Depends on the age. So you can have anything from inches to many feet.
The trunks on this species aren't any narrower or more stout than most plants.

Are you trying to get something that is more narrow or stout? For example a Dawn Redwood and Burr Oak have a very stout trunk as they age.

Eastern red cedar is another plant that varies greatly in width.

I see squat, flat, arrow like and pyramidal forms on a regular basis as it a very weedy speices in my area.

No, we've picked this tree to plant, and I'm trying to find out the tree's Protected Root Zone, in an effort to tell us how far inward on our property to plant it.

Personally that is something I wouldn't worry too much about unless its a species sensitive to root disturbance or soil compaction.

I had several very old Tilia americana at my last house that had their root zone greatly disturbed. A water line was put in 15' out from the trunk. If you can imagine water lines go down pretty deep in zone 5.

They sputtered the next year but came back stronger over the next 4 years.

Here, red cedars are trees that get so big, then they get topped by a storm, and start growing horizontally instead of vertically.

Tomorrow I can get some idea of the trunk size of our largest one. It is near the driveway, so currently surrounded by a moat of snow.

I see that quite regularly here as well with wet snows. I see this species breaking apart more than Silver Maple and Cottonwood.

Then why is it suggested everywhere as a windbreak? And not only that, as a first row windbreak?

I don't question at all what you two are saying, only that I'm confused why it's considered extremely wind and snow tolerant. And it's grows in Zone 2, that alone should make it tolerant to nasty winter weather. I don't get it.

By the way, mad_gallica, thank you so much for doing that for me. I appreciate that you would take your time out of your day to help someone on the internet. It means a lot. Thank you!

I responded to the suitability of juniper on your other thread where I saw it first. As far as locating plants, I would probably move your forsythia to within a very few feet of your property line as a marker so the neighbor stays on his side and to block as much as possible until your evergreens achieve some height. Then take the typical width of whatever evergreen you decide to plant and divide in half. That is the distance I would plant the evergreens from the property line. You don't want them right near the property line since in most places, any branches that stray over his property he can cut as long as it doesn't kill the tree, and you want them as thick and dense as possible. That will also be far enough so that any digging the neighbor does shouldn't harm your trees' roots.

DH and I just decided a minute ago, before he left for work, to just do a nice lilac hedge, a nice TALL one. That way we don't have to worry about snow load or wind, or straying roots, plus I already know they love growing in my yard and voles leave them alone. And we won't have to deal with trunks splitting 15 years down the road, because of a bad storm. I am so grateful to all of you for your help. We just think because of our specific location ie: our neighbors, that large conifers are not going to be right for us. But I am going to buy some dwarf ones, because I see the value and beauty they offer.

NHBabs,

Look at my next door neighbor's ( a nice man) sugar maple, that he planted about 2 inches in from his property line that abuts the Christmas Tree neighbor. My Christmas tree neighbor has already told him he will cut ANYTHING and everything that leans over the line and his trees. That little picket fence is ON their property line. My Xmas tree neighbor is aggressive and has the money and heavy equipment to pretty much cause any and all havoc that he desires. That also went into our decision to not get the big conifers.

I personally have seen Eastern Red Cedar everywhere in that range. 24 inches is very rare...that would be an ancient tree. Usually I see them with trunks 6 to 12 inches.

My parents have a slew of them. VERY wind resistant. They live on the coast, and I've never seen an Eastern Red Cedar come down in a storm. My parents also get a decent amount of snow, and I've never known it to bother the Eastern Red Cedar.

The major reason they are recommended as wind breaks though is they tend to keep lower branches and are extremely salt tolerant. There aren't that many salt tolerant evergreen trees to choose from for Zone 6 and North. Salt tolerance is a necessity for coastal windbreaks and windbreaks along northern highways that are heavily salted in the winter.

They are a somewhat slow growing but VERY long lived tree that is generally pretty happy with human modified habitats...so the only limitation on their height in landscapes in this area is at what point the new owner decides to go for a different look and chop them down.

