Introduction
Need
A fuel appraisal photoseries provides a quick, easy method to estimate fuel information where in-depth surveys are not possible. Since photoseries plots are selected to represent the various fuel conditions that are likely to be encountered on the landscape, they may be used in any situation where estimates must substitute for observed values. The photoseries plots may used as inputs to fire behavior prediction software to represent wildland fire situations or in planning for prescribed fires and hazard fuel reduction projects. This photoseries has been compiled to meet two basic needs: to provide fuel information for early post-fire lodgepole pine forests (Cover type LP0), and for mixed conifer forests on andesitic soils in northern Yellowstone NP. Ottmar and Vihnanek provide fuel information for mature lodgepole pine forests in their Natural Fuels Photoseries.
Genesis
Initially a fuel appraisal photoseries was developed for Yellowstone National Park (YNP) by Liebl et al. (1995). In 2001, it was compiled into a database and given the name YELL-1. The photoseries was based on work done by Fischer (1981a, 1981b). Its use for fire behavior prediction was limited by a lack of fuel bed depth, live herbaceous, live woody, and canopy fuel loading measurements .
About this time Boundary Fire ignited and spread to 150 ha in the LP0 cover type, or early post-fire lodgepole pine. Fire behavior analysts struggled to represent the LP0 cover type using the existing 13 standard FBPS fuel models. The carrier fuel was elk sedge which suggested a grass model, but once in the tree crowns it behaved like a brush model. Fire effects were represented by slash models given the amount of heavy downed fuel and subsequent soil heating. Simultaneous with the Boundary Fire, spread was stopped at the edge of LP0 at the Moose and Stone Fires. Since so much of YNP is currently in the LP0 cover class, an attempt was made to understand why some fires were burning in LP0 and others not. Twenty-four plots were sampled based on methodology by Ottmar et al. (2000) for basic surface fuel loading, site features, and ground- and tree-layer information. Several sites were sampled to represent LP0 areas burned under wildland fires. The result was a fuel appraisal photoseries for LP0, called YELL-2 (Miller et al. 2004).
In 2003 developed areas in the park were being considered for hazard fuel reduction to reduce the risk of crown fire on fire-fighter safety. A basic question arose: how much to balance fire potential against retaining the esthetics of a national park forest? Little canopy fuel information existed for the park. Developments in estimating canopy fuel factors from easily measured tree characteristics allowed the creation of a fuel appraisal photoseries that included canopy layers (FPS 2005). Ottmar et al. (2000) had already completed a surface and canopy fuel photoseries for rhyolitic soils on the Yellowstone Plateau. We therefore focused on andesitic soils in the northern third of the park from lower elevation Douglas-fir forests to higher elevation spruce-fir and mixed conifer forests. The resulting eleven photoseries plots, also based on the methods of Ottmar et al. (2000), became YELL-3
Although serving different purposes, the YELL-2 and YELL-3 photoseries are similar enough to combine in this dataset.
LP0 Cover Type
The early post-fire lodgepole pine cover type, or LP0 (Despain 1990) resulting from the fires of 1988 covers extensive areas of Yellowstone. It is not adequately modelled by the standard 13 FBPS fuel models. At the time of its development, beginning in 2000, the 40 new Scott and Burgan (2005) fuel models were not available. Fires that burned through the LP0 cover type during the fire seasons of 2000-2003 allowed a heuristic approach to fire behavior prediction; the fires both required and allowed development of, local fuel models (Miller et al. 2004). Photoseries plots were installed in LP0 throughout the range of variation in the park. Three plots were installed ahead of fire-use fires. One burned. Others were installed near the post-fire perimeter to represent the pre-fire fuel conditions. Still others were installed to represent the balance of the variation in the LP0 cover type through the park. Analyses of the fuel and weather conditions allowed some basic, predictive ability and the generation of three custom, surface spread fuel models (Miller et al. 2004).
Canopy fuels
The science of crown fire modelling has historically lagged behind that of surface fuels because canopy fuels are hard to measure. With increasing interface development there is pressure to reduce the threat of crown fire, particularly in stand-replacement regimes such as lodgepole pine and mixed spruce-fir forests. A better understanding of the relationships between canopy fuels and fire behavior will allow fire behavior analysts to better predict typical parameters such as fireline intensity, flame length, heat per area, spread rate, spotting distance, and fire effects. While this ability is useful, fuel managers are also increasingly looking to crown fire models to provide target conditions for hazardous canopy fuel reduction projects that balance retention of desireable forest features against firefighter safety and structure protection. Land managers may know that current canopy fuel loadings are unacceptable but are uncertain what fuel conditions they should target under fuel reduction plans. We present a canopy fuel figures for andesitic Douglas-fir and mixed conifer forests to assist in hazard fuel reduction treatments and burn plan prescriptions.