Burying trees below grade

[Vancouver]

My lot is kind of uneven and to bring things up to grade I might have to fill in around my cedars (cypress). Is this bad for the trees?

I have preserved nature on my lot and kind of supply a park to the neighbourhood. Neighbours cut down all their trees and bask in the sun but still have all the benefits of my trees. They also flattened their lot leaving a big hill on my property line. There has to be a way to get revenge. I guess I could put up a pink fence.

I'm planting cedars along my property line and hope to cut down trees closer to the house when the newly planted trees get larger. It's an acre lot. Any suggestions on where to plant trees to max privacy and still get some sun. I live in Vancouver, bc. I'm plainting red cedar(cypress). At least i think they are red cedar. Not sure what yellow cedar looks like.

 

[Jay Banks]

Van,
Any filling of soil around existing trees is problematic. Changing grade on sites accounts for most of the tree mortality I see.

But you say your planting trees as well. I would fill first than plant. Be carful when filling with heavy equipment (even a skid-steer loader) they tend to compact the soil which will cause additional problems.

 

[Vancouver]

I know what you mean. We subdivided and most of the tree on the new lots died from , i guess, drainage ditches and heavy equipment, etc. I'm trying to plant the new trees where it is up to grade close to road. Thanks for the good info

 

[Wulkowicz]

Over at Park 480, back in Chicago, the new park would have taken some time to get past its infancy, so I kept some existing cottonwoods in the southe-east corner for their mature size and filled in around them. The right, or front, grade change is a bit over a foot or so; the left, or back side, is probably about 3 + feet. Both grade changes went past the drip line of the trees,

They're very happy, but remember cottonwoods are flood plain trees and accustomed to finding one morning that a river has dumped 6 feet of silt on their feet.

I should also say that this is my drough-proof park and the cottonwoods have access to the drainage/irrigation/aeration system on both sides--and I think this was important to their success under such severe grade changes,


Bob Wulkowicz

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[Wulkowicz]

The Drought-Proof Park

Park 480 Dearborn Park in Chicago, and now named Piggly Wiggly or something like that...


Here's a drawing of the Park proper with the ground excavated dwen to 6 feet to illustrate the system. The system exists in symmetry under the top drawing half as well.

I divided them in half to experimentf with treatment and control work, but they are presently joined together

The park has been in existence for some 10 years with no irrigation system and the park sends no storm water out to the surrounding sewer systems. When droughty times came back to Chicago, I have had to refill the internal system <u>3 times</u> in those 10 years with a visit from me, and with a refill time of 2 or so hours each time. That's pretty labor deintensive.

The water levels can be controlled to an 1/8 of an inch over 3 acres and what would have been a catastrophic storm water probem for the neighbors has been eliminated.

I told the landscape architects at the District that this park would allow them to show if they had any genius, since it was designed to last 100 years without any interventions, and so we might actualy see their trees in full and grand maturity.

This is the first time I know of that a park utility and support system has been built conforming first to the landscape designs. Ordinarily, the landscape staff marks holes where trees go--how boring. Here, the civil engineering staff places drainage, aeration, and irrigation concepts specifically in relationship to the initial placement of trees and other landscaping.

Landscape design comes first, as it should in a park, and the rest of the civil designs follow suit. There are no moving parts, and the materials are expected to last 100 years--really.

As far as I know there has never been any system maintenance, knock on trees.

In my general irritating fashion, I also designed it as a series of consciously defiant reciprocal civil engineering demonstrations to show that you can do the opposite of traditional standards and designs, and the alternatives work just as well. The park "pipes" have no pitch, It also uses no "pipes" in any traditional or even physical sense, and the project received a very kind reference in Phillip Craul's new book, <i>Urban Soils.</i>

The project also received a design grant from the National Endowment for the Arts, whose jury never did decide if the project belonged in the category of art or engineering. Personally, I was most proud of the project's escaping being labelled one or thuther, and then stuffed in one particular box. Park 480 is still a free spirit. How refreshing.




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Ask away.


Bob Wulkowicz

 

[treeguy347]

In general, how much fill can you safely put around a tree?

 

[John Paul Sanborn]

It depends on what you are trying to accomplish.
Short term retention of existing canpopy to establish new trees, then you can fill pretty high as long as you do not use heavy equipment wich will compact the soil. Thou of course, very few studies have been donr on this, and none wrealy long term. Some are currently ongoing.

For the long term;25, 50, 100, 200 years- raising the grade around trees becomes problematic in that the bark tissue is not addapted to contact with moist soil. Insect and disease can easily follow. Smiley at Bartlet labs also has reported a noticable increase in pine vitality by just clearing the basal area of soil.

Second you will encourage root growth in the "zone of trunk expantion". This is the cylinder of space around the tree that will become its mature basal diameter. Not DBH, but where the flair and other "rapid taper" structures come in.

Third is my own pet theory; all old large trees have well developed flair and palisade structures. Open grwon trees will have more the stand grown trees because they need more "anchor" roots or and put more force on these structures.

Thses larger roots that devlop into palisade are called "First order roots".

Smiley has noted that fused root plates and "elephant's foot" of roots is a major indicator of decay in the basal-flair region and root rot.

My observations tell me that trees with fused roots do not usualy have good palasade structures and usualy are not very old.

I gather form this that if we have roots nwe roots growing so that they cross the first order roots and fuse/graft then these FOR's will not be able to gain the taper to become paisade structures.

As thwe bumper stickers read "It takes 100 years to get a 100 year old tree". So if we want these trees to last several human life times then we need to properly maintain the basal area. In natural settings there are perionds of errosion that will clear the flair of soil so that roots cannot grow. In landscape setting with turf or mulch mounds, this area is an environment condusive to root growth. Periodic excavation and pruning of roots that cross the FOR's would increase the probability of palisade development and decrease the development of a fused root plate.

Of course not every tree would need this treatment, just the ones the owners want to grow to full maturity.