Benefits of a Tree Island

First off, some of you might be asking “what is a tree island?” Picture a tropical island surrounded with water, there is your island. Now place that island in your landscape surrounded by turf grass, plant a tree in it and, voila, you have a “tree island”. In landscape design, you might create the opposite effect, having the turf grass as an island surrounded by tree berms and other designated areas. Since our focus is on trees (that’s what arborists tend to do), we pretty much call anything that has separated trees from turf “tree islands”.

There are multiple purposes involved, but the two most common are:
1. Creativity in design – a way to make your landscape more interesting. (Personally, there is nothing more boring than seemingly endless acres of lawn with a lonely tree popping out here and there).
2. Separation of diverse plant species requiring different cultural practices, allowing more efficient management of each landscape component.

There is no doubt a tree island can set off a specimen plant(s) to advantage: drawing attention to unique structure, colorful foliage, showy blooms. The tree island may also be planted in a variety of compatible species for maximum effect and improvement of soil health. (A topic for another blog.) But an important feature is the ability to provide a buffer zone from management practices that are harmful to those plants within the island.


© 2017 McNeill’s Tree Service

Tree islands also may provide diversity through compatible plant varieties.

Lawn care management practices can literally be deadly on trees. Weedwacking, the use of mechanical tools to mow grass and weeds away from the trunks, is more harmful than most people realize. They cannot conceive a little string can cause significant injury to a massive tree. Well, they can and do. And they can kill a young, thin-barked tree in an amazingly short period of time.

© 2017 McNeill’s Tree Service

Damage is seen at the base of the tree where the bark is missing.

Lawn mowers also inflict damage. The repeated running into the tree causes permanent injuries. We were called out to remove an ash tree which was over 50 percent dead. The homeowners asked what we thought was killing the tree. One of the first things we do is look at the base of the trunk. Investigation revealed a significant injury encompassing almost 50% of the circumference of the tree. After we had made the final cut, I counted tree rings to see when the damage had begun. I told the homeowners the damage started approximately 11 years prior. The husband admitted that was about when he got his riding lawn mower and the flange of the mower hit the tree on that side almost every time he mowed.

© 2017 McNeill’s Tree Service

Damage from flange on riding lawn mower.

© 2017 McNeill’s Tree Service

Basal cut showing results of repetitive damage.

We have a tendency to think trees can withstand anything we do to them because we generally don’t see immediate consequences of our actions.

Other lawn care management practices which can harm trees and other plants are commonly used chemicals. Many products have “weed and feed” components. In addition to fertilizer an herbicide is included to deal with broadleaf weeds, such as dandelions. Trees are broadleaf species and some species are very sensitive to those chemicals. Tree islands at least back the herbicides off from the critical root zone. We recommend hand pulling or spot treatment of broadleaf weeds that cannot be tolerated rather than wholesale broadcasting of herbicides.

A short note on the roots of trees. They do not stop at the drip line. Many people feel you can do or apply anything if you stay outside the drip line. Well, the roots are out there. In fact, they can grow much further away from the trunk than the tree is tall. Tree roots grow wherever they can. They need space, oxygen and water. Some grow close to the surface, some can go much deeper. Many roots do congregate at the surface as that is where the most space, oxygen and water are and so are able to take up anything applied to the soil.

When designing a tree island, a common practice is to lay down weed fabric prior to applying some form of top dressing. This is not recommended when the top dressing is of an organic nature, such as wood chips, compost, or bark, which is what we recommend. Landscape fabric will block the biological exchange between the organic mulch and the mineral soil below. This means none of the benefits mulch can provide the soil will be available. This caution goes whether the fabric is pervious (allowing water and air to penetrate) or impervious (blocking water and air).

If you are using some kind of non-organic top dressing, such as rock, then it becomes less of an issue. I have personal prejudices against some of the non-organic products, but these will be dealt with in a future blog specific to top dressings.


This may seem an odd topic for an arborist and blatant lover of trees.  But when dealing with innumerable clients over the years as well as speaking to groups (who are not directly clients), you have to stay realistic.  Some people are just simply not as enthralled with trees as we (arborists and lovers of trees) would like to think or take for granted.

The biggest issue we hear: “They’re so messy!”  Well, I can’t really argue that but it is tempting to ask if they have any children and if there is any maintenance involved with cleanup.  Since I am trying to keep avenues of discourse open, I bite my tongue there.

Yes, trees produce debris.  That actually is a good thing.  And important, even mandatory, in a healthy environment.  (I will go into this a lot more in my blog(s) on soil organic matter and healthy soil – yet to come.)  In a natural setting that debris is integral to supplying nutrients back to the soil and soil organisms and hence the trees themselves via the complex breakdown of the organic matter (what we are calling “debris”).  We tend to want our areas a bit too tidy.

