In November and December 2019, wildfires in the lower Richmond River district of north-eastern New South Wales burned large tracts of forest including the territories of three pairs of Barking Owls Ninox connivens where breeding activity and two active nests were being monitored. Fortunately, an inventory of large trees and stags (≥60 cm diameter at breast height (dbh)) had been conducted on site prior to the impact of the fires. The two nests were destroyed and many large trees and stags were lost or severely damaged. In the four months following the fires, two 1ha plots were established at the centre of each of the three owl territories. Assessments of these plots demonstrated that 22.6% of the large trees and stags were lost or severely damaged, with a third of this total being ≥100 cm dbh. Despite wide variation in the pre-fire canopy tree structure and floristics, and fire extent and severity among the three territory centres, the percentage large tree loss or severe damage was not substantially different among the territories. Overall, there was a slightly higher percentage of smooth-barked canopy tree species lost or damaged compared to rough-barked species, but this result was biased by the absence of rough-barked species from one of the territory centres. The factor that appeared to be the major influence on large tree and stag loss or severe damage across the owl territories was the pre-fire presence of medium or large-sized basal fire-scars. A total of 72.7% of trees and stags with medium or large basal fire-scars was lost compared with a total of only 12.9% of trees and stags with small basal fire-scars. The loss of, or severe damage to 22.6% of large trees and stags recorded by this study from one wildfire event is considered unsustainable given the increase in frequent severe fires predicted by current climate change modelling. Pro-active protection measures are required to counter such losses of large trees and stags in these forests, and examples are provided of some specific measures recommended for this purpose.