existing trees, raising the land for house build

[gamb00ler]

We are about to raise the land on our Hang Dong lot in preparation for a later build.

 

We have 7 trees that are all located close to one side and the rear property line.  We wish to raise the level by about 1 meter.

 

Five of the trees appear to be the same species.  A Thai friend said he thinks those are green mango trees.  The sixth is a different species and the last is not worth saving.  Two of the "mango" trees are probably too close to property line to save.

 

The three "mango" trees are about 6 meters tall and the other tree we wish to save is 7 meters.

 

How severely will the trees be affected by the base being buried by 1 meter of landfill dirt?  Does the kind of dirt we use matter?

 

Here's a close up of the "mango" tree leafs.

 

 

[bubba45]

I'm no expert but I think burying the base of a tree might not be good.  If you're on Facebook, there's a few helpful groups regarding trees and plants.  If you search you'll find them.  One I belong to is only for tree identification, another is an identification and discussion group.  Just a thought.

[bbudd]

Burying 1 meter at a go will stress them for sure

Why not just build a block or woven bamboo surround around them then gradually raise the level

Ideally with leaf compost and fertilizer

Did that here successfully

 

[DefaultName]

Build a block enclosure round them, put in a pond liner (up the tree trunks as well).  Instant "tree moat" and fish to watch - or eat depending on what you put in.

 

Well, it's an idea........  ????????

[gamb00ler]

Thanks to all.  I will probably try the gradual approach to raising the level around the trees we wish to save.

[natway09]

If they are really worth saving which looking at the photo, I think not,

just build a simple retaining wall, which will also give you a level pathway around the house

[chilly07]

 Always remember that tree roots extend well beyond the spread of the canopy extract vast amounts of water and can break through reinforced concrete. It is best to keep trees well away from houses outside of the anticipated root spread . Seasonal ground movement will happen anyway exacerbated by the presence of roots so pile well past the roots to base rock. If you must retain them mangoes will grow to great heights so keep them well pollarded to restrict root growth

[Mister T]

I would not have mango trees within 50 metres of a house or any other building. Termite company told me that termites love to have their nests under the mango then forage from there.

[GreasyFingers]

Filling around them should kill them, but 6 metre mango trees are too high for most people to harvest unless you like climbing. Personally I would fill the land (objective no.1) and plant new trees to be ready for when you build. And then keep them pruned.

[drtreelove]

It can be detrimental for tree health and survival to raise the grade in the root zone. Extraordinary measures can be taken, but it's still a gamble on whether the tree will adapt.  Filling soil against the trunk and root collar of the tree is often a death sentence. Raising the soil grade over the absorbing root system is sometimes tolerated by the tree, but it can also mean a long slow decline and eventual mortality. You may not know until the damage is done and is irreversible. 

 

The primary issue is aeration of absorbing roots and the fill soil creating hypoxia (lack of oxygen), which can impair root function and lead to root rot. Impaired drainage and wet roots that can't dry out in between rains or watering can create root rot.  The standard is not to raise the grade more than 6inches (15 cm) in a period of one year or more, without providing an aeration and drainage system. Fill 4 to 6 inches max, then wait for the absorbing roots to re-surface before adding more. 

 

Does the kind of dirt we use matter?  YES. For trees and other plant materials, think "soil", rich in mineral nutrients, organic matter and soil organisms.  For fill material, clayey subsoil is often used, which will be okay if you don't expect plants to thrive in it without serious soil building improvements. 

 

https://www.tinyplantation.com/soil-fertilizers/soil-vs-dirt#:~:text=Soil vs Dirt There is a big difference,but it is not where it should be.