Austin Tree Experts



austin tree blog

October 19, 2009

Constructing In-Ground Swimming Pools Around Trees

Quite possibly the only thing better than being under a shade tree in the summer is taking a dip in the pool. If you are planning to build an in-gound pool near one of your prized trees be careful. You are going to be digging a big hole in the ground and will likely be taking many tree roots in the process.

The kind of tree you will be working around will be a big factor regarding the amount of disturbance the tree will tolerate. For example, live oaks will take a lot of abuse; I’ve seen pools built within a few feet of the trunk of a live oak and the tree survived. American Elms, however, do not fare well after substantial root injury.

My general rule of thumb for any construction around trees has been to try and give at least 15′ of clearance from the tree trunk. If you are digging or leveling the soil within 15′ you are asking with trouble. This holds especially true when digging out for a pool.

A good thing to do before you start digging is to use an airspade and dig some trenches to find out where you have big tree roots. An airspade is a high powered air compressor that can blow away dirt without damaging tree roots. Doing a few test digs will give you an idea of how much trouble you are getting into.

Regardless of your exact proximity to the tree trunk, any trees near the pool should be put on a fertilizer regimen to help the tree repair wounds and regrow root system. Often, trees that are not right next to the pool, but adjacent to the path used for equipment access get damaged, too. Don’t forget about these trees.

High traffic areas around the pool and along the access path should be de-compacted using and airspade to restructure the soil. This is critical to providing the trees a good soil environment for the roots to regrow.

The bottom line is that pools can be built near trees without having to sacrifice the trees. But, certain steps must be taken to ensure your pool design allow for sufficient tree preservation measures. You should go into the design process with an open mind and willingness to sacrifice some pool features to save your tall green friends.

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Filed under: Construction Sites — Keith @ 7:26 am

September 23, 2009

Construction Site Tree Protection

There are several facets of construction site tree protection that need to be covered. Most of the basics are pretty straight forward. Since all construction sites are different, the tricky part is understanding the impact to trees on your particular site. Some of the things you can do yourself, and some of the techniques will require you to hire a professional tree guy.

The most important part of construction site tree protection is fencing off root zone areas so construction workers don’t have access. The ideal situation would be to fence off the entire area within the tree’s drip line (the extremities of the branches reach). The tree roots definitely go out further. But, this would protect enough root zone to yield minimal damage to tree roots. In many cases, protecting this much tree root zone on a construction site is not possible, so fence off as much area as possible.

For areas that are likely to receive high traffic apply a 3-6” layer of mulch to reduce soil compaction. The thickness of the mulch will vary with the type of traffic. For foot traffic, a 3-4” layer will suffice. If heavy equipment will be driving across the root system, a thicker layer will be appropriate. If there is to be regular equipment activity, put plywood across the mulch to further distribute weight and reduce soil compaction.

Understanding that trees are going to suffer root damage during the construction process, it is important to engage a regimented fertilizer / treatment program to help the tree repair injuries. Ideally, this would start before construction begins, but it’s better late than never.

In addition to root injury, trees will typically require some pruning to allow room for the new structure and for traffic underneath. Over-pruning might be required to meet the goals of the construction project. All the more reason to fertilize the trees regularly.

The last construction site tree preservation technique I want to discuss is soil restructuring. The idea here is to till the areas of the construction site that received high traffic to un-compact the soil. Using and airspade to blow out the soil with air allow the earth to be tilled without destroying tree roots. Mixing in some finely ground mulch or other organic matter will further improve root growing conditions.

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Filed under: Construction Sites — Keith @ 7:07 am

September 8, 2009

Soil Restructuring. An Important Part of Tree Care.

Soil restructuring is one of the most powerful tools we have for tree health management. The idea is to till the soil; improving its structure will allow valuable air and water to more easily penetrate the soil. While fundamental in gardening theory, this task is not easy at the scale of a large tree.

One of the first challenges we must deal with is maintaining tree roots while tilling the soil. After all, we are trying to help the trees here! This challenge is overcome by use of a tool called an airspade. An airspade is an over powered air compressor that blows away dirt without damaging the tree roots. There is just enough power to displace soil, but not enough to cut through roots.

