Once Again, Fires Threaten Giant Sequoias

The Railroad fire broke out near Yosemite on August 29.  Recent humid, cooler weather has assisted fire crews achieve 43% containment, with 12,000 acre scorched.  However, dryer conditions are expected today, with the possibility of lightening strikes.

The fire is burning in an area of dry pine and cedar trees, creating difficult firefighting conditions.  Tuesday, the fire burned through Nelder Grove, containing over 100 mature giant sequoias.  Fortunately, the extremely thick bark protected the trees from damage, while all the under brush was burned.

Hopefully, firefighting crews can get the upper hand on the fire and prevent further damage.

Railroad Fire Threatens Giant Sequoias

Worried About Your Tree?

We have gone from record drought to record amounts of snow and rain throughout California.  While the winter storms have wreaked havoc on our infra-structure (Oroville dam spillway, flooding in San Jose, etc, they have been a blessing for drought starved trees throughout the west.  Years of inadequate rainfall reduced soil moisture leading to an incredible dieback of trees numbering over tens of millions within the state.

The urban environment creates stresses not normally encountered in the wild.  In cities and suburbs, trees contend with confined planter area, compacted soils, improper or inadequate irrigation, poor maintenance practices, improper pruning, shading by homes or buildings.   Stresses created by the urban environment reduce tree life expectancy, sometimes by as much as 50%.

During the drought, I have seen an increase in tree failure, whether a limb drop or whole tree failure.  In most instances, crown, limbs, branch and twig dieback were the obvious symptoms of the drought.  Many times, clients mistakenly thought the dieback was caused by disease or insect, however root dieback from minimal soil moisture was the cause of crown dieback.

Now, with the heavy rainfall and wind, tree failure due to saturated soils are on the increase.  Trees remain upright due to their root system.  Structural and buttress roots grow outward from the trunk at the (root crown), out to the edge of the crown (known as the dripline).  At the dripline, the structural roots are 1-2″ in diameter.  They continue to grow outward, branching into the small, fine feeder roots that absorb moisture and nutrients.  Depending on local conditions, tree roots may extend 1.5 times the tree crown diameter.  Based on San Diego soil conditions, most roots grow within the upper three feet, typically 80% of the roots are within the top 18-24″ of the soil.

Roots in dry soil are held in place by friction.  However, when rain saturates the ground, it acts as a lubricant, lessening the soil friction holding roots in place.  When wind combines with excess weight from rain or snow, the energy is transmitted down the trunk to the roots.  Soil root friction reduced by saturation causes roots to loose anchorage, resulting in a failure.  When roots fail to support the tree, it is assessed as a root failure.  When the entire root ball rotates up from the soil, it is a soil failure.

Homeowners with large trees in close proximity to their property should examine their trees for any change in condition as a warning sign of a potential problem.  Changes to be aware of include:

  • Is the tree leaning?
  • Are there soil cracks at the base of the tree?
  • Is the soil lifting, tilting or rippling at the tree base?
  • Are there dead limbs or branches in the crown?
  • Is there a progression of twig, branch and limb dieback?
  • Did the tree drop it’s leaves abnormally early?
  • Did the tree not leaf out as in the past?
  • Any obvious open cavities, cracks or splits?
  • Any animals or insects nesting within a hollow, cavity or crack?
  • Any fluids, abnormal sap flow or other discharges from the tree?
  • Has irrigation been reduced or eliminated to the tree?
  • Has there been construction activity near the tree?
  • Have the roots been disturbed by any nearby utility or sidewalk work?
  • Is the tree sitting in water, is there proper drainage?
  • Has there been a change in grade near the tree?

If you can say yes to any of the above, your tree may have acquired defects that increase the risk of failure.  The increased risk of failure may result in property damage or personal injury to your family, friends, or any pedestrian near the tree.  A tree with a history of previous failures possesses an increased risk of failing.  Trees may not present any obvious signs or symptoms of a defect.  Unseen decay may exist within a limb or trunk, or as a root rot.

Whether commercial or residential property, if you are concerned about the health and safety of your trees, you should contact an arborist certified by the International Society of Arboriculture, (ISA).  Once certified, the ISA allows arborists to enroll in specialized training to earn the credential of a Tree Risk Assessor Qualified.  While anyone may attempt to assess the health and structural integrity of a tree, certified arborists who are qualified in tree risk assessment represent the industry standard and best management practice for tree risk assessment.

