It has been a hard summer climate wise and as we go into fall it is nice to start getting some relief from the heat. As the heat tones down, we are still facing a drought, which is not as severe as areas to our west but is still significant across much of the Panhandle. In our tree cover, the stress from the harsh summer this year is starting to show. You can see it in trees around the area, and it particularly seems to affect certain trees and conditions more than others. Where you are starting to see it most is in our ever-present pines, which make up the majority of our forest and tree cover in our region. If you keep a look out you may notice some pines in the areas with yellowing or brown needles or that are losing their needles. Those are clear signs of a possible bark beetle attack, which is a common issue when pines are stressed or damaged. Trees planted in the last year that are not yet fully established often show stress in a hot dry summer like this year. Even older and well-established trees in areas are showing some signs of stress from the hot dry conditions we have had this summer. Some trees are less adapted to dryer areas and when planted off site can experience more stress in dry conditions. If you look around across the Panhandle right now you can see clear signs of stress in some trees. It becomes more evident in late summer and early fall as the accumulated stressors of summer push trees into physiological conditions that cause stress responses. The big question is what to do if you notice a landscape tree that is exhibiting signs of stress, particularly drought stress.
Pine damaged by construction equipment. Barking injuries like this can encourage bark beetle attacks. Photo Credit: Ian Stone
For pines the issue is likely to be bark beetles, of which there are several types. All pine bark beetles are native to our area and the degree of damage they do varies by species and conditions. The issue with stressed trees is that most bark beetles attack those trees. When a hot dry summer occurs bark beetle activity increases as the stressed trees become less able to fend off attacks by these beetles. Unfortunately, when bark beetles attack a pine in an area the best answer is prompt removal and disposal of the infected tree material. To protect high value trees in an area where bark beetles are active there are some injection pesticides that can prevent infestation, but once a tree has been infested and begun to show symptoms little can be done to bring it back. When bark beetles attack a stressed pine, most are effectively finishing off a tree that may have died regardless. The key is to prevent them from spreading to other pines in the area or attracting them to a stressed tree in an area. With trees already stressed in our area the big prevention option is not to damage or stress any pines already on the landscape. Most pine bark beetles are attracted to trees by chemicals in pitch and resin given off by wounds or damage. Often the stress from new landscaping projects or construction around pines can cause several to succumb to bark beetles. Your best prevention is to keep equipment well away from the tree and avoid damaging or injuring the tree, especially scraping areas of bark off. Larger and older trees can be vulnerable, as well as overcrowded trees that are too dense or overtopped by others. As the cooler weather approaches bark beetle activity should decrease along with the risk of losing a pine to these pests.
Recently constructed sidewalk. Construction activities extended well into the root zone of the tree, which can cause stress and damage. Photo Credit; Ian Stone
For other trees there are additional precautions that can be taken to lessen the potential that a tree will succumb to drought and other stress. Newly planted trees or those established in the last several years are particularly at risk and should be watered regularly during this dry period. Until rains return, a good method of slowly applying water deeply to the root zone is best. Properly applied mulch can help keep the soil cooler and moist around a newly planted tree. Drip irrigation, soaker hoses, and similar methods are best, and a method that specifically applies water slowly to the tree’s root zone gives the best results. Watering your lawn does not supply sufficient water to landscape trees, especially in drought conditions. Lawn irrigation is designed to apply irrigation needed to the top portion of the soil that is available to the grass. Trees have completely different requirements and need different watering methods and amounts. If you don’t have dedicated irrigation available and you have a tree that needs water, you can use irrigation donuts or bags. These are often a good solution for a tree that needs watering temporarily. Once a tree is well established it usually can withstand even severe drought, but during the establishment phase paying attention to water needs is critical in a summer drought like we have had.
Large established trees are also not immune from the heat and dry conditions that have plagued the Panhandle this summer. Usually when conditions change these trees recover but may abort some branches or exhibit some leaf drop while stressed. Leaf drop is a phenomenon that can occur when deciduous trees are stressed. It is a method of conserving water needs by reducing the leaf demand. Usually, the tree will recover and leaf out again fine next year. A tree may abort some branches or have some branch tips die back to make it through a rough period. Trees that are overcrowded, overtopped, or have other issues are the most at risk from environmental stress. This is why good tree selection along with proper tree care and maintenance is essential. When a hot dry summer like we have had comes along well cared for and maintained trees do best. Trees that prefer more moisture like bald cypress, red maple, sycamore, and some oaks can be planted in dryer sites, but when a severe drought comes along they often don’t have the ability to handle the moisture stress that trees adapted to dryer sites can. This is why site selection is so important, it is when we have extreme conditions that off site plantings typically suffer the worst and those can be larger more established trees.
