When you hear the term timber cruise, what are they talking about? The answer to this is very simple. Timber cruises are a system used to estimate the volume of timber in any defined area. The person or persons doing this cruise may use any of a number of different methods to arrive at this estimate. When you hear the term sample plots, timber cruises are referring to just what it sounds like. A number of samples are taken amounting to a set percentage of the total area and then calculating from that the total volume. A 100% cruise is just what it sounds like, every tree is measured. An estimate of the volume of timber may not be a true cruise. Someone may have just walked through the area and made this estimate using their experience of similar patches of timber.

How accurate are these estimates? As a rule, the majority of professional timber cruises are fairly good estimates of the true volume but occasionally you can find timber cruises to be off by as much# as 50% plus or minus. I have seen professional cruises listing species as being different than the actual species of trees that were there. Who is doing the cruise? I have encountered cruises by professional foresters, landowners, log buyers, loggers, truck drivers, persons associated with secondary forest product manufacturers, and several others. I know of several consulting forestry firms that were sued because the volume logged was different than the volume estimated on the cruise. While talking to a real estate broker one time about a parcel for sale he stated to me that he knew that the cruise was accurate because he did it himself. To me this was a little humorous because the broker had clearly added the words with the written listing that "Neither the seller nor the broker guarantees the accuracy of the cruise".

Usually whoever wants the cruise done, landowner, buyer, or other, also wants this cruise converted into a monetary value for an estate or total v#alue of the logs when delivered to the mill or export market. This value arrived at will vary as to the price per MBF or ton these logs are sold for, the lengths cut, breakage or utilization of merchantable timber by the logger, etc. I have seen some log prices drop or raise as much as 40% in only a one month period. In short the value of the timber may be a lot different in February 1999 than in August 2001.

Did those cruising the timber show separate the volume within Riparian Management Areas as defined by the Forest Practices Act in the State of Oregon? This can effect the volume permitted to be harvested under state regulations for up to 100 feet on each side of a large fish bearing stream (average annual stream flow of ten cubic feet per second or greater) or up to 50 feet on each side of a small fish bearing stream defined as having an average annual flow of two cubic feet per second (approximately 7 1/2 gallons) or less.

Over the years I have learned the term timber cruise is someone's estimate of the volume on a parcel and only that. The value placed on this estimated timber volume may at times be accurate but it is my advice to not bet the farm on it.

Editor's Note: Master Woodland Manager, John Foster, is a partner in Oregon Tree Farms, Ltd.