Sir firstly the height and diameter as per act needs to be cosidered, as 1.35 meterers state in rules the Grith is just that you need to mention same in the Forms given while taking permission it is not defination of tree it is just infromation they obtain to decide the case(just a detail in application form B)

Now you have to ways first engage a tractor in night peacefully uproot the trees silently but just donot trasport same  just make sure they are chopped in filed into small locks and in future slowly can used as firewood. Now i would strictly not sugges you first way as it is illegal you need to file an application in FOrm B fill in all relevant details and ask for permission and when the permission is granted you need to report same.

If a person desires to cut, dispose or fell a tree then the person has to make an application to the concerned Tree officer for permission. Such application (has to be accompanied by attested copies of such documents as 

Ownership over the land.The number and kind of trees to be cut.The reason for cutting the tree.After inspection, the Tree Officer may either grant permission in whole or in part or for the reasons recorded in writing.

Obtain permission from tree authority for cutting the jungle trees in your land as they are at height of30 cms from ground level and 8-9 cms in diameter 

2) measure of height to constitute a tree should be 1.85 metres as mentioned in act 

3) provisions of rules cannot over ride provisions of act

1. As per the information mentioned in the present query, makes it clear that you have been going into the right directions as been going through the act of law for your desire for felling the trees.
2. Yes, you need to make an application for the same as mentioned in the act itself.
3. Thereafter, an inspector would come to inspect the same to see as to whether it has been falling under the ambit of category of felling tree as per the definition and description of the trees given in the act or not.
4. Once it is said to be on by inspector, trees would be fallen by the department staff only.

Don't ask permission to cut the trees , ask some contractor that you wants to sale out these trees then he automatically will get the permisssion and your headche will go and as far as I am of the opinion that in Delhi there are some contractors who do this work and they have valid licence for the purpose.

You may tender an application before the concerned authorities giving the actual description of the trees in your farm, while requesting permission for felling the trees.

The officials may make a visit to inspect them and would give a report as per their inspection.

HYou can also prepare a report from your side and present your arguments before the forum and try to get the desired result