Impacts of Fire and Fire Surrogate treatments on forest soil properties: a meta-analytical approach

Abstract

The soils underlying the 12 Fire and Fire Surrogates Network include six soilorders and 7.1 in pH, and exhibited ranges of twofold in bulk density, fourfold in soil organic C (SOC)content, 10-fold in total inorganic N (TIN), and 200–1000-fold in extractable Ca and K.Nonmetric multidimensional (NMS) ordination of pretreatment soil conditions arrayed theFFS sites along gradients of pH/base cation status, net N transformation rates, bulk density,and SOC. At the network scale, mineral soil exposure was significantly greater in fire-only(mean of 9.2first posttreatment year, and this persisted through the later sampling year (second throughfourth year, depending on site) in the fire-only treatment (fire 4.1density was not affected significantly at the network scale. TIN concentrations during the firstposttreatment year increased after all three manipulative treatments, but this effect did notpersist to the later sampling year. Neither SOC content nor soil C:N ratio was affected by anyof the treatments at the network scale. At the individual site scale, the combined mechanical

fire treatment produced more significant site 3 treatment 3 year effects than did the fire-onlyor mechanical-only treatments, though in most cases even the statistically significantdifferences produced by the manipulative treatments were modest in magnitude. Ordinationof first-year standardized effect sizes produced no discernable separation of the threemanipulative treatments but did separate the three sites with the greatest fire severity (based onproportional fuel consumption) from the majority of the network sites, with changes in pH,TIN, SOC content, and soil C:N ratio correlating most strongly with this separation.Ordination of the effect sizes from the later sampling year produced somewhat clearerseparation of treatments than did the first-year ordination, though fewer sites were representedin this second ordination. Overall, the network-wide effects of the FFS treatments on soilproperties appear to have been modest and transient.

Citation

Boerner, R.E.J., Huang, J., Hart, S.C. 2009. Impacts of Fire and Fire Surrogate treatments on forest soil properties: a meta-analytical approach. Ecological Applications 19: 338–358.