4.3. Canopy reduction treatment

We performed a canopy reduction treatment with the aim to increase the light that reaches our planted seedlings. Competing vegetation was removed, climbers and lianas were cut and saplings and small trees of pioneer species were girdled. The light environment at each planting point was measured with hemispherical photographs at two occasions – one year before and after treatment – using a Canon 50D digital SLR camera with a Sigma EX DC 4.5 mm F2.8 circular 180° fisheye lens. Photos of the canopy were taken with the camera facing upwards from 1.3 m above the ground, with the help of a monopod with a self-levelling and stabilizing mount (SLM8 from Delta-T), at 1.5 m distance from a planting point in the two directions along the line. We collected data during the early morning, from 30 min after sunrise to 9 am to obtain good quality photos in which sky and canopy were clearly distinguishable. Average values for the two photos were used in the data analysis. The Delta-T HemiView software was used to analyze the hemispheric photos to obtain data on the proportion of visible sky, leaf area index (LAI), and global site factor (GSF) (^{Supplementary Table 4}).