What is Crown Dieback in Trees?

What is Crown Dieback in Trees?

The crown of a tree is the leaf bearing twigs and branches and the spreading green foliage that we see. A heathy, full crown is a good indication of a healthy and vibrant tree. The crown and the foliage it supports is the energy collector and the center for photosynthesis, which is how the tree produces the energy it needs to live. For a tree to live and thrive, a full crown of leaves is essential, and an unhealthy and thin crown is an indicator the tree has issues. Crown dieback is often not noticed until it is relatively severe and at that point it can be too late. If a tree drops below a certain percentage of live crown it can no longer support itself and continues to decline. The good news is that if you notice your tree is starting to show signs of crown thinning and dieback you can likely intervene to improve its health or diagnose a problem early.

Tree Showing crown dieback, note the dead branches and lack of foliage on the outer branch tips.
Photo Credit-Ian Stone

Crown dieback, which is also referred to as crown decline, is a progressive issue that starts small and can progress to the point that only small sparse areas of foliage are left. It is a tree’s response to various stressors, including environmental conditions and severe rot/decay.  As a response to severe stress, the tree begins to abort part of the leaves and some of the small branch tips. If the stress continues to worsen, the tree will continue to abort more of the crown, producing progressively more dead wood. The tree is essentially trying to prune itself back to a manageable level of foliage based on the stress it is encountering. This can occur in both small, young trees and mature, established trees. A variety of conditions cause the stress that begins this process. For instance, you may notice crown dieback in young trees planted in compacted urban conditions such as parking lots and paved areas. Trees in these conditions experience stress from the compacted soil and encounter subsequent issues with water and nutrient stress. Large mature trees in an area that experienced recent construction may also exhibit dieback, especially if buffers and setbacks are not maintained or significant fill dirt is brought in. Issues from root disturbance and compaction cause stress and root dieback, which in turn causes visible crown dieback. Additionally, trees that are experiencing rot, decay, and other vascular disease issues will often begin to exhibit dieback. As the rot or vascular disease progresses, the tree is less able to transport water to the crown, which results in the crown dieback that can be seen as the crown thins. Often, in cases of rot, crown dieback will be the primary visible symptom that rot is occurring, as the rot can be concealed deep in the tree. While multiple stressors can be the cause of crown dieback, it is a clear indicator a tree is stressed and in trouble. If this condition goes unnoticed, it can progress past the point that the tree can be saved. However, if noticed and caught early, good tree care techniques can be applied that may restore the tree to heath. In cases of severe rot and decay, having the tree examined may prevent structural failure of a tree exhibiting crown dieback.

If you have a tree on your property that is exhibiting crown dieback, it is a good idea to have the tree examined by a professional to determine the extent and nature of the issue. Key signs of dieback are bare branch tips and dying foliage during spring and summer. It is natural to have some dead wood in a tree, but extensive dead wood around the entire perimeter of the crown is a cause of concern. With good diagnosis, the proper tree care techniques can be applied to help a tree recover. Waiting and hoping a tree with crown dieback will recover on its own is not a good course of action. Recognizing crown dieback and taking early action is the key to success. Contacting a Certified Arborist (www.treesaregood.org ) is a good step in getting an opinion on the extent of dieback, if the tree is recoverable, and how to best address the issue. You can also contact your local County Extension Office or Florida Forest Service County Forester for assistance.

Video: Tree Planting Basics

Video: Tree Planting Basics

Our winter season is a good time to install many trees and shrubs. Here is a basic review of a few planting practices to make sure that your new plants get off to the good start.

Backyard Landscaping Tips to Support Birds This December

Backyard Landscaping Tips to Support Birds This December

NATURE’S NOMADS

Florida has a diverse array of birds. Warblers, raptors, shorebirds, and more may be spotted now in North Florida. Your yard or landscape can serve as an ideal habitat for wildlife, particularly birds. Even a modest quarter-acre plot can be intentionally designed to offer a supportive environment for a variety of birds. Transforming your backyard into a sanctuary for birds might allow you to witness these fascinating visitors firsthand.

"Rudbeckia' photo by UF/IFAS
“Rudbeckia’ photo by UF/IFAS

CONSIDER NATIVE PLANTS

Bring a touch of local charm to your yard by choosing native plant species whenever you can. Native birds have a natural connection with these plants, having evolved alongside them. What’s more, landscapes featuring Florida-native plants demand less attention and resources compared to those with non-native varieties. Native plants are well-suited to the local soil conditions, usually need less fertilizer, and boast better resilience against common pests and diseases. Embrace the beauty of native flora while making your yard a low-maintenance haven for both birds and nature.

