Light Environments in Temperate New Zealand Podocarp Rain- Forests
Light environments in two lowland New Zealand podocarp rainforests are described using data from quantum sensors. Mean daily total photosynthetic photon flux density (PPFD) in the forest understorey varies from 2.6-5.2% incident PPFD in summer and 1.0-2.5% in autumn, and in gaps from 5.0-16.6% in summer and 6.3-8.3% in autumn. Pronounced differences in understorey PPFD occur between clear and overcast days. Overcast days tend to have a lower proportion of 2-minute periods with very low mean PPFD than clear days.