How Much Is My Tree Worth?

While it is obvious that trees have considerable ecological, societal, psychological and aesthetic value, it is often difficult to quantify this value. While property owners can estimate the general value of a given tree by using various calculators or formulae, determining a precise figure requires the services of a qualified tree professional.

Different Types of Value

Property owners may be interested in the value of their trees for many different reasons. They may have experienced storm damage and require guidance for making claims – this is known as the replacement value of a tree. Determining the replacement value of a tree requires comparing the tree in need of replacement with the market value of a comparable specimen. This is most commonly applied to small- and medium-sized trees, as it is rarely realistic for property owners to replace large specimens.

Alternatively, property owners may be planning to install new trees and want to know how they will affect the resell value of the property. Determining the real estate value of a tree (or group of trees) requires understanding the local ordinances, growing conditions and market conditions, as well as the characteristics and relative value of the trees in question.

In other circumstances, it is desirable to know the value of a tree in terms of utility savings. Trees can drastically alter the heating and cooling costs of a home, and several different protocols have been developed for determining the dollar value of these savings.

Arborists and tree appraisers consider a variety of criteria when determining the value of a tree. They consider the size, species, location and condition of the tree to determine the value to replace a given tree or group of trees.

Nature of the Value

Trees provide a variety of benefits for properties. Some of the most important ways trees do so include:

  • Reducing storm water runoff. Runoff water causes erosion problems and ferries pollutants from roads and parking lots to rivers, lakes and streams, where it harms many different aquatic organisms.

  • Absorbing and storing carbon dioxide. This helps to reduce the amount of greenhouse gases in the atmosphere, which cause the Earth’s climate to change.

  • Reducing air pollution. The extensive surface area of trees helps give airborne particulate matter a surface to which it can adhere.

  • Cooling the surrounding area. Trees cool yards, neighborhoods and commercial areas by providing shade and through the process of transpiration. Trees needn’t mature before producing benefits: Even small trees can be placed so that they shade air conditioning units, which may significantly lower cooling costs (depending on the location of the unit and other factors).

  • Increasing property values. Home buyers often prefer those properties that feature numerous mature trees. This increases the curb appeal of a property and, ultimately, the sale price.

  • Providing food for wildlife. Trees are important components of local ecosystems. Properties that feature numerous trees with high wildlife value support the local wildlife community — a highly desirable benefit for most properties.

  • Improving the aesthetics of a property. Simply put, trees are pretty. They help make a property look mature, complete and visually balanced; all of which increase your enjoyment of the property as well as its value.

Determining the Yearly Savings

The best way to determine the value of your trees is to have a qualified arborist appraise them for you. By having an arborist carefully examine your property and analyze the location, size and species of trees present, you can learn not only the value of your trees, but also what steps you can take to raise their value further.

You can arrive at a ballpark figure for the replacement cost of a tree by researching the cost of similar trees. However, a homeowner’s assessment is usually insufficient for claim purposes; a professional opinion is necessary in almost all cases. Real estate value is slightly more subjective, and it is very difficult to make apples-to-apples comparisons by perusing the classified ads, making this another situation in which a professional opinion is necessary.

Determining the amount of energy savings a given tree produces usually requires the help of a professional. However, the USDA Forest Service has produced a tool, called i-Tree, which allows you to learn a great deal about the value of the trees in your yard. You needn’t be an expert to use the software either; you simply answer a few straight-forward questions, including the species in question, the tree’s size and condition and your location, and the software estimates the tree’s value.

The package only presents broad estimates – you still need a good arborist for detailed information – but it is a very helpful to for homeowners, landscapers and commercial property owners to understand how their trees are affecting their wallet.

Trees of Suitable Stature

Trees of Suitable Stature

Property owners often enlist tree care professionals to “fix” the problem of a large tree in a small space.

Unfortunately, few mitigating strategies can correct this problem. Trees need plenty of elbowroom; once confined in a small space, they are apt to decline and eventually require removal.

