Pines in decline

Trees facing impacts from conditions of past years

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GREEN COVE SPRINGS – Many Florida residents enjoy having pine trees on their properties. Whether landowners rely on pine trees for timber production and income, a wind break for protection of structures or simply appreciate the visual and environmental benefits to their land, it’s upsetting to discover your trees’ health is on the decline.

Unfortunately, many residents are finding just that, looking up into their tree canopies to discover browning needle clusters and noticing large fallen branches this past fall and winter.

An insect infestation

In addition to these distant decline indicators, residents of Clay County are finding signs of beetle activity in the bark of their pine trees. In most cases, the culprit of these insect invasions is the southern pine beetle or Ips engraver beetle, insects that burrow into the bark of the tree, forming colonies by carving out tunnels or galleries underneath the bark, and feeding on the phloem tissue of the tree. A clear indicator to the presence of engraver beetles underneath the bark is the formation of pitch tubes on the tree; these are formed when resin pressure from within the tree pushes resin out through the entrance burrows of the insects, resulting in hardened globs of resin on the bark.

Trees get stressed, too

When residents identify the cause of their dying pines, they hope to determine a fix-all solution, but the problem doesn’t start with beetles. Engraver beetles target trees that are stressed or weakened, therefore the presence of these insects is not the initial cause of tree decline, but rather an indication of another underlying issue. Residents across the county are finding pines with beetle infestations and

dying needles, which points to a wide-reaching tree stressor. Fluctuating and severe weather conditions are known to cause stress for pine trees, but with moderate rain and mild temperatures in the county for several months, there is no apparent weather-caused problem. Forest professionals agree that poor environmental conditions can have delayed stress impacts on trees; looking back on the weather of the past year or so, the area endured droughts the previous summer and winter, a stressful event that is likely the cause for decline of pine tree health today.

What do we do now?

While we watch pine trees in the area decline, unfortunately, there’s not much we can do for those trees already heavily impacted. But there are management practices we can implement to save the remaining trees by promoting tree vigor.

• Remove the damaged and dead trees. Engraver beetle colonies can spread between trees when the colonies become large enough, so removing the infected trees can save the surrounding ones from attack.

• Thin dense stands of trees; as pine trees get older and larger, they compete more with surrounding trees for resources, which can cause delayed growth and weakened stands.

Pine trees in the area have been in poor health, exhibiting stress and weakness from past droughts. While we can’t easily eliminate engraver beetles or put a stop to tree stress, we can utilize certain management practices to reduce these problems and protect our trees. For more information on pine trees and forest management, contact UF/IFAS Extension Clay County at (904) 284-6355.

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