Although I have extolled the wonders of leaves in a previous post, so I beg your indulgence to take a look at a different expression of the leaf: pine needles. Pine needles have always amazed me in their unbelievable efficiency; for their size and density, they generate the significant amounts of energy needed by some of the largest trees in the world.
Pines have four types of leaf:
- Seed leaves (cotyledons) on seedlings, born in a whorl of 4–24.
- Juvenile leaves, which follow immediately on seedlings and young plants, 2–6 cm long, single, green or often blue-green, and arranged spirally on the shoot. These are produced for six months to five years, rarely longer.
- Scale leaves, similar to bud scales, small, brown and non-photosynthetic, and arranged spirally like the juvenile leaves.
- Needles, the adult leaves, which are green (photosynthetic), bundled in clusters (fascicles) of 1–6, commonly 2–5, needles together, each fascicle produced from a small bud on a dwarf shoot in the axil of a scale leaf. These bud scales often remain on the fascicle as a basal sheath. The needles persist for 1.5–40 years, depending on species. If a shoot is damaged (e.g. eaten by an animal), the needle fascicles just below the damage will generate a bud which can then replace the lost leaves.
Their simplicity and hardiness are truly amazing!
This image was taken during a recent walk through Oxbow National Wildlife Refuge with a Canon EOS 5D Mk III with an EF 100mm f/2.8 lens. Exposure settings were 1/200 second at f/11 and 400 ISO.