VARDAMAN VIRTUAL FORESTRY COMPANY

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PINE PLANTATIONS ARE SET IN CONCRETE THE DAY THE SEEDLINGS GO IN THE GROUND, SO APPRAISAL OF FIRST-YEAR SURVIVAL IS AN ABSOLUTE MUST

Now that pine plantations are recognized as very profitable investments, it is essential to evaluate their development at every stage, but especially after growth stops in their first year. Except for unpredictable future casualty losses, conditions at that time almost fix timber and money yields. We must determine whether the plantation as it now is will produce the required internal rate of return (IRR). The first step is to count how many living trees are relatively vigorous and free to grow, but before we start counting, we must know how planted trees usually develop and what we are looking for.

In the first plantation bought by Vardaman Pine Plantation Partners, we established four 0.2-acre research plots under the direction of Dr. Harold Burkhart of Virginia Tech. Each tree was numbered, and its location in the plot was determined accurately. After the growing season each year, we measure each tree, record groundline diameter in millimeters and total height in inches, and send the data to Dr. Burkhart for analysis.

If you were on the ground or if we could hand you a three-dimension model of the plot, you'd see at a glance that the seedlings, which looked so much alike in January 1994, have developed at markedly-different rates. We have tried to show this with the map.

The symbols are centered at each tree's location. The hand-planted rows run from upper left to lower right; they are fairly straight, and spacing in them is good, but not perfect. Figures on either side of the symbols are our way of showing the "growing power" of each seedling. Each figure is the product of D2H (groundline diameter in inches squared times height in inches); those left of the symbol are 1994, and those on the right are 1995. Tree symbols show "winners" with a 1995 score of 215 or more, big dark dots show "losers" with a 1995 score of less than 170, and circles with a dot show "maybes."

The map shows that growing power of the plantation may have been set in concrete the day it was planted. The growing power of each seedling came from its unique genetic make-up and the spot where it is standing and not from its relationship to adjacent seedlings. Little trees usually don't catch up with big ones; if they aren't salvaged, the big ones will eventually kill them. Furthermore, with few exceptions that may have been caused by tip-moth attack, their growing power was revealed in 1994; future winners then usually scored better than 7, while future losers scored less than 7.

The first thing to realize is that, because of the irregular pattern of first-year mortality, determining average per-acre survival doesn't help much. You can easily see why. If you had only three acres and all trees lived on one acre and all died on the other two, average survival would be only 33%, indicating that the plantation was a failure. But that's not the way it is. Actually the situation is perfect in one-third of the plantation; the problem exists only on two-thirds of it. To the maximum feasible extent, you must determine the situation on each acre.

We do this by counting survival and condition (free to grow or not) on 1/20th-acre circular plots spaced 330 feet apart along parallel cruise lines spaced 330 feet apart. We use 1/20th-acre plots because the radius

of 26.33 feet is long enough to lap over several rows even in widely-spaced plantations. We keep a separate tally for each plot. Furthermore, we tally the plot with great care since each tree on it represents survival of 20 per acre. We never tally plots until other vegetation has been killed by frost; we learned long ago that seedlings are very easy to miss at other seasons. If we are still uncertain and the decision is important enough, we double the sampling intensity.

We don't count all living trees. Mortality in a plantation is not a regular thing. Most of the trees that die do so in the hot, dry weather of the first summer when they are trying to recover from the shock of transplanting. Then mortality almost ceases and doesn't resume until about age 8 when the trees begin to compete with each other. Our objective in this survival check is to identify and count those that will be present at age 8, the first age at which PTAEDA2V will predict a stand table.

The map shows that you can generally spot the winners in the first year, and we always count them. Then we look for obvious losers, such as those with from 1 to 5 on the left side of the tree symbol, and we don't count them. (Spotting losers is no trick at all.) We give the benefit of the doubt to the rest.

The final step is to run a PTAEDA2V+ECONV analysis of the situation on each plot. In most markets IRR won't change much as survival drops from 400 to 280; value of harvests are nearly equal regardless of spacing because fewer trees have more space and grow faster to more valuable sizes. With even more growing space, however, limbs grow larger and live longer, so unit values decrease because of large knots. Nevertheless, even one limby tree per acre is worth something and should be considered in evaluating the entire plantation. Such an analysis, easy enough with a computer, will reveal whether work is needed and, if so, what and where.

Proper site-preparation gets the planted seedlings off to a good start, but sometimes promotes prolific germination of pine seed that were already on the ground or blew in from nearby trees. Those checking first-year survival sometimes find hundreds or thousands of young volunteers among the planted pines. These are normally no problem; during the first few years, they merely take the place of herbaceous or hardwood competition that would otherwise be there, and we expect that such competitors will occupy less than 5% of the closed canopy. We ignore the volunteers and tally only the planted trees or those of similar size and vigor. When distinguishing the planted seedlings from the volunteers is too difficult, we make a note of it so that we can come back several years later when the limbs have grown together and re-appraise the situation.

Once we get the yields from each plot, mere arithmetic is enough to combine them. Simple, huh?