Much like an iceberg, a tree is as present within the soil as it is above, and in its pure fractal genius, nature has endowed trees with a dendritic architecture that mimics the form that reaches for the sky, as though the soil line were but a mirror dividing ego and alter-ego.  (It bears noting that this mirror image is somewhat of a funhouse-reflection, both shallower in depth and broader in spread than its aerial counterpart.) A tree (making an attempt at) living in a hyper-urban environment, surrounded by impermeable hardscape, is about as divorced from its evolutionary origins as one can be, and understandably has more issues than National Geographic.  Conversely, though, understanding the plight of trees living in suburban settings seems to require a greater stretch of the imagination.  I use the term suburban here in a very specific application referring to the growing conditions of the tree, without regard to the larger mise-en-scene.  A native balsam fir growing deep in the backcountry can still be subject to typical suburban conditions and stresses if it is underplanted and surrounded by turfgrass.  The human residents may be off the grid, but the tree might as well be living in Massapequa.

By far, the single greatest conflict we encounter vis-à-vis trees in the cultivated landscape is that they are more often than not situated in the midst of that perfect green blanket of American hagiography.  One can be forgiven for not immediately grasping the inherent conflict, but it is really quite obvious if one considers where and how trees exist in the wild.  There certainly is not a lawn anywhere in sight.

With this understanding, removing the turf ought to be a no-brainer, but the solution is incomplete without some replacement that proffers ameliorated biological function.  Again, the answer is accessed by looking at and around wild trees.  What we find is decomposing plant material, and plenty of it: a mélange of leaf litter, old twigs, bark, and wood, all contributing to the gradual creation of humus, the ambrosia of woodland plants great and small.  This key cycle is what is most glaringly absent in the life of the suburbanized tree, but it can be most easily approximated by mulching within the drip-area of the tree.  While the population of microbes may not be distributed in a way beneficial to the tree at first, it will shift and diversify over time so as to fall closer in line with what one would expect to find in nature.  To dip into a postmodern cliché, it's a bit of a Field of Dreams situation.

While such projects may seem daunting, they need not be so.  In fact, one need not even remove the turf; it can simply be smothered into soil-building biomass by layering a biodegradable barrier such as newsprint or cardboard over it before mulching.  One can still plant the area with groundcover perennials after the grass below has died and decomposed, a process which consumes only a few months of the growing season.  Areas mulched in such a way in either the autumn or the spring are normally ready for planting by late in the subsequent summer.

We often ask, or rather demand, that trees grow for us in suboptimal conditions.  It is not realistic to expect that every tree in the landscape will find its home in a mulch ring or garden bed.  Similarly, part of the fun of horticulture is found in pushing the envelope in terms of what we can and should grow in our cultivated landscapes.  In short, sometimes suboptimal siting is inevitable, and in such cases, trees need all the help they can get.

One way to provide this assistance is through so-called "deep-root" fertilization, by which one injects a targeted dose of nutrients directly into the zone populated by a tree's feeder roots.  This treatment gives the tree the raw materials it requires to develop in a healthy and resilient manner, better able to withstand the caprices of an often harsh environment.  Since this passing season brought a great deal of stress in the forms of a persistent dry spell, late freezes, and disease issues, fertilization of important landscape trees is highly recommended to prevent those stresses from accumulating into a loss of vigor in the future.