With the cool weather hopefully we will get a reprieve and some rain soon. Given that fall is one of our dryer periods it may be likely that drought conditions could persist until early winter. Good care and tree maintenance is essential to getting your trees through stressful periods like this summer. For younger trees watering and care is essential while they get established. For older established trees avoid doing any construction or other disturbing activities around them until conditions improve. If you have trees that are exhibiting signs of decline or pest attacks call your local extension office or Florida Forest Service County Forester office. With any luck, colder weather with winter rains will be here soon and trees in our area will recover over the dormant period.
Landscaping in the Panhandle of Florida comes with many opportunities and challenges in this diverse plant environment of coastal, flatwoods (aka pine woodland), sandhills, and clay soil areas running adjacent to the Alabama/Georgia lines. Sandy soil is the predominate soil of the panhandle area from coastal saltwater marshes and brackish bay waters to wetlands and drier well drained quartz sandy soils of the sandhills. Unique ecosystems can be found in all these areas. One of the areas with the largest plant diversity is the Longleaf Pine savannahs found in the sandhills. Now comes the question of landscaping decisions for your residential living.
Native landscape plants. Photo Credit: Stephen Greer, University of Florida/IFAS Extension – Santa Rosa County.
Understanding your soils and how to improve them where you live is critically important before putting the first plant in the ground. We live in an area of abundant rainfall and this will impact the chemistry of your soils. Make an appointment with your local horticulture agent at the University of Florida IFAS Extension office in your county to discuss your soil and landscape ideas. Taking soil samples will likely be needed. With instruction you can easily collect the samples needed to be sent and received to determine the best options.
With abundant rainfall, leaching of key nutrients will occur removing base cations that can include potassium (K), magnesium (Mg), calcium (Ca) and others. This all leads to soils being more acidic in nature. Nutrient resources may need to be added and checked every 2-3 years, just be sure to follow the soil sample recommendations. Soils near wetland areas can leach differently than the deep quartz sandy soils of the sandhills. Adding organic amendments is a recommended practice. Just how much will depend on your soil setting; talk with your horticulture Extension agent. Often new homesites and commercial construction areas have soil brought in to raise or level construction locations. Understanding the movement of water through these newly added layers to the existing soil below will determine drainage and nutrient movement within this site. It can be confusing making decisions about adding soil nutrients, lime, and organic amendments.
Challenges in new soils in landscape. Photo Credit: Stephen Greer, University of Florida/IFAS Extension – Santa Rosa County.
Once all this is settled you can start thinking about how to enjoy this wonderful Panhandle outdoor living opportunity. Creating living spaces comes in many ways from building patios, porches, decks, outdoor kitchens, and strategically places chairs and benches. Talk with your family and others who may enjoy these places with you. Gazebos or barbeque grill areas may be in the plans. Placing these into the landscape takes planning. Draft designs and think of creative solutions for the site. Look at the site elevation changes from high areas to low wetland areas. Will you need “No See Um” screen for the porch to keep out the small insects or install ceiling fans to keep the breeze moving?
There are many questions to be asked. Create a list to be addressed before beginning a project and then determine the cost. Enjoy the adventure!
Trees provide shade, aesthetics, and perspective to the landscape. However, they only serve as burdens if not properly selected and maintained. To help determine what trees do best under certain conditions and to provide information on tree care, this month’s Gardening in the Panhandle LIVE! was all about trees.
Florida maple beginning to exhibit fall color. Photo credit: Larry Williams, University of Florida/IFAS Extension – Okaloosa County
Tree Selection
Some trees grow faster than others. That’s not always a good thing, but if you’re trying to select a tree that grows fast and will provide shade in your yard then you might want to give the following species a try. Click on the links for more information.
