Big Hole - USBGH001 Additional Site Information Emily K. Heyerdahl, Richard F. Miller Dating Method: Crossdated Sample Storage Location: USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory, 5775 US W Highway 10, Missoula, MT 59808 Reference: Heyerdahl, E.K., R.F. Miller, and R.A Parsons. 2006. History of fire and Douglas-fir establishment in a savanna and sagebrush-grassland mosaic, southwestern Montana, USA. Forest Ecology and Management. 230: 107-118. Abstract: Over the past century, trees have encroached into grass- and shrublands across western North America. These include Douglas-fir trees (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco) encroaching into mountain big sagebrush (Artemisia tridentata Nutt. ssp. vaseyana (Rydb.) Beetle) from stable islands of savanna in southwestern Montana. Our objectives were to quantify the relative area occupied by mountain big sagebrush and grasslands versus Douglas-fir savanna in the Fleecer Mountains of southwestern Montana today and in the past, and to identify the historical role of fire and other factors in maintaining this distribution. To do this, we reconstructed a multicentury history of tree establishment and surface fires from 1120 trees sampled on a grid of 50 plots over 1030 ha covering a modern mosaic of sagebrush-grasslands and Douglas-fir trees. We compared these histories to time series of climate and land use, and to spatial variation in topography and soil moisture availability. Beginning in the mid-1800s, Douglas-fir trees established in areas in which trees did not persist historically. In 1855, less than half the plots (42%) had trees whereas today, most plots do (94%). This encroachment was synchronous with the cessation of frequent surface fires, likely caused by the advent of domestic livestock grazing, and perhaps by the start of several decades of relatively dry summers. Douglas-fir savannas historically occurred on fire-safe sites more often than did sagebrush-grass. Our inference that frequent fire excluded Douglas-fir in the past was supported by the results of a simulation model of fire and associated vegetation dynamics. In the continued absence of fire, mountain big sagebrush and grasslands in southwestern Montana are likely to become more homogeneous as Douglas-fir trees continue to encroach. Individual Tree Information (plot ID, tree number, number of samples, number of samples dated, species, condition, UTM-E(NAD27, zone 12), UTM-N(NAD27, zone 12): 4C,40,1,1,Pseudotsuga menzeisii,live ,347758,5078067 4C,41,1,0,Pseudotsuga menzeisii,live,347767,5078075 4C,42,1,1,Pseudotsuga menzeisii,log,347739,5078052 4D,21,1,1,Pseudotsuga menzeisii,snag,348209,5078105 4D,40,1,1,Pseudotsuga menzeisii,live,348145,5078126 4D,41,1,1,Pseudotsuga menzeisii,live,348231,5078158 4D,42,1,0,Pseudotsuga menzeisii,live,348171,5078127 4I,40,1,1,Pseudotsuga menzeisii,live,350893,5077596 4K,1,1,1,Pseudotsuga menzeisii,stump,351673,5078068 4K,20,1,1,Pseudotsuga menzeisii,stump,351673,5078068 4K,22,1,1,Pseudotsuga menzeisii,stump,351673,5078068 5E,40,1,1,Pinus contorta,live,348783,5077675 5E,41,1,1,Pinus contorta,live,348749,5077688 5E,42,1,1,Pseudotsuga menzeisii,live,348755,5077579 5E,43,1,1,Pseudotsuga menzeisii,live,348837,5077556 5F,40,1,1,Pinus contorta,log,349222,5077649 5G,40,1,1,Pseudotsuga menzeisii,live,349715,5077514 5G,41,1,1,Pseudotsuga menzeisii,live,349697,5077954 5I,40,1,1,Pseudotsuga menzeisii,live,350510,5077321 5I,41,1,1,Pseudotsuga menzeisii,live,350519,5077382 5I,42,1,1,Pseudotsuga menzeisii,live,350521,5077378 5J,40,1,1,Pseudotsuga menzeisii,stump,351362,5077558 6B,40,1,1,Pseudotsuga menzeisii,stump,347176,5077095 6B,41,1,1,Pseudotsuga menzeisii,stump,347172,5077093 6B,42,1,1,Pseudotsuga menzeisii,stump,347243,5077103 6C,40,1,1,Pseudotsuga menzeisii,live,347644,5077017 6C,41,1,1,Pseudotsuga menzeisii,live,347631,5077032 6C,42,1,1,Pseudotsuga menzeisii,live,347701,5077033 6D,40,1,1,Pseudotsuga menzeisii,live,348166,5077019 6D,41,1,1,Pseudotsuga menzeisii,live,348144,5077089 6D,42,1,1,Pseudotsuga