The data set contains vertical profiles of diffuse light transmittance measured within six forest plots in montane Atlantic forest, São Paulo state, Brazil. The plots measured include intact, previously logged and secondary forest in a large continuous forest block of the Serra do Mar State Park (Parque Estadual de Serra do Mar), and two forest fragments outside the park. In each plot 10 - 12 individual light profiles were recorded; the data set contains these individual profiles and averages profiles for each plot based on both height above the ground and depth below the canopy. Each profile was measured only once. Data was collected March - November 2015 as part of the NERC Human modified Tropical Forest Programme.
Publication date: 2017-10-06
This dataset is part of the NERC-FAPESP project ECOFOR. Data were collected from 4 plots in the Serra do Mar State Park (Nucleo Santa Virginia), and in two forest fragments on private land. Individual diffuse light profiles were produced by suspending a string of photosyntheticall active radiation (PAR) sensors from a tree branch. 10 - 12 profiles were collected per plot, and each profile was always at least 20 m from other profile locations. Sensors in the profile were separated at 1 m intervals. A reference open sky sensor was placed nearby. Sensors collected data from each profile for a minimum of 1 hour and maximum of 3 days, always including a period of diffuse light. Data were manually examined to identify diffuse periods, and for all records from diffuse periods the % light received compared to the open sky reference was calculated (% transmission). The mean % transmission across the diffuse period for each sensor was calculated to produce the light profile. Any missing values in the profile were interpolated or extrapolated. Average profiles for the plot were made using height above the ground and depth below the canopy top.