A lot of times you’ll read a particular tree species prefers moist, well-drained soil. Some coastal soils are very well drained and require supplemental irrigation after establishment to keep some species alive. One tree that does well in sandy, well-drained soils without supplemental irrigation is the sand live oak. Another tree, that would never win a popularity contest, but does well in sandy soils is the sand pine. This tree has a gnarly growth habit, which would make it an interesting focal point in the landscape. Turkey oaks are another option for dry spots.
There are a lot of fruit tree species that can be grown successfully in the panhandle. The key to good fruit production is selecting trees that are adapted to the average number of chill hours (usually calculated by the number of hours between 34ºF and 45ºF) your yard receives on a yearly basis. Some peaches, plums, and nectarines have been developed for our climate. Citrus such as satsumas and tangerine hybrids grow well in the panhandle, but sometimes require cold protection. Persimmons, loquats, and pears are other fruit trees that grow well.
If you already have mature trees in your yard, then you may be looking for smaller, understory trees to enhance your landscape.
Living this far south, you often have to really seek out trees that change color in the fall. Dogwoods, Florida maples, and blackgum trees all have great fall color. Some of the red oaks also have nice fall color. Two that come to mind are the nuttall oak and the Shumard oak.
Trees can cause a lot of damage if planted too close to sidewalks or buildings. To determine if a tree will fit in a confined space, you will need to consider its mature trunk flare diameter.
Florida is the southern extreme for growing ginko trees. If you decide to plant a ginko tree, make sure to select a male cultivar to avoid stinky, slippery fruit.
To successfully plant a tree, you need to start with a healthy tree. If the tree you purchase was grown in a pot, make sure it isn’t rootbound and doesn’t have encircling roots. You also should inspect the tree’s form, branching structure, and look for the presence of included bark. Please read “Selecting Quality Trees from the Nursery” for more tips on what to look out for when purchasing a healthy tree.
Some trees are more tolerant than others of high winds and flooding. Please read this publication about tree failure from hurricanes to help determine what tree species are better adapted to these weather events.
Santa Rosa County Master Gardener Pruning a Stone Fruit tree at the WFREC. Photo Credit: University of Florida/IFAS Extension
Tree Maintenance
Armillaria is a common fungal pathogen that infects trees from their roots. Other major diseases are more specific to certain species. A more comprehensive list of tree and shrub diseases can be found on the Ask IFAS website.
Tree establishment period depends on a lot of factors. Once a tree is established, it’s roots can be equal to about three times the distance from the trunk to the dripline.
Fallen leaves can help add nutrients back to your yard. Even if you are trying for a manicured lawn, you may want to rake up the leaves and use them elsewhere in the landscape.
Regardless of the species, most fruit trees benefit from a good pruning. Deciduous fruit trees should be pruned to maintain good branch structure and form, while citrus may benefit from a light hedging.
Trees are a wonderful addition to any landscape, but it’s important you select the right tree for the right place. Hopefully this article provided some information to guide you in the right direction.
A biologist with Blackwater State Forest checks longleaf pines for signs of red cockaded woodpecker nests. Photo credit: Carrie Stevenson, UF IFAS Extension
Longleaf pine is a granddaddy among the trees of the Southeastern United States, once covering up to 90 million acres throughout the coastal plain. Tall and stately, slow-growing and dense, it was one of the most desirable trees in the forestry and shipbuilding industry for two centuries. Its sap was used to produce turpentine, tar, and pitch, especially to coat and waterproof the bottoms of wooden ships. Its tall, upright form made for a perfect ship’s mast. Between the years 1830 and 1935, approximately 90% of the Southeast’s old growth longleaf trees were harvested, and much of the land was used for farming or development.
Besides its commercial uses, the longleaf ecosystem supports a wide diversity of other plants and animals. The endangered red-cockaded woodpecker nests only in the wood of old (100-500 years!) longleaf pines, and the canopy shades a grassy groundcover often dominated by wiregrass. Gopher tortoises, the endangered indigo snake, and quail also thrive in longleaf pine ecosystems.
