So imagine a steep 8 foot tall cliff with a tree on top. Then the hill goes up a little farther. at the 8 foot mark...there's a 80 foot tall 20" round dougless fir tree on the edge. At the bottom of the cliff at ground zero....Ive dug out my new 5 foot deep pond. At no point when I was digging....did I ever hit root from the tree. It looks to me like tree has shifted slightly..but I cant really be for sure or not. The question I have is.....A) Will this tree hold. Its use to being on a cliff...its just I took 5 feet away from it. B)Once the water fills it up....will that support it? C)Do roots of a tree sense that its slipping and dig in a little more?

Any info would help....
thanks.

I'm afraid once the pond fills up, the dirt supporting the tree will but much less firm since it will be wet all the time.

On the bright side, trees fallen into a pond make great structure.

What if its heavy clay? Wont it support it like a bag of water against it?

face,

couple comments from el dorado.

chances are the tree wont make it either because of saturated soil failure or drowned roots (insufficient oxygen exchange in saturated soil) in either case as theo says, you'll have a nice big BG condo when it falls in.

another factor, is the pond exposed to much wind? erosion even in clay is possible along the shoreline, an undercut can develop, and eventually the tree comes down.

on the other hand, the tree could last many years before suffering. doug firs have a pretty good tap root (similar to a ponderosa) but they do prefer well drained soil conditions and an intact drip line for shallow root feeding and oxygen exchange.

good luck

Yeah the tree is 8 feet above the waterline. I doubt the roots would go down that far. But I could be wrong. Somone told me once that the root system of a dougless fir is only 3 or 4 feet deep. Also.....I never hit at roots when I was digging....so most of the root ball could be way back in the hillside. I was thinking about hooking a chain with a come-along (sp?) to it. Just for insurace. But Ill probebly just end up cutting it out of there. I dont want anymore dirt filling in the pond.

I'd be a little more optimistic than some. I grow a lot of Douglas Fir on my tree farm. Firs have a relatively fine root system compared to pines, and do well if the soil they are in is well drained. It sounds like you did not do anything to disturb the root/soil condition in a way that would change the support for the tree. The greatest risk for that tree, being that it is so large, is wind. I'd say if the prevailing winds are from the cliff side, and the tree is in the open by itself, it may come down sometime in a wind storm. ie root support on the cliff side are not as strong and it then will be falling away from your pond. However chanches are the prevailing winds are tward your pond or the tree would not have survived as long as it has. Time will tell. The Doug Fir is a great tree; Enjoy it. If it is shading your new pond it will help keep the water cool for the fish, if you should want to stock it. Keep the grass and other vegistation on the cliff to prevent soil erosion.

Yeah theres plenty of other fir trees around it. Its quite will protected from wind. So far....Its holding just fine.....and we've had a rough winter. I guess only time will tell.

I have a very large oak tree next to one of mine. It has taken about 7 years for it to almost die. But, it is gonna die and turn into a water turkey roost. I doubt that it will ever fall into the pond.

Time to notch it on the pond side and let it become structure. Let the water turkeys go somewhere else to roost.

Its on a steep bank, but its no where near the water. From the base of the tree to the water line is about 4-5 feet. Only time will tell...but I doubt it will die.

So what IS the soil type? If you haven't seen slumping of the slope, you may be fine unless your soil is very well drained and you opened the water table below the tree, but I doubt this was your situation.

Ok I just saw you are right here in Portland... unless you are way out in the east county, we don't have enough sand in our soils to cause any trouble.

Its heavy red and a little blue clay soil. No sand at all. It's still holding strong.

There have been trees right next to the water that look like they will last for ever, and some trees that are 10 feet from the shore line that have died. What is the exact formula That is hard to tell. The decision of whether to keep the tree is What will happen if it dies DO YOU WANT IT IN THE WATER? HOW HARD IS IT TO CLEAN UP? Lately my advice is to let the tree stay and enjoy it as long as it lasts.

OTTO