Erik C. Berg

Fuel consumption and fire characteristics during understory burning in a mixed white pine-hardwood stand in the Southern Appalachians.

We characterized fire behavior and fuel consumption resulting from an understory prescribed burn in a mixed eastern white pine-hardwood stand in the Southern Appalachians. Three stands were used for the treatment. Flame lengths, ranging from 0.3 to 1.5 meters (m) for backing fires and from 1.2 to 4.5 m for head fires, reached maximum heights where evergreen understory was found. Rates of spread ranged from 1.8 to 3.0 m per minute for head fires and 0.3 m per minute for backing fires. Fire intensity, measured with ceramic tiles painted with heat-sensitive paint, varied across stands. Mean peak flame temperature ranged from 129 to 290 °C. Pre-burn mass totals were similar among stands, except for stand 1, which had substantially greater humus mass than the other stands. Consumption of litter and humus layers in the forest floor was positively correlated with flame temperature. Small wood (<8 centimeters diameter) consumption was not correlated with temperature. Over all stands, 50 percent of the mass in small wood and litter was lost during burning, and 20 percent of the humus layer was consumed. The losses in the humus layer represented about 40 percent more humus mass consumption than would have occurred in a fell-and-burn treatment. The humus layer is an important nutrient reservoir for plant growth. Maintaining this layer through careful selection of burning conditions will minimize losses during burning and maintain long-term site productivity.

Logging utilization in Idaho: Current and past trends

A study of commercial timber-harvesting activities in Idaho was conducted during 2008 and 2011 to characterize current tree utilization, logging operations, and changes from previous Idaho logging utilization studies. A two-stage simple random sampling design was used to select sites and felled trees for measurement within active logging sites. Thirty-three logging sites and 815 felled trees were measured. Results of the 2008/2011 study indicated that harvesting efforts removed 1,011 cubic feet (cf) of timber volume from growing stock for every 1,000 cubic feet (mcf) delivered to the mill, created 24 cf of growing-stock logging residue, and that 13 cf of non-growing-stock (stump wood and tops above 4 inches diameter outside bark (dob)) were delivered to the mill. This compared to 1,086 cf of growing-stock removals that created 95 cf of growing-stock logging residue and utilized 9 cf of non-growing-stock per mill-delivered mcf in a 1990 study. This study confirmed two long-term timber harvesting trends in Idaho: declining diameter at breast height (dbh) of harvested timber, and declining amounts of logging residue generated per unit of mill-delivered volume.