In addition, conifers can photosynthesize all year. Hardwoods shed their leaves in the fall and are therefore unable to make food all year, which is unfortunate for they have a higher nutrient requirement. Even with the period that they do have leaves, they are at a disadvantage for the rain is least prominent in the summer at the Cascades, when the leaves are still on. In addition, the humidity accompanying the heat is very low, and the stomata of the hardwoods respond by closing. By closing the stomata, it is inhibiting water uptake.
Hardwoods are at a disadvantage in the winter, as well.
It is during the winter in the Cascades that most of the water comes down. The conifers take advantage of this. Even in very cold soil temperatures, conifers are able to extract water from the soil. As mentioned, the conifers photosynthesize the whole year. During the winter, the hardwoods do not have any leaves, and so they cannot plan on obtaining any nutrients during the winter.