Final answer:
Conifer trees like spruce, fir, and pine have needle-shaped leaves with waxy cuticles and sunken stomata, which reduce water loss and help them survive in cold or dry climates.
Step-by-step explanation:
The part of the conifer tree that helps it survive very cold or dry climates in the coniferous forests is the leaves. Conifers such as spruce, fir, and pine have needle-shaped leaves with a waxy cuticle and sunken stomata, helping to reduce water loss. These adaptations are crucial for conserving water and maintaining photosynthesis under harsh conditions, giving coniferous trees a competitive advantage over broad-leafed deciduous trees in cold and dry environments.