Landscape Consultants HQ   LANDSCAPE CONSULTANTS HQ

Join Landscape Consultants HQ for our newsletter with professional landscaping advice. You can opt out at any time.

Hazard Trees

An Immediate Threat

hazard tree

Hazard trees are trees that pose an immediate threat to people or property. If a land owner has been told by an arborist that a tree on their property is a hazard, from that point forward, the owner is legally liable for any injuries or damage unless they take action right away to remove the hazard. Once an arborist is called in to determine if a tree is a hazard, their responsibility as an arborist is to notify someone what action should be taken. Even if a tree is an immediate threat, it may not fall or break apart right away. Taking quick action can prevent costly damage.

How do you know if a tree is a hazard?  Call in a certified arborist. Arborists have specific evaluation criteria to determine if a tree is unsound. A potentially dangerous tree is a legal issue. Being an arborist doesn’t require a college degree like a forester, but it does require very specific knowledge about tree structure and health. You can find an arborist using a tool available at the web site for the International Society of Arboriculture. They provide certification credentials for arborists and verification of certification for clients.

Deciding if you need to call in an arborist often involves common sense, but sometimes the threat is less obvious. This photo illustrates a tree that is clearly an immediate threat to people and property, but when you see a street tree with roots oozing out over the curb or the sidewalk, the tree may appear perfectly healthy above the ground. The roots are attempting to compensate for a very bad planting situation and an unstable, top-heavy crown. Healthy, stable trees can be hazards, too. A perfectly healthy tree becomes a hazard when it is planted too close to the edge of a high-speed highway, because not everyone stays on the paved travel lanes! When in doubt, call an arborist.

Tree Ordinances

Fighting City Hall

tree ordinances, local regulations, permitting

Tree ordinances are a necessary hassle because people often, for their own benefit, want to remove trees on public rights of way. As a landscape professional, you may be asked to help craft a local ordinance. The ISA (International Society of Arboriculture) has a downloadable document with guidelines for developing and evaluating tree ordinances

Citizen groups, for environmental or other altruistic reasons, want to plant trees anywhere and everywhere, without planning for the effect of trees as huge fixed objects under power lines, blocking signs, and in the clear zone on public rights of way. Tree advocate groups might plant without maintenance or safety considerations. Something as harmless as planting a tree can become highly polarizing. People get emotional about trees! If they are told not to plant them in certain areas, they get extremely offended. Arguments about which trees are best take over a lot of civic planting projects. A tree ordinance can calm down the anger and provide direction for group decisions.

Developers sometimes try to expose outdoor advertising or their latest retail shops by taking down trees. They use their economic strength, political pressures, and legal technicalities to go beyond necessary and reasonable tree removal. Enforcement of a tree ordinance can mean a quick career killer for low-level bureaucrats, and special waivers are common to allow free “economic development” for those with clout.

Written ordinances are essential to provide consistent and fair treatment for all parties. I don’t know which is worse, really. Reckless tree removal or thoughtless tree planting. If everyone removed only the trees necessary for construction and planted trees and planted only in locations that were planned thoughtfully with expert assistance, then there would be no need for tree ordinances. Tree ordinances are here to stay.

Fruit Trees

Edible Landscapes

fruit tree, fig tree, edible landscape, potage

Fruit trees can add beauty in the garden as well as sustenance—think French jardin potager! They are a bit different from typical large canopy shade trees, though. Here are some unique fruit tree characteristics that will help you provide both food and ornament to your garden.

• Fruit trees are edible, of course, so they are especially attractive to deer—so much so, that if you have a problem with deer in your area, you should leave the task of growing fruit to professional orchard farmers with fencing and whatever other tools are needed to protect the trees

• Fruit trees are short-lived. Expect a fruit tree to last about thirty five years. They expend a lot of energy to produce, and they burn out when relatively young (for trees).

• Fruit trees can go through an early decline unless you keep the soil pH up with regular applications of lime. Fig trees in particular like a lot of lime to keep them healthy.

• Late cold snaps can zap the fruit or flower production of fruit trees. Either way, you end up with aborted fruit. In areas where late cold snaps are a problem, you can choose varieties that bloom late in the year to avoid this problem.

• Fruit trees require artistic pruning for optimal production. On commercial fruit orchard farms, strategic pruning is a major part of the cultural practices for results. The professionals prune for maximum sunlight, concentrated energy, and proper aeration to prevent diseases.

Tree Groves on the Roadside

Using Trees for Design Advantage

fall color, grove of trees, trees in landscape design

For designing roadside landscapes, start with trees. Once your inspiration has been realized and you have addressed issues like slope, circulation, function, and hardscape features, you can begin your planting plan. The easiest way to provide a low-maintenance landscape for a large roadside site is to limit your plant choices to two types—trees and turf. Keeping things simple looks nice and makes the upkeep worry-free! After planting, only a few maintenance tasks need to be done each year to care for this configuration.

