What’s the Story behind Hollow Trees?

Hollow trees make such ideal habitats for so many types of birds, squirrels and other animals that it almost seems as if nature created them primarily to fulfill such purpose. Hollow trees across the world are home to many types of wildlife, and have also played important roles in folklore throughout the years. According to National Geographic News, male tree-hole frogs in the rain forests of Borneo have been found to utilize the unique acoustics of hollow trees to tune the pitch of their mating calls to be louder and more appealing to females. Rotting, hollow tree branches serve as the mating and breeding habitat for these tree-hole frogs as they take advantage of the sheltered, moist environment to lay eggs. Hollow trees fall naturally into the life cycle, but have you ever wondered why some trees are hollow in the first place?

Understanding the reason some trees are hollow involves first taking a look at how trees sustain life. Tree trunks and branches are comprised of a series of layers, with each serving a vital purpose. The visible outer bark of the tree protects the interior of the tree from the elements as well as disease, fungi, animals, insects and dehydration. The next three layers just inside the outer bark transport food and sugars from the leaves to the rest of the tree, create new growth and transport water and nutrients from roots to other parts of the tree. The innermost layer of the tree, called heartwood, serves as a supportive core and is comprised of strong woody tissue that is no longer alive. Tree growth occurs when new layers of tissue form and push outward, while dead cells become part of the supportive heartwood.

In order for a tree to defend itself, exterior layers must compartmentalize decay before it spreads to the supportive heartwood of the tree. If outer layers fail to do so, a hole known as a rot cavity will form, which is likely the result of fungi causing decay in the heartwood of the tree. This often happens after the tree has acquired a wound, such as from pruning or damage from a storm. Over time, this rot cavity can become larger, eventually resulting in a complete hollowing of the tree’s heartwood. As long as the outer, living layers of the tree remain intact and are of sufficient thickness as compared to the hollowed area, a tree can often survive after developing a hollow.

While historically hollow trees have been filled with cement and a number of other substances, most experts now agree that filling a cavity or hollow trunk is more detrimental than effective at supporting the tree. It is important to note that while some hollow trees are structurally sound, others represent a hazard and should be supported or removed. Hollow trees that are weak can become hazardous and pose threats to people, buildings and other property in the vicinity. If you have a hollow tree on your property, it is advised to have it inspected by a certified arborist, who can determine whether it is living and assess its strength. If the tree is structurally weak, an arborist can determine whether it can be salvaged through effective cabling and bracing techniques, or if removal is necessary.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading Austin tree service provider in Central Texas (Travis County and surrounding areas). Central Texas Tree Care offers services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management and fertilization. For more information please visit http://www.centraltexastreecare.com.

The Anatomy of a Tree

Trees of different species vary greatly in size, shape and overall appearance. Generally, however, trees are comprised of the same basic components, with a root system in the ground anchoring a strong, vertical trunk that supports a crown of branches, twigs, and leaves. Here we examine these basic components of a tree and the functions associated with each:

1. Crown: The crown is the upper portion of a tree consisting of the branches, twigs and leaves. Crowns vary significantly among different types of trees. Crowns can range from condensed, cylindrical shapes to widespread, almost spherical shapes. The crown serves the vital function of displaying its leaves so that they may capture the energy necessary for photosynthesis, and also filters particles from the air and minimizes the impact of rain falling on the soil that supports the tree.

2. Trunk: The trunk is the primary means of support for the tree, and it consists of several layers of tissue which serve specific purposes. Here we describe each layer, beginning from the outer layer and moving inward:

-Outer Bark: The outer bark is the visible part of the trunk, and it helps protect the interior of the tree from dehydration, adverse weather, insects and diseases. As living matter within a tree grows, its outer bark becomes tauter and begins to split, contributing to the outer bark’s cracked appearance.

-Phloem: Just inside the outer bark is a layer of inner bark called phloem. Throughout its short life, phloem tissue transports food and sugars from the leaves where they are produced to the rest of the tree. When phloem dies, it turns to cork and becomes a part of the defensive outer bark layer.

-Cambium: Just inside the phloem layer lays the thinnest layer of the tree, a watery layer called the cambium. Cambium cells constantly divide during growing season and are responsible for the growth in diameter of the trunk, roots and branches.

-Xylem: The xylem, or sapwood, is a layer situated just inside the cambium layer. This layer, which is comprised of the youngest wood in the tree, transports water and nutrients from the roots to the leaves and other parts of the tree. As new cells form and the tree grows, interior xylem cells die and become a part of the tree’s heartwood, discussed next.