Not super sensitive to root disturbance...they are a tough tree.

They aren't very shade tolerant, though. Aesthetically they look best when they have no shrubs or trees around them...they get more symmetrical. They can look a bit shabby when clumped up together with other trees. (Why arborvitae are more often planted).

They come in male and female, and I think one of their better aesthetic features is the blue-grey berries...make sure you plant both genders. (Or if they grow wild in your area just plant females.) On an old tree the shredded bark is also interesting. The foliage can get a dull olive color in the winter, though. I've heard there are cultivars with bluish foliage but those are hard to find and I've never personally seen them.

The 'protected root zone' is an area of concern primary with new construction and the resulting damage to existing roots and any grading or compaction of the surrounding soil. It is much less of a concern when any root disruption is localized to a single area, as in your theoretical example of a neighbor's potential excavation/disruption along the property line.

VA juniper between DC and Baltimore, MD:

If you end up doing the shrub hedge would you consider something with more interest?

For example a viburnum could give you more attractive branching, blooms, fall color and berries. Classic Viburnums is a great source for all things Viburnums.

Lilacs have great blooms but are otherwise blah like grass.

If you have decent moisture retention, Viburnum carlesii would be a great choice. Its fragrance rivals lilac and its much more attractive with much more interest. Its mostly resistant to crown borers and leaf beetle to boot.

Or you could do a mix of shrubs for season long interest. I wanted to separate the main drive from a work area that tends to have large tree trunks along with sheds, heavy equipment, our solar panels, etc. So I put in a mix of evergreens and deciduous shrubs and small trees (my height limit is 20-30 feet since it's south of the solar panels) and then tucked in perennials and vines around the edges. Even in winter when about half the plants are missing leaves, the mix of plants gives good blockage to unattractive sight lines.

In December of 2010 after one full growing season looking west down the length of the bed to give an idea of size when planted and spacing of the backbone shrubs. It looked sparse for two seasons but since the plants are in about 3 staggered rows, it filled in faster than a single row.

After 4 growing seasons with some added perennials but not much in the way of added shrubs it is fairly full. Late October 2013

June 2014 looking East along the front of the bed.

Looking west down the back side as fall color is just beginning to develop - no perennials since this is the work area side.

Here's a photo in taken late November 2014 that shows most of it.

I am not suggesting that this is what you should do, just an alternative to having to find one plant that will both accomplish what you want that will look appealing all season. This bed is very little work, getting perhaps 10 hours of work per season, and if I had renewed the mulch, it would be even less time.

NHBabs - that's very much the sort of thing I was suggesting on ILMP's other thread, rather than a wall of conifers. The specification has now gone from 40 foot dense conifers to a lilac hedge so it's hard to know what to suggest.

floral_uk z.8/9 SW UK: Compromise and get Japanese Tree Lilac (Syringa reticulata)?

if i drive an hour to ann arbor.. i pass a couple million of them.. clogging the roadsides ...or overtaking any any previous farm land ....

and i probably have 100 of bird planted ones.. in my beds ...

real PIA plant.. imo ... invasive in some places ... and get this.. native in others ... go figure ....

and do note.. your use of the common name confuses it with what it really is.. a juniper ....

ken

ps: the other thing clogging those same miles is the invasive olive .... its a battle royale.. lol ...

https://www.google.com/search?q=invasive+juniperus+virginiana&biw=907&bih=739&source=lnms&sa=X&ved=0ahUKEwiCzvvw-pLSAhUJ6YMKHcZKCGgQ_AUIBygA&dpr=0.9

By the way I was suggesting simplicity for a reason

Dh went to work yesterday and was talking to his admin assistant, a young man who is a disabled veteran, and who just bought a house a couple weeks ago, and his assistant said that he has Junipers that are blue and around 15ft tall. They're called Blue Point Junipers. Apparently they only grow to 12-15ft tall. DH was instantly hooked.

