VARDAMAN VIRTUAL FORESTRY COMPANY

The Most Direct Link to Knowledge Workers in the Southeast Forest Economy

The Current Drought and the Coming Tree-Planting Season

by David B. South

Much of the South is currently experiencing a drought. The heat and lack of rain decreased topsoil moisture with 93% of Alabama, 76% of Georgia, 65% of Tennessee, and 45% of South Carolina rated short or very short.  In these areas there have been record or near-record low streamflow levels.  To see a map showing them with daily updates, click on the U. S. Drought Monitor:

http://enso.unl.edu/monitor/monitor.html

No one knows how long this drought will last, but one of the best ways to kill a seedling is to plant it when the soil is dry.  If we do not get some rain during the next few months, the top foot of soil might become dry as a brick in some regions.  If these are conditions when your planting crew shows up this fall, send them home.  You will be taking a very big economic risk if you decide to plant in dry soil while hoping it will rain during the next few weeks.

Do not get fooled into believing that a 1" rain will give the soil a good soak.  The best way to check soil moisture is to dig a hole with a shovel and feel the soil at both the surface and at a depth of 15 inches.  If there is moist soil at the top and the bottom, then survival should be high if large-diameter seedlings (with a large root system) are properly planted.  When squeezed in your hand, moist soil should stay is a ball when your hand is opened; dry soil will fall through your fingers.

You might also check the latest map of “Calculated Soil Moisture Ranking Percentile” by clicking on this link:

                                 http://www.cpc.ncep.noaa.gov/soilmst/img/curr.w.rank.daily.gif

If your planting area is not in a green zone, soil moisture is likely to be inadequate.

When the soil is moist, you must ensure that seedlings are planted in a manner that will increase the chances of survival.  Deep planting will usually increase the survival of loblolly and slash pine on most well-drained sites.  I recommend planting the root-collar about 3 to 6 inches below the soil surface.  Some tree planters object to this because they must make a deep planting hole requiring use of a shovel or more time to make a deep hole).  Therefore, if your area is suitable, I recommend that you use machine planters.  Machine planters typically plant seedlings deeper than hand planters and survival in droughty years is therefore usually higher.  In some years, survival with machine planting might average 16% to 29% higher than that with hand planters.  Besides making a deep hole, another advantage is that machine planters usually do not prune roots prior to planting (pruning roots by hand-planters often reduces survival).  If the site is not suitable for machine planting, then planting with a shovel will result in higher survival when compared to pruning roots and planting seedlings quickly with a "hoedad."  For much more information on this important subject, click on this link:

http://www.ag.auburn.edu:80/aaes/information/highlights/summer99/pine.html

I strongly recommend use of "morphologically-improved" seedlings (seedlings grown at low seedbed densities) since they often have slightly higher survival than "regular seedlings."  The cost is higher but when planted with a machine in moist soil, they can help avoid a planting failure.  In addition, the "morphologically-improved" seedlings can produce more wood after 10 to 15 years.  For more information on this subject, click on this link:

http://www.forestry.auburn.edu/sfnmc/shovel.html

Recent studies suggest that use of certain lifting machines can reduce survival and early growth.  Therefore, once low-density, large-diameter seedlings are ready to lift at the nursery, make sure the roots are not stripped away during the lifting process.  The key to a successful planting job is making sure there are no weak links anywhere in the system.