The complaints escalate come autumn when those glorious leaves that have been giving us wonderfully-appreciated shade all summer, and which we love to oooh and aaah over in their fabulous color displays, start to fall.  And keep falling.  In fact, they seem to multiply on their way down to the ground.  A fact that has yet to be scientifically proven but anecdotal evidence suggests….

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© 2017 McNeill’s Tree Service

At that point, faced with a yard full of 2-foot-deep leaves, FAR more than you can mulch and use in your garden or flower beds, to say nothing of the whining of the designated rakee in the family, you are seriously contemplating cutting all offenders down.  If you live in town, this problem is compounded by the fact that leaves have no respect for property lines.  They not only fall over the fence from your neighbor’s trees but they BLOW IN from who knows where!  If a tree identification was to be taken from your property by the leaves on site, you would assume you lived in an arboretum, an impressive one at that!  Where in reality you may have one, maybe two, species actually situated on your place.

But you take comfort in the fact you will get them all raked up and that will be that for the season.  Ok, except for the next wind that blows all those errant leaves from, apparently, the next state, ….and the fun resumes.  Encouraging words like “it provides good exercise”, or “it’s called job security” (my personal favorite which so far, no one appreciates), or “it’s a wonderful family activity” (unless you have a dog and then they spend as much time scattering the piles as you do raking them; however, the dog is getting good exercise and a sense of bonding with the family, so there’s that) are little solace at this time.

And what on Earth do you do with all those sacks of leaves????  Well, many cities have places to dump them.  In some areas they will magically disappear if left bagged on the curb.  They actually are tremendously good for gardens, both vegetable and flower, as well as top dressing any other area involving soil.

When you do rake up your leaves, make sure you leave a substantial amount under the tree they fell from.  If you don’t have a tree island under your tree…. well, we need to talk.  There will be a blog about that coming up as well.


Trees have a genetic growth rate for development based on their species and influenced by their environment.   People often base a selection of a tree on growth rate preferring something where they will see rapid results rather than opting to buy a tree perceived as “slow” growing.    And many species which have the reputation for being slow growing may actually grow fast in their youth.

Before you succumb to the desire for instant gratification, consider some of the following points because, as is often the case in life, there are trade-offs.

Fast-growing species tend to have weaker wood and can be shorter lived than slow growing species.  This relates to their ability or “strategy” in dealing with disease and insect pressures, which is the topic of another blog although briefly addressed in Trees Don’t Heal, They Seal.

A fast-growing tree whose wood is weak can be a higher maintenance tree than slow-growing species.   They may require more intensive or ongoing clean up as they have a tendency to be “self-pruning”.  A lovely example being a willow tree that will shed limbs or twigs every time the wind blows.   They often require pruning on a shorter rotation in order to keep them in check within the landscape.  They may quickly outgrow the site, or need pruning simply to maintain a desirable structure.

© 2017 McNeill’s Tree Service

There is a certain mindset that states a tree can be made to grow faster by fertilizing.  Well, that is true.  However, pushing vegetative growth (which is what fertilization does) is at the expense of the tree’s ability to put resources into root development, storage and defense; important functions for health and longevity in trees.   As I just stated, a fast-growing tree will generally require pruning on a shorter time rotation than a slow-growing one, add in the fact of forcing growth to make it grow faster, and you end up compounding that issue.  And that wonderfully succulent growth is candy to many insects as well as disease organisms.  Many fast-growing trees already have a long list of insect and disease organisms, increasing that probability by fertilization, and you have a tree with a maintenance schedule and cost factor you may not have counted on.

Bottom line:  faster is not always better.  When it comes to trees you often want to bank on the tortoise, not the hare.

Protect Your Tree During the Winter

For the most part, trees are able to take care of themselves pretty well.  However, since we take them out of their native environments and plant them where they may, or may not, have grown by themselves, there are a couple of things we can do to help them out on a seasonal basis.

Flat tree guard on oak

Illustration of using the flat tree guard tied loosely around the trunk.   © 2017 McNeill’s Tree Service

If you live in an area that actually gets winter, you know, cold temperatures, snow…that kind of thing, you need to consider protecting your trees’ trunks.

The candidates most likely to need this are young, newly transplanted trees.  Why?  Because their bark is thin.  Thin-barked trees are particularly susceptible to sunscald which is an environmentally-caused, abiotic, injury which can be seriously damaging.

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The problem is created in the winter when the sun is lower in the sky and typically occurs on the south and southwest sides of trees.  The sun heats up the bark, the sap in the cambium flows, the sun goes behind a cloud or sets creating a sudden drop in temperature which can cause lethal freezing.  The damaged tissue is now susceptible to pathogenic organisms as well as having sustained the initial physical injury.  The damage is seldom seen for months if not years as the dead and dying bark does not slough off the tree immediately.  When finally noticed, this is seen as a “sudden” event by the homeowner but the damage actually occurred in the past.


