David Williams wrote:Without knowing how densely he wants them planted out it's hard to say and being no expert i hope others will continue adding to this thread
If it was me doing it i would leave the slope as is , planting trees in rows , and the second row offset in a diamond grid pattern , and place a small berm on the lower side of each planting
Thus allowing for the tree berms to slow the water down , and retain it for a period , allowing it time to soak to the roots , while keeping the existing soil structure in place , undamaged as it has already been capable of holding the erosion for 20+ years as you say..... Just my two cents
Peace and Love Dave oxoxoxo
John Elliott wrote:I would say neither. I'm basing this on my drives up and down I-15 through the Fallbrook, CA area, noting that they just popped the avocado trees right into the hillside, and don't do much in the way of swales and terraces. If you go to Google maps and use the street view feature, you can see what I'm talking about without ever having to burn any gas.
Here's a reference that discusses erosion control when putting in an avocado orchard.
David Williams wrote:I Tree planted for 2 years on roadsides and non arable farm areas with "Landcare" groups , we planted in everything from rich deep black loams to rock infested clays, and we rarely made any attempt at swale making admittedly since the trees planted were endemic to the area, On hilly area's and planting tube stock plant (not really advanced) would use the excavated soil to make a small berm around the dig site , might have only been 2-3 inches deep on the down side of the hill , and planting area's was anything from 10 inches to 100 inches annual rainfall...
Killian O'Brien wrote:I'm trying to think long-term. With rainfalls getting heavier even with our low overall rainfall, catastrophic rains are becoming more common anywhere rain falls. This slope with features that drive water to specific areas (the tree plantings) seems like an invitation to getting gulleys started and needing repair.
Dave Keck wrote:net and pan earthworks work well for steep slopes. basically each tree gets it's own catch basin and water is overflowed down to the next tree catch basin. you wouldn't want the overflows to go straight down hill to the next tree, but across the slope and down slightly. It forms a sort of diamond pattern with the basins. hope that helps.
Killian O'Brien wrote:He seems to want the root system in this 3 ft. circle.