# ****************************************************************
# ** Please acknowledge the contributors and the International  **
# ** Multiproxy Paleofire Database when using these data.       **
# ****************************************************************
#
# Site name: Archuleta Mesa Plot C6
# Investigators: Peter M. Brown and Rosalind Wu
#
# Dating Method  : Crossdated
# Collectors     : Peter M. Brown, Rosalind Wu
# Species name   : Pinus ponderosa, Juniperus scopulorum, Pseudotsuga menziesii
# Common name    : ponderosa pine, Rocky Mountain juniper, Douglas-fir
# Country        : United States
# State          : Colorado
# National Forest: San Juan National Forest
# Ranger district: Pagosa
# UTM easting    : 0301356 (NAD83, 13)
# UTM northing   : 4115479 (NAD83, 13)
# Elevation      : 2441 m
# Slope          : 8 deg
# Aspect         : 280 deg
# Sample Storage Location: Rocky Mountain Tree-Ring Research, Inc., 
# Ft. Collins, CO
#
# Fire scar data from this site are available in FHX2 format at:
# ftp://ftp.ncdc.noaa.gov/pub/data/paleo/firehistory/firescar/northamerica/usach021.fhx
# along with associated metadata at:
# ftp://ftp.ncdc.noaa.gov/pub/data/paleo/firehistory/firescar/northamerica/usach021.txt
#
# Methods: See Brown and Wu 2005. Increment cores were removed from 10 cm
# height above ground level on living trees and cross sections were cut 
# from logs and snags such that one surface was 10 cm above the estimated 
# root-shoot boundary. Sampled cores were no more than a field estimated
# 10 yr from pith to minimize pith offset when assessing pith date. On 
# increment cores and cross sections that did not include pith but inside
# ring curvature was visible, pith dates were estimated using overlaid 
# concentric circles of varying diameters that take into account both 
# average inside ring widths and an estimated distance to pith. Pith dates 
# at 10 cm height were corrected to germination dates by subtracting
# 5 yr, the average time we estimated for seedlings to grow from germination 
# to 10 cm height (P. M. Brown, unpublished data).
#
# Reference: P.M. Brown & R. Wu. 2005. Climate and disturbance forcing of
# episodic tree recruitment in a southwestern ponderosa pine landscape.
# Ecology 86:3030-3038.
#
# Abstract:  Strong but relatively short (annual to decadal length) climate 
# change can have broad-scale and long-lasting effects on forest communities. 
# Climate impacts forests through direct effects on tree demography (mortality 
# and overstory recruitment) and indirect effects on disturbance regimes. 
# Here, we compare multicentury chronologies of tree recruitment from a 
# 307-ha ponderosa pine forest in southwestern Colorado to reconstructions
# of fire years, hydroclimate, and the El Nino-Southern Oscillation (ENSO).
# Few trees predate a regional multiyear megadrought centered in the 1580s. A
# prolonged pluvial in the early 1600s resulted in a pulse of tree recruitment
# that corresponds to recruitment seen over much of the Southwest. Other cohorts
# in the early 1700s and mid-1800s established during multidecadal fire-
# quiescent periods. These periods correspond to shifts in ENSO that apparently
# resulted in dampening of interannual wet/dry oscillations responsible for
# fuel buildup and drying. Fires, mediated by stochastic climate variation,
# acted as a density independent regulation on tree populations since
# establishment was not limited by overstory tree density, but rather by
# fire-caused mortality of seedlings and saplings during periods of more
# frequent fires. Even-aged cohorts in ponderosa pine forests likely have
# little if anything to do with episodic mortality caused by more severe
# fires, but rather relate mainly to episodic recruitment opportunities.
# Fire cessation after Euro-American settlement in the late 1800s resulted
# in an increase in tree density and changes in forest composition, which
# are major factors that have contributed to recent severe wildfires in other
# Southwestern forests. Our results document clear linkages between synoptic
# climate forcing, fires, and recruitment episodes, and highlight the
# importance of regional historical processes on contemporary forest
# composition and structure.
#
# Comments: The first 2 letters of the tree ID represents the species: PP=Pinus
# ponderosa, JS=Juniperus scopulorum, PM=Pseudotsuga menziesii.
#
	1	Tree ID
	2	Year
	3	Feature
PPC63,1880,pith
PPC63,2002,bark
PMC64,1733,earliest ring
PMC64,2002,bark
PMC65,1747,pith
PMC65,2002,bark
PMC66,1782,earliest ring
PMC66,2002,bark
PPC67,1675,pith
PPC67,2002,bark
PPC69,1676,pith
PPC69,2002,bark
PMC610,1920,pith
PMC610,2002,bark
PPC611,1577,pith
PPC611,1801,fire scar undetermined
PPC611,1802,last ring
PPC612,1579,pith
PPC612,1852,last ring
JSC614,1902,earliest ring
JSC614,2002,bark
PMC615,1885,pith
PMC615,2002,bark
PPC616,1882,pith
PPC616,2002,bark
PPC617,1869,pith
PPC617,2002,bark
PPC618,1816,pith
PPC618,2002,bark
PMC620,1889,pith
PMC620,2002,bark
PMC622,1880,pith
PMC622,2002,bark
PMC624,1882,pith
PMC624,2002,bark
PMC627,1882,pith
PMC627,2002,bark
PPC629,1900,pith
PPC629,2002,bark