Effects of potassium content in heartwood and soil on heart-wood color of slope planted sugi (cryptomeria japonica d. don)

The relationship between heartwood color and potassium contained in heartwood and soil was examined. The heartwood color was bright and potassium content was lower in the lower slope, while the heartwood was dark and potassium content was higher in the upper slope. Consequently, a negative correlation was obtained between heartwood color and potassium content. The results suggested that the heartwood color in the upper slope was dark because of high potassium content. Moreover, potassium content in soil was higher on the upper slope. This explained that the upper slope soil has the potential for high potassium supply.