DOI: 10.25921/gr7q-6v25
title: NOAA/WDS Paleoclimatology - Merschel fire data from Wanoga Butte, central Oregon - IMPD USWAN001

description: Context In the interior Northwest, debate over restoring mixed-conifer forests after a century of fire exclusion is hampered by poor understanding of the pattern and causes of spatial variation in historical fire regimes. Objectives To identify the roles of topography, landscape structure, and forest type in driving spatial variation in historical fire regimes in mixed-conifer forests of central Oregon. Methods We used tree rings to reconstruct multicentury fire and forest histories at 105 plots over 10,393 ha. We classified fire regimes into four types and assessed whether they varied with topography, the location of fuel-limited pumice basins that inhibit fire spread, and an updated classification of forest type. Results We identified four fire-regime types and six forest types. Although surface fires were frequent and often extensive, severe fires were rare in all four types. Fire regimes varied with some aspects of topography (elevation), but not others (slope or aspect) and with the distribution of pumice basins. Fire regimes did not strictly co-vary with mixed-conifer forest types. Conclusions Our work reveals the persistent influence of landscape structure on spatial variation in historical fire regimes and can help inform discussions about appropriate restoration of fire-excluded forests in the interior Northwest. Where the goal is to restore historical fire regimes at landscape scales, managers may want to consider the influence of topoedaphic and vegetation patch types that could affect fire spread and ignition frequency.
description: This site was sampled to reconstruct fire and establishment history across a dry to moist forest ecotone in central Oregon.

Ring boundary fires were assigned to the preceding calendar year expect in four extensive fires where scars appeared in the dormant wood of one year and the ealywood of the following year (1679, 1740, 1777, 1840)

White fir (Abies concolor) and grand fir (Abies grandis) hybridize in the sampling area and are difficult to identify in the field so we did not attempt to distinguish between these two species, but report them as a combined category

Several metadata files are provided with the FHX file.   -999 in any file indicates no data.

Two supplemental files and tree establishment data are provided:
https://www.ncei.noaa.gov/pub/data/paleo/firehistory/establishment/northamerica/uswan001.dat provides tree establishment data, and information on all sampled trees. The sample_type field indicates what type of sample was taken (fire-history - a cross section taken to reconstruct surface fires, large tree establishment - a core or cross section taken for a tree >50 cm in diameter to reconstruct establishment and fire history if fire scars were present, medium tree establishment - a core or cross section taken for a tree 30-50 cm in diameter to reconstruct establishment and fire history if fire scars were present, proxy tree establishment - a core or cross section taken to represent a rotten tree that could not be sampled due to decay). 

https://www.ncei.noaa.gov/pub/data/paleo/firehistory/firescar/northamerica/supplemental/uswan001-saplings.csv provides information on trees <30 cm that we tallied by species and diameter class (measured at breast height, 1.38m) in 7.28-m radius plots. Diameter classes: 7.5 (5-10 cm), 15 (10-20 cm), 25 (20-30 cm).

https://www.ncei.noaa.gov/pub/data/paleo/firehistory/firescar/northamerica/supplemental/uswan001-plot-data.csv provides location and descriptive information on the plots.