Avoid this by starting out with a suitable tree for the space available. Below are some excellent trees that remain reasonably sized throughout their lives.

As always, be sure to plant the right tree in the right spot, and consider your property’s sun exposure, drainage characteristics and soil chemistry before selecting the species.

Desert Willows

Desert willows (Chilopsis linearis) are one of the most desirable small trees. While the largest examples may reach 30 feet in height, the majority are about half of this size. While not a true willow species, the desert willow’s long, narrow leaves resemble those of the true willows. However, unlike the water-loving willows, the desert willow is an arid-adapted species. The colorful blossoms of the tree are a favorite food source for hummingbirds.

Pacific Wax Myrtle

Pacific Wax Myrtles (Myrica californica) are rather small trees that seldom exceed 20 feet in height. These drought-tolerant plants require well-drained soils to thrive. They do not produce showy flowers, but their fall fruit is an important food source for some of California’s native birds.

Scrub Oaks

Scrub oaks (Quercus beberidifolia) are a nice option when the available space demands a small tree, but you want to plant a species with a high wildlife value. Reaching 15 feet in height and spread, scrub oaks are decidedly puny by oak standards, but their acorns are still tasty to a variety of species. Some of these shrubby trees may require pruning to develop into a tree-like shape.

Redbuds

The western redbud (Cercis occidentalis) is a wonderful tree for small spaces. Producing bright purple flowers in the spring, and emerald green and heart-shaped leaves a few weeks later, red buds are very handsome trees. While their leaves fall in the winter, the seedpods remain on the branches, giving the tree a very interesting look. Redbuds rarely exceed 20 feet in height or spread, and they are drought tolerant, making them doubly attractive for space-conscious landowners.

Many Different Maples

A variety of maple trees remain relatively small and make excellent additions for your yard. Among others, trident maples (Acer buergeranum), Amur maples (Acer ginnala) hedge maples (Acer capestre) and vine maples (Acer circinatum) all grow about 20 to 30 feet high. Additionally, several different types of Japanese maple (Acer palmatum) make excellent trees for tight spaces – many cultivars remain less than 10 feet high at maturity.

Crepe Myrtles

Some of the most popular small ornamentals, crepe myrtles (Lagerstroemia spp.) thrive in most warm, sunny climates. It is important to select a cultivar that suits the site. While some cultivars remain less than 20 feet high, other varieties can approach 100 feet in height. Some crepe myrtle cultivars have attractive, peeling bark.

Dogwoods

Like the native Pacific dogwood (Cornus nuttallii), flowering dogwoods (Cornus floridana) of the east coast, have the potential to grow up to 50 feet tall, but most specimens top out around 20 to 25 feet high. Unlike the tiny fruit of their eastern relatives, Pacific dogwoods produce prickly, orange-red, golf-ball-sized fruit. Dogwoods require well drained soil, and are somewhat drought tolerant.

Golden Rain Tree

The golden rain tree (Koelreuteria paniculata) is a unique and beautiful species that stays relatively small. Although occasional specimens may reach 40 feet in height or spread, most are less than 30 feet in both dimensions. Tolerant of drought, air pollution and a variety of soil conditions, golden rain trees fare well in California yards. Golden rain trees do have one significant drawback: They have become invasive in Florida, Louisiana, Alabama and Texas, which offsets some of their beneficial traits.

Saucer Magnolias

Saucer magnolias (Magnolia x soulangeana) are the attractive products of selective breeding. These popular trees, which are hybrids produced from crossing a Yulan magnolia (Magnolia denudata) with a Mulan magnolia (Magnolia liliiflora) bear purple-pink flowers and dark green, glossy leaves. Saucer magnolias, which fail to exceed 35 feet in height, are more tolerant of alkaline conditions than most magnolias are.

