Do the deceased benefit and accrue good deeds from Sadaqah Jariyah (ongoing charity), such as paying for the planting of trees in a school for people with special needs?

The reward of charity reaches the deceased and benefits them. Similarly, any act of devotion performed by a living person, and whose reward is dedicated to a deceased Muslim, benefits them, especially supplication (Du'a), seeking forgiveness (Istighfar), giving charity (Sadaqah), and fulfilling obligations that allow for deputization. Planting trees carries a great reward and is considered an act of charity for the planter.