Category Archives: Street Trees

Summer Tree Failure

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A failed Norway Maple on SE 49th. This picture was taken June 28th, five days after a big rain event. You can see that this tree has been struggling for some time as evidenced by the dead branches still in its crown and the stressed flagging leaves up there. The girth of the trunk is greater than the width of its planting space. It is pinched beneath the overhead lines and the requirements for street trees regarding road clearance. It’s height has been ‘controlled’ and limited over the years.

Trees fail all of the time and when they are older, this can be quite spectacular, or devastating, if your car, home or an individual have the misfortune of being in the its path.  Like most people I used to believe that most such failures happened as the result of storms, and many do, but it is relatively common for trees, or major limbs, to come crashing down with calm conditions in the Spring. The new flush of growth brings with it a great deal more tissue and water weight than a tree in active growth has previously supported or, for a tree struggling, compromised by the burden of significant rot in its core and/or limbs.  Look at any tree and look at its girth, its canopy spread and on many species, its long, often horizontal limbs and try to imagine their weight.  To help with this fill a couple of buckets with water, lift them and try to hold them horizontal away from your body.  Trees are static structures, comprised of countless overlapping fibrous layers, much of it hard and rigid with a great deal of compression and torsional strength.  The were ‘born’ for this.  Few of us would last for more than a few seconds trying to support so much of our own weight on extended arms.  We shouldn’t be surprised when they fail, even as elegant and as well ‘engineered’ as they are. Continue reading

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Tri-Met’s Orange Line Landscapes: Clinton & SE 12th to Harold St.

This shows the banded pattern common today in long mass plantings each swath a single species.

This shows the banded pattern common today in long mass plantings each swath a single species going for a kind of landscape scale ‘graphic’ pattern that is less concerned with ‘fit’.  This is near the Clinton/ SE 12th stop.

Size matters.  In horticulture it changes everything.  Things that are inconsequential, or maybe even enjoyable in the backyard garden, can quickly become daunting or onerous when the scale is ramped up.  Working at a commercial or institutional scale has to change your entire approach to the landscape.  In a small garden it is easier to accommodate mistakes, the conflicted combinations and those issues of horticultural ‘fit’ that we missed when we design or install.  Scale, however, rubs our faces in it everyday, makes us pay with aching backs as unintended consequences play out across the thousands of sq.ft. and acres.  It becomes a matter of physical survival and undermines your professionalism.  You become perforce part laborer, part diagnostician, designer, plantsman and critic….Out of necessity you sharpen your critical thinking skills and the last thing you ever wanted, your sales skills, as you work to sell your ideas to management who are absurdly ignorant of the problems you face everyday in the field.  And, then, eventually, you retire, but you don’t turn it off…you can’t.

Which brings me to the MAX Orange Line and its landscapes.  When I did horticultural design review for large capital Parks projects, it often felt like a dueling match.  I would pour over the design, whatever the stage it was in, match that with my particular knowledge of site conditions and my maintenance experience within Parks.  I would state my concerns on paper and in meetings with the Project Managers and Architects.  I was stubborn and consistently found myself up against a process that undervalued horticulture and my input.  Good horticultural practice was regularly placed in a losing position opposite not just that of the Landscape Architects but of a very political process that tried to give the public what it wanted as long as it fit within the Architect’s vision.  Horticulture always came out a poor third, even though good horticulture always saves money in the mid and long runs.  It was exasperating.  The public, by and large is ignorant of horticultural practice and no effort is made to educate them at any level. Continue reading

Choosing a Tree: Issues of Structure and Growth

Right Plant Right Place covers a lot. Usually when you hear it used the speaker is referring to matching the plant with the growing conditions: soil, sun, climatic conditions, size, etc. Here, I’m going to address the physical structure and growth of a tree as it relates to place, Carpinus betulus ‘Fastigiata’, in this case, as it is often used as a ‘street tree’. The Upright European Hornbeam has proven its value as a street tree. It is very adaptable to conditions in our region that exist at the curb. That being said there are questions of structure and growth that need to be asked if such a planting is going to be aesthetically successful over the longer term.

Hornbeams across the street from my house after pruning

Hornbeams across the street from my house after pruning

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Katsuras as Street Trees: picking the right tree

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Sometimes it pains me to take walks.  I was on my way home from the Imperial Bottle Shop and Tap Room, walking down SE 26th south of Powell Blvd when I came across these four Katsura trees planted in a 4′ wide parking strip, no curb parking with a painted bike lane right next to the curb.  Katsura trees 24″ from the bike lane.  How is that going to work?  Trees grow.  Branches extend and caliper up.  Branches hit bicyclists and pedestrians in the face and people crash and or break branches. (Yes, I know these can be limbed up over time but we all know how often that doesn’t happen and what are these trees going to look like if all of the branches are cut off of the street side up to 14′ for traffic clearance.  Trucks regularly use this street.)  And then there’s the whole it’s just the wrong plant for the growing conditions thing.  Katsuras grow in the mixed woodlands of Japan with moderate temps and summer rainfall.  So that looks like 3 strikes out of 4 pitches.  Landscape architects still love these…so do I, but planting them in positions with reflected heat with limited root runs through compacted mineral soils!!!! It’s 90 degrees today, their foliage is stressed even with their water bags filled around their bases.  I have seen many more bad examples of Katsura use over the last 25 years than i’ve seen appropriate.  If you’re going to plant them plant them in a woodland or along the edge where they will be protected from intense direct  sun and make sure they have a long cool root run.  This is so wrong.  Now we’ll all have to watch these limp along getting by stressing until they die or become so damaged someone removes them. Continue reading