Measuring bushfire fuels is important to many different people for so many different reasons;

Calculating the likely success of first attack; prioritising fuel reduction treatments; figuring out optimum fire frequency; calculating fuel accumulation rates; assessing risks and hazards; measuring carbon release; estimating smoke production (to name a few).

This project poses questions to those interested in fire fuels: Why collect fuels data? What do we seek to learn from fuels data? Should we collect fuels data across Australia in a uniform way? How would we store the information? What are the gaps in the knowledge about fuels? and more...

Tuesday, August 2, 2011

Getting My Eye In - Assessing Fuels Visually

Bob Vihnanek is a forester who leads the research support team for the Fire and Environmental Research Applications Team at the US Forest Service, Pacific Wildland Fire Sciences Lab. His research interests are in fire effects, fire history, and quantification of biomass as fuel.

Bob has been working on producing the Natural Fuels Photo Series (NFPS) for the last 30 or more years with Roger Ottmar and others. The NFPS are a set of photos with the associated fuelbed characteristics data. The data is collected through destructive sampling so it represents the actual quantification of fuels, at the sites that were selected to represent each fuel type and condition being documented. At present there are 15 volumes in the NFPS that record and quantify fuels data across regions within the US, with one volume each from Brazil and Mexico. The NFPS volumes are presented in ring bound folders printed on special, tough, almost waterproof paper that was designed to be taken out, and used in the field.

Sites include standard, wide-angle and stereo-pair photos. The inventory data that accompanies the photos summarises vegetation composition, structure and loading; woody material loading; density by size class; forest floor depth and loading, and other site characteristics. One vegetation type may have as many as 17 or more fuelbeds described in different conditions, such as in different seasons, when fuels can be radically different at exactly the same site.

The NFPS has also been digitised and is available on the web in electronic form. The Digital Photo Series (DFS) database allows for searching, downloading, side by side comparisons and customised site generation.

Out in the Okanogan National Forest on our trip to Winthrop, Bob demonstrated the use of the NFPS. He showed us how to use the pictures in the NFPS and match to the fuelbed under scrutiny. Parts or strata of one fuelbed can be combined with another fuelbed to construct a more representative assessment of the site and its fuels. As with all visual guides, practise makes perfect!

Bob explaining the use of the NFPS to Lucrecia and me, Jon checking data in the background

The selected fuelled for the site we were surveying

This is a squirrel midden! It contains chewed up nuts and seeds and is considered a jackpot fuel!

Roger being a good sport and showing me the old man's beard lichen 

Thanks Bob & Roger!

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