So now we're back to getting conifers for the screen. And we're going to keep the Forsythias and just keep them pruned small, well, not too small, about to 6ft or so.

I'm probably going to get 6 of them and plant them 5ft apart behind the Forsythias. Then the rest of that border will be shrubs of some sort. I will definitely mix it up a bit. I'm going to buy the Junipers in a small size because I'm still a little spooked. EVERY tree I have ever bought and planted on this South side of my house since 2009 (the year I started planting) has died. A crimson King died within months of planting, 3 October Glory Maple trees developed massive cankers their first winter, and they were wrapped with tree paper up to their branches, all 15 of my European Hornbeams develop massive cankers on their trunks after their first winter, and they were all burlapped! My Golden Raintree croaked 3 years in for no apparent reason, I had a red rocket Maple that died too after its first winter, and finally my recent RedBud tree died after the first winter. So, my South yard is where trees go to DIE. :(

Shrubs on the other hand abound and thrive. So while I could buy the Junipers in a larger size, I want to get them while they're young just to see if they can withstand my little micro climate of bitter southwest winter winds. Conifers don't get cankers do they? I read these Junipers will stop wind in their tracks. We'll see.

Where do you get these trees that keep dying?

I've seen them get pretty big..... biggest I think I've seen is probably about 30-35ft. They take well to shearing and formal pruning and they also make great specimens. Just watch out... the needles WILL stick you.

What waynedanielson said. Did you get all the trees that died from the same place? It could suggest they are being planted wrong. What time of year were they planted? Was the burlap removed from the roots? Look carefully to make sure the new trees aren't planted too deep. That would be more of a threat to trees then shrubs. You could order a soil test...could the neighbor be using excessive amounts of fertilizer?

Blue Star Juniper are gorgeous. Juniper in general tend to be pretty tolerant of wind.

All those dead trees make me think that they were all planted wrong, like planted in the erroneous belief that planting deep is good > trees get stressed and sick > die

There are some really old ones in a funeral home in my town. They are kinda tallish and the trunks are not that thick. They may be close to 24 inches but they are also very old.

I shouldn't have said cankers, I thought the word cankers was interchangeable with frost crack and sunscald, and now I know that they're not. My trees had frost crack and/or sunscald, due to being planted on the south/southwest part of our house. The trees i planted were susceptible to it, which I didn't know at the time. The Crimson King didn't survive no doubt because I didn't water it enough. I watered it, but it was like 8ft tall, and i only watered it about 5 gallons a week (puny for my fast draining soil). And probably the same could be said for the red rocket maple. But the golden Raintree died during a bitter cold winter. I read it was to zone 5, but most sites have it at zone 6, so it wasn't right for my zone in the first place.

Dh and I decided this morning that we're going to do a 6ft L fence blocking the 3 properties that abuts ours, including the next door neighbor, the neighbor's Christmas tree property, and the empty tract of land belonging to his parents. The entire fence will be about 150ft long. That's an immediate 6ft screen. And no waiting for 10 years for conifers to do the job. He's going to take some time off in May or June and we'll do the fence. Just a simple wood fence. No one around here has a fence. Not a single solitary person. But then they don't have 3 properties abutting their backyard either. We're doing an L fence because we don't want to close off our entire back yard. We like the openness to be outside barbecuing and being able to say hello to neighbors walking down to the lake, or the elderly couple who lives up the road, they must be close to 80yrs now, and they walk hand in hand every spring and summer past our house, and then back. I love them. I would hate being fully blocked off from ever seeing them. I admit every spring I look for them, and always a little scared they won't walk anymore. I have 3 Lilacs on that side, and they are quickly growing and will provide some screen, so the yard won't be fully exposed to the road. We also live out in the middle of nowhere, so the only people who drive past here are the people who live here, and the few people who take our road as a short cut to a nearby town.

And now, I'll be able to relax and plant what I want, and for no other reason than pure pleasure. Who knew! lol We still plan on planting Junipers and other shrubs, but now they''ll be here and there, for a focal point, not for a screen.