When to Nurture and When to Remove

One of the most difficult decisions an arborist is often called upon to make is whether or not to remove a tree. It might be a tree we?ve taken care of for years, or it could be the first time we?ve ever seen it. In either case, I never make that decision without also realizing that I?m considering the fate of a living being. That having been said, as with just about everything else in this crazy world of horticulture, a myriad of factors should and do come into play in making these decisions. Though I definitely qualify as a tree hugger, sometimes the best decision is to take a tree out.
 
The single most important cause for tree removal is safety. Not only is it our duty to consider the health of the plants we maintain, we must also always remember to protect our clients and the public at large. The most obvious case of this would be a large declining specimen that is threatening to drop large limbs, or to actually just fall over.
 
However, sometimes the tree?s in fine health, it?s just that the location of the planting is entirely inappropriate. I think the most common example of this that I see is the ridiculous use of small date palms in narrow planters around business establishments. In the many years it would take for the palm to mature to the point that the highly dangerous inner portion of the fronds would be out of the reach of potential harm, there are so many opportunities for mishap, that the plant should be removed or relocated. The same holds true of many other desert trees full of thorns, and care is warranted in their placement and maintenance. I suppose I?m picking on the date palms here because the sharp protrusions are so stiff and injurious. I know this, having been stuck by them myself so many times.
 
When considering the potential danger of a plant, be sure to take into account the potential target. If the tree is out in the back portion of a large wooded lot, where people seldom tread, the potential for harm and damage is greatly reduced when compared to a specimen that sits between the driveway and walkway, and has one precarious large limb poised over the living room. We need to have extra concern, and show added caution as the likelihood of a target being hit increases. The value of a target is also a major consideration, with human life being at the high end of that scale. Somewhere further down the scale is the Lexus in the driveway, and towards the bottom end would be a patch of untended shrubs.
 
The likelihood of failure is measured against the value of the potential target. Using the above examples of a tree in the back of a wooded plot versus one hanging over the house and walk, defects can be more readily tolerated in the former that would warrant remedial action or removal in the second.
 
Now, supposing you?ve reached the conclusion that the combination of target and potential for failure are such that the limb in question needs remedial action, the type of remedial action must next be decided. Is the tree of sufficient value to warrant the labor-intensive installation and maintenance of bolting and guying hardware? Or is it still small enough that you can begin the process of heading back and lightening the load while other lateral limbs will, over the coming season(s), begin the process of filling in the space that is currently occupied by the suspect branch?
 
Unfortunately, in some cases when the potential for failure and damage are high, and the limb in question represents a very substantial part of the canopy, and bolting and guying have been ruled out as an option, the remedial act of removing the branch would leave such a devastating wound and so disrupt the structure and form of the tree, that removal of the entire tree is warranted.
 
Another set of cases that might call for tree removal are disease issues. Tree diseases that are long term, difficult or impossible to cure, highly contagious and very detrimental to the health of the tree might all cause an arborist to recommend removal of a specimen. Each of the above mentioned disease factors should be taken into account in making the decision.
 
The soundness of the trunk, the main supporting structure of a tree, is also of major concern. In cases where internal decay and hollowness are known or suspected to exist, one should attempt to discern the structural soundness of the remaining wood, and its ability to continue to support the load it bears. The fairly recent introduction of new tools, such as the resistograph, and formulas developed for use with it, allow the arborist to make much more reasoned judgments as to whether to allow the tree to remain standing or be removed.
 
Perhaps the most oft overlooked (and unseen) factors in determining long-term tree viability are root issues. Underdeveloped or poorly placed roots cause the demise of many trees. Unfortunately, the resulting lack of stability can take down an otherwise fine specimen. One indication of root structure problems can be the lack of well-defined buttress bases where the trunk enters the ground. By this, I mean the swell of tissue from the trunk outward, indicating the presence of a large buttress root. If a fairly large and continuous portion of the circumference of the trees trunk does not show such a ?swell? of tissue, it could be an indication that there is no substantial root development in that direction. Another clear sign of lack of stability is the heaving or movement of the ground around the base of a tree, particularly in conjunction with a storm event. Sometimes the ground will maintain the signs of heaving. However, I sometimes make a point of inspecting trees during high winds, in order to observe otherwise hidden signs of defects, either in the ground or canopy. Of course I avoid standing directly downwind of suspect trees in such events. After all, a good arborist is not a dead arborist.
 
When it comes to tree removal due to unsatisfactory root development, without doubt, the vast majority of trees that I recommend for removal are still very young. It seems all too common a phenomena to have young trees not develop proper root systems, and I think this occurs for a combination of one or more of the following three reasons. First, and perhaps foremost, is the frequent use of plant material that has been left in the nursery container for too long, and has developed girdled roots. Secondly, when drip irrigation is used to irrigate these trees, all too often (almost always), all of the drip emitters are placed within a few feet, if not a few inches, of the trunk. Unless understory plants are used in the nearby vicinity, surrounding the tree in question, the root system will often not develop beyond the relatively small area of wetted soil at the base, and structural stability is lost. Third, it is my belief, and that of many other arborists I have spoken to, that when ?water-adventitious? desert trees such as Mesquite are irrigated too frequently, the trees develop a great deal of lush top growth, without expending much in the way of effort to develop roots. After all, why should it bother to develop roots when the roots it has are plenty to provide the water it needs, which is usually the critically short factor for desert trees. As the result of the above listed factors, I often walk up to such trees even after they?ve been in the ground for several years, and give them a good shake, only to find they are almost as unstable as they were on the day they were planted. Because those trees are still relatively young, often the best policy is to replace them now, rather than wait and develop a larger tree that will then likely fail. I think it?s better to be proactive in such cases, and remove and replace the tree with healthy stock.
 
Please bear in mind that I really am a tree lover. But I think we must maintain our objectivity as arborists, and keep in mind our clients best interests. Unfortunately, that means we must sometimes take out trees that are unsuitable.