Kärnfärgen

Kärnfärgen, often translated as "heartwood color" or "core color," refers to the darker, more mature wood found in the center of a tree trunk. It is distinct from the sapwood, which is the lighter, outer layer of living wood. The formation of heartwood is a natural process where the tree's metabolic activity shifts inward, leading to changes in the wood's cellular structure and composition.

These changes typically involve the deposition of various compounds, such as extractives, tannins, resins, and oils. These substances can impart a darker hue, increased density, and enhanced durability to the heartwood. The specific color and properties of heartwood vary significantly among tree species, ranging from pale brown to deep reddish-brown or even black.

Heartwood is generally considered more resistant to decay, insect infestation, and fungal attack compared to sapwood. This increased resistance is attributed to the presence of these protective extractives. Consequently, heartwood is often preferred for applications where durability and longevity are important, such as in outdoor furniture, construction, boat building, and musical instruments.

The transition from sapwood to heartwood is not always sharply defined, and some trees may have a significant amount of sapwood or a gradual transition zone. The amount of heartwood in a log also depends on the age and species of the tree. Older trees tend to have a larger proportion of heartwood. Identifying and distinguishing heartwood from sapwood is often a crucial step in wood grading and selection for various uses.