The stomata are recessed into pits on the needle and aligned in a groove on its underside. The groove in the needle creates a small layer of still air which slows the loss of water vapor by diffusion. Water loss is further reduced by the thick waxy coating common to pine needles. Under these circumstances the stomata close-up to prevent loss of water from the tree. Waxy, resinous needles, combined with low bacterial activity in the cold subarctic climate combine to produce a thick mat of undecayed litter at the forest floor.
Conifers possess a shallow, extensive, yet compact, network of roots.
Birch intermixes with spruce in an open canopied Northern Coniferous forest. Filamitous fungi surrounding the root ball extend hairs into the needles lying at the surface, breaking them down into substances usable by the trees. Food for larger animals is sparse in such an ecosystem and they are likely found where wind throw or fire has created openings in the forest for deciduous shrubs such as birch, aspen and willow to invade colonize. Much of the northern coniferous forest of Europe and the eastern United States has suffered from the affects of acid deposition. Acid deposition refers to the depositing of acids in both solid and and liquid form.