menzeisii,log,348175,5077097 6E,40,1,1,Pinus contorta,snag,348671,5077370 6F,40,1,1,Pseudotsuga menzeisii,snag,349415,5077077 6F,41,1,1,Pseudotsuga menzeisii,live,349403,5077089 6H,40,1,1,Pseudotsuga menzeisii,live,350224,5077042 6I,40,1,1,Pseudotsuga menzeisii,snag,350760,5077128 6I,41,1,1,Pseudotsuga menzeisii,snag,350751,5077176 6I,42,1,1,Pseudotsuga menzeisii,live,350732,5077007 6K,40,1,1,Pseudotsuga menzeisii,live,351703,5077093 6K,41,1,1,Pseudotsuga menzeisii,live,351715,5077114 6K,42,1,1,Pseudotsuga menzeisii,stump,351720,5077130 6K,43,1,1,Pseudotsuga menzeisii,stump,351738,5077038 7B,40,2,2,Pseudotsuga menzeisii,live,347157,5076535 7B,41,1,1,Pseudotsuga menzeisii,live,347182,5076535 7B,42,1,1,Pseudotsuga menzeisii,snag,347291,5076639 7C,42,1,1,Pseudotsuga menzeisii,live,347479,5076582 7C,43,1,1,Pseudotsuga menzeisii,log,347476,5076579 7C,44,1,1,Pseudotsuga menzeisii,snag,347520,5076595 7C,45,1,0,Pseudotsuga menzeisii,log,347651,5076584 7C,46,1,0,Pseudotsuga menzeisii,live,347643,5076596 7C,47,1,0,Pseudotsuga menzeisii,log,347849,5076345 7D,44,1,1,Pseudotsuga menzeisii,stump,348027,5076387 7D,45,1,1,Pseudotsuga menzeisii,stump,348079,5076467 7D,46,1,1,Pseudotsuga menzeisii,log,348132,5076456 7D,47,1,0,Pseudotsuga menzeisii,log,348204,5076623 7D,48,1,1,Pseudotsuga menzeisii,stump,348258,5076676 7D,49,1,1,Pseudotsuga menzeisii,stump,348247,5076700 7D,50,1,1,Pseudotsuga menzeisii,stump,348247,5076700 7E,40,2,0,Pseudotsuga menzeisii,log,348575,5076858 7E,41,1,1,Pseudotsuga menzeisii,live,348541,5076834 7E,42,1,1,Pseudotsuga menzeisii,log,348507,5076842 7F,40,1,0,Pseudotsuga menzeisii,snag,349169,5076741 7F,41,1,1,Pseudotsuga menzeisii,live,349175,5076584 7F,42,1,1,Pseudotsuga menzeisii,live,348875,5076919 7H,40,1,1,Pseudotsuga menzeisii,snag,350105,5076583 8C,40,1,1,Pseudotsuga menzeisii,log,347816,5075977 8C,41,2,2,Pseudotsuga menzeisii,log,347697,5076212 8C,42,1,1,Pseudotsuga menzeisii,log,347710,5076262 8C,43,1,1,Pseudotsuga menzeisii,log,347710,5076261 8D,40,2,2,Pseudotsuga menzeisii,log,348196,5076085 8D,41,1,1,Pseudotsuga menzeisii,log,348196,5076085 8D,42,1,1,Pseudotsuga menzeisii,live,348066,5075983 8D,43,1,1,Pseudotsuga menzeisii,live,348067,5075983 8F,40,1,1,Pseudotsuga menzeisii,stump,349259,5076322 8F,41,1,1,Pseudotsuga menzeisii,live,349252,5076320 8F,42,1,1,Pseudotsuga menzeisii,live,349256,5076264 8G,40,1,1,Pseudotsuga menzeisii,live,349580,5076348 8G,41,1,1,Pseudotsuga menzeisii,live,349569,5076305 8G,42,1,1,Pseudotsuga menzeisii,live,349563,5076303 8H,40,2,2,Pseudotsuga menzeisii,stump,350263,5076120 8H,41,1,1,Pseudotsuga menzeisii,live,350261,5076116 8H,42,1,1,Pseudotsuga menzeisii,live,350263,5076145 8H,43,1,1,Pinus contorta,snag,350264,5076220 8I,40,1,1,Pseudotsuga menzeisii,live,350641,5076148 8I,41,1,0,Pseudotsuga menzeisii,live,350657,5076182 Fire History Graphs: Fire History Graphs illustrate specific years when fires occurred and how many trees were scarred. They are available in both PDF and PNG formats. The graphs consist of 2 parts, both of which show the X axis (time line) at the bottom with the earliest year of information on the left and the latest on the right. The Fire Index Plot is the topmost plot, and shows two variables: sample depth (the number of recording trees in each year) as a blue line along the left Y axis, compared with the percent trees scarred shown as gray bars along the right Y axis. Below, the Fire Chronology Plot consists of horizontal lines representing injuries by year on individual sampled trees. Symbols are overlain that denote the years containing the dendrochronologically-dated fire scars or injuries. The sample ID of each tree is displayed to the right of each line. The Composite Axis below represents the composite information from all individual series. The symbols used to represent the fire scars or injuries, and the filters used to determine the composite information, are shown in the legend. These graphs were created using the Fire History Analysis and Exploration System (FHAES). See http://frames.nbii.gov/fhaes/ for more information.