-Heartwood: The central, supporting core of the tree is heartwood. Heartwood is comprised of dead tissue that no longer transports water, but serves the important purpose of supporting the tree. Although heartwood can be considered dead, it will not become weaker or decay as long as the protective outer layers of the tree remain undamaged.

3. Roots: Trees often have extensive root systems, which take in water and minerals from the soil that are necessary for the tree’s survival. Roots also store sugars, anchor the tree and help control erosion of the soil below. Tree roots are usually relatively shallow where oxygen is abundant in the soil, but the roots of mature trees can span laterally to distances measuring two to three times the size of the crown. Though fairly shallow roots are common for trees, some trees also have tap roots that reach deeper into the ground.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading Austin tree service provider in Central Texas (Travis County and surrounding areas). Central Texas Tree Care offers services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management and fertilization. For more information please visit http://www.centraltexastreecare.com.

How Trees Respond to Damage

Trees have inhabited the earth since prehistoric times, and have adapted to survive in some of the harshest of conditions. Throughout their existence, trees have been the subject of damage brought on by inclement weather as well as birds and other animals. In modern times, trees are faced with an increased threat of damage as a result of human activities. Unlike animals, trees do not have a process of healing damaged tissue, or in other words, trees cannot replace damaged tissue with healthy tissue. Instead they have developed a way to seal off a damaged area to protect against further damage through a process called compartmentalization.

If a tree is on the receiving end of a vehicle accident, for instance, its bark will likely incur some damage from the impact. With the protective boundary of bark compromised, the wood comprising the interior of the tree becomes vulnerable to harmful insects and fungi. Without the ability to create a protective barrier around the damaged area, the tree would be faced with death and decay. Instead, a damaged tree will begin to seal off the wound area in order to protect the rest of the tree. New bark forming around the wound is referred to as callous tissue, and this new protective tissue serves to protect the rest of the tree from damage as well as prevent it from drying out. If you have ever seen a tree with what appears to be an abnormal growth protruding from its trunk, you have probably seen firsthand the result of this natural defense. Being struck by a vehicle is an extreme incident through which a tree can incur damage, though other forces such as birds, squirrels, storms and pruning are more common culprits for tree damage.

Although trees are equipped with an ability to seal off wounded areas, all trees do not survive after damage leaves them susceptible to infestation and decay. It can take a tree several years to fully seal off a wounded area, and further damage may occur before the area is fully covered by the new layer of protective tissue. Many factors contribute to a tree’s ability to successfully repair a wound, such as the tree’s age, species, extent of damage, and weather conditions. If the wound is compartmentalized successfully without further damage or decay, the tree is likely to survive.

If a tree on your property has incurred damage, it is advised to hire a tree service professional to assess the extent of damage. While trees with minimal damage may repair themselves naturally without intervention, excessively damaged trees may need to be removed so that they do not become a hazard.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading Austin tree service provider in Central Texas (Travis County and surrounding areas). Central Texas Tree Care offers services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management and fertilization. For more information please visit http://www.centraltexastreecare.com.

Plant Trees, Save Energy

Most of us are aware that planting trees can help boost the value of our homes, but did you know that strategically placed trees can alleviate energy costs year round? Not only does the presence of trees naturally cool the air through the process of evapotranspiration, but trees can serve as both sources of shade and wind barriers to reduce the energy demands on your home.

Although here we offer general suggestions as to the placement and types of trees you may plant to reduce the energy costs in your home, it is important to understand that many other factors not addressed here must be considered in the decision regarding where trees should be planted. For example, trees must be planted appropriate distances from buildings, concrete, power lines, air conditioning units, underground cables as well as one another, and planting decisions should be made based on the type and mature size of the tree. It is advised to consult with or hire a certified arborist prior to implementing any of these suggestions.

The idea behind planting trees for the energy benefits is to shade your home in the summer and create a barrier to block the bulk of cold winter winds. The most effective approach to strategic tree positioning is affected by the environment in which you live. In the warm climate of south Texas, for instance, shading a home in the summer would take priority over blocking wind in the mild winters. Likewise, a homeowner in Canada would place more emphasis on protecting against winter winds than shading the home. Some tips for planting trees to reduce energy costs are:

-Shade the sides of your home receiving the most direct sunlight. The east and west and, to a lesser extent, south sides of your home receive the most sunlight. While some experts argue against planting shade trees on the southern end of a home, most agree that shading the east and west sides of the home can result in true energy savings. Deciduous trees are preferred for this type of shading because they shade well during the summer and lose their leaves during the winter, allowing sunlight to pass through when it is desirable.

