If your friend has no income from the Christmas tree farm he started this year, he may not be able to set off the expenses incurred in starting and running the farm against his salary or interest income. This is because expenses incurred in relation to a business or profession can be set off only against the income from that business or profession.

However, your friend can still claim the expenses incurred in starting and running the Christmas tree farm as a deduction under Section 35ABB of the Income Tax Act, which provides deductions for certain capital expenditures incurred for the purpose of business of growing and maintaining a specified variety of trees. The deduction can be claimed for a period of 10 years, and can be set off against the income from the Christmas tree farm in future years.

In the current year, if your friend has no income from the Christmas tree farm, he may not be able to claim the deduction under Section 35ABB, but can still maintain proper records of all the expenses incurred for the purpose of the Christmas tree farm, such as bills, receipts, and invoices. These records may be useful in future years when he starts earning income from the Christmas tree farm and can claim the deduction under Section 35ABB.