Tip of the Iceberg

Many other trees, including citrus trees, apple trees and serviceberries, remain small and work well in tight spaces. Just remember to consider the height of the mature tree, the spread of its crown and diameter of its root system before making a selection. For more information, check out this guide to native and drought tolerant trees, from the Las Virgenes Municipal Water District.

serotinuous

Serotinous Survival Strategies

The heat-sensitive cones of a lodgepole pine tree. Photo from the National Park Service.

The heat-sensitive cones of a lodgepole pine tree. Photo from the National Park Service.

Over the millennia, plants and trees native to fire-prone regions have evolved a number of adaptations that allow them to persist in these challenging habitats. Some plants have subterranean rhizomes that rapidly regenerate the aboveground portion of the plant after it burns in a fire. Others produce seeds that lie dormant until exposed to fire, smoke or some other stimuli.

These measures help ensure that even if all of the mature plants succumb to the fire, the buried seeds or rhizomes germinate or sprout to perpetuate the species, once the fire passes.

Coddled Cambium and Cooked Cones

Trees often utilize slightly different adaptations. Unlike small perennials and annuals, some trees are capable of surviving low-intensity fires. They often accomplish such feats through the development of thick bark, which protects the tree’s delicate cambium layer. (National Park Service, 2014) If the cambium survives, the tree will recover in most cases.

An adaptation that helps some pines from fire-prone areas, such as ponderosa pines (Pinus ponderosa), to survive fires, relates to their ability to jettison their limbs. Ponderosa pines are a self-masting species, which means that they drop their lower limbs as they grow taller. This helps to reduce the amount of tinder and kindling between the ground and the canopy, and therefore reduce the amount and severity of fire damage in the canopy.

This allows many mature trees to survive low-intensity fires; but what about their seeds? The seeds of many trees are incapable of surviving in the soil until the next fire passes through; so, many trees have evolved alternative methods for ensuring the perpetuation of the species.

One such method is a phenomenon known as serotiny, in which the heat of a wildfire causes their fruiting structures (cones in the case of pines) to release seeds. They accomplish this with resins and saps; these substances cover and contain the seeds, but when the fire passes through the area, it melts the sap, releasing the seeds.

Variable Viscosity

Some species exhibit variable resin production. For example, lodgepole pines (Pinus contorta) are very tall, thin conifers, native to the western United States (including northern California). Way back in 1985, Patricia S. Muir and James E. Lotan studied a population of lodgepoles in Montana. Publishing their results in the journal “Ecology,” the researchers found that serotiny varied among populations of the trees. Some lodgepole pines produce thick resin, while others fail to produce any, and release their seeds upon maturity. (Lotan, 1985)

This variation sets up an interesting dichotomy: Areas dominated by serotinous trees quickly recover after fires, as the mature lodgepoles release a great number of seeds en masse.  These seeds strike the relatively bare soil, have few competitors and quickly grow to replace those lost to the fire. Such stands perpetuate over long periods of time.

However, when such lands suffer from non-fire-related disturbances, such as clear cutting, the serotinous pines struggle to recolonize the area. In these places, the non-serotinous individuals and populations thrive while the serotinous individuals and populations suffer.

No Absolutes

Without temperatures high enough to melt the cone resin, the cones never release their seeds. While cones less than one foot from the bare, sunny ground sometimes warm enough to melt the resin and release the seeds, this does not happen very often. This helps to explain why some serotinous lodgepole pines persist in areas without fires. Likewise, because a few trees (and more importantly, seeds) survive almost every fire, a handful of non-serotinous lodgepoles pop up in many fire-ridden areas.

Nevertheless, the numbers look as the hypothesis (resin helps provide the trees with a competitive advantage in fire-prone areas) predicts they should. Muir and Lotan found that most areas featured a 75: 25 split. Accordingly, over thousands of years, those areas prone to periodic fire exert a selective pressure that favors serotinous trees, while those areas that do not experience periodic fires produce pressures that favor non-serotinous trees. (Lotan, 1985)

References

Lotan, P. S. (1985). Disturbance History and Serotiny of Pinus contorta in Western Montana. Ecology.

