Though the temperature hovered no more than a few degrees above freezing the morning of Nov. 5, the ground was still soft enough for more than 100 volunteers to plant native vegetation along Thistle Run in western Catonsville.
The trees improved the stream's health in a number of ways, according to a release from the group.
In addition to tree roots anchoring the soil and preventing it from being blown or washed away, trees also filter out air pollution, provide habitat for wildlife, prevent pollutants in the soil from entering the waterway and provide a canopy that prevents flooding, the release stated.
The Maryland Department of Natural Resources did a tree planting in the same area about a year ago, but the trees they planted "didn't take," said Betsy McMillion, executive director of the Friends.
McMillion noted only 50 of the hundreds of trees planted survived from the DNR project.
Saturday, volunteers planted 40 sycamore, 10 black gum, 10 willow oak, and 10 pin oak trees as well as 10 red osier dogwood bushes, all native species, she said.
"With all the tree plantings we have done in the past, sycamores seem to have the best success rate," McMillion said of the popular large, hearty trees.
"We plant 5-foot trees," she said. "They have about a 90 percent (survival) rate over a three-year period."
McMillion's group planted 20 more trees than they usually do at plantings and added 10 bushes, McMillion said.
"This is an area that our organization for about five years was very concerned about," she said. "At least once a year, we'll come back and do tree maintenance.".
One reason the organization has such great concern for the stream is its location.
Flowing through a horse farm, the stream can become polluted by horse waste seeping into the water, McMillion said.
As part of the DNR project, a fence to keep the horses away was constructed about 100 feet away from the stream, which was as narrow as a foot in some spots, McMillion said.
The farm is not at fault, McMillion said, noting any type of waste or fertilizer could cause a problem.
"Horse waste is full of nitrogen, and two of the main problems in the Chesapeake Bay are phosphates and nitrates," McMillion said, also noting fertilizer as a potential pollutant.
A nitrate is a nitrogen atom surrounded by three oxygen atoms.
Jeff Klein, 31, a Catonsville resident who works as the stream watch coordinator for the Friends of the Patapsco Valley and Heritage Greenway, said projects such as Saturday's impact the environmental health of the entire area.
He pointed out that the stream trickles into the Patapsco River, which in turn empties into the Chesapeake Bay
"(The stream's) caked with algae, so even having trees here to shade the stream is going to prevent some of the algae from growing," said.