Can I plant food plots under a timber canopy?

Marginally — most food plot species need 50%+ sunlight to produce useful biomass. Mature timber typically transmits only 5-15% of incoming sunlight. Better strategies in timber: timber-stand improvement (selective thinning to open canopy), forage chicory or shade-tolerant clovers, or establish plots in existing openings (logging decks, openings, edge cover).