hey randy,
that's a can of worms regarding time since there are many anomalies around GPM, machine cycle speeds, amount of rock/dirt, type of tree, root ball but going on the laws of averages, from my experience on oak, hickory, walnut, hedge, locust, hackberry, pine, cedar, in those sizes it will be a while and you will be faster with a smaller bucket vs larger - why.........because to penetrate hard items such as rocks, clay, roots, the ability to get through, around, between is so much easier and less digging with the smaller bucket. Clay sticks to everything and roots bind it as well as rocks, I can assure you the root balls will be as big or bigger than your tractor/loader and backhoe on a 45hp unit not to mention weigh as much and more - I seriously doubt you will even be able to get the entire root balls out with your machine unless you use some engineered leverage manipulation. I have 10K lb skid steer and on 18 inch stumps its a 2 hour job to get a stump ball out in our soils if things go well. Then what the heck do I do with the monstrosity once its out of the ground you sure as heck are not going to lift it and my machine is a 2500lb lift machine. most 45hp tractors are going to weight from 2500 to 4500 add the backhoe and loader you might be lucky to hit 6500 - good luck moving that rootball, you are basically adding more and more time and effort and stress on everything including your own frustration.
I can move and roll the root balls but where do you put them? you will have a heck of a time pushing them around in the timber and get them hung up on things and take more time and stresses etc......
they do not dissolve, they do not rott quick, they do not get much lighter, we place them in ditches, lakes/pond for cover for fish, as we are building/taking them out because they are truly obstacles
my concern for you would be wearing out your machine quickly, breaking things, getting hurt, all of those things trying to do a job that needs something much larger. not trying to talk you out of anything but I would rather work with a rock than a stump.
I agree with the others a 45hp tractor would be adequate for most all other things but I think you will get frustrated quickly with the stumps and then have a backhoe that you are pondering uses for it since the stumps have won out -
For what you are looking at the easiest would be a large excavator/trackhoe - however you will then be looking at taking out good trees trying to get it to the stumps due to its size, that is why most would probably recommend a dedicated backhoe that weighs 14 to 20K lbs OR the stump grinder of larger size that would do the trick.
IF you have other uses for the backhoe attachment, by all means consider it and give it a shot but from your honest description to an honest experienced stump battler, I have lost many a battle with them and they are overwhelming in many ways.
just for reference, I had an entire house/lot/foundation to clear from a fire on 4 acres - rented a 220 Volvo excavator, including delivery I had it for a week to the tune of 3000 - 2200 for the rental, 800 for delivery/pickup -
took out the entire log house, concrete foundation, broke up everything and cleaned out burned trees/stumps, and done in 5 days and did it all myself - you can do things very quickly with the right sized machine.
all of the BIG trees on this property acreage including mine are in the 40 to 80 yr range, when I put in the road the oldest we had to harvest was 96 according to the rings - the large 80 to 96 yr trees were in the 22 inch diameter range so a little larger than yours but not a lot. Oaks, hickory, mostly hardwoods - the Volvo 220 is around 50K lbs - It still took me about 20 to 30 mins to get one out and then again like I said what to do with a giant rootball!!!!
trees with an 18inch diameter will have a tap root that you will not be able to chew through most likely other than a nibble at a time with your backhoe attachment due to the leverage and weight you have to force the break to happen and likely you will end up digging the dirt away then using your chainsaw - reach will be an issue trying to excavate the root ball on something that size also and chewing around it. Again, it will take time so be prepared - I would perfect my art on smaller ones and maybe save the big ones for later/bigger machines.
I would HIGHLY recommend getting a machine out there to try before you commit to a purchase, you need to realize what you are getting into and your machines limitations and prepare for the other stuff.
hope this helps.....