-Shade windows. Windows receiving direct sunlight allow a lot of heat into a home, reducing energy efficiency during the warm months. Special care should be taken to shade windows, especially those facing east and west, without planting too close or sacrificing desirable views.

-Shade concrete or asphalt. Because such surfaces absorb light and heat the surrounding area, paved areas, especially dark colored ones, should be shaded for maximum cooling around the home.

-Shade the air conditioning unit. Trees may also be planted to strategically shade outdoor air conditioning units. This gives the air conditioning unit cooler air from which to pull, saving energy. It is important to ensure that the air intake has room for ventilation and does not become blocked.

-Block winter winds. In addition to shading a home during the summer, trees can serve as a barrier against cold winter winds and help reduce heating costs in a home. Evergreen trees such as spruces and firs are best for creating such barriers, which are called windbreaks. Windbreaks should be positioned upwind of a home, often on the northern side, in a straight or curved row. Be sure to verify the direction from which winter winds hit your home, because features such as mountain ranges can have an effect on wind direction.

Trees should be planted appropriate distances from a home in order to effectively shade the home, and the correct distance is determined by the trees’ mature heights and crown sizes. It is advised to consult with an experienced arborist who is familiar with your local climate prior to planting trees at your home.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading Austin tree service provider in Central Texas (Travis County and surrounding areas). Central Texas Tree Care offers services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management and fertilization. For more information please visit http://www.centraltexastreecare.com.

Do I Need to Hire an Arborist?

Much of the time, the trees that adorn the properties of our homes and businesses do not need our attention to thrive. Sometimes, however, a tree needs specialized care in order to coexist safely in an environment surrounded by people and animals as well as buildings, automobiles, roads and power lines. Neglect of a tree in need of treatment or repair can quickly turn a beloved shade tree into an eyesore and an imminent hazard.

If a tree is damaged, diseased, or dead, it represents a real threat to people, animals, other trees and structures in its vicinity. Bearing in mind the unforeseeable extent of harm that may ensue if a tree fails, the need for proper tree care becomes blatantly obvious. But how can you tell whether the situation warrants the advice and service of a certified arborist?

Many property owners attempt to manage tree problems on their own in effort to save a few bucks. While DIY tree care may seemingly save money up front, long term tree damage and bodily injury can result from a lack of knowledge of proper tree maintenance and treatment. Even attempting a job that appears simple on the surface, such as pruning branches that have grown too close to your home, can quickly go awry if handled by a non-professional. Aside from damage to a tree that can result from pruning its branches incorrectly, damage to the home caused by your negligence is likely not going to be covered by your homeowners insurance. Tree service professionals have the experience to get the job done without damaging the tree or your home, and are covered by insurance to protect your valuable assets in the event that an accident does occur (ensure that an arborist carries insurance against personal and property damage prior to hiring).

A major problem with DIY tree care is that the average person does not have the background knowledge to identify potential hazards. While to the average person a tree may appear normal and healthy, a certified arborist can identify obscure symptoms of structural weakness, insect infestations, disease or death that may call for an alternative means of treatment or constitute tree removal altogether.

A certified arborist can correct tree issues that have already developed, but can also prevent future problems by identifying and correcting potential hazards. For instance, some trees grow in a pattern that eventually leads them to become too unstable to support their own weight. Left untreated, an unbalanced tree can fail unexpectedly, endangering everyone and everything in its path at that unfortunate moment. However, the same tree can be saved if its condition is identified in advance. An experienced arborist can identify the potential for structural weakness and employ techniques such as cabling and bracing to help support the tree and encourage a healthier growth pattern. Hiring an arborist is advised if your trees have never been professionally inspected, even if they show no obvious signs of problems.

If you own any trees that are in questionable health, have incurred damage or have never been inspected for problems, it is advised that you enlist the services of a certified arborist in your local area. The International Society of Arboriculture website is a valuable resource for locating a certified arborist in your area or verifying ISA certification of an arborist you are considering.

About the Author: Andrew Johnson is the owner of Central Texas Tree Care, a leading Austin Texas tree service provider in Central Texas (Travis County and surrounding areas). Central Texas Tree Care offers services such as pruning and removals, cabling and bracing as well as arborist reports, diagnostics, pest management and fertilization. For more information please visit http://www.centraltexastreecare.com.