When you get older you keep warm with the wood you gathered as a youth.

What it means
The wood that warms an old person was gathered when they were young and strong. The proverb says that comfort in old age comes from the work done earlier in life.
Bambara · West Africa
Source and context
From: Bambara, West Africa
Source: Bambara (Bamanankan, Mali) oral-tradition proverb, widely and consistently attributed to Bambara across several proverb collections (e.g. stronglovequotes.com), though no single primary source page could be confirmed to contain it. Earlier recorded here as documented on ankataa.com and consistent with Kassim Kone, "More than a thousand Mande Proverbs" (1995) and Charles Bailleul, "Sagesse bambara" (2005); ankataa.com's actual Bambara-proverbs post, fetched directly, does not contain it, and neither does africanmanners.wordpress.com's 25 Bambara proverbs.

The meaning given here is our own reading. Other interpretations exist.