Question

In temperate regions, cambium is less active during winter season and forms fewer xylary elements that have narrow vessels, this wood is called as (a) spring wood (b) autumn wood (c) heart wood (d) sap wood.

Short answer

The wood formed in temperate regions during the winter season with fewer and narrow vessels is called 'spring wood' (a).

Step-by-step solution

Understanding the Characteristics of the Wood Formed During Winter

The wood formed during the winter season in temperate regions is known to have fewer xylary elements with narrower vessels due to the reduced activity of the cambium.

Identifying the Type of Wood Based on Seasonal Characteristics

Knowing the characteristic features of the wood such as the fewer and narrow vessels, it is possible to identify the type of wood as it corresponds to a particular term described in the options.

Matching the Characteristics to the Correct Option

Among the options given, the term that correctly describes the wood with fewer and narrower vessels formed during the winter season is known as 'spring wood'.

Key concepts

Spring Wood

In the context of dendrology, which is the study of trees, the term 'spring wood' refers to a particular type of wood that forms in trees during the early part of the growing season. This typically corresponds to spring in temperate regions. As trees emerge from the dormancy of winter, the cambium, a layer of actively dividing cells between the bark and wood, becomes more active, leading to the production of new wood cells.

During this period, the vessels or tracheary elements formed are usually larger and more numerous compared to those formed later in the year. This happens because there is typically more water available in the environment during spring, which facilitates the growth and expansion of these vessels. The presence of larger vessels makes spring wood generally lighter in color and less dense than wood formed during other seasons.

Seasonal Growth Patterns and Tree Rings

One can often see the differences in wood formed in different seasons as concentric rings when looking at a cross-section of a tree trunk. These rings not only indicate the age of the tree but also provide insights into the environmental conditions during the tree's life. Spring wood, with its characteristic larger vessels, contributes to the formation of these rings, often appearing as the lighter part of the annual ring.

Wood Formation

Wood formation, technically known as xylogenesis, is a complex biological process involving the differentiation of cells from the cambium into xylary elements that collectively make up wood. This process is influenced by a variety of factors including temperature, water availability, and daylight hours, which vary seasonally in temperate regions.

During the warmer and wetter spring and summer months, cambial activity is heightened and the cells produced are typically larger, resulting in what is called 'early wood' or 'spring wood'. As the seasons progress towards autumn and the environmental conditions become less conducive to growth, the cambium becomes less active, and the cells it produces are smaller and have thicker cell walls. This wood is referred to as 'late wood' or 'summer wood'.

Environmental Impact on Wood Formation

The environment plays a crucial role in wood formation. For instance, a wet spring will likely result in more abundant and larger xylary elements, while a drier season may lead to reduced cambium activity and thus smaller wood cells. The combined effect of these variations across different seasons results in the formation of distinct annual rings that can be observed in the cross-section of a tree.

Xylary Elements

Xylary elements are the fundamental building components of wood in plants. There are primarily two types: vessels and tracheids. Vessels are tube-like structures that facilitate water transport throughout the plant, serving a critical role in the plant's vascular system. Tracheids are elongated cells that also transport water and provide structural support to the plant.

In temperate regions, as the cambium's activity fluctuates with the seasons, so does the structure and function of these xylary components. Wintertime sees a reduction in cambium activity due to colder temperatures and less water, resulting in narrower vessels and tracheids. As this occurs during the winter season, the wood that is formed is denser and has a reduced capacity for water transport when compared to the wood formed during the spring.

Comparison of Vessels and Tracheids

The size and arrangement of these xylary elements are not only important for the transportation of nutrients and water but also significantly contribute to the mechanical properties of the wood. For instance, the narrower vessels and tracheids of the winter or 'late wood' make the wood harder and more resistant to compression, while the wider vessels of 'spring wood' allow for greater water transportation but make the wood softer and less dense. Understanding these components is essential in fields like forestry, botany, and wood science.