How does eucalyptus’s tannin leaching affect surrounding surfaces under chairs?

Eucalyptus wood, prized for its durability and natural resistance to pests, contains high levels of tannins—organic compounds that can leach out when exposed to moisture. When used for outdoor chairs, this tannin leaching often leads to noticeable stains on surfaces beneath them, particularly on light-colored pavements, decks, or concrete.

The process occurs as rainwater or humidity draws tannins from the wood, depositing them onto the ground below. These stains appear as dark, reddish-brown marks that can be stubborn to remove. The severity depends on factors like wood age, weather conditions, and surface porosity.

To mitigate tannin leaching, applying a sealant to eucalyptus furniture helps block moisture penetration. Regular cleaning with oxalic acid solutions or specialized tannin removers can treat existing stains. Alternatively, placing protective mats under chairs prevents direct contact with vulnerable surfaces. Understanding this natural process allows for better maintenance of both eucalyptus furniture and the areas surrounding it.