Campus Tree Removal Part of Maintaining a Healthy Urban Forest

March 16, 2016


trees on campusNothing has been more welcome on campus this spring semester than the El Niño-fed series of storms that has brought much-needed rain to the region.

And in the warming breaks between the drops and amid the puddles some not-so familiar sounds have become common: the buzz of the chainsaw and the crunch of the wood chipper.

Between 30 and 35 trees, some 50 years old, have been removed from the Stanislaus State campus in the last two months. While the removal of a tree never is the preferred outcome, often there is no good alternative.

According to Hugo Hernandez, director of landscape, custodial and events for Facilities Services at Stanislaus State, the constant evaluation of trees is a major part of his larger task of maintaining the overall health of what he calls the region’s largest urban forest.

“Our tree program includes a complete year-round assessment of more than 4,500 trees and more than 50 species on this campus,” he said. “We look for trees that are stressed and showing signs of dehydration or effects of pests in the trunk or foliage. It’s extremely important that we determine the cause of the problem because then we can start the proper treatment to keep our trees healthy.”

The decision as to when, how and why trees are pruned or removed involves many factors, according to Stuart Wooley, assistant professor of biological sciences.

“We have to consider landscape trees differently than we consider that same tree in the natural world, or even in a yard,” Wooley said. “A landscape tree needs to be maintained in a way that suits the landscape purpose or purposes, which is a different aesthetic than a tree in the Sierra forest. The different consideration also means that as the campus landscape changes — expanding parking, building, changing climatic conditions — the urban forest of landscape trees will also be altered. We have to recognize that we live in a managed environment and that the landscape can change, and that is OK.”

Maintaining a healthy urban forest, even when it involves the occasional removal of trees, fosters a diversity of foliage with benefits that are nearly limitless, Wooley said.

“First off, who doesn’t love a big, majestic tee,” Wooley said. “People coming to campus are attracted by way it looks, and trees intrinsically give allure to the campus. But there are other values. Trees help keep the campus cooler, and if placed properly they help keep parking lot and road maintenance costs down by keeping those surfaces cool.

“From a biology teaching perspective, we utilize the trees — identifying them and using them as source material all the time in class, and we talk a lot about the diversity of trees on campus, so they’re a huge resource for us.”

Hernandez said that it’s always preferable to nurse sick trees back to health, but in many cases the only answer is to remove a sick tree before its illness adversely effects surrounding trees. Recently, two large trees adjacent to the Reflecting Pond had to be removed after being invaded by mistletoe. While mistletoe plays a fun and even romantic role in celebrations around the holidays, the reality is that it’s a dangerous tree parasite.

“Mistletoe attaches to and penetrates the branches, absorbing all of the water and nutrients from the host,” Hernandez said. “The parasite is transmitted by birds that eat the seeds, so it is necessary that we remove these trees in order to save the rest of our trees.”

Another arboreal problem is rooted in the enthusiastic planting of trees when the current Stanislaus State campus opened in 1965. It was the intent of the campus planners to create the urban forest now enjoyed by everyone at Stanislaus State, but many of the trees planted 30 to 50 years ago were planted too close together.

“Being planted too close together isn’t usually a problem when the trees are young or when all of the trees receive sufficient water to remain vigorous,” Hernandez said. “It isn’t until water is reduced that trees in close proximity to each other start to decline and eventually die.”

And some of those trees planted in the 1960s, while strikingly beautiful, do not fare well in the Central Valley’s arid climate and during the drought have suffered greatly — even to the point of dying before they could be removed.

“A lot of the trees we have lost due to the drought are Sequoia sempervirens, commonly known as coast or coastal Redwoods,” Hernandez said. “These trees require ample watering and are not the best-suited trees for our climate.”

Every time a tree is removed, Hernandez said, plans are made to replace it with a tree best-suited for its campus location, climate and its relationship for the next 50 years to all the foliage around it.

“Our plan and goal is to replace the majority of the trees that we have removed,” Hernandez said. “Our focus will be to replace the trees that require removal with a species more suitable to our Central Valley climate to ensure that we remain the largest urban forest in the region.”