What are the abiotic factors for the coniferous forest?

The coniferous forest is a largely homogeneous band of pine forest circling the sub-arctic longitudes. Across Canada, Alaska, Russia and the Scandinavian nations these evergreens dominate the landscape.

Interesting factors in this ecological domain, outside of the conifers themselves include the following.

Heat regulation: because of the relatively dark coloration of the pines, more heat is collected from the meager sunlight. This helps to increase the length of the growing season. The dense layering of branches and needles also creates an insulating still air space.

Soil/subsoil: Over eons of homogeneity and dominance of pine forest, the below ground homeostasis has developed along with the trees themselves. Beneath their roots are many yards of partially decomposed detritus. As in peat bogs, much of this material is incompletely broken down, due to the harsh chemical composition and cold and frequently frozen ground. Were this to warm drastically, it is theorized that vast latent stores of greenhouse gases would be produced by more active microbes, potentially triggering a cascade of increasing global warming.

The unique conditions of very long summer days and very long summer nights, low liquid precipitation (water is provided by snowmelt) are distinct.

One might consider the absence of such biotic factors as plentiful herbivores, competing plant species, or human development relevant.