Needles

• The waxy covering of the pine needle is flammable, helping fire eliminate its competition.Comstock/Comstock/Getty Images
  
  Retaining needles for three years, as conifers do, extends the photosynthesis period but also increases water demand and water loss. Pines and other conifers have a needle structure that is assembled tightly so the vascular tissue is protected and water loss is reduced. Dense foliage reduces air movement around the needles, slowing evaporation. The needle is covered with a waxy cuticle that keeps snow from accumulating and slows transpiration. But the wax is also highly flammable.
  
  

Fire Adaptations

• Fires clear out underbrush and open the forest to the sunlight pines need.Goodshoot/Goodshoot/Getty Images
  
  Pines like full sun so that shaded lower branches drop as the tree matures. This helps mature pines survive ground fires. Fires keep underbrush from outcompeting and choking out pine trees, so pines can maintain their dominance. In some species of pines, the cones will only open and release seeds in response to the intense heat of a forest fire. The ash of the forest fire provides nutrients to the soil that are conducive to the seeds of the pine.
  
  

Reproduction

• Pine needles are arranged in a manner unique among conifers.Jupiterimages/Photos.com/Getty Images
  
  Pine needles mature in bundles, or fascicles, of long, needle-shaped leaves wrapped at the base with short, scale-like leaves. Unusual circumstances can trigger growth of a new shoot or even roots for an entire pine tree. More typically, mature cones are shed from the tree, the cone scales separate and the winged seeds are released. Fire-resilient pines readily produce seeds in abundance and tend to have highly serotinous cones -- the cones that open in response to intense heat. Fire-resistant pines are tall, have thick bark, long needles and large seeds, and they initiate seed production slowly.
  
  

Winter Water Transport

• Even in winter, occasional thaws can make liquid water available to trees.Brand X Pictures/Brand X Pictures/Getty Images
  
  Liquid water can be accessed by coniferous trees periodically in the winter. But the line of transport has to be unfrozen as well to move the water through the tree. Water in trees moves upward through tube-like cells in the xylem called tracheids. When this water freezes, this water column is broken. Conifer trees have evolved a response to ice formation that permits restoration of the water column instead of having to grow new xylem cells every spring.