There is no “cure”.  (See Blog on Trees Don’t Heal, They Seal) Prevention, though, goes a long way.  In late fall, install a protective shield on the south/southwest side of the trunk.  It may go all the way around the trunk if using one of the white tubes sold for this purpose.   If your tree has grown too big for the tubes (generally sold in 2” and 3” sizes), you can use flat, white corrugated protectors and tie them on.

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Two sizes of tree guard tubes. Both come in the longer length, the wider one has just already been cut to fit a tree. © 2017 McNeill’s Tree Service

Whereas this is generally only necessary for young trees until their bark is sufficiently thick enough to withstand normal winters, there are a few trees that remain susceptible their entire lives.  Species such as Mountain ash trees, Sorbus spp., and the extremely popular Autumn Blaze maple, Acer freemonii, ‘Autumn Blaze’, are two examples.  Protection for trees which stay sensitive to sunscald can be accomplished by planting understory shrubs and perennials on the south/southwest side of the tree which will give it winter protection as well.

© 2017 McNeill’s Tree Service

Trees Don’t Heal, They Seal

Trees cannot regenerate tissue over a wound as humans do.  They seal off the injury and encapsulate it, hopefully stopping pathogen entry or progression in the process.  But the wound is always there and visible on the inside if not also from the outside.

This is why responsible arborists try to take as much care as possible to minimize wounding caused by pruning.  Because, technically, all pruning cuts are wounding the tree.  But then so is the swing set attached to a limb, the bump from the car, the bicycle leaned against it, the dog tethered around the base, the lawn mower hitting it every time you mow, and don’t even get me started on weed whacker injuries!

Every poster, sign, birdhouse, decoration affixed to a tree is injuring it to one degree or another.  Cats mark the trunks with their claws, birds peck holes as they go for larva under the bark or accessing sap exudations, tapping to produce maple syrup, the list simply goes on and on.  In fact, I often say, trees live in spite of us, not because of us.

When a tree sustains an injury, an air embolism is created.  The tree responds by trying to contain the damage this will cause by initiating chemical responses of various strengths, containing it from progressing up and down the trunk (axially), into the center of the tree (radially) and sideways (laterally).  There is a more powerful reaction produced as a barrier which inhibits disease or dysfunction from extending out into new wood formed after the initial injury.

Arborists will know this sequence by the acronym CODIT, Compartmentalization of Decay in Trees, as initially described by Dr. Alex Shigo, with the boundary zones, Walls 1, 2 and 3 and the barrier zone of Wall 4.

Dr. Dirk Dujesfieken has described this process further and CODIT is now being referred to as Compartmentalization of Damage in Trees.  Discussion of the CODIT Model and the CODIT Principle are lengthy subjects and topics for future blogs.

© 2017 McNeill’s Tree Service

GET ACQUAINTED WITH McNeill’s Tree Service

Welcome to McNeill’s Tree Service website.  Our company was created by my husband, David, in 1985.

Born in Massachusetts, David had always had a passion for being outdoors and climbing trees.  More than once as a child, his mother found him high up in trees on their property.   Upon the family moving to California in the 1960s, that passion became his vocation when, as a teenager, he was taken under the mentorship of Ed Hobbs, an arborist in the Bay Area.  David was a natural.

We moved to Montana in 1984, and David soon hung out his shingle, letting it be known he was an experienced arborist in residential tree care.  Wanting to keep the company small, I joined him in the field as ground support.

As time passed, we developed a reputation for quality work at reasonable prices.  At some point in time, I realized David’s passion had become mine and decided to pursue certification through the International Society of Arboriculture (ISA) program for Certified Arborists.  Passing this test opened the dam to craving more knowledge regarding trees.  Taking on-line courses through Dakota College at Bottineau, North Dakota, I gained a diploma in Arboriculture and Urban Forestry Management.  At the same time, I took and passed the test for the highest certification ISA offers:  Board Certified Master Arborist (BCMA).  This gave me the distinction of becoming the first BCMA in Montana.

David and I share a thirst for ongoing education and knowledge on anything related to trees and soils.   I have been pleased to be invited to speak at numerous clubs on all aspects of tree care and health, guide tree walks, and have presented at the Tree Care Industry Association (TCIA) EXPO, our national arborist’s association annual conference, speaking on the importance of soil health in the residential setting.

Information on tree care is readily available on the Internet and in books.  But the sheer volume of information, often contradictory, can be confusing and frustrating to the home owner as well as to many arboricultural professionals.   It was the desire to help make sense of it all that was the driving force behind initiating this website and blog.

I look forward to sharing articles, new information, and answering questions in the time to come.

Sylvia McNeill, ISA-BCMA RM-7117B

McNeill’s Tree Service