A longleaf pine in its grass stage. Photo credit: Carrie Stevenson, UF IFAS Extension
The longleaf pine is highly adapted to fire while in its “grass” stage and as an older tree, allowing it to tower over smaller hardwoods that are cleared out in natural and prescribed fires. This clearing allows its own seeds to sprout and thrive, and for low-growing grasses to dominate the understory. Pines can be difficult to differentiate in the southern forest, but longleaf pines have deep (up to 8-12 feet) taproots and long needles—up to 18 inches—in fascicles of two or three. The needles grow in spherical bunches that look like cheerleading pom poms.
As ecologists and foresters have realized the important role these trees play in the landscape, significant efforts have been undertaken to restore much of that habitat on both public and private land. Locally, Blackwater State Forest and neighboring Eglin Air Force Base have replanted and managed thousands of acres of longleaf habitat. Foresters and nonprofits also work with private landowners to reestablish these stately pines.
Pine bark beetles are frequent pests of stressed pines in the southern United States. The five most common southern pine bark beetle species include three in the genus Ips. Ips beetles usually colonize only those trees that are already stressed, declining, or fallen due to environmental factors. Infestations may occur in response to drought, root injury, disease, lightning strikes or other stresses including flooding.
Ips calligraphus usually attacks the lower portions of stumps, trunks and large limbs greater than 4” in diameter. Early signs of attack include the accumulation of reddish-brown boring dust on the bark, nearby cobwebs or understory foliage. Ipscalligraphus can complete their life cycles within 25 days during the summer and can produce eight generations per year in Florida. Newly-emerged adults can fly as far as four miles in their first dispersal to find a new host tree, whichever one is the most stressed.
Most trees are not well adapted to saturated soil conditions. With record rainfall this past April, the ground became inundated with water. When the root environment is dramatically changed by excess moisture, especially during the growing season, a tree’s entire physiology is altered, which may result in the death of the tree.
Water saturated soil reduces the supply of oxygen to tree roots, raises the pH of the soil, and changes the rate of decomposition of organic material; all of which weakens the tree, making it more susceptible to indirect damage from insects and diseases.When the ground becomes completely saturated, a tree’s metabolic processes begin to change very quickly. Photosynthesis is shut down within five hours; the tree is in starvation mode, living on stored starches and unable to make more food. Water moves into and occupies all available pore spaces that once held oxygen. Any remaining oxygen is utilized within three hours. The lack of oxygen prevents the normal decomposition of organic matter which leads to the production and accumulation of toxic gases such as carbon dioxide, methane, hydrogen sulfide and nitrogen oxide. Additionally, within seven days there is a noticeable root growth loss. Roots only develop when soil oxygen levels are at 5% -15%. Over time, the decaying roots are attacked by pathogens. The loss of root mass from decay and fungal attack leaves the tree prone to drought damage. After only two weeks of saturated soil conditions the root crown area can have so many problems that decline and even death are imminent.
When a tree experiences these anaerobic soil conditions it will exhibit symptoms of leaf loss with minimal to no new leaf formation. This usually appears two to eight weeks after the soil dries out again. Many trees will not survive, especially the more juvenile and mature trees. However, well established trees may still decline several years later, if they experience additional stresses such as drought or root disturbance from construction.
There is little that can be done to combat the damage caused by soil saturation. However, it is important to enable the tree to conserve its food supply by resisting pruning and to avoid fertilizing until the following growth season. Removal of mulch will aid in the availability of soil oxygen. Basically, it is a “wait and see” process. While water is essential to the survival of trees, it can also be a detriment when it is excessive, especially for drought tolerant pine species such as Sand Pine, which is prevalent throughout the coastal areas.
For urban and residential landscape trees, preventative strategies to avoid tree stress and therefore reduce the chances of infestation include the following:
1) avoiding compaction of, physical damage to, or pavement over the root zones of pines,
2) providing adequate spacing (15-20ft) between trees,
3) minimizing competing vegetation beneath pines,
4) maintaining proper soil nutrient and pH status and
5) limiting irrigation to established pine areas.
When infested trees are removed, care should be taken to avoid injury to surrounding pines, which could attract the more harmful pine bark beetle species Dendroctonus frontalis, the Southern Pine Bark beetle.
There is no effective way to save an individual tree once it has been successfully colonized by Ips beetles. In some cases, the application of an approved insecticide that coats the entire tree trunk may be warranted to protect high-value landscape trees prior to infestation. UF/IFAS Extension can assist with recommendations.
