458 Highway 98 North
Okeechobee, FL 34972-2578
Phone: (863) 763-6469
E- mail: firstname.lastname@example.org
July 19, 2006
Feature Article - for release the week of July 23, 2006
Dan Culbert - Extension Horticulture Agent
What’s Bugging my Pine Tree?
Our office has received many requests for help recently with pine trees that suddenly die. Many callers report piles of sawdust on the ground and holes in the bark. Residents are desperately seeking that magical “silver bullet” that can bring these anchors in their Florida Yards back to life.
Our office is good, but we are not divine. Many of these trees have been dead for some time, they just didn’t know it. Today’s column will talk about how summer heat, storm damage, insects and construction issues that can spell doom for local pine trees.
A new Extension bulletin has just arrived at our office, authored by several UF professors including Dr. Ed Gilman. It deals with many issues on how hurricanes have affected our urban forests. One specific section talks about pine trees.
What causes yellowing of the needles and pine death? The causes are not completely understood, but it is likely due to hidden damage produced by bending and twisting during hurricane force winds. Prolonged winds may also rip smaller roots without breaking the larger support roots.
The injured stems and roots are unable to supply the water and nutrients needed in the crown, resulting in yellow needles and pine decline. And recent hot summer temperatures have caused the trees to use up the last of their reserves. They’ve run out of steam.
Pines are very sensitive to wind damage. They can snap, uproot or lean during storms. A pine still standing after a hurricane may have internal damage that is not visible. Before making a decision to remove these trees, wait and see if the tree lives.
• Pines may die slowly over a period of 6 months to 2 years after wind storms.
• Some may remain green for a year or more, then suddenly turn yellow and quickly progress to brown needles.
• Pines with all brown needles are dead and should be removed.
• Monitor pines carefully for insects. Weakened pines may be more susceptible to beetles and diseases.
If your pines are not entirely dead, but still showing signs of damage, here are the steps to take in cleaning them up after a storm:
• Step 1: Remove hazards, such as dead, broken and hanging branches.
• Step 2: Remove branches with no needles or brown needles.
• Step 3: Leave branches with yellow needles for now.
• Step 4: Wait and see how pines do the following year.
What about those beetles?
Pine Forests in northern Florida have been hammered by a beetle known as the Southern Pine Bark Beetle. These insects lay eggs in the bark, hatch into grubs, and burrow into the trunk. These grubs can quickly attack the pines and rapidly spread from tree to tree. In the case of this insect, removing infested trees is good way to halt the spread of this problem, BUT its’ not what’s going on in our Florida Yards.
The Southern Pine Bark Beetle (SPB) attacks only certain kinds of pine tress, and we are fortunate that this insect has not developed a taste for the kinds of Pines found growing in our area (photos below). To the best of our knowledge, SPB does not eat Slash Pine or Sand Pines, and there are very few Longleaf Pines left growing in this area. SPB is not causing the local piles of sawdust.
Slash Pine are the most common pines in our area. Needles are 6-12 inches long. Photo: Carol Bailey
Sand Pine grow in well drained soils such as Scrub habitats. Twisted needles are 4 or less inches long. Photo: Dan Culbert, UF/IFAS
|Longleaf Pine grow slowly and have needles longer than 12 inches. Photo: UF/IFAS|
There are several other species of Pine Bark beetles found on local pines, but they are generally “decomposers”. Ips engraver beetles and the black turpentine beetles usually attack pines that are already dying or dead. Spraying insecticides on these critters will NOT be very helpful in bring the dead tree back to life. And using these products will probably cause a lot of damage to other desirable and non-target organisms in your Yard.
Pine Bark Beetles of Florida
Black turpentine beetle, [top, left] Dendroctonus terebrans is found at the bottom six feet of trunks.
Southern pine beetle, SPB (Dendroctonus frontalis [botton, left] does not infest pines found in southern Florida.
Ips beetles [3 species at right] are found on the upper sections of pine trunks.
Diagram by John Foltz, UF/IFAS
Buried Alive and Run over
Pines are often found growing in vacant land that is being developed into sites for homes and other buildings. The roots extend wider that most people are aware of and are sensitive to long term changes in moisture and growing conditions.
Bulldozers and trucks rolling over roots will kill the pines. Adding fill over roots will smother them. Trees that grew up with Mother Nature alone don’t do well once excessive irrigation, fertilizer or pesticides are added to keep the new green grass growing underneath the branches. If any of these activities have been around your pines, you can often bank on spending money to remove them before too long.
If you have enough room so they will not fall on buildings, do consider replanting small pines in your Florida Yard. Plant them well enough away so that when they reach maturity the will not be a risk to your roof. Groups of pines hold up to the wind better that single trees, so plant them in clumps. They can add lots of diversity for wildlife and be an important part of our urban tree canopy. Don’t give up on them.
I’ve placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu. If you need additional information on pine trees, please email us at email@example.com or call us at 863-763-6469. Local residents can stop by our office at 458 Hwy 98 North in Okeechobee, and visit our Okeechobee County Master Gardeners from 1 to 3 PM on Tuesday afternoons.
Trade names, where used, are given for the purpose of providing specific information. They do not constitute an endorsement or guarantee of products named, nor does it imply criticism of products not named. The Florida Cooperative Extension Service - Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research, educational information, and other services to individuals and institutions that function without regard to race, color, sex, age, handicap, or national origin. Florida Cooperative Extension Service / IFAS / University of Florida. Larry A. Arrington, Dean
Dutton, Dick & Culbert, D. Trees & Construction. Okeechobee: UF/IFAS Extension Service, 8/4/04. http://okeechobee.ifas.ufl.edu/News%20columns/Trees%20&%20Construction.htm
Foltz, John L. Pine Bark Beetles in Florida. Gainesville: UF/IFAS Extension Service, June 2001. http://eny3541.ifas.ufl.edu/pbb/PBB_ID.htm
Gilman, Edward F., Duryea, Mary L., Kämpf, Eliana, Partin, Traci Jo, Delgado, Astrid and Lehtola, Carol J. Assessing Damage and Restoring Trees After a Hurricane (ENH-1036) Gainesville: UF/IFAS Extension Service, June 2006, p.9. http://edis.ifas.ufl.edu/pdffiles/EP/EP29100.pdf