri) on soil isotropic variation occurring during organic decomposition. Results suggested that canopy density and depth of letter layer were greatest determinants of soil microclimates, and soil macrofaunal communtities have a greater effect on divergence of soil morphologies than microclimate. Variation in decomposition processes under plant communities caused differences in heavy isotope enrichment of soils.

Impacts
A greater understanding of shrub and woodland soil ecosystems is enhanced through the gained understanding of processes that drive microclimate character and nutrient composition of the systems. This understanding provides an improved platform for research study development and management decisions in these ecosystems.

Publications

Johnson-Maynard, J.L.; Shouse, P.J.; Graham, R.C.; Castiglione, P.; Quideau, S.A. 2004. Microclimate and pedogenic implications in a 50-year-old chaparral and pine biosequence. Soil Sci. Soc. Am. J. 68:876-884.
Quideau, S.A.; Graham, R.C.; Feng, X.; Chadwick, O.A. 2003. Natural isotropic distribution in soil surface horizons differentiated by vegetation. Soil Sci. Soc. Am. J. 67:1544-1550.
Vathanasian, V. 1999. Hydrologic evaluation of the San Dimas Experimental Forest. Pomona: California Polytechnic Institute; master thesis.

Progress 10/01/02 to 09/30/03

Outputs
The unit successfully completed the maintenance burning of 15 plots at each Arizona long-term research study area, Limestone Flats and Chimney Spring, in October 2002. Long-term periodic measurements on fuels and vegetation were completed. Data and photos from permanent points were used to compile a photo series illustrating the impacts of repeated prescribed burning of fuel accumulation and overstory density. The San Dimas Experimental Forest (SDEF) was burned by the Williams Fire in September 2002. With the exception of the Tanbark compound, virtually all of the forest was burned including four of the buildings. Many of the ongoing research projects at SDEF were modified to capture the effects of wildfire on the experiments. Where possible, the damaged infrastructure has been replaced and we are working to reactivate some watersheds. Post-fire rehabilitation treatments have been applied in some watersheds. Plant and watershed recovery will be measured as funds are available. Several articles related to soil nutrient dynamics under various cover types in the lysimeter area were published.

Impacts
Soil development under various vegetation types in the San Dimas lysimeter has been shown to occur much faster than conventional wisdom thought. Recent research suggests that the presence of earthworms in these soils is related to the type of vegetation growing there. The earthworms affect the soil porosity and the amount of water the soil is able to hold. This relationship may affect how the vegetation survives during drought periods which in turn influences the fire risk posed by the vegetation.

Publications

Tice, K.R.; Graham, R.C.; Wood, H.B. 1996. Transformations of 2:1 phyllosilicates in 41-year-old soils under oak and pine. Geoderma 70: 49-62.
Johnson-Maynard, J.L.; Graham, R.C.; Wu, L.; Shouse, P.J. 2002. Modification of soil structural and hydraulic properties after 50 years of imposed chaparral and pine vegetation. Geoderma 110: 227-240.
Aochi, Y.O.; Farmer, W.J.; Graham, R.C. 2003. N2, CO2, and 1,2-dichloroethane as molecular probes of soil microstructure. Geoderma 114: 369-388.

Progress 10/01/01 to 09/30/02

Outputs
The unit successfully completed the maintenance burning of 15 plots at each Arizona long-term research study area, Limestone Flats and Chimney Spring, in October 2001. The unit also completed the collection of mitigation data, including cambium temperatures and fuels, for eight mature southwestern ponderosa pines. This data will be included in a larger data set to evaluate the effectiveness of mitigation on the survival of mature yellow pine during initial entry prescribed burns. The unit completed taking all 131 permanent photo points at both Chimney Spring and Limestone Flats through contract. It also completed the yellow pine mortality survey for the Chimney Spring and Limestone Flats study areas in Arizona. At San Dimas Experimental Forest, the abundance of earthworms and macroarthropods under individual chaparral species was found to differ. Native earthworms were found under manzanita (Arctostaphylos glauca) and exotic species were found under scrub oak (Quercus dumosa). The highest abundance of macroarthropods occurred in the summer and did not vary between shrub types. Analysis of soil organic matter from San Dimas and several sites in the Sierra Nevada suggests that vegetation, not climate, controls the soil organic matter composition of the soils. This has implications for models of total carbon storage and turnover in soils.

Impacts
(N/A)

Publications

No publications. 2002