Need suggestions for erosion control

We moved into an old home and property that had been neglected for many years, and are trying to gradually wrestle it back into shape. The front perimeter of the property is ringed by old pines and a couple old oaks that, unfortunately, sit very close to a steep drop-off. The edge has clearly been eroding for years, and is continuing to do so. We have high winds here, and several of the pines have already lost their tops in windstorms. Several of the trees have a large portion of their roots exposed and hanging over the drop with no soil; we had to take down an old oak last fall because more than half of its roots were exposed in midair: sitting duck for the next windstorm.

This ring of trees is important to us for privacy, shade, and just because they're lovely old trees; but I fear we're inevitably going to lose most or all of them to erosion. I'd like to plant a new ring of trees a bit further from the edge, both in hope of slowing the erosion and also to provide privacy if we do lose the old trees over time. I'm thinking a mix of fast-growing conifers to provide year-round privacy, along with some deciduous trees for some welcome additional fall color and deeper rooting for erosion help. I don't feel I have the experience to make the best decisions on tree selection, how far from the edge to plant, etc., and am hoping for some advice and suggestions. I'll post several photos to show you the situation. Here's a part of the ring of perimeter pines.

Part of the problem might be that evergreens tend to kill any ground level plants beneath them by a combination of too much shade and the build up of needles which act as a kind of natural mulch. One wildflower type that might grow there would be a sorrel (oxalis). If you could successfully introduce these under your pines that might help. Violets might grow also although they are considered invasive. If you want to keep the pines you might also try rhodadendrons, not directly under them but perhaps on the slope.

Thanks for the reply, shadowgarden. We already have wild violets growing, well, wild everywhere on the property; and you're right, they're one of very few things growing directly under the pines. The poison oak, of course, does just fine, and had all the trees completely wrapped when we moved in. We got rid of it there posthaste, but it keeps creeping up from down by the roadside.

I wasn't thinking of planting the new trees directly under the pines, for just the reason you mentioned, but rather at least a few feet further in from the perimeter. A surprising amount of light comes through the pines; they are so tall that the canopy is quite high, and some have already been topped by windstorms. The litter of needles is another issue, and is quite real.

Planting on the slopes or roadside is not really a viable option, for two reasons. Purely from personal preference, I'd rather not spend another couple weeks in misery as I did after hacking and spraying the poison oak vines that were climbing all these trees. I could no doubt get over that hangup; but the more compelling reason is that DOT reserves the right to "maintain" the roadside area and slopes because they serve as drainage ditches/swales. Last fall DOT came through and clear-cut everything at roadside level and most of the vegetation on the slopes; had I planted anything there, it would have been mowed and chipped. It was after DOT did the clear-cut that we could see how many of the trees have their roots exposed and unsupported.

Have you tried any of the native clumping grasses? I planted some Pink Muhly grass a few years ago that got nice and full, and it even spread some by seed on it's own. In late winter you can just stick a match to it and burn it down, and the next spring it will come back looking great.

How about camellias? They love it under pines in the shade. Evergreen for privacy, roots would help hold the soil and winter color. If you pick the right ones out you could have something blooming from late Oct till march. Gardenias also would do pretty well there. In my zone hydrangeas love it in the shade and they don't seem to have a problem with pines.

Basicly you need to get plants growing with fairly big roots to hold the soil and as a wind break. Then you can add a thick layer of mulch and add some ground cover. BTW oak trees don't like their roots covered up, it will actually kill them if you added a foot of dirt or so.