However I have doubts about two elements in your argument:

1. Use of interest rate as discount rate
   
2. Role of interest rate in liquidation decision

A project's cash flows are not discounted at an interest rate. They are discounted according to the weighted average cost of capital of the project owner - called a discount rate. The important distinction here is that cost of capital contains both time value and risk elements.

This is most commonly derived using the Capital Asset Pricing Model (CAPM) according to the formula:

Risk free rate + beta * (Market return - Risk Free rate)

Here the risk free rate is the equivalent of your treasury bill. The second term is made up of beta (a measure of the risk of the individual project relative to the market of projects) times the spread over the risk free rate that a project of market level risk demands.

This is important because the majority of the CoC capital of the forest (or any other) project could come from the risk element, not the risk free element.

This would imply that stable political systems that provide some assurance of returns over the longer term are far more protective of resources than those that do not. This is intuitive and seems to be proven in reality. If you could lose the forest in five year, the incentive to cut goes way up. This is the case in many developing countries where politicians or land owners would rather have a million dollars in a Swiss bank account than 10 million dollars in forest assets.

Maybe the reason that Maxxam was pressured to cut down their holding was not the prevailing interest rate, but rather the contribution to their cost of capital (discount rate) from junk bonds, which require a higher rate of interest than most other debt financing.

If you are looking for a very rough and easy number to use as a discount rate, try 10%. This is not far off of the average return of on US publicly traded stocks over most time periods going back as far as 100 years. While an individual stand alone project with concentrated ownership would require a premium and forest project have their own risk features (more or less than the market), we can ignore that for now.

Plus, a question:

I am a bit confused by the meaning of 41 years in the post, although I expect this is my fault. If we use my 10% discount rate figure, this comes down to 11 years (1.1/.1). Are we now better off after only 11 years?

I think it means that $X = an annuity of $kX for that number of years. An annuity of 10% of X for 11 years is worth X today. An annuity of 2.5% of X for 41 years is worth X today. I can't relate this to your use of 41 years in the post, but again expect this is my fault. It's just after lunch here and my mind is not yet clear.

2) Role of interest rate in liquidation decision

Unless the interest rate only impacts your project, the situation seems far more complex. In the Maxxam case, junk bonds force up their cost of capital, but not those of competitors. However, the underlying interest rate is the same for everyone and thus must be subject to adjustments in the greater economy.

If everyone saw higher rates and wanted to cut, there would be a lumber surplus and prices would go down. To the degree that the interest rate reflects inflation, the increases in discount rates (in the denominator) would be balanced by an increase in prices (in the numerator).

Is there any evidence that resource liquidation follows trends in interest rates? Was it high in the 70s and low in the 90s.

I don't know the answer to this one. I'll try to figure it out while hoping someone else provides the answer first.