If you do the job right, it's not so much that you'd be risking their lives as it is you'd be increasing follow-up maintenance (watering) and possibly temporarily slowing their growth a little more (transplant shock). If it's possible to do the job earlier, I would. If it's not, do it when you can and just keep up with proper watering, religiously.

Here is a link that might be useful: Planting a Tree or Shrub

Thanks!! I'll do it as soon as possible and water them well.

i cant believe that one of them grew.. during winter dormancy ... ????

also.. brandon said to water PROPERLY .... with regard to your soil type.. watering 'well' ... might not be right ... they will want a good drink at transplant.. and near total drainage.. wand NEAR drying.. before the next DEEP watering.. with a PROPER mulching ... NEVER let them totally dry this summer.. AND NEXT.. but dont drown them ... insert finger and water WHEN THEY NEED IT ....

trees are moved in dormancy.. hopefully 6 to 8 weeks prior to budding out... so as to give the roots time to get working.. before the stress of making leaves ...

all things done PROPERLY .... per brandon's link ... they will never know they were moved ...

there is little advantage to buying such large trees ... stock half that size.. will outgrow this size.. due to less transplant shock and shorter 'establishment' .. given 5 years.. of NOT moving them.. lol ... there is little instant gratification.. when trying to buy larger trees ...

good luck!!!

ken

ps: they are maples.. you will be hard pressed to kill them .... with proper watering ...

Oh didn't know you replied.
i cant believe that one of them grew.. during winter dormancy ... ???? It must be my delusion. They just feel much larger now. haha
Now I read Brandon's link more carefully.....
I asked the gardening company to remove the burlap of new maples I planted (my friend's advice.) The company said, they remove a cage and burlap off the top of the tree but leave them around the rest to keep the roots stable until they start to grow. They do not interfere with the grow. The one I dug out from the front yard also had cages and stuffs with it. So at least this gardening company is not the only one that leaves them.
Should I get rid of those when transplanting them?
There is one maple I would not transplant. Should I dig it and get rid of those for this maple, too?

If they really said to wait "until they start to grow", then they are idiots. You'd either remove it at planting or leave it there for good (for it to eventually rot, assuming the burlap is the biodegradable type). You definitely wouldn't want to try removing it after the tree starts to become established.

If it were me, I'd try to completely remove the burlap, BUT, if it's a reasonably large rootball and removal of all the burlap is not possible, it wouldn't be the end of the world to only remove the burlap off of the top AND sides (going down the side at least 1' from the surface level). The tree will put out most of its roots in the top 1' of soil, so removal of the burlap beneath the bottom of the rootball is somewhat less important.

See section 3C of the above link, which basically says the same thing I just said.

What they meant is that the burlap will rot after it plays the role of supporting the roots. If I sounded like they said they'd remove the burlap later, my fault. Okay, so COMPLETE removal is not a must. I feel much better now. :-) THANKS!

Even natural burlap can remain intact for many years, underground, in many cases. Different conditions result in different decomposition rates, but even in relatively good cases, some root system damage can result. Trees start growing roots as soon as they are planted and don't wait until the burlap rots (which may be a matter of years). But again, the burlap left on the top and around first foot deep around the sides of the rootball is what should be of most concern.

BTW, I'd guess that, even today, a big percentage of nursery planted B&B trees are planted with at least much of the burlap left on. Of course, nursery planted trees usually don't stay around for as long as their wild counterparts. My worry is for the long-term optimal health of the tree. Many nurseries are much more concerned with whether the tree survives through the warranty period. They know that it's unlikely for someone to think about their contribution to the death or poor health of a tree after many years go by. I'd be much more worried about potential effects from burlap, left in place, on trees that were planted for posterity than with trees that may not even be of concern to the current property owners in a decade or so.

Be very careful in watering. We lost a tree last year because we unknowingly watered it too much. We had only been in this house a couple of months when we bought a flowering tree for the slope in front of our house.

Our logic was that it is on a slope, it will quickly dry out, we have to keep it water and we watered it religiously.

What we did not realize that there were gravel veins in the ground and a couple came out just above the tree. Water from above us perked through the ground and provided water to the tree. This was in mild dry spell, so as the tree started to die, we though it needed more water..

Point understand the geology of the ground you house is built on to prevent these types of problems. Walk around your yard. Is there wet spots in place that should be dry? If so the water may be coming out of the ground from the slope above your house.