Jack pine establishment on ash from wood and organic soil

Wildfires after prolonged drought consume quantities of fallen trees and soil organic layers. We hypothesized that conflicts within the literature about establishment success of conifers on the resulting ash were a result of the different types of ash used (from wood or peat) and degree of leaching. This was tested using jack pine (Pinusbanksiana Lamb.) in field and laboratory experiments. Ash from peat was chemically neither detrimental nor advantageous to jack pine establishment. No seedlings survived on unleached wood ash. Leaching improved germination and survival, but leached aspen ash was usually a poorer substrate than leached ashes from conifers. There was no consistent differences between ash from different conifers nor degree of decomposition prior to burning. Chemical analysis of the wood ash suggested the high pH of 10.6-12.5 caused by high hydroxide and bicarbonate levels to be directly harmful.