Construction damage to tree

Question

Construction workers have cut a large section of roots from the base of the trunk of the tree in question and I'm trying to find ways to save it.

Some background information: It's a 50 foot tall, perhaps 40 year old tree in the polyalthia family.. Similar to the polyalthia longifolia in terms of leaves etc but just a bushier variety it seems. I live in bangladesh and it's winter now. below are wiki links to the different types etc.

variety.https://en.m.wikipedia.org/wiki/Polyalthia

https://en.m.wikipedia.org/wiki/Polyalthia_longifolia

They were cut without my permission, to install a pillar and the roots are very big since it is from the base. I am watering it daily on the sides and at the base where they cut it every other day to prevent rot. I did however add an organic mix fertiliser by raising the ground level just a few inches, both of which I hear might not be a good idea. Though the tree is supposed to shed leaves this season and grow new ones at the same time, chunks of leaves are going yellow which is not normal and the baby leaves seemed to have stop growing.. I would have attached photos but could not find a way.

This tree has a lot of sentimental value and I'm trying ways to save it and would love to hear some expert advice. I'm also thinking of loosely tying the tree to a two storey building next to it in different directions to stop it from falling over when it gets windy since two very major roots were cut, which in my opinion were some of the most important ones as there is a brick sewer on the other side and I think the roots on that side would have had to go down instead of laterally making the severed lateral roots integral for structural stability.

Would greatly appreciate some advice to save this tree.

Answer 1

By the time a tree is 40 years old they have adjusted to the neighborhood and do not like changes in the level of the soil or amount of roots. These suggestions work for most trees:

• do not raise the level of the soil more than a half an inch (1 cm) per application. Do top dress up to twice a year with compost or other organic matter.
• after the damage to the roots the best practice is to water the whole area under the tree and leave it alone. Pruning is not required.
• some leaf drop is inevitable as the roots that support those leaves are gone. If the area of roots removed is less than a third of the area under the tree there is a good chance the tree will recover
• if the tree is loose in the ground and could fall and damage property or people then removal should be considered. Loosely tying a tree that is 50' tall will not stop it falling in windy conditions

This reference is fairly technical but does show that there are a lot ideas about tree roots that are not correct. The life of a tree is immensely complex and there is much more to learn.