Tree risk assessment is the current best management practice to determine tree risk of failure associated with defects.  The assessment utilizes a level two basic visual assessment and a two page ISA format for the assessment protocol.  The assessor may determine more advanced assessment techniques are required, however usually a basic visual assessment will suffice.

If you have noticed a change in the health or condition of your tree, take proactive measures before a catastrophic accident, call a certified arborist knowledgeable in tree risk assessment.

Click here to read an article published in the LA Times Risk Assessment article.

“Arborgeddon” – PTCA Hosts Another Great Seminar and Field Day

Ficus tree roots engulf a curb, seen during Field day at Balboa Park

Ficus tree roots engulf a curb, seen during Field day at Balboa Park

The Professional Tree Care Association (PTCA) of San Diego hosted their annual seminar and field day, a two day event on Friday, August 22 and Saturday August 23, 2014. This was the 25th annual event and like many of the previous seminars, this was another informative, educational experience bringing together a wide diversity of speakers and audience!

The seminar was on Friday and this years theme centered on the ongoing California drought and ramifications to trees. There were a number of great speakers, starting with Mr. Ron Matranga who provided an overview about trees in times of drought, current and future water restrictions . Dr. Roger Kjelgren, Professor from Utah State University, provided a simplified method for landscape irrigation demand estimation. Dr. Linda Chalker-Scott, the Urban Horticulture Extension Specialist from Washington State University discussed how to treat and avoid drought stress in landscape trees and Ms. JoEllen Jacoby, the Water Conservation Landscape Architect for the City of San Diego enlightened us about planning for current and future water restrictions (gulp, better get some rain this winter)!

Ms. Mary Matav, Agronomist from Agri-Serve presented information on how to combat pests and drought, followed by Dr. Tracy Ellis, Entomologist with the San Diego County Department of Agriculture, scaring all of us about tree insect interceptions and quarantines in San Diego County.

A great roster of speakers who delivered relevant information in a beautiful setting at Balboa Park in San Diego. On Saturday, the event transferred to the field, where information discussed at the seminar was applied and viewed in the field, an aspect of the field day I find very beneficial.

As usual, Dr. John Kabashima, the Environmental Horticulture Advisor with the UC Cooperative Extension, presented new, current information on the latest insect threat to our ornamental and agronomic trees in California, that being the Polyphagous Shot Hole Borer, (PSHB). As many of us already know, this destructive ambrosia beetle is now active throughout the Southern California.

The PSHB is an invasive ambrosia beetle that carries the fungus Fusarium euwallaceae.  The female tunnels through the bark and lays galleries of pre-fertilized eggs and grows the fungus, which becomes food the newly hatched beetles.  The fungi infects the tree with a disease called Fusarium Dieback (FD), which interrupts the transport of water and nutrients through the vascular system of the tree.  In essence, this is a vascular clogging disease resulting in dieback and death of a large host of trees.   Unfortunately, there is no cure at the present time and beware of PSHB/FD look-alikes.  Here is very informative attachment Dr. Kabashima provided that really provides current information about this insect.  Handout is published from the University of California and the UC division of Agriculture and Natural Resources.   PSHB Information

Many thanks to all of the hardworking voluntary staff of the PTCA.  What a great local association, I am very proud to be a member of.  The PTCA is an active association promoting the best in tree care and tree knowledge.  An association composted of tree care companies, certified and consulting arborists and tree care  professionals, the PTCA continues to provide current and relevant topics for it’s membership and community at large.  Thanks again PTCA, looking forward to next years Seminar and Field Day!

What to do With Your Xmas Tree?

Fortunately, most municipalities now have recycling programs for green waste, making it easier for homeowners to recycle their used Xmas tree.  Recyclers grind or shred trees into a mulch which is then composted and eventually becomes available as a bulk or bagged mulch product.  This is certainly a preferable option than the “old days” when trees were commingled with regular trash and buried in landfill sites.

