Oftentimes, when growing environments around putting greens are evaluated the focus is on morning sunlight during the summer months. Without a doubt, this should be a critical focus when targeting trees for selective removal. However, trees blocking sunlight during late fall, winter and early spring should also be considered for removal. Trees that cause shade during these times can negatively impact putting greens in a variety of ways:
- Shade during late fall can shorten the window for recovery if turf declines during the summer months.
- Sunlight during late fall and early winter helps the turf harden-off and prepare for winter dormancy.
- Shade during winter can increase the risk for winter injury, especially in scenarios where morning sun is followed by afternoon shade on Poa annua putting greens. The extra few hours of shade in the afternoon can increase the rate that the temperature drops and increase the risk for crown hydration injury during freeze and thaw cycles.
- Shade during early spring will delay spring greenup and recovery from aeration or other damage that may have lingered from the previous season.
Winter shade is also problematic if you are growing bermudagrass in the Northeast. An increasing number of facilities are establishing cold-tolerant bermudagrass on range tees and on fairways in the southern portion of the region. While these grasses are more tolerant to cold temperatures than older varieties of bermudagrass, it is important to remember that they are still warm-season grasses and are susceptible to winter injury. The winter of 2018 was a reminder of this fact and in many cases the worst winter injury was observed in areas where turf was shaded during the winter months.
There is no surefire way to prevent winter injury on Poa annua putting greens or bermudagrass in the Northeast, but improving growing environments is a critical step to reduce the likelihood. Growing environments have a profound impact on turf health and performance throughout the entire season – not just during the summer months. If you would like help identifying specific trees that are contributing to turf health issues at your course, contact your USGA agronomist to learn more about our Tree Evaluation Visits.