In most scenarios, we will till the top 4-8” of soil depending on the site conditions. We’ll then add about 2” of finely ground mulch or other organic matter and then re-till the soil to get it all mixed up good. Once this part of the process is completed we’ll top dress it with about 4” of mulch.

The end product is an inviting soil that is great for growing anything. This is as close to mimicking a natural forest floor as we can get in an urban environment. Add a few small to mid size shrubs to provide an additional layer of shade to the soil surface and some irrigation and you’ll have a full blown tree utopia!

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Filed under: Fertilize, Sick Tree — Keith @ 7:44 am

September 1, 2009

What is a Good Fast Growing Shade Tree for Austin and Central Texas? – Red Oak

What is the best fast growing shade tree to plant in Austin? Here is my answer: red oak. There are several factors that must be considered, and there are special precautions you need to take. No tree is fool proof.

Red oaks grow fast to provide shade quickly, plus they are long lived and hardy. Here is a red oak 6 years after planting

Red oaks grow fast to provide shade quickly, plus they are long lived and hardy. Here is a red oak 6 years after planting

The general trade off for fast growing trees is that they are shorter lived and require more maintenance, but you get shade faster. And, typically, slower growing trees live longer and tend to require less maintenance in a typical urban landscape. The red oak is a good balance. This tree has a rapid growth rate, 3-4 feet per year, and has a solid wood you would expect from an oak which makes them less prone to limb failure during storms. The norm for fast growing trees is that they have weak wood that require regular canopy thinning to reduce the likelihood of limb failure. Red oaks require very minimal pruning throughout their life, comparatively.

You do need to pay special attention to red oaks during the first few years after planting your new red oak. These trees are especially susceptible to transplant shock. Keep in mind that they have spent the first few years of their life in a tree farm that has maintained perfect growing conditions to grow trees fast. So your tree has just been relocated from a tree utopia to the virtual desert that is your yard. It is important to water and fertilize your tree properly during the first 1-3 years (read our fertilizer blogs).

Get past the first few years and you will have a fast growing shade tree that will grace your neighborhood for 75 years or more. In as little as 6 years you will have a tree that really looks like a tree, not just a stick in your yard.

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Filed under: Landscaping, Tree Planting — Keith @ 8:43 pm

August 10, 2009

Tree Fertilizer Part 1. An Introduction.

Fertilizing your tree will provide a big impact to the health of your tree in both the short term and long term. More than pruning, more than any other tree care service. There is a lot to know about tree fertilizers. This article is meant to be an introduction to tree fertilizer. I highly recommend you read my three other articles in this series: When to Fertilize trees, How to Apply Fertilizers to Trees, and What Products to Use for Fertilizing Trees.

You can compare tree fertilization to your own health care. Without it, you are not going to wither and die tomorrow. But, with proper health care (fertilization regimen) your tree will have a healthier, more full canopy of foliage. And, if a good fertilization regimen is followed for a few consecutive years, sick trees can return to a healthy state and regain extended life expectancy.

One of the biggest misconceptions I find people to have is a perception that tree fertilization mostly make a tree grow faster. I can see where someone would come to this conclusion. Most of us get our experience in fertilizers from grass fertilizing. Grass fertilizers do result in faster growing grass. Trees are different that grass. Grass is in a constant state of growth and trees only grow a few times a year; we call these growth increments flushes. The ultimate goal with trees is to time the right treatments so that roots are stimulated to grow faster, but foliage is stimulated to develop better (not grow faster).

Timing is critical. Here are the basics you need to know about timing: most root growth takes place in the fall; most foliage growth takes place in early spring; there is not much growth in the middle of the “growing season.” With this knowledge you should be able to deduct that fertilizing in the summer would be a waste of time. During the spring you should use unconventional treatments to stimulate healthy development not conventional fertilizers that would stimulate growth. Your conventional fertilizer should be applied in the fall when roots are doing most of their growing.

Here are some common comments I hear about tree fertilizing:

Q: These trees were growing here long before I was here. They didn’t need fertilizer before, why now?
A: Ok, true. But, before you were here there was a natural balance of nutrient recycling. Now, the soil’s litter layer is gone and replace with grass.

