The "Berliner Testament" would actually be unfavorable because, in the worst case, two inheritances would occur shortly one after the other and inheritance tax would be charged twice. Therefore, it is not regulated that way here. The legal succession is fine. If Dad dies first, Mom inherits half and I inherit half. She lives in the old house and does not have to pay inheritance tax on it, I live in the new house and do not have to pay inheritance tax on it either. The forestry operation (a forest is always a forestry operation) is also inherited tax-free since it is being continued. So in the end, inheritance tax is only charged on the leased agricultural land, and both of us have a tax exemption of 400,000 EUR each. You just have to make sure that the valuation of the field includes not only its market value but also the rather low lease price. In Brandenburg there is an extreme difference between sale prices and lease prices.
If Mom dies first, it looks different. Since she owns nothing of the real estate, she also has nothing to bequeath there. The burden for me would then be significantly higher.
It will probably come down to us dividing our residential property physically, and virtually dividing the field and forest areas into thirds. But that still has to be clarified within the framework of tax advice. Even the tax consultant did not know that a house always belongs to whoever owns the land...
By the way, the fact that there are no own grandchildren is not a problem for him. He sees it rather positively: That way I can choose myself whom to pass it on to someday. We know enough examples from the environment where it would have been better if the people were not related...