Thursday, June 23, 2011

Shade on Hole #5 Green

As the Summer Solstice came and went this week, I snapped a few interesting and telling photos of hole #5 green that illustrate some of the challenges associated with maintaining that particular green. June 21st, the first day of summer is when the sun should be highest in the sky and thus providing the maximum amount of sunlight to those of us in the Northern Hemisphere. The sunlight of particular significance is morning sun, or in our case sun coming from a south (remember even at the solstice, the sun is still to our south) and east (as the sun rises). Sunlight, or lack thereof, has a very large and identifiable impact on turf, and most especially on the highly managed, low cut turf we use on our putting greens. Below are several photos of hole #5 green at about 8:30 AM on June 21st.

Morning sun is important to our creeping bentgrass greens because air temperature and the rate
of photosynthesis are inversely proportional, that is to say that as temperatures climb, the rate of photosynthesis declines. Most basic functions within the creeping bentgrass plant begin to cease as the air temperature approaches 85°F, including photosynthesis which provides energy to the plant. What this means as the green begins to get full sun at approximately 11 AM in June and July, the air temperature is usually in the mid to upper 70's and sometimes higher so the window for the plant to use the full energy of the sun to make its food or energy is extremely limited and perhaps non-existent if temperatures are closer to the critical point of 85°F. So as a short term fix the plants use several internal defense mechanisms and processes to survive as best they can. This leads to slower growing plant that produces characteristics such as coarse or wide leaf texture and spindly or leggy growth habits that are generally viewed as undesirable for putting green turf.

The answer to this issue is not as simple as cutting down all of the trees surrounding the green but rather, selectively thinning the wood line to eliminate the trees that cause shade issues and saving those that give the hole its character. While efforts have been made in years past to selectively thin the wood line on a smaller scale, this coming winter there will more likely be a thinning on a much larger scale to improve the environment in which hole #5 green sits.