Wood Anatomy and Composition

Study Notes

The study of wood anatomy involves analyzing the different parts of wood to understand their arrangement, structure, and function.
It focuses on features that can help identify unknown wood samples and determine the best uses for the material.

Wood is primarily composed of the cell walls of dead cells.
It's the hard, fibrous tissue that makes up the stems, branches, and roots of trees.
Three types of cells are found in plants:
- Conducting cells: Elongated, axial cells that transport water and nutrients.
- Support cells: Elongated, axial cells that provide structural support.
- Storage cells: Short, thin-walled cells with living protoplasm that store and distribute food.
The proportion of these cell types varies within different plant species and locations within the stem, influencing wood properties and uses.

Wood anatomy has various applications in:
- Forestry: Helps foresters manage and harvest resources efficiently for revenue.
- Taxonomy: Assists in identifying unknown wood samples for documentation.
- Phylogenetic Studies: Helps determine the evolutionary relationships between different wood types.
- End-Use Determination: Optimizes the conversion of wood into various products based on its characteristics.

Key characteristics of woody plants:
- Vascular: Contain specialized conducting tissues (xylem and phloem) for transport.
- Perennial: Live for multiple years and have stems that persist.
- Secondary growth: Can grow in diameter due to the production of new tissues.

Trees: Woody plants exceeding 20 feet in height with a single, self-supporting trunk.
Shrubs: Woody plants that typically grow below 20 feet with multiple stems.
Woody Lianas: Climbing vines that use various mechanisms (twining, clambering) to reach sunlight.

Softwoods:
- Belong to the gymnosperm subdivision (e.g., conifers).
- Characterized by needle-like leaves and naked seeds.
- Commonly known as evergreens due to their year-round foliage.
Hardwoods:
- Belong to the angiosperm subdivision (e.g., flowering plants).
- Feature broad leaves with seeds enclosed in ovaries (fruits).
- Often referred to as deciduous plants because they lose their leaves seasonally.

Softwoods and hardwoods differ in cell types, their abundance, and arrangement, leading to distinct properties.

Tropical climates have trees like palms, rattan, and bamboo that are monocotyledonous, meaning they have one seed leaf.
These monocots have unique structural features compared to typical woody plants.

Straw: (e.g., rice, wheat) Used for producing corrugated boards, fiberboard, and low-quality wrapping papers.
Esparto: A grass from Spain and Northern Africa.
Sugarcane Bagasse: Fiber from sugarcane processing.
Bamboo: Found in various regions and used for construction, furniture, and other products.
Manila Rope: Derived from the abaca plant and used for making bags, sacks, and other items.
Cotton Stalks: Used for fiber production.
Leaf Fibers: (e.g., abaca, pineapple) Source for natural fibers used in various applications.