Abstract
Wildfires in boreal forest ecosystems usually spare tree stands called post-fire residual patches. There aretwo types of post-fire residual patches: (1) patches that only escaped fire by chance, probably due to localmeteorological conditions unsuitable for fire spread at the moment fire reached their surroundings(random post-fire residual patches), and (2) patches with lower fire susceptibility, that escaped severalconsecutive fires, likely due to particular site characteristics (fire refuges). Special conservation effortscould target fire refuges owing to their old age, long ecological continuity, and potential specificbiological diversity. Here we compared the stand characteristics of 13 post-fire residual patches fromthe eastern Canadian boreal mixedwood forest to develop guidelines and information for forest managersto differentiate fire refuges from random post-fire residual patches. Two main structural characteristicsdifferentiated fire refuges from random post-fire residual patches: mean tree diameter and thickness ofthe soil organic matter layer. Thick organic matter accumulation in fire refuges is likely linked to apaludification process, which in turn reduces stand productivity, and thus, mean tree diameter.