Timber income shows up on the schedule, but it does not tell you when the last thinning happened or what stocking density looked like before the sale

The distinction you are drawing between site index as a measure of potential and actual stand condition is one that gets glossed over in most retail timberland listings, and your forester contact is right to call it out.

For anyone reading this who is newer to timber: a timber cruise is a systematic field measurement of a standing forest, a registered forester walks the tract, samples the trees, and produces a report showing actual volume, species mix, and diameter distribution. Site index is a number from a soil survey that estimates how tall the dominant trees on that soil type should be at a reference age, usually 25 or 50 years depending on species. A high site index means the soil can support fast growth. It says nothing about whether that growth happened.

The basal area point matters practically. Basal area is a measure of how much tree trunk cross-section exists per acre. A stand that is overstocked has too many stems competing for light and nutrients. When you thin an overstocked stand early for cash flow rather than stand health, you are pulling smaller, lower-quality material, and the pulpwood market pays by the ton at a price that reflects that quality. The proforma income from that thinning will be lower than the schedule shows, and the residual stand may take longer to reach the next merchantable event.

I am not a forester and cannot tell you how to evaluate a specific cruise report. A registered forester, one with no financial relationship to the seller, is the right person for that, and I would add a timber attorney to that team before closing.

What region is the tract in, and has the seller produced any cruise documentation at all?

The site index assumption is doing exactly the work you named, and it compounds in a specific way that proformas tend to obscure. When site index is pulled from county soil surveys rather than a site-specific measurement, you are already working with a range, not a point estimate. Entering it as a single number and then running a deterministic harvest schedule treats that range as certainty. Any overstocking or early competition stress then layers on top of a figure that was already approximate.

The basal area reading by diameter class is the critical piece here. A current cruise gives you actual stocking, but the diameter class distribution tells you whether you have a merchantable thinning or a salvage situation. Pulpwood-grade material from a pull-forward thinning on overstocked loblolly can trade at a meaningful discount to schedule-quality chip-n-saw or saw timber, and that per-ton price difference runs through every subsequent harvest in the rotation because stand composition at first thinning shapes what the residual stand looks like at age twelve or fifteen.

The risk you did not name directly: buyer's price per acre already assumes some level of mismanagement is priced in. At $2,800 per acre for a loblolly tract, the question is whether the discount is sufficient given what a cruise actually reveals. Sellers who present a schedule without harvest records are often not concealing anything deliberately. They bought from someone who managed loosely, and they genuinely do not have the records. That still lands on the buyer as an underwriting problem, and the adjustment factor applied to the projected schedule needs to be explicit and conservative.

Tax treatment on timber income and cost depletion has some complexity worth confirming with a tax professional before you close on anything.

What discount rate are you using on the projected cash flows, and are you running any sensitivity on per-ton price to reflect the spread between pulpwood and chip-n-saw at that first thinning?

What is the basal area per acre right now, because that single number tells you whether year four is a silvicultural thinning or a distress cut dressed up as one.

Confirm the stocking density before the site index number means anything.