National Park Service. (2014). NPS.gov. Retrieved from Fire Ecology: http://www.nps.gov/yell/parkmgmt/fireecology.htm

The Limits to Tree Height: Why Redwoods Don’t Grow 500 Feet Tall

To a large extent, the ultimate height of a tree is determined by its genes. Most of the remaining influence comes from the quality of the site in which the tree is growing. In other words, an oak tree may be genetically predisposed to reach about 60 feet in height, but the amount of sunlight and rain it receives determines if it will be a 40-foot-tall runt or an 80-foot-tall behemoth.

However, even trees with great genes and ample resources are still constrained by physical factors, such as gravity and the surface tension of water. It appears that these physical constraints create a cap on the ultimate growth of trees. Accordingly, even California’s tallest redwoods (Sequoia sempervirens), British Columbia’s tallest Douglas firs (Pseudotsuga menziesii) or Australia’s tallest eucalyptus trees (Eucalyptus regnans) are unable to grow much taller than they already do.

How Trees Drink

First, a review of some basic tree physiology:

  • Water enters a tree via the roots, and then travels throughout the trunk, branches and twigs, via an assortment of vascular tissues, until if finally reaches the leaves.
  • Water escapes the leaves (a process called transpiration) via small holes in the leaf surface, called stomata. The individual stoma open and close to alter the rate of this process, which varies over the course of the day.
  • The leaves use a very small percentage of the water reaching them for basic cellular processes and photosynthesis, but most escapes into the atmosphere.

Passive Pumping

The movement of water through a tree is not an active process. Trees do not “suck” water from the ground, nor do they “pump” water up their trunks. Instead, trees rely on the surface tension of water and something called capillary action to draw water up through the tree. The process works because of both the attractive forces between individual water molecules and the attractive forces that occur between water molecules and other molecules.

Surface tension is produced by the cohesion of individual water molecules – this is why water forms droplets instead of spreading out. Capillary action is exhibited when liquid is placed in a narrow tube. The water molecules are attracted to the molecules in the tube (adhesion); but normally, gravity pulls harder on the water than the tube does. However, if the tube is narrow enough, the adhesive forces can overcome gravity.

Sponges illustrate this principle well: If you place a sponge (which is full of tiny capillaries) half-way into a glass of water, it will draw some of the water up into the sponge via the same mechanisms that trees use.

The water transpiring from the leaves creates a void, which cohesion and adhesion work to fill. This creates tension that further helps to draw the water up the tree. The rate at which water transpires from the tree influences the tension placed on the water column. The faster the water exits the tree the greater the tension on the water column.

Tree Height Limits

As you can imagine, it takes far more tension to raise water to the top of a 400-foot tall tree than it does a 40-foot-tall tree. Ultimately, some trees reach heights where the tension necessary to draw up the water becomes too great. When this happens, the column of water breaks down and bubbles may form in the capillaries – these bubbles break the surface tension of the water and leave voids in the system. The voids cause the capillaries to stop functioning properly, and become useless. This leads to a reduction in vigor, and prevents the tree from growing any taller.

In 2004, George Koch and three colleagues examined this mechanism in order to determine the theoretical maximum height of trees. By studying some of the tallest trees in the world (including California’s own “Hyperion,” which is the world’s tallest documented tree), the team concluded that the tallest possible trees may be able to reach about 425 feet, but not much more. Were trees to grow taller than this, the tension would simply be too great. (George W. Koch, 2004)

Problems with Climate Change

The method by which trees drink not only limits their ultimate height; it also limits their ability to survive climate change.

The tension on the water column is dependent on many factors aside from the height of the tree. These factors include air temperature, solar radiation, groundwater availability and wind speed. Generally speaking, when the air gets warmer, drier or windier, the water evaporates from the leaves more quickly. This increases the tension on the water column, and as we have seen, excessive tensions can cause permanent harm.

