Partnering with Keep Houston Beautiful and HLS Enterprises, the Astros have committed to plant one tree for every home run they hit this season, and three players planted four on Tuesday.
Carlos Lee, Brad Ausmus and Mark Loretta helped plant the oak trees at Union Station Trail, a walking and biking trail located at 815 Live Oak Street.
The four trees represent the home runs hit the past two months. The remaining trees will be planted in the fall, when weather conditions are better for the trees' growth.
Lee, who owns a ranch in Boling, said he is used to doing yard work.
"They're not used to this," he said of his fellow players. "They're probably really hot and ready to be in the shade. I told them to come out and spend a day working out at the ranch and see how it's like to be a rancher."
Lee is very involved in the Astros' community service efforts, he said, because he sees it as a way to repay fans for their support. He even brought his son Karlos and daughter Karla, who helped cover and water the trees.
Ausmus said he felt a need to help the environment.
"We're hoping to save the environment for future generations," he said. "There's dozens of things [we can do to help] nowadays in terms of saving energy, saving fuel, obviously planting trees -- not only to improve the landscape, but trees are an important source of oxygen."
Krysten Oliphant is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.