not-yet-known not-yet-known not-yet-known unknown Ongoing climate change is increasing the flammability of vegetation, ensuing intensified fire episodes in the boreal forest of eastern North America. Fire activity of the last decades suggests that we are probably at a tipping point in terms of fire regimes, raising new questions about the impact of these fires on the biodiversity and structure of the boreal forest. By integrating a compelling paleo-dataset (charcoal, pollen, chironomids, testate amoebae) with model simulations of vapor pressure deficit (VPD) and plant-available soil water (ASW) spanning the last 8,000 years, we demonstrate that drier spring conditions over the past 4,000 years led to fewer but larger and more severe fire episodes, peaking during the last 250 years. This shift in the fire regime fostered a parallel rise in fire-prone conifer species across landscapes, notably Pinus banksiana Lamb. (jack pine). We infer that the predicted increase in VPD along with decrease in ASW triggered by climate change will alter the fire regime and will amplify the transition towards more pyrogenic vegetation within the boreal forest of eastern North America