A new, convenient method to estimate canopy-gap size using a camera is proposed. Canopy-gap size was estimated from two images taken with a vertically mounted, digital camera at high and low points (P
h and P
l) beneath a canopy gap. The actual (
AOBS) and estimated (
A
1.0) canopy-gap sizes were highly correlated (
R2 > 0.93) for 16 canopy gaps in the
Cryptomeria japonica D. Don. plantations, and the relationship between
A1.0 and
AOBS was expressed as
A1.0 = 1.16
AOBS. Thus, the method overestimated actual canopy-gap size by an average of 16%.
Key words canopy-gap size - digital camera - image processing