"Snags" photo by UF/IFAS
“Snags” photo by UF/IFAS

MAKE SAFE COVER AVAILABLE

When trees face disease or reach the end of their life, think about leaving them as standing snags—imperfect yet invaluable shelters for wildlife to feed and nest. Additionally, creating a couple brush piles, especially near other plants, offers fantastic cover and feeding spots for birds. These piles not only provide a feeding opportunity for our feathered friends but also act as protective hideouts in open spaces. Embrace the natural cycle by turning aging trees and brush into welcoming havens for local wildlife.

INCLUDE A VARIETY OF LAYERS

Birds take to the skies, and for a thriving habitat, it’s essential to have various levels in your environment—tall trees, medium-sized trees, high and low shrubs, and groundcover. The more diversity, the better, as different bird species rely on different layers for their needs.

Tall trees play a crucial role, creating a sort of continuous woodland environment where birds can gracefully move from tree to tree. The choice of trees and shrubs you plant significantly influences the overall health of your landscape. Opt for species that suit your specific site and soil conditions to ensure a welcoming and supportive environment for our avian friends

"Birdbath" photo by UF/IFAS
“Birdbath” photo by UF/IFAS

ADD A WATER SOURCE

Water is a vital ingredient for wildlife environments, and birds reap the rewards from any water source you offer. It can be as easy as placing a shallow dish or bowl filled with water or adding a small fountain to your outdoor space. Just remember to switch out the water regularly to thwart mosquito breeding and ensure a clean and refreshing oasis for our feathered companions.

UTILIZE BIRD FEEDERS

A delightful way to connect with nature and witness birds up close is by using bird feeders. Not only does this provide an opportunity for observation, but it also supplements the natural food sources available to birds near your garden. For those interested in incorporating bird feeders, it’s important to remember proper care and maintenance. Neglected feeders can become breeding grounds for mold and bacteria, posing a risk to the health of the birds. A recommended practice is to clean feeders at least once every 1-2 weeks, or more frequently in wet or humid conditions, using a diluted bleach solution. For nectar feeders, a simple wash with soap and hot water is sufficient. Always ensure the feeders are thoroughly dry before refilling them with bird feed. This way, you not only create a welcoming space for our feathered friends but also ensure their well-being through responsible feeder care.

WINTER WANDERERS

Creating a bird-friendly backyard in North Florida is not only a satisfying project but also a meaningful way to help protect our feathered friends. By making smart choices in your landscaping, you can turn your outdoor space into a welcoming sanctuary for birds. The benefits are twofold: you get to enjoy the colorful variety of bird species visiting your backyard while also contributing to the conservation of biodiversity in the area. Let your backyard showcase the harmonious relationship between humans and nature’s nomads. For tips on landscaping that supports birds, reach out to your local county extensions office.

Colorful Trees

Colorful Trees

Florida’s natural areas—a great source of pride and enjoyment to its citizens—provide recreation, protect biodiversity and fresh water supplies, buffer the harmful effects of storms, and significantly contribute to the economic well-being of the state. Unfortunately, many of these natural areas can be adversely affected by invasive plant species. An estimated 25,000 plant species have been brought into Florida for use as agricultural crops or landscape plants. While only a small number of these have become invasive, Chinese tallow (Triadica sebifera) is one of them. 

As the trees begin to turn various shades of red, many people begin to inquire about the trees.  While their autumn coloration is one of the reasons they were introduced to the United States, it took years to realize what a menace the trees become.  Triadica sebifera, the Chinese tallow is locally referred to as popcorn tree due to the appearance of the developing seed heads, white three-chambers seeds covered in a fatty wax. It was introduced to Charleston, South Carolina in the late 1700s for oil production and use in making candles. However, the seeds are also tasty snacks for birds and can float long distances in the water, enabling it to spread to every coastal state from North Carolina to Texas, and inland to Arkansas. In Florida it occurs as far south as Tampa, displacing other native plant species in those habitats.  Therefore, Chinese tallow was listed as a noxious weed by the Florida Department of Agriculture and Consumer Services Noxious Weed List (5b-57.007 FAC) in 1998, which means that possession with the intent to sell, transport, or plant is illegal in the state of Florida.

tree with red leaves
Fall color of Chinese tallow

Individuals can help mitigate the problem of Chinese tallow trees in Florida’s natural areas by removing them from their property. Mature trees should be felled with a chain saw by the property owner or a professional tree service. The final cut should be made as close to the ground as possible and as level as possible to facilitate application of an herbicide to prevent sprouting. Stumps that are not treated with an herbicide will sprout to form multiple-trunked trees. If it is not objectionable for dead trees to be left standing, certain herbicides can be applied directly to the bark at the base of the tree (basal bark application).

