There's been limited success creating burls in boxwood by putting close-fitting metal bands around stems.

NPR: Excerpt: 'A Splintered History Of Wood'

Burls can also be coaxed into African thuja by repeatedly burning certain areas of the trunk and branches.

NPR: Excerpt: 'A Splintered History Of Wood'

Burls are often described as a "cancerous growth"-and this description may not be too far from the truth.

NPR: Excerpt: 'A Splintered History Of Wood'