As summer heads into autumn, it is a great time to have your trees inspected for the upcoming winter months. In California, the ice and snow problems that can wreak havoc on trees in other parts of the country are not major concerns, but as last winter showed us, rain and wind can also cause plenty of tree-related problems. The major factors to be inspected before the rains return are tree structure, presence of decay, and root- and soil-related stability.

Branch structure plays a major role in tree failure potential, and certain structural defects increase the likelihood of failure. Long, over-extended branches are a common failure point, especially when previous pruning has stripped or ‘lion-tailed’ the branches, removing interior growth and leaving weight at the ends. Co-dominant branches, or branches that are nearly the same size as the

Preparing for winter weather by Drew Zwart, PhD

trunk at the point of attachment, are another common failure point. Mitigation of co-dominant branches (or trunks) is easiest with structural pