Field capacity is the amount of water the soil can hold after being completely saturated. Clay soils have a very high field capacity, but sandy soils have a very low field capacity. So pines and other gymnosperms do much better in areas where there is often little or no water in the soil, in habitats that are very dry. From the standpoint of plant physiology, cold is the equivalent of dry, because getting enough water is a problem in both environments. Forest in the far North, or at higher elevations, are also dominated by gymnosperms because water in the soil may be mostly frozen most of the year.
Sandy soils are also poor in nutrients.
Sand passes water quickly, and the water leaches out the nutrients from the sand as it filters through. Pines do better than angiosperms in these nutrient-poor soils. Pine needles are also an a adaptation to reduce water loss. And they re the perfect shape for wind-pollinated plants, like conifers. The major natural disturbances in the pine forest are fire, wind, and man.