Tuesday, July 27, 2010
Tree Program: Say goodbye to the redwoods
I would like to be more optimistic about the condition of SGCC's many redwoods, but the realist in me refuses to ignore the signs of decline. Redwoods seemed to be the tree to plant as they are fast growing, evergreen, and fairly durable. They are not native to this region, but driving around town, you'd never know as they've become a favorite for homeowner landscapes and street borders. In fact, I will be planting a few in my yard just 30 minutes north and they will do just fine.So why are the redwoods that line the fairways and dot the rough slowly fading into firewood? Two reasons: sodium buildup in the soil and a high water table.
Our water source isn't the worst water out there, but it isn't the best either. Coupled with our dense clay soils and high water table, the sodium present in our water builds to levels toxic to redwoods. We've tried to flush the soil surrounding these trees using gypsum and heavy irrigation just as we would the greens. A flush on the greens requires nearly 6 inches of irrigation to drop the sodium by 50% in a sand green. This is with water flowing through the profile at a decent rate. That kind of drainage is not possible around the redwoods.
Another factor is the climate itself which is not favorable to redwoods for 8 months of the year. Stockton is too hot and dry for redwoods which prefer large amounts of rain, well drained soil, and moist, foggy air. The morning fog in Big Basin Redwoods State Park is just what the massive trees need to make it through a warm day. Some studies estimate that redwoods take up 30-40% of water straight through the needles, although the real benefit is the reduction of water loss, not water uptake. Stockton can be a very foggy place in the winter, but summer air is dry with humidity levels below 50% on average, 20-30% by mid-day.
The slow decline of the redwoods roughly occur in 3 years upon the first symptoms by my estimates. A tree will turn brown coming out of winter and drop many needles. New growth fills in the thin spots and it looks back to normal for the first season. Here is a picture of some redwoods left of #13 fairway which just started to show some stress this spring. They recovered fairly well, but next year will be worse.
The next two years repeat the cycle, but the rebound is not as good. Density and color are obviously compromised and the limbs begin to shrink inward and droop toward the ground. By the fourth season, removal needs to be scheduled. This last pic is a tree left of #10 green. There will be little to no green needles when summer 2011 rolls around.
So that explains the problem and next time I will share some of the solutions and plans to rebuild the forest. The main component of this plan is selecting trees that are well suited to our micro-climate including saline soil, high water tables, and hot, dry summers. There are plenty of trees that will grow very well in Stockton and we have many to observe right here on the course.
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