Herbicides that contain the active ingredient triclopyr amine (e.g., Brush-B-Gon, Garlon 3A) can be applied to cut stumps to prevent re-sprouting. The herbicide should be applied as soon as possible after felling the tree and concentrated on the thin layer of living tissue (cambium) that is just inside the bark. Herbicides with the active ingredient triclopyr ester can be used for basal bark applications. Only certain triclopyr amine products may be applied to trees that are growing in standing water.  If trees are cut at a time when seeds are attached, make sure that the material is disposed of in such a way the seeds will not be dispersed to new areas where they can germinate and produce new trees.

Space in a landscape left after removal of Chinese tallow can be used to plant a new native or noninvasive tree for shade, or some other landscape purpose. Although Florida is not known for the brilliant fall color enjoyed by other northern and western states, there are a number of trees that provide some fall color for our North Florida landscapes.  Red maple, Acer rubrum, provides brilliant red, orange and sometimes yellow leaves. The native Florida maple, Acer floridum, displays a combination of bright yellow and orange color during fall.  And there are many Trident and Japanese maples that provide striking fall color.  Another excellent native tree is Blackgum, Nyssa sylvatica. This tree is a little slow in its growth rate but can eventually grow to seventy-five feet in height. It provides the earliest show of red to deep purple fall foliage. Others include Persimmon, Diospyros virginiana, Sumac, Rhus spp. and Sweetgum, Liquidambar styraciflua.  In cultivated trees that pose no threat to native ecosystems, Crape myrtle, Lagerstroemia spp. offers varying degrees of orange, red and yellow in its leaves before they fall. There are many cultivars – some that grow several feet to others that reach nearly thirty feet in height. Also, Chinese pistache, Pistacia chinensis, can deliver a brilliant orange display.

There are a number of dependable oaks for fall color, too. Shumard, Southern Red, and Turkey are a few to consider. These oaks have dark green deeply lobed leaves during summer turning vivid red to orange in fall. Turkey oak holds onto its leaves all winter as they turn to brown and are pushed off by new spring growth. Our native Yellow poplar, Liriodendron tulipifera, and hickories, Carya spp., provide bright yellow fall foliage. And it’s difficult to find a more crisp yellow than fallen Ginkgo, Ginkgo biloba, leaves. These trees represent just a few choices for fall color.  Including one or several of these trees in your landscape, rather than allowing the popcorn trees to grow, will enhance the season while protecting the ecosystem from invasive plant pests.

For more information on Chinese tallow tree, removal techniques and native alternative trees go to: http://edis.ifas.ufl.edu/ag148.

Preventive Tree Care Before High Winds Strike

Preventive Tree Care Before High Winds Strike

Recently, I spent some time with my uncle at his home in Perry, Florida. Perry specifically and Taylor County as a whole were one of the hardest-hit areas from Hurricane Idalia. My uncle said that most of the powerline poles had been replaced in his and surrounding neighborhoods as a result of this storm. Some were still being replaced when I was there. Every home in the area had large amounts of tree debris cut and piled up along the streets for pickup. Most every pile had the remains of large pine trunks intermingled in the debris.

Tree debris along street following hurricane Idalia in Perry, FL
Tree debris along street following Hurricane Idalia in Perry, Credit Larry Williams

The only damage to my uncle’s home was from a neighbor’s large pine tree. The top of that tree was blown through the air and slammed into his roof, puncturing the roof and leaving a large hole through the bottom of the garage ceiling. In addition to the direct wind damage and resulting downed trees, with a storm such as Idalia, there will be much follow up removal and pruning of leaning, partly uprooted, and damaged trees.

Trees are an important part of our ecosystem, economy, landscape and heritage here in North Florida. As a matter of fact, Taylor County began a Pine Tree Festival in 1955 to help educate the public about the timber industry in that area. Now known as the Florida Forest Festival, the goal of the festival is to promote the benefits of our state’s forests as well as to celebrate people who protect and work in them. The 68th Annual Florida Forest Festival is scheduled to take place in Perry on October 28, 2023. Here is a link with more information on the festival: https://floridaforestfestival.org.

It is important to not wait until a storm event such as Idalia to inspect and manage trees on your property. An ounce of prevention is worth a pound of cure when preventing tree damage. Even without a major storm, we have relatively high winds associated with our frequent thunderstorms here in Florida. Compared to many parts of the United States, we live in a fairly high-risk area for storm damage with lots of large trees.

Professional help sometimes is your best option when dealing with trees. Property damage could be reduced by having a professional arborist evaluate unhealthy, injured or questionable trees to assess risk and treat problems.

Hiring a certified arborist can be a worthwhile investment. To find a certified arborist in your area, contact the International Society of Arboriculture at 888-472-8733 or at www.isa-arbor.com. In addition, here is a UF/IFAS Extension link with a wealth of information related to trees and hurricanes: https://hort.ifas.ufl.edu/treesandhurricanes.