What he is refering to is symbiosis life,insects fungi and other plants that feed and live off the dead plant matter which in turn breaks down to provide nutrients and nitrogen back into the soil for the living flora to feed on.This is a natural cycle and by taking it away through burning this symbiosis life will disappear and with it the flora and birds that thrive upon it will go.
Im not far off attending a weekend stay in a hornbeam woodlands that has been left unattended and unmanaged for a while,the result is a healthy layer of dead broken down plant matter and good soil that has encouraged a healthy carpet of blubells to grow everywhere.This is natures work at its best and feel that the only work us humans should partake in is managing trails to preserve trampling the rest of the ground flora,treating diseased areas and vermin control.
Great Vid and a Valid point put across....