COURSE CARE
When Trees And Grass Compete, Trees Win December 15, 2017 By USGA Green Section

When trees compete with turf for resources, playing conditions often decline.

Every golf course has a finite amount of space, sunlight, nutrients and water to support plant life. Unfortunately, trees and turfgrass often compete for these resources, and they don’t always like to coexist. Remember, it is unusual to find trees in grassland prairies and we don’t often find turfgrass under forest canopies.

While trees can enhance a golf course, they also require continual management to prevent them from causing turf issues. Trees near putting greens require special attention because they can cause serious problems on these important playing surfaces. Consistent tree management helps limit competition between trees and turf for sunlight, water and nutrients.

Trees have an obvious height advantage over turf when it comes to capturing sunlight. Putting green turf is also at a major disadvantage in terms of leaf area available to capture sunlight. To compensate for limited leaf area, most high quality putting greens require full sun conditions throughout the day.

Trees also block air movement, negatively affecting the turfgrass growing environment. Insufficient air movement contributes to wet, soft playing surfaces that are slow to dry. Disease and turf loss are more common in areas that remain wet for extended periods. As such, it should come as no surprise that the most problematic putting greens on a golf course usually are the ones surrounded by trees. When problem trees are removed, these same putting greens often perform better.

Competition from tree roots is another issue. The majority of tree roots are quite shallow, often occupying the same space as turfgrass roots. This results in competition for water and nutrients, a battle that trees will usually win. Tree roots also frequently grow into putting greens, damaging drainage systems and in some cases even disrupting ball roll. For these reasons, root pruning is periodically needed around trees growing in close proximity to fine turf areas.

Furthermore, tree debris causes playability issues and can damage the blades of expensive mowers. Many valuable labor hours are required to remove tree debris from putting greens each year; labor hours that could have been allocated to other tasks. There are also some trees – such as hackberry, juniper, oak, sycamore and black walnut – that produce natural chemicals that can be toxic to other plants, including turfgrass.

Trees can be lovely to behold, but their location on a golf course must be carefully considered to avoid difficult and costly turf problems. Successful tree management requires routine monitoring, mapping and, when necessary, selective pruning and removal to maintain healthy turf.