Cordillera Pelada - CHCOR001 Additional Site Information Antonio Lara, Shawn Fraver, Juan Carlos Aravena, Alexia Wolodarsky-Franke Dating Method: Crossdated Sample Storage Location: Laboratory of Dendrochronology, Universidad Austral de Chile. Valdivia, Chile. Reference: Lara, A., S. Fraver, J.C. Aravena, A. Wolodarsky-Franke.1999. Fire and the dynamics of Fitzroya cupressoides (alerce) forests of Chile`s Cordillera Pelada. Ecoscience 6: 100-109. Establishment date data from this site are available at: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/firehistory/establishment/southamerica/chcor001.dat Abstract: Widespread mortality of Fitzroya cupressoides (alerce) is found throughout the Coastal Range of south-central Chile. In order to better understand the dynamics and mortality of Fitzroya in the Cordillera Pelada ("barren range", within the Coastal Range) we realized an investigation to determine the influence of fires in these landscapes. We study two sites where scarred stumps were available. The first area called Stand B was ca. 0.3 ha and the second one called Piedra del Indio was ca. 0.5 ha. Only in the stand B we established a study plot, from which we collected information on tree regeneration, age and size class of living and dead trees, radial growth rates and we could determine the relationship between fire and Fitzroya establishment, because in the case of Piedra del Indio the area was completely logged and no age structure date were collected. The year in which each fire scar was formed as well as the inner and outermost rings on stumps were determined by measuring ring widths series with a master tree-ring chronology developed for el Mirador (Neira, 1995). On several samples, fires could not be dated to a particular year, since the rings around the scar were rotten. In these cases, fire dates were treated as aproximations, and were adjusted to match exactly-dated fire years when they fell within five years from them. Fire dates in this way were used to produce a fire chronology for both sites. We dated a total of 21 fire scars. The oldest dated fire ocurred in 1397 (Piedra del Indio) and the most recent in 1943 (stand B). In stand B, the oldest fire scar was dated to 1739, from a tree that formed part of a previous cohort. In this stand, the trees that formed the main cohort became established between the years 1744 and 1756 (based on innermost rings and pith dates at ground level). These dates indicate that most Fitzroya trees became established between 5 and 17 years after the 1739 fire. Growth patterns in stand B since 1795 are clearly related to the ocurrence of fire, there are two sharp and rapid growth releases on the trees that survived both fires, one beginning in 1879 and the other in 1945, follow the fires dated in 1876 and 1943 and are probably the result of reduced competition among the survivors and an increase in resources that typically follow fires. The recurrence of fire in the area and its potential role in forest dynamics is reflected by fire intervals of 67 and 137 years in stand B, and 104, 107 and 147 years for Piedra del Indio. These intervals take into account only those fires that could be precisely dated. Our results show that repeated fires have played a major role in the dynamics of Fitzroya forests in Cordillera Pelada, at least durig the last 600 years, and that Fitzroya can survive low-intensity fires, forming up to four fire scars on the same tree, finally we can conclude that fire is the main cause for widespread Fitzroya mortality in this area. Comments: Stand B tree ids begin with "B-", while Piedra del Indio tree ids begin with "PI-". The PI-1 1681, PI-2 1539 and 1739, and PI-4 1681 fire scar dates are approximations. Fitzroya cupressoides (Mol.) Johnst., is a long-lived conifer endemic to the temperate rainforests of southern Chile and portions of adjacent Argentina. In Chile it occurs throughout te Coastal Range between Corral and Chiloé Island (39º50`S-42º35`S) and throughout the Andean Range between Cerro Puntiagudo and Río Yelcho (41ºS-43º30`S). It is a threatened species, protected by law in Chile and Argentina and it is also listed under the Convention on International Trade in Endangered Species (CITES). Fitzroya can attain a size of up to 5 m in diameter and > 50 m in height and growths in sites characterized by high precipitation, typically with poorly drained, low fertility soils where competition from other tree species is minimal. Fitzroya can live longer than 3600 years, making it the second longest- lived species worldwide, after Pinus longaeva. The Fitzroya stands we sampled are located in Monumento Natural Alerce Costero and in adjacent private land of the Cordillera Pelada in the Lakes Region (40º10`S, 73º42`W). Fitzroya stands are often open (crown cover <50 with a dense shrub cover, consisting principally of Bamboo, Chusquea nigricans, along with Desfontainea spinosa, Berberis serrato-dentata and other species. The Cordillera Pelada consists of gentle slopes and flat mountain plateaus, with metamorfic bedrock of Paleozoic to Precambrian age and its climate is classified as cold temperate maritime, with very high annual precipitation (annual precipitation exceeds 4000 mm). The sampling sites are located on fairly level terrain and at elevation of 900 m. In the case of stand B, we establish a plot and we extracted from living and dead trees >5 cm diameter at breast height (dbh), one or two increment cores at ca. 30 cm height above ground for age determination and construction of tree-ring width chronologies. To determine tree ages, we used standard tree-ring methods of Stokes & Smiley (1968). Since most tree cores did not reach the pith, the number of rings to center was estimated by Duncan`s (1989) method, we accepted a maximum estimate of 25 rings to center. Samples that presented a higher number of estimated rings to center were treated as minimun ages. Cores with rotten centers, in which the intact portion represented at least 75 f the radius length, were also included under the minimun ages. 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.