In late January, South Carolina experienced a severe winter storm. This storm brought snow, sleet and freezing rain to much of the state. The freezing rain was a major problem in the midlands and south, where it caused heavy damage to forests in 15 South Carolina counties.
The worst damage was to thinned pines where main stem breakage was the predominant symptom. Unlike some earlier ice storms, very little windthrow occurred. Affected hardwoods experienced stripping of limbs, along with main stem breakage. Heavy damage also occurred to trees in urban areas (especially live oak), but this damage was excluded from our survey.
From past ice storms, we can extrapolate the insect and disease activity to be expected from this event. Ips engraver beetles will quickly infest broken pine tops. Ips and Black Turpentine Beetles will also attack standing pine boles with three limbs or less. In the past, very few green pines with more than three live limbs were attacked by any bark beetles. Southern Pine Beetle has not been a problem following ice damage in South Carolina. However, several years ago in Virginia, there was a Southern Pine Beetle outbreak associated with ice damage. Luckily, most of the damage from this storm occurred outside the historic range of SPB. As a precaution, we will establish plots in damaged timber to monitor the associated insect activity.
Pines may also experience other insect and disease problems resulting both directly and indirectly from the storm injury. Annosus root disease occurs in most of the ice impacted area and may infect stumps of pines removed during sanitation thinning. After infecting a stump, the disease grows through the root system and can spread to and kill adjacent pines. Pine stands with ice damage and previous annosus infections should be clearcut, since the disease will likely kill many of the residual trees. Pales weevil may be a problem on pine seedlings replanted on damaged sites that were clearcut immediately following the storm. The weevils may also attack and kill one or two-year-old seedlings growing adjacent to impacted stands.
Hardwoods damaged by ice should not experience much direct mortality due to their injuries. However, ambrosia beetles, various borers and pathogens will attack the injured hardwoods and lead to indirect mortality. Heartrots will also enter damaged hardwoods and cause further defect and degrade.
Shortly after the ice melted, the Forestry Commission performed aerial surveys of the damaged timber. The survey required 21 man-days to complete. During this 20% survey, we mapped damage to stands of commercial pulpwood and sawtimber. Damage was plotted as sporadic, light, moderate and heavy. Acres of pine and hardwood of each type were noted along with the degree of damage and type of timber (pulpwood or sawtimber). Over 1500 data points from the survey maps were entered into a database and analyzed to determine the amount of damage to the forests. All damage was converted to cords for uniformity of analysis. The results of this survey are attached.
Landowners are strongly encouraged to seek advice of a professional forester before terminating damaged timber stands. Often, there are sufficient residual stems to maintain a productive forest. Prices for timber usually fall significantly following such a natural disaster. In some cases, it may be more cost-effective to accept losses from the storm and allow residual trees to grow for a few years.
If you have questions about the survey or potential insect and disease problems, contact the Forest Health Unit of the SCFC, and we will be glad to provide advice. Recommendations for site-specific forest management practices may be directed to SCFC Project Foresters, consulting foresters or other professional foresters.
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