Dr. Evangelos J. Biblis
Dr. Honorio F. Carino
Professor Emeritus
Professor
School of Forestry & Wildlife Sciences
Auburn University, AL 36849, U.S.A.
Tel. - (334) 844-1090, Fax - (334) 844-4221
E-Mail - biblisej@auburn.edu or
carinhf@auburn.edu
Abstract
The expected volume and value (based on Summer 2000 prices) of structural dimension lumber derived from plantation-grown timber of 25-, 30-, 35-, 40-, and 50-year old loblolly pine (Pinus taeda L.) were estimated and used to determine stumpage values through regression analysis. Also, incremental analysis in conjunction with discounted-cash-flow techniques were used to determine the economic desirability of deferring the harvesting of a loblolly pine plantation stand of a given age for purposes of producing structural dimension lumber.
The results of the study provide compelling evidence that indeed the volume and quality of sawlogs from loblolly pine plantations generally increase with stand age. It was found, for instance, that for 25-, 30-, 35-, 40-, and 50-year old loblolly pine stands like those investigated, the expected total volume yield of stress-graded dimension lumber could be as much as 94.4 m3/ha. (16.2 mbf/acre), 122.4 m3/ha. (21.0 mbf/acre), 151.0 m3/ha. (25.9 mbf/acre), 179.0 m3/ha. (30.7 mbf/acre), and 235.0 m3/ha. ( 40.3 mbf/acre), respectively. On average, the expected annual increase in volume yield could be about 5.61 cu.m./ha. (0.96 mbf/acre). The increased quality of older loblolly pine plantation timber was clearly reflected by the percentages (based on volume yield) of stress-graded dimension lumber graded No. 1 & Better, which were 16.0%, 36.2%, 46.7%, 49.3%, and 83.0%, respectively, for 25-, 30-, 35-, 40-, and 50-year old stands. This was also reflected by the expected unit value yield which were $106/m3 ($250/mbf), $123/m3 ($290/mbf), $140/m3 ($330/mbf), $157/m3 ($370/mbf), and $192/m3 ($450/mbf), respectively. On average, the expected annual increase in unit value yield could be about $3.42/m3 ($8/mbf).
Not surprisingly, the stumpage value of loblolly pine plantations based solely on the value of structural dimension lumber produced also increases with stand age. For 25-, 30-, 35-, 40-, and 50-year old stands like those investigated, the expected total value yield of stress-graded dimension lumber could be as much as $10,006/ha. ($4,055/acre), $15,055/ha. ($6,100/acre), $21,140/ha. ($8,531/acre), $28,103/ha. ($11,346/acre), and $45,120/ha. ($18,133/acre), respectively. On average, the expected annual increase in value yield could be about $1,399/ha. ($566/acre).
Also, it was determined that it would be economically desirable to defer the harvesting of a 25-year old plantation stand of loblolly pine like the one investigated by 5, 10, 15, or 25 years if the minimum acceptable rate of return on investment (MARR) is less than 8.5%, 7.7%, 7.1%, or 6.2%, respectively. For a 30-year old stand, it would be economically desirable to defer harvesting it by 5, 10, or 20 years if the MARR is less than 6.9%, 6.4%, or 5.6%, respectively. For a 35-year old stand, it would be economically desirable to defer harvesting it by 5 or 10 years if the MARR is less than 5.9% or 4.8%, respectively. For a 40-year old stand, it would be economically desirable to defer harvesting it by 10 years if the MARR is less than 4.8%.