If you have a large tree, prune off some branches and reduce the overall size to ensure local curbside pickup.  If you have the room on your property, you can do your own recycling via a compost bin, pile or simply leaving the tree in an area where it will slowly decompose on its own.  Leaving a tree whole may also become home to birds and other animals for shelter or nesting site.  Make sure all tinsel and other decorations have been removed from the tree.

If you  have a live tree, it can be re-planted into the outdoor landscape.  Remember, depending on the variety of pine tree, these are typically large growing trees.  Despite the small size now, ten to twenty years down the road, you may have a forty to sixty foot tall tree.  I have seen this issue while consulting on residential sites where a neighbors Xmas tree planted near the property line grew to fifty-five feet, with limbs and roots encroaching into the clients property, damaging concrete improvements and posing an increased safety  risk.  If you are going to re-plant the tree, make sure you have the space for a large pine tree to grow, avoid planting near property lines, driveways, sidewalks and patios.

For more information about Xmas tree recycling, check out this article at:

Making the most of the Christmas Tree

Can a Tree Capture Particulate Matter from the Air?

For years, certified arborists and urban foresters have learned the many benefits of trees. Energy savings are one of the foremost known benefits of trees as they shade building during the summer reducing the need for air conditioning and deciduous tress allow sunlight to reach structures during winter months, solar radiation decreasing the need for winter heating.

Another known benefit for trees are their ability to reduce storm water runoff and erosion, particularly during the winter months. Tree root systems bind soil particles and slow storm runoff from roofs and other impervious surfaces, trees act as bio filters, slowing storm and irrigation water runoff and allowing the water time to slowly percolate into the soil profile rather than run off into the street or storm drain system.  By forcing water to pass through the soil profile, rather than runoff into storm drain systems, the soil mass filters impurities before the water enters into streams, ponds and aquifers.

Birch Tree planting works as filter

A Birch street tree planting used for testing as a green filter to remove particulate matter from the air we breath

Continue reading “Can a Tree Capture Particulate Matter from the Air?” »

Trees and Solar Power – Environmental Conflict or Can the Two Co-Exist?

I attended a recent seminar in San Diego entitled Trees and Solar Power:  Natural Partners, sponsored by the California Urban Forest Council (CAUFC).  It was a very informative seminar, bringing together professionals from the solar and tree industries, as well as city planners, landscape architects, arborists and related professionals.

Even with decades experience as a landscape contractor, certified arborist, professional horticulturist and land development infrastructure project manager, I was not aware of the current solar and arboriculture laws.  For example, the State of California and many other states enacted solar legislation decades ago.  Due to the oil crisis in the 1970’s and 1980’s, there was increased interest in promoting alternative energy sources.  Many states adopted laws to encourage renewable energy technologies, solar being one of them.

In 1978, California enacted the Solar Shade Control Act, in part to protect consumer rights to install and operate solar energy systems on a home or business and to protect consumer rights to access sunlight.  In 2008, the law was amended due to a very public controversy between two Santa Clara County residents being criminally prosecuted and convicted under the Act for allowing their redwood trees to cast shade on a neighbors solar panels.

Based on the Solar Shade Act of 2008, a site plan reflecting the pre-existing conditions at the time a solar system is installed should be a mandatory permit and legal requirement.  As lawsuits increase due to conflicts between trees shading solar collectors, a site plan showing trees in place pre-existing a solar installation will become an important legal instrument.

We derive many benefits from large trees, from their beauty and aesthetics to the shade and passive cooling affect they have on our homes and businesses.  The same is true for deciduous trees in the winter when they drop their leaves, permitting solar radiation to warm our homes.  In a residential setting, large existing trees will invariably cast shading onto a structure.  It is incumbent upon a solar company to analyze shading from the Client and neighboring trees for correct solar panel design and installation.

If a solar company identifies trees as a potential shading  conflict with a rooftop solar installation, a certified arborist and or professional horticulturist should be added to the design team.  Depending on the tree species, growth form, and distance from the structure, there may be several alternatives available to mitigate tree shading without complete tree removal or butchering the tree through indiscriminate topping.

Have a certified arborist or professional horticulturist consult with the solar company to ensure retention of the desired landscape aesthetics combined with the energy savings benefits of rooftop solar.

Read the full article at Trees and Solar-Environmental Conflict or Can the Two Co-Exist?