Here's some evidence to back up my assertions. It mostly from our papers but there's plenty more great work out there. These are just convenient for me to dig out. https://twitter.com/fireregimes/status/1362114298881990657

First this figure demonstrates the very limited moss/litter consumption during prescribed (*) compared to wild (coloured shapes) fires. Not surprising, during Rx burns moss fuel moisture averaged 275%. Way above thresholds for ignition. See: https://bg.copernicus.org/articles/13/389/2016/

Now you could burn when the moss layer is dry enough to ignite. This does make fire much more difficult to control as the available fuel load is significantly increased and with it fire intensity. How dry does the moss need to be?

We've got some data on ignitability from small smouldering sources but that's it. Ignition potential of moss will be a function of its moisture and the heat flux from the flaming fire. This is an area for research. https://era.ed.ac.uk/handle/1842/7640

Moss and litter layers have steep moisture gradients even where the surface is dry enough to ignite. That's why combustion completeness declines sharply with increasing ground fuel load (see first Figure)

During most prescribed fires heating of soil is limited though this can be increased where moss layers are thin or ignited. This figure shows temperatures at the peat surface (below moss) and 2 cm below the peat surface as a fire passes over. https://doi.org/10.1016/j.jenvman.2017.08.017

Fire has longer-term effects on soil microclimate increasing average temperatures in summer and reducing them in winter. Diurnal temperature variation is also much greater in burned plots. Black unburned; red, yellow, blue burned (different severities). https://doi.org/10.1016/j.jenvman.2017.08.017

These microclimatic changes may be partly what explains increased C fluxes in the immediate post-burn period. There's a lot of variability. Burning on average pushes bogs and heathlands to be small net CO2 sources

This is a snapshot though. the "Unburnt" areas have been burned at some point. Critical question is how long tto become net sinks again? These are systems in a dynamic equilibrium with fire - we need to understand net fluxes across the whole burn cycle. https://doi.org/10.1016/j.jenvman.2018.12.036

One of the big concerns with regards to C is that fire damages Sphagnum. Our monitoring shows rapid post-fire recovery and it regenerates vegetatively following Rx fire. Here Fv/Fm is an index of plant health based on chlorophyll abundance. https://doi.org/10.1080/17550874.2017.1394394

This can be illustrated nicely in photos of the change in Sphagnum condition. HT Alistair Hamilton of @SRUC for these.

Saying Sphagnum is damaged by fire is silly. It's like saying grass is damaged by cows. It's a question of severity of impact and the disturbance regime. In a dynamic, meta-stable system the question is if recovery to pre-fire conditions occurs within the inter-fire window

So Sphagnum can recover from individual fires. A reasonable question to ask is whether Sphagnum would be more or less abundant if areas are left unburned. The jury is out with conflicting studies and different responses across specific species.