Q: Fertilizing is just going to make it grow faster, then I’ll have to prune it more.
A: We just discussed that a good fertilizer regimen doesn’t stimulate growth. Quite the opposite, healthier trees will produce fewer dead limbs over time, therefore, reducing pruning needs.

Q: I don’t like putting chemicals in my yard.
A: You shouldn’t. But, what are you considering as chemical? Fertilizers are less harsh that virtually any cleaning supply you use and you actually get that stuff all over your hands and up your nose. And, if you get your timing right you can reduce your application rate dramatically. We target about ¼ lb nitrogen per medium sized tree per year. That’s 12 times less that what is recommended for 1000 sq. ft. of lawn. Every other product we use is not chemical at all (see my article on what products to use for trees).

One last topic I want to discuss before leaving is soil restructuring. Many of the trees in our urban environment get left with small little islands of soil to grow from. There is a tool called an air-spade we use to air-till the soil and mix organic matter in. Tilling with this over-powered air compressor allows us to till the soil without destroying all the tree roots. This treatment is a huge improvement to the soil structure and is great for all trees, especially those in limited rooting environments.

Buzz it!
Filed under: Fertilize, Sick Tree — Keith @ 7:34 am

July 30, 2009

How Summer Heat Stress Affects Your Trees

Summer heat stress is one of the number one tree killers I run into. Okay, realistically no tree ever dies from just one problem, but rather a cumulative affect of many stress factors. Heat and drought stress are stress factor that almost all trees in the central Texas area deal with on an annual basis. So, if your tree has some other factor stressing it out, the summer heat might be the straw that breaks the camel’s back. I see more trees die during the summer time than any other time of the year.

Crepe Myrtle with droopy leaves

Crepe Myrtle with droopy leaves

Some trees suffer from heat stress more than others. For example, live oaks and cedar elms cope very well; sycamores and cottonwoods with will begin shedding leaves with moderate heat levels if water is scarce.

One important factor to consider when trying to quantify damage from heat stress is to take note of the date when your tree loses all its leaves. My experience has been that if a tree can hold its foliage through July into August then it will usually leaf out full the following spring. In some cases the tree will even put on a new set of foliage in September to effectively produce more sugars for itself through the fall growing season. Worst case scenario is if your tree succumbs to a heat wave in the spring. We’ll often get a hot spell in April or May that will reach 100F. If your tree loses all its leaves this early it probably won’t bounce back.

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Filed under: Sick Tree — Keith @ 8:30 am

April 15, 2009

Tree Pruning: volume 4, When to Prune Trees

“When is the best time to prune trees?” This is one of the most common questions I get asked. The truth is there aren’t many timing concerns for tree pruning in the Austin area. Let’s start with the most common mistake I hear people make about when to prune trees in Austin, Texas.

You cannot adapt rules from other climates to Austin. If you go to the north east part of the country there are imporant guidelines. There, the dormant season is long and the trees are much taller. This means that bigger trees have less time to get all their growth cycles done. During the spring and fall months, trees in this area have intense sap flows. Pruning during these times will lead to bleeding wounds which leads to every insect and disease in the book. In Austin we don’t have this problem. Our seasons tend to run together; you can prune any time and not get bleeding wounds. Except with American Elms, these trees will produce bleeding wounds regardless of when you prune them.

The only concerns we have in Austin, Texas for when to prune trees is geared specifically around one tree diesase, oak wilt. There is one beetle know to spread the disease and it is active for only a few weeks during the spring. The timing of activity varies from year to year but it is generally always between March and May. The Texas Forest Service recommends you avoid wounding trees during this time. There adoption of this rule is based on concerns of homeowners capacity to understand and remember intricacies of the disease spread. If you are working with a professional who makes proper cuts and treats wounds, there is no risk of disease in pruning wounds.

In conclusion, the answer of “when to prune trees in Austin, Texas” can be answered by two sentances: If you hire a professional, knowledgeable arborist, you can prune any time. If you are doing the pruning yourself, avoid pruning between March and May.

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Filed under: Pruning — Keith @ 7:07 am