What is Heartwood?
Heartwood is the dark, dense wood in the center of a tree trunk. It's the "heart" of the tree - no longer alive but providing strength and durability.
Formation Process
From Sapwood to Heartwood
As trees grow, inner sapwood gradually converts to heartwood:
- Living sapwood transports water and nutrients
- Cells die as outer layers add new sapwood
- Chemical changes deposit extractives (tannins, resins, oils)
- Color darkens due to these compounds
- Density increases making wood harder and more durable
Characteristics
Physical Properties
- Dense and hard: Stronger than sapwood
- Dark colored: Brown, red, purple, or black
- Dry: No longer contains water
- Aromatic: Often fragrant from oils and resins
Durability
- Decay resistant: Extractives prevent rot
- Insect resistant: Less attractive to borers
- Stable: Less prone to warping
- Long-lasting: Can endure for centuries
Valuable Heartwoods in Costa Rica
Cocobolo (Dalbergia retusa)
- Orange-red to deep purple heartwood
- Extremely dense and oily
- Highly valued for fine woodworking
- CITES protected
Teak (Tectona grandis)
- Golden-brown heartwood
- Rich in natural oils
- Excellent for outdoor furniture
- Plantation grown
Cedro (Cedrela odorata)
- Aromatic, cedar-scented
- Light to dark red-brown
- Resistant to termites
- Traditional boat building
Heartwood vs. Sapwood
| Feature | Heartwood | Sapwood | | ---------- | ------------------ | ------------------------ | | Function | Structural support | Water/nutrient transport | | Status | Dead cells | Living cells | | Color | Dark | Light | | Density | High | Lower | | Durability | Excellent | Poor | | Value | High | Low |
Commercial Importance
- Premium lumber: Most valuable part of tree
- Furniture and construction: Preferred for quality work
- Musical instruments: Tonal qualities
- Carvings: Dense and workable
- Durability products: Outdoor decking, boats
Why It Matters
- Tree identification: Heartwood color helps ID species
- Timber selection: Choose for appropriate uses
- Conservation: Old-growth trees have more heartwood
- Sustainability: Young trees have less valuable heartwood