Current log prices for Douglas-fir are listed on the Oregon Department of Forestry's Log Price Information page. You'll see there that in first quarter 2008, the prices for 2S and 3S (2 Saw and 3 Saw - common log grades for sawmills) Douglas-fir sawlogs have varied between $375 and $450 per MBF.

So assuming these loaded truck volumes and current log values, a loaded log truck would have between about $1300 and $2250 worth of logs on it.

Douglas-fir is the dominant softwood species in western Oregon; ponderosa pine is the main species in eastern Oregon. You can see the other main commercial species (as well as current prices) on the log price information page. The other species include western hemlock, Sitka spruce, white fir (and other true firs), western redcedar, incense-cedar, Port-Orford-cedar, lodgepole pine and sugar pine. Red alder is the main hardwood species.  

Your next option might be to use a programmable calculator and input the formula from Chapter 3 of the Wood Handbook: Wood as an Engineering Material. See page 3-5 of the text. The formula uses temperature and relative humidity as the inputs along with several constants.

Lastly, you might also consider using a small thermohygrometer (usually about $50) and a table of EMC values based on temperature and humidity - such as Table 3-4 from the Wood Handbook.  

There is no rule on air velocity. The faster one dries, the more velocity is needed. Faster drying occurs at higher temperatures, greater wet-bulb depressions, and with sapwood. Species, such as pine, with a lot of sapwood need more airflow than Douglas-fir which is mostly heartwood. When drying at higher temperatures, airflows are typically 750 to 1500 ft/min. Otherwise you can get wet lumber in the center of the loads. We hear of 3000 ft/min in some ultra fast kilns.

High airflow can have negative impacts if surface checking is a problem. The other negative is that airflow is expensive. Eight times as much electricity is required to provide 1000 ft/min as is required for 500 ft/min. Thus, one should only use high airflow if needed and then only after everything else is in order - the load should be baffled well and the stacking and loading should be done to promote good airflow.

This is a short answer to an important question. Two to three hours are devoted to these points during our annual How to Dry Lumber for Quality and Profit workshop.  

TAPPI's "Paper University" attempts to answer this question with their How Much Paper Can be Made from Trees. Citing a book from the American Forest & Paper Association, they report that one cord of air-dried hardwood (which weighs about 2 tons) will produce about 1/2 - 1 ton of paper. 

From what I can gather, barrel makers (coopers) define tightness as the width of the growth rings. As such, tightness is a function of the growth rate of the tree and would thus not vary by species, per se, but rather would depend on the environment where a tree grew. For example, an Oregon white oak (Quercus garryana) grown on the dry, south slope of a hill would likely have narrower growth rings than the same species grown on the north slope of the same hill. Also, foresters can impact growth rate by fertilizing, by altering the spacing between trees when they are planted, and by removal of some of the trees as the forest develops.

In short, assuming I understand correctly how the barrel industry defines tightness, we cannot specify grain tightness by species but rather must depend on where a tree is grown and any practices foresters have undertaken to impact growth rate for the trees.

As a related point - oaks are known as ring-porous hardwoods. That is, in the spring, large diameter earlywood pores (a.k.a. vessels) are formed. After 2-3 rows of these large pores, the much smaller diameter latewood pores are formed until the end of the growing season. This cycle from earlywood to latewood forms the annual growth ring. The interesting thing about oaks is that, the faster they grow, the greater the percentage of the growth ring is comprised of latewood pores, and thus the denser the wood. Thus, slow-grown (tight-grained) oak would be lower density than oak from trees that grew more rapidly. I'm not sure how this impacts barrel making, but just mention in the event there is some potential connection to how the industry views the quality of barrel staves.