A 2012 study by Brendan Choat and 23 other researchers showed that the threshold at which these sorts of problems occur is remarkably close to the tensions trees normally produce. This held true for a wide range of tree species, across several different habitats. This means that if global temperatures rise relatively little, trees are likely to suffer greatly, as many will begin to transpire at rates that will cause them irreparable harm.  (Brendan Choat, 2012)

References

Brendan Choat, e. a. (2012). Global convergence in the vulnerability of forests to drought. Nature.

George W. Koch, S. C. (2004). The limits to tree height. Nature.

 

 

Poisoned Trees to be Removed in New Zealand

http://www.voxy.co.nz/politics/poisoned-trees-be-removed-kinloch/5/161640

TaupA District Council in New Zealand will have arborists remove some trees in Kinloch that died due to poisoning. There are six trees that need to be removed and they include gum, pine, and cedar. These trees, located at the Marina Terrace Recreation Reserve, were poisoned earlier this year and even though there was an attempt to save them, they died. The arborists will remove the trees at the end of July. John Ridd, District Manager of Parks and Open Spaces Manager, commented on the poisonings and noted that this type of incident is increasing. “It poses a threat to our environment and also our safety; a dead or dying tree can be a danger to the public. We’re lucky to have such a great environment here in TaupA District. It’s pretty disappointing that a few people are destroying some great trees.”

Although many people appreciate the trees that are in the public parks and along streets, Ridd says that a few people are causing problems. Complaints have been made to the Council of residents damaging or destroying trees. Because of these complaints, the council has reminded people that it is a crime to poison trees on Council land. If someone damages a tree in a public place, they could face a fine of $20,000 and in serious cases the police could bring criminal charges. There is a maximum penalty of ten years imprisonment for cases involving danger to live, and seven years in other cases. Anyone concerned about certain trees can contact a specific Council phone number to bring these trees to Council attention, and if anyone sees trees being damaged can contact either the Council or the police.

The person responsible for the poisoned Kinloch trees has been convicted and is now paying reparation to the Council.

Malibu Trees

Trees

Trees

State Parks workers, working to replace rocks that had fallen off the revetments in response to wintertime erosion of the sea wall, removed a coral tree growing within the sea wall. The sea wall needed emergency repairs to preserve the historic Adamson House at the Malibu Lagoon State Beach. Suzanne Goode, senior staff scientist with State Parks, said the tree was not native to the area. “The tree was growing out of the sea wall, and it had to be removed in order for us to protect the sea wall. We are sorry that we had to remove the tree,” she said. Malibu resident Andy Lyon, an opponent of the Malibu Lagoon State Beach overhaul plan, said the tree was planted by surfers in 1971 and didn’t need to be removed. He expressed concern that this incident was indicative of how the lagoon overhaul – a plan to replace non-native vegetation with native vegetation – will occur. “If this is any indication of how the lagoon project will be handled, it’s not a good sign,” he said.

 

Removing Gingko Trees Would Set Precedent

Residents on Hayes Street in Birmingham, Michigan, do not look forward to fall, when vegetation starts falling from trees. This residential street has 28 female Gingko trees that drop leaves and fruit on lawns, streets, and sidewalks. The leaves are not a problem, but the fruit is –when crushed the fruit releases a very unpleasant odor that residents say is a nuisance.

To combat this smell, residents have petitioned the City Commission to take action against the smell. The assistant city manager, Joe Valentine, was in attendance at the meeting when the petition was presented, along with a bag of the smelly fruit. Valentine has first-hand experience with the smell, because he lives on the street. He said of the Gingko fruit, “…once they mature and fall to the ground, when you crush them they have an odor to them. It causes an inconvenience, and that’s an understatement.”

So far, many residents would like to solve the problem by cutting down the trees, but Valentine says that isn’t likely to happen because there is a city ordinance in place to protect healthy trees that aren’t a nuisance or a danger to people. Injectable treatments to reduce fruit production and increased street cleanup were ideas that were discussed. There was also a worry that a precedent would be made if the Gingko trees were removed. “We don’t want to remove trees for just any reason. There’s a lot of trees in the community that people consider a nuisance because of flaky bark, roots…and we don’t just remove those trees,” said Lauren Wood, director of public services for the city.

But one resident said that increased street sweeping would do nothing for sidewalks or yards.

Residents Want Pine Trees Cut

Old tree

Old tree

Pine trees lining West A Street in Dixon, CA are being considered for removal. There are 45 trees in all, and they line a street that goes into the city’s historic downtown district. Residents on the street have complained that the pine trees are dropping large quantities of pine needles into their yards and onto sidewalks.

The pine trees were planted more than 25 years ago when the street had few houses built on it, and most of the residents feel that the trees are a nuisance. Roy Powell, a resident on the street, said of the needles, “They get all over my sidewalk. I’d like to see them cut the trees down and maybe plant something a little different that doesn’t require high maintenance from me.” Another neighbor commented, “It’s just extra yard work for anybody and none of us like extra yard work.”

Although the town is considering the request, not everyone wants the trees to be removed and feel the trees serve a number of purposes throughout the year. If the town does decide to cut the trees down, each tree would cost $1000, for a total of $45,000.

 

Village Considers Replacement Trees

Yellow Springs, Ohio, has been considering the best replacement trees on a street where power lines are being buried and the existing Bradford pear tree roots will be cut. The Bradford pear trees are already severely topped to keep them from impacting the power lines they are under, and the trees are about 35 years old. “Even if you leave them in [after the sidewalk construction], you’re going to lose them in a year or two anyway,” said urban forester Wendi Ban Buren. Burying the lines will allow newly planted trees to grow to their natural height without the need for topping.

Bradford pear trees are no longer recommended as a landscaping choice, so the discussion has centered on what other choices are good for street trees. Native trees have been considered, but they usually do better with space to grow their roots, rich soil, and plenty of water. Instead, street trees need to be able to survive in a 5 x 5 foot tree pit, have deep root systems to keep from impacting nearby foundations, and be fruitless. Thornless honey locust, male gingko, berryless sweet gum, state street maple, lace bark elm, columnar oaks, linden, London plane, and red spire pear are all possible options.

Yellow Springs has no formal landscaping plan, so it needs to work with the Yellow Springs Tree Committee, which has planted 2000 trees on public property in the last 30 years. Village Manager Laura Curliss is working to establish a working relationship with the Tree Committee. ‘I’d like to work with the Tree Committee on a placement plan for trees in the future,” said Curliss.

Trees Cut and Sidewalks Repaired in Napa

Napa California has been working on repairing sidewalks in a two-block area that tree roots have uplifted. At an uplifted sidewalk on Montgomery Street, a pedestrian had tripped, so city crews reviewed the sidewalks and trees in the area. What they found was that there were many instances of uplifted sidewalks due to tree roots. Speaking of the spot of the tripping incident, Parks Superintendent Dave Perazzo said, “There was significant sidewalk lift at this location due to tree roots. Access to the home’s driveway was impacted as well as drainage from their property.”

Once it was confirmed that trees were the cause of the sidewalk deterioration, the trees in the area were cut down. Crews first examined the roots and trees to see if shaving or grinding roots would be possible to save the trees. Unfortunately, some of the trees were found to be decayed or hollow, and the branch attachments would probably become public safety hazards, as the trees grew larger. It was also found that 25% of the roots would have to be removed for most of the trees in order to complete the sidewalk repair – and this would cause a problem in tree stability.

Once the sidewalks are repaired, replacement trees, which neighbors were able to have a choice in, will be planted.