Young pine tree stem. Light micrograph (LM) of a section through a one year old primary pine (Pinus sp.). The cells of the outer epidermis are thick-walled and covered with a thick layer of cuticle to prevent water loss. Beginning to form underneath the epidermis is the cork cambium (phellogen) which has produced 2 to 3 layers of cork, this helps to resist forest fires. The vascular cylinder (centre ring ) consists of a thin layer of phloem (blue) and first year xylem. Embedded in the xylem (orange) are scattered resin canals. The pith is at centre. Magnification: x10 when printed at 10 centimetres wide