Thanks for the interest! I also unfortunately do not know of any oxygen time series from terrestrial forests. However, any environment, terrestrial or otherwise, where periodic bursts of oxygenic dismutase enzyme activity occur (e.g., superoxide dismutase, catalase, chlorate dismutase, a putative nitrite dismutase, etc.) could possibly have nighttime oxygen spikes. The bigger question in this context would be what causes the activity to occur in such a discreet burst at night? This is an avenue of inquiry I'm pursuing with my data presently...
As far as direct production versus stored oxygen, do you mean gaseous oxygen storage in cellular/structural compartments, or the sequestration of oxygen-containing compounds for subsequent extraction of molecular oxygen?
Either of these could be considered a release of stored oxygen, but both of these process can also occur as the result of photosynthesis (e.g., byproducts of CAM processes in plants, which consequently do not occur in marine plants due to a lack of stoma). The more ecologically relevant question is whether or not the oxygen release is coupled to some sort of carbon fixation (i.e., primary production). A definitive answer to that question would require a carefully controlled study using stable isotopes to trace the metabolic fate of oxygen and carbon, similar to the experiments carried out by Ettwig et al., (2010) using M. oxyfera. We have yet to perform such experiments using the organisms in our study, so I can't really comment on whether or not carbon fixation is actually occurring alongside the oxygen release.
Hope that helps answer your questions! Please let me know if you have any more.