Join Memorial Park Conservancy, Trees For Houston and Houston Parks - HPARD for the largest volunteer event of the year at Memorial Park! On January 19 at 9am, volunteers will come together to plant about 850 native trees along East Memorial Loop. The tree planting is part of the ongoing ecological restoration efforts to reconnect balanced and healthy ecologies within Memorial Park. Memorial Park Arbor Day is a celebration of National Arbor Day, which is in April for more temperate climates of the U.S. Memorial Park is a park for all Houstonians, and all Houstonians are invited to participate.