• The grass needs to be mowed.

• The plant beds need to be mulched around the edges about twice a year.

• The soil needs to be fertilized.

• An arborist needs to be hired every seven years or so to evaluate the health and structure of the trees to keep them thriving.

• The trees need to be watered during severe droughts.

The design is only care-free if the trees are consolidated into plant beds and spaced close enough so the natural leaf litter falling from the trees provides adequate ground coverage. The leaf canopy will provide enough shade to prevent a lot of weeds from volunteering between the trunks. A spacing of ten to twenty feet on center is about right. By consolidating the trees in groves, tractors can navigate all the turf areas methodically, without having to circle individual rings around each tree.

Ancient Trees

Landscapes with Soul

ancient trees, giant sequoia, legacy landscapes It seems as if ancient trees possess souls. Standing next to a Giant Sequoia feels very different from standing next to a typical park tree. There’s a palpable presence. The age and majesty of ancient trees certainly make them worthy of reverence for their beauty and respect for their survival.

When watching the Lord of the Rings trilogy, my favorite scenes were ones that included the Ents, ancient spirits that looked like trees. That fantastic idea seems perfectly reasonable when visiting Sequoia National Park. My first response as we entered and saw the Giant Sequoias was to gasp for breath. You hear the word “awesome” used a lot, but these trees are truly deserving of the adjective. It would have been no surprise to see them slowly move and begin to walk.

Giant Sequoias live in groves. They are cousins to the smaller, Dawn Redwood. They grow up to almost 300 feet tall. Gravity restricts the height that water can be drawn up to the top branches, or they might grow taller. Researchers have studied their plumbing to emulate in experiments with an elevator to space. The trunks can reach up to 100 feet in diameter. That as wide as a large house. You can see the history of previous fires in the intriguing scars left behind. They can live for 3,000 years.

Redbuds and Hot Feet

declining Redbud treesMulch Redbuds for a Long Life

Redbuds are great, native trees if you can keep them alive. They can take full sun, and will reseed eagerly. They make a beautiful, delicate early-spring presence at the edges of woods. They can handle challenging roadside and urban environments. And yet, you may find your nice grove of Redbuds suddenly start falling apart and losing leaves.

Why do Redbuds decline? They hate hot feet. If you allow grass to grow up to the edge of the trunk, the roots will not have the protection from the burning sun they need. Generously mulch the ground under the entire drip line so their roots aren’t baked by heat and summer droughts. It’s that simple. For long-lived Redbuds, keep their toes cool.

Roadside Trees the Smart Way-Setbacks

Roadside Trees the Smart Way

roadside design, tree setbacksIf you’re a designer creating a new streetscape plan, a civil engineer putting the finishing touches on your road project, an environmental consultant preparing a mitigation proposal, or a community improvement district landscape architect preparing a showplace entrance for your local interchange, chances are you will be using trees as the primary vertical design elements of your planting scheme.

You may be thinking that anything you draw would be an improvement. Your proposal may not be as benign as you hoped, especially when trees are involved. Trees are a statistically significant cause of traffic deaths and a frequent trigger for utility outages. They can pose a big problem for maintenance crews, and they can block sight lines for pedestrians and cars trying to enter or cross the roadway. Businesses and sign owners can be very upset if your proposed trees block their signs.

People plant trees all the time, because trees provide wonderful shade, color, wildlife habitat, buffers, and visual beauty to the landscape. When located wisely, trees can provide all the benefits, without any of the worries. You can avoid a lot of problems by locating your new trees well beyond the clear zone.

The clear zone is typically the width of the roadside beyond the travel way where an errant vehicle might possibly recover and get back on the road. If it is kept clear of fixed objects, then most of the vehicles that run off the road can get back on the road safely. If there is a fixed object the area that should be clear of fixed objects, then the driver is not so lucky. Curbs do not slow vehicles moving over 25 MPH, and vehicles that hit fixed object going over 35 MPH usually result in considerable injuries or death. 

The clear zone is based on the horizontal curvature of the road, traffic volume, the speed limit of passing cars, and the slope of the adjacent roadside. The faster cars go, and the steeper the downslope, the wider the clear zone area will be. If you can’t “meet the clear zone” minimum setbacks, then don’t plant the tree, with notable exceptions. 

Commemorative Trees

Commemorative Trees

commemorative trees, sumacCommemorative trees are a great way to honor someone special. When you plant a tree to honor someone, spend your funds on the best tree you can find up to 4 inches in diameter, and cherish the memory of the person with the knowledge you have left something behind for others to enjoy. The gesture of the new tree will last, even if the commemorative plaque is tossed away with passing time, which it almost always will be.

Pages