Working With an Arborist

Arborists specialize in arboriculture–the care of trees, shrubs and woody plant material outside of a forest setting. They may work in a municipal or utility setting, keeping public trees healthy and safe, or utility right-of-ways cleared. They may work in a commercial setting, caring for private trees, removing dead or problematic trees, or providing consultation services. Certified arborists are well trained in the health and care of trees, and versed in the municipal requirements for urban trees.

The International Society of Arboriculture (ISA, http://www.isa-arbor.com/) is a great resource for finding a certified arborist, learning more about arboriculture, and finding out about certification. Becoming a certified arborist requires several years of field experience, rigorous testing, and ongoing education. The ISA provides certification in these key areas:

· ISA Certified Arborist

· Arborist/Utility Specialist

· Arborist/Municipal Specialist

· Tree Worker/Climber Specialist

· Tree Worker/Aerial Lift Specialist

· Master Arborist

An arborist is a wonderful asset for your urban garden. I’ve used Brende and Lamb in the San Francisco Bay Area for years, to prune and care for our big oak and elm trees. If we had contacted them at the first sign of trouble, we might have been able to save the maples.

Street trees in Dublin, California

Arborist to the Rescue

It's the retaining wall

Our arborist came to assess the health of our trees, and give an estimate for pruning some of the big trees. This is something we do every two or three years to keep the trees in scale with the property, and ensure safety.

He also gave a diagnosis for the death of the three maple trees - last year’s broken sprinkler and the retaining wall conspired to flood the roots and drown the trees. Roots need oxygen in the soil in order for the tree's hydraulics to work. The water and oxygen exchange draw water up the trunk and out through the leaves. With flooded roots, the tree suffocates.

The soil may have also become compacted. Soil compaction can be a problem with clay soil. The solution to this is aeration to increase pore space in the soil, enabling a better exchange of water and oxygen. The process involves using an aerator to dig holes in the ground every 18 inches, and fill the holes with compost.

Once we remove the trees , we'll be  planting new maple trees, because we miss their beauty, elegance, and grace. 

Evil Comes to Eden

Death has come to my little piece of Eden - three Japanese maple have died. All three maples stand in a row, near a retaining wall, which separates the slope of the yard from the patio. All three maples have thrived since we moved into our home fourteen years ago. All three maples now show the same symptoms – first the buds did not develop last spring, then mushrooms and conks began to grow in the fall, then the bark peeled on the northern face of the trunks in the winter. Looking back, death happened over a period of time, so I could have take action sooner.

One of the maple trees - notice the
peeling bark

And, looking back, I can see several events that may have contributed – several years of drought, followed by two very rainy seasons. There was as sprinkler incident last spring, where we realized we had an underground leak, which might have flooded the root zone. Perhaps the soil itself is infected with something. A beetle infestation might explain the peeling bark (although, in the Arboriculture class I took last fall, we learned that pest infestations may be a secondary symptom for a tree that is already in a weakened state).

Symptom: dead branches

Symptom: peeling bark

Symptom: conk (the fruit of a wood-rotting fungus)

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Another possibility is that circling roots may have strangled the trees (I also learned in the Arboriculture class that many container grown trees develop circling roots; after they are planted, the trees grow fine until they reach a certain size, and then the roots cut off the vascular system and strangle the tree). And a final thought is that every living thing has a life span, and eventually dies. Enough speculation, it is time to call in our arborist, Brende and Lamb of Berkeley (http://www.brendelamb.com/), to diagnose the problem. They have been pruning my big trees and providing guidance for years.