Archives for posts with tag: tree growth

Trees are a treasure, a joy to have around.  They provide a habitat for birds, insects and other critters; act as a buffer against wind, rain and snow; and are the main generator of atmospheric oxygen and consumer of carbon dioxide.  Plus, they are beautiful to behold.  If they are not the focus of a picturesque view, they are probably framing it.

But sometimes they get in the way.  Usually, this is merely an annoyance, such as when they block the view (see, for example, August 12, 2013).  Other times, though, trees can block solar exposure, often to detrimental effect.  I’ve become painfully aware of this phenomenon in the garden as the summer has wound down.

I noticed this morning, for instance, that the garden is still in the shade long after 8:00 am, the hour at which it came into full sun at summer’s peak.  Two months after the summer solstice, however, the sun is already quite a bit lower in the sky and as a result, the tall trees to the east of us are obstructing its direct rays.  It is light in the early morning but it is not exactly sunny.

Similarly, this afternoon, the tips of the fir trees on our neighbor’s property, just to the southern side of our pool fence, are casting a shadow on the south wall of the planters.  The inclination of the sun will only get lower as the days pass while the trees will only get taller with each passing year.  Soon, the shadows will pass across the vegetables shortly after midday, further shortening the growing day.

This is in spite of the fact that we removed two large trees in the spring (see May 17, 2013 and May 17, 2013, part 3).  Their absence has made a huge difference in the garden’s afternoon sun exposure but as it turns out, the impact’s duration is limited to the period starting a month before the solstice until a month afterwards.  Outside of that two-month range, we will feel the effects of the changes in solar exposure in the house more than in the garden.

Which brings us around to the beneficial aspects of solar shielding (to end on a positive note, lest anyone think that I am hostile to trees).  In warm climates, properly placed trees prevent solar gain within buildings and reduce their cooling load.  Where the weather is warm the year round, evergreen trees maintain a constant screen.  Alternately, where winters are cold, deciduous trees conveniently drop their leaves, allowing solar radiation to pass and provide natural heating.

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A recent article by Pamela Doan in the June 21, 2013 issue of The Paper (see “When It’s Okay to Kill a Plant”) led me to some further reflections on tree removal.  I share the writer’s angst over removing a tree—or any other plant in the garden, for that matter—and, like the author, I also agonize over the decision (see, for example, February 6, 2013).  I agree that there are several factors to consider and believe that removing a tree should not be undertaken lightly.

One issue she did not address is that often, removing a tree improves the conditions for the trees that remain.  For example, we live in a deeply wooded area where there is little to check the growth of the trees.  Each year, thousands of maple seed whirligigs twirl to the ground and many, if not most, of them germinate.  I (and my aching back) know this because hundreds of seedlings pop up in our gardens and patio areas every spring.  I must pull them out like weeds lest the house be swallowed up.

A proportionally larger number of seedlings sprout in the woods where there is no one to pull them out.  Instead, they take root firmly, continue to grow unabated and, with the passing years, become taller and larger.  They all crowd together like riders on a subway train, producing a dense canopy of sun-seeking branches above and a deeply-shaded understory below.  Commuters lucky enough to get a seat on the subway during rush hour know how it feels to be beneath the tangle of outstretched limbs.

The trees produce elongated trunks as they push their leafy tops higher and higher in search of a clear view of the sun (imagine the subway riders standing on tiptoe to read the advertisements that form a frieze along the sides of each car).  The trees wind up over-tall, spindly and top-heavy.  Aesthetically, they are lacking and the inefficiency of their shape cannot be good for their health.  Also, the preponderance of maple trees crowd out other varieties, reducing the diversity of species (probably 3 of 4 or 8 of 10 trees around us is a maple).

In a better world (or, at least, a better woods), I would take the same approach to the maple trees as I do with the radishes and beets:  thin early, thin often.  A larger spacing would lead to fuller trees that would not need to grow as high to gather their solar radiation (and they would look better) while still shading the forest floor.  Fewer maples would allow other tree varieties—oak, elm, poplar, even evergreens—a chance to increase their numbers and would make the entire woods less susceptible to harmful diseases or insects.

Like the crowding on rush-hour mass transit, it is a situation that is not easily changed.  I have often surmised that we could spend a week with a chainsaw, pruning and culling, and hardly make a noticeable difference in the local population density, never mind the entire woods or beyond.  Instead, we will take it tree by tree and consider the possible beneficial impacts—incremental and local though they may be—that could result from a tree’s removal.

I’ve found that the best way to assess the impact of the removal of trees is not to do it at all, at least not consciously.

If, after a tree has been trimmed or felled, I do not notice anything different, then usually I conclude that removing it was the right thing to do.  This has happened in the past when a tree was removed while we were away.  When we returned, we did not immediately realize that the work had been done.

Alternatively, if I do become aware of the change, it becomes a question of how I become aware of it.  For example, if I get the feeling that something is missing, that there is an unnatural gap in the treescape, it can mean that the removal was too extreme or not well chosen.  Luckily, this has not happened to us very often and fortunately, when it has happened, the surrounding trees eventually grew in to fill the void.

If, however, I get a feeling of openness—sunlight or airiness where there was none before—or notice a new and exciting view, previously obscured, then we probably made the right choice.  This was the case today.

With the two trees gone, the garden remains in the sun until after 6 o’clock, an extension of the growing day of at least three hours.  As an added bonus, we can now see a vignette of the surrounding mountains, framed by the remaining trees.

We finally arranged for our tree guy, Jerry, to come by with one of his helpers to remove the two maples that shade our garden in the late afternoon (see February 6, 2013).  We had meant to get this done before the trees sprouted their leaves (it would have made less of a mess) but didn’t get around to it.  Now that the garden is in full swing, though, we need the extra solar exposure.

When Jerry removes a tree near the house, he follows a very careful and elaborate procedure.  First, he cuts off the outer branches, then he tops the tree, and brings the trunk down section by section.  Sometimes, as a final step, he removes the stump by grinding.  The stump-grinding equipment is truck-mounted so accessibility is an issue; consequently, we have several stumps on our property.

Jerry chips all but the largest branches and takes the rest away.  When we have needed firewood, he has cut the trunk into appropriate lengths and left it for me to split and stack (see, for example, February 5, 2012).  Tree removal is a very labor-intensive activity but when Jerry and his crew are done, the only signs of their having been there are tire tracks and a scattering of sawdust.

The same approach would not be practical for today’s project.  The trees in question are just outside the border between our pool area and the surrounding woods, a transitional zone between order and chaos.  They are over 100 feet from the road and their bases are on a steep slope.  The trees could be cut down in the same way but removing the branches and wood would require an unjustifiable amount of effort.

So instead, we will leave the downed trees in place.  And if we are going to do that, there is no reason to cut them into pieces.  Bringing them down in one fell swoop (each, for a total of two fell swoops) is more appropriate.  (I had hypothesized that felling trees was the literal origin of the saying, “one fell swoop,” but my research revealed otherwise.  Fell can mean cruel or fierce while swoop in this context refers to the sudden dive of a bird of prey.  Given the sound a tree makes when it is felled, I like my story better.)

Felling a tree with a single cut at the base is much more difficult than it might at first seem, especially if the direction in which the tree will fall is of concern.  In fact, it can’t be done reliably with only one cut.  If the saw is not properly aligned with the direction the tree wants to fall (due to the location of its center of gravity), the weight of the tree will close the kerf as the tree starts to lean and that will bind the blade.  Unfortunately, I have to admit that I know this from firsthand experience.

Most often, three cuts are needed.  The first two cuts are made on the fall side of the tree to remove a wedge of the trunk.  This forms a hinge about which the falling tree will rotate.  The third cut is made on the side opposite the wedge and if all of the cuts have been done properly, the tree will start to fall due to gravity before the final cut makes it all the way through the trunk.

Geometry cannot be ignored, however, and even if the cuts are made correctly, the tree still might want to fall in another direction.  Based on Jerry’s assessment, this is the case with our trees, both of which are leaning slightly uphill, towards the pool.  Obviously, this is not the direction we want the trees to fall.  To counteract the trees’ gravitational tendencies, Jerry attached a rope near the top of each one to pull them in the direction he wanted them to fall.

Getting the ropes into the trees took a certain amount of finesse.  For the first tree, Jerry knotted the rope to a length of lightweight line—string, almost—at the end of which was a small beanbag slightly bigger than a Hacky Sack.  He carefully launched the beanbag up and into the tree with an underhand motion, aiming for a branch high on the trunk.  It took two tries but the second toss sailed through the crotch and dropped back to the ground.

Using the lightweight line, Jerry hoisted the main rope up to the top of the tree and back down.  Then, he formed a loop (tree work requires as much knotting skill as sailing, it appears) and cinched the rope around the tree trunk.  His helper took the free end downhill (the direction we want the tree to fall) until the rope formed about a 45-degree angle with the horizontal.  There, he anchored the rope to another tree trunk.

Using an in-line winch called a come-along, the helper took out the slack in the rope and then applied some tension.  At this point, Jerry starting cutting the notch on the fall side of the tree.  After confirming that the rope was taut enough to prevent the tree from shifting in the uphill direction, he completed the notch.

Then, the dramatic part began.  The helper continued to winch up the rope while Jerry commenced the final cut.  As the helper cranked up the tension, we could hear the tree trunk creaking and see it starting to list downhill.  When the tree was leaning by about 15 degrees from the vertical, there was a loud crack as the trunk gave way.  Both Jerry and his helper moved back and with a loud thwump, the tree fell to the ground, precisely where Jerry had intended it.  Quite a spectacle!

The second tree had several branches extending almost horizontally from the trunk.  Jerry judged that these outriggers would interfere with a clean fall so he decided to cut them off.  He strapped on a lineman’s belt and climbing spikes and scrambled nimbly up the tree, pulling two ropes with him.

When he got near the top of the tree, he tied himself off with one—his safety line—and looped the other over a branch to use a belay line for the cut branches.  I have described this process before (see October 31, 2011) and it is particularly elegant when Jerry rappels between locations, his chainsaw and pruning blade dangling from his belt.

After trimming and dropping the protruding branches, Jerry returned to earth.  He freed himself from his safety line, knotted a loop in it and cinched it up to use as the tension rope.  His helper again marched the end of the rope downhill and, following the same procedure as before, he and Jerry brought down the second tree, felling it almost exactly parallel to and on top of the first tree.

Described this way, it seems like it would take a long time to perform all of these steps.  But after only an hour and a half, Jerry and his helper were packing their gear up and heading to their next project.

As discussed before (see, for example, June 10, 2012, part 2), the trees around our house and garden are constantly growing and because they are so closely spaced, they are growing not outwards but upwards.  The result?  Their canopy is getting higher and denser and we are falling ever more deeply into the shade.

Last year, I observed that the solar panels on the roof (with which we heat the swimming pool) do not get any direct sunlight until sometime between 10:00 and 11:00 in the morning and move back into the shade starting as early as 2:00 pm; by 4:00 pm, the upper panels are completed shielded by trees.  This greatly diminishes their effectiveness at heating the pool water.

The planters have a longer solar day (see June 20, 2012) but even in the garden, shade begins to have an impact as early as 4:00 pm as the shadows start to creep across the west planter.  The area to the west of the planters, where we plan to grow squash this year, is fully shaded by 3:00 pm.  This may not be enough sunshine for a vegetable as needy as zucchini.

There’s not much we can do about increasing the morning sun—all of the trees to the east of us are on a neighbor’s property—but we do control the woods to the west.  In particular, there are two tall maples just outside the pool fence that are casting most of the afternoon shadows.  They will have to go.  We are fortunate that the ground slopes down steeply just beyond our pool and many of the trees that might otherwise be a problem need not be considered.

Widening the exposure of the solar panels, on the other hand, will require more drastic action.  The main culprits in their obstruction are the old oak tree that hangs over the west side of our house and a huge maple about twenty feet beyond it to the west.  Each is very tall and has already lost its lower branches.  And because they are on the edge of the woods, the two trees have reached outwards with their upper limbs, unlike their more constrained siblings located further into the woods.

Both of these trees have caused us trouble in the past:  We had the maple cabled many years ago to restrain a splitting trunk; the oak tree most recently dropped two large branches on the house and patio after a snowstorm a year and a half ago (see October 30, 2011, part 2).  So far, we have limited our approach to pruning but at this point, any pruning we might do would leave only barren (and funky-looking) trunks.

No, if we do anything they must also be removed.  But doing so will leave a noticeable void behind.  I’ve been resisting it for years because I know I will feel their loss.  A ranger at Yellowstone National Park once asked us (while we were gathered around a campfire) whether we had ever had an experience with rocks.  It took me a few years to grasp what she was getting at—the idea that the natural environment has a presence, an identity—and even if I have not had any experiences with trees, per se, I definitely feel their presence.  Losing these two will be a sad event.

And it will be a big project.  We brought in our long-time tree man, Jerry, to take a look at all of the trees we are planning to take down.  He’s done a lot of work here (see, for example, October 31, 2011) but this would be larger than any other takedown he has done for us.  The two maples at the end of the pool will simply be cut and allowed to fall down the hill (much more difficult and dangerous than it sounds) while the larger maple and oak will have to be carefully broken down, branch by branch and section by section.  Removing the wood once the trees are down will be a major undertaking all by itself.

It will be a great sacrifice but I think it will be for the greater good (of the house, garden and environment).