Turf & Rec

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Turf must trump trees on golf courses: Moeller

March 8, 2013  By  Mike Jiggens

Trees have an important role to play in the world. They are nature’s
air conditioners, cooling the area around it, they contribute toward
privacy and noise abatement, and infuse significant amounts of oxygen
into the air.
But on golf courses, trees may not necessarily be so friendly.

“Trees and turf don’t get along,” said the USGA green section’s Adam Moeller, who spoke to members of the Greater London Association of Golf Superintendents (GLAGS) in February at their winter conference at London’s West Haven Golf & Country Club.moellerweb

“The sunlight and air movement the putting green receives is by far the most important factor in your success for that particular green,” he said.

Trees growing in close proximity to greens can significantly impede sunlight and air movement, contributing to problematic putting surfaces.


Clay root zones 10 to 12 inches below the surface may not drain as ideally as they should, but they can work as long as their growing environment is good, Moeller said. In other words, as long as there is ample sunlight and air movement, they can work.

That’s not to suggest it’s the most ideal type of root zone, but the growing environment is more important than the root zone, he said.


“The biggest challenge with trees that we have to deal with is, by far, golfer education.”

It’s an issue the USGA’s green section has been promoting in recent years. Golfers must understand that trees and turf do not get along and trees are not essential to a golf course.

Oakmont Country Club in Oakmont, PA, site of the most ever U.S. Open championships and venue for the 2016 major tournament, removed several thousand trees from its property over the past decade. Moeller said the course actually became more difficult to play after their removal, adding both the course rating and slope did not significantly change afterwards.

“In general, removing trees is not going to impact the slope or rating of a golf course.”

Golfers are apt to think that if a tree is present, the course is more difficult to play, but Moeller said even if a row of 50 trees are removed, the game is still challenging enough that most golfers are not going to shoot par or better.

Although trees add aesthetic value to a golf course, they may be growing in a less-than-ideal location and are apt to be more of a hindrance to a green’s health than a contributor towards its playability or visual appeal. Their simple removal is something which many golfers will resist based on both environmental and cost concerns.

If a tree has to stay in place, the superintendent must consider other options to ensure a green’s long-term health, Moeller said.

“Will you be able to maintain that green the same as all the others?”

In the end, it makes more sense to cut a tree down than to relocate a green, he said, adding a tree is temporary and will eventually die at some point.

When looking at trees, golfer safety is first and foremost, he said.

“When you’re looking at the trees on your golf course, the more you’ll be surprised at how many have obvious structural flaws and appear to be somewhat unsafe.”

Trees can also cause traffic issues when they are located around greens and tee complexes, creating wear and tear concerns.

In agronomic terms, trees have a large impact on summer and winter turf conditions, Moeller said, with temperatures colder during the winter and warmer in summer. This can lead to more disease pressure and weaker turf.

Weighing a tree’s removal against having to deal with disease issues, “it seems pretty obvious,” he said.
Excessive and prolonged shade will restrict photosynthetic activity, preventing the plant from not being able to produce sufficient carbohydrates. This will lead to less root mass.

Morning shade is the worst, Moeller said.

“That’s the one you have to get rid of as soon as you can.”

Unlike afternoon shade, which can help to moderate soil temperatures, morning shade is detrimental.
Morning shade also leads to lingering dew and more pronounced frost issues.

During his presentation, Moeller showed pictures of two greens from Dublin, Ohio’s Muirfield Village Golf Club—one which had a half-inch root system and the other which was about three inches. The only difference between the greens was the amount of sunlight penetration they received. The more shaded green contributed to the smaller root system.

As important as sunlight is to a green, the amount of air movement it receives is arguably the bigger concern, he said, adding air movement issues tend to be overlooked as not having a high enough priority.
Where tree cover around a green is so dense, stifling air movement, many golf courses have installed fans to artificially move air.

“It used to be unheard of to have a fan in Ontario. When we think about the benefits of fans, they’re pretty significant.”

Moeller presented data from two different greens from the same golf course in which air temperature gauges were placed on the turf and left to sit for five minutes. On one green, where air movement was restricted, the temperature above the canopy was recorded at 97 degrees Fahrenheit. The second green, located about 100 yards away, was in full sun and subjected to ample air movement. Even though the air temperature was the same in both locations, the temperature above the canopy was about 10 degrees cooler on the green with free-flowing air movement, “which is a huge difference.”

An industrial box fan powered by a generator can be helpful. Fans on golf courses originated in the American southeast, Moeller said. As a rule, they are turned on in May in that area once temperatures reach about 85 degrees Fahrenheit. The same temperatures are realized in Canada, but they arrive later in the season.

The benefits of fans are just as important to Canadian golf courses, even though their operation is required for as long as they are in the American southeast.

Portable gasoline-powered fans are a viable option for golf courses which don’t necessarily want them on site all the time, Moeller said. Ranging in cost from about $5,000 to $7,000, fans can either be wired in-ground or powered by gasoline. The latter option produces more noise output, but have the benefit of portability.

“If you can take down some vegetation or some trees, that’s the better way to go.”

The effective range of a 50-inch fan is about 130 feet, but Moeller suggested testing a fan’s efficiency against irrigation flags set up at various locations on a green.

There’s no substitute for sunlight to melt frost, he said, suggesting it may be easier to convince golfers about the need to thin out or remove trees which would speed up frost melt and allow golfers to begin their round that much sooner.

Moeller said superintendents may want to consider monitoring sunlight and shade patterns on their greens during the longest and shortest days of the years, observing where it’s rising and setting, taking note of various sun angles and determining where thinning can take place. He said certain trees may not be causing shade issues during the summer, but they might be in the winter because of the seasons’ differing sun angles.

If a green is particularly small, it may not be able to afford to have any shade falling on it whatsoever, he said.

Although there are benefits to removing trees to enhance sunlight penetration, the downside is that the turf “risks getting a bit of a sunburn because it’s not used to getting that much sunlight. That’s something you need to keep an eye on if you do take trees out.”

Ideally, a green should receive three to four hours of full sun in the morning and a total of eight to 10 hours throughout the day.

When first planted, trees on a golf course may have seemed like a good idea at the time, but, as they mature over the years, they become a problem, Moeller said.

Anyone considering tree removal on a golf course should hire professionals to do any pruning or cutting work, he stressed, noting the practice can be extremely dangerous if left to someone with little or no experience in that area.

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