To determine the correct set of statements about springwood, let's analyze each of the given statements:
- It is also called early wood: This is correct. Springwood is indeed referred to as early wood because it forms at the beginning of the growing season.
- In the spring season cambium produces xylem elements with narrow vessels: This statement is incorrect. During the spring season, cambium produces xylem elements with wider vessels to facilitate the rapid transport of water and nutrients.
- It is lighter in colour: This is correct. Springwood tends to be lighter in color compared to autumnwood due to its larger, less dense cells.
- The springwood along with autumnwood shows alternate concentric rings forming annual rings: This is correct. The alternation between springwood and autumnwood creates the visible annual rings in the wood.
- It has lower density: This is correct. Due to the larger cells and wider vessels formed during spring, springwood is less dense than autumnwood.
Based on this analysis, the correct statements are (a), (c), (d), and (e). Thus, the correct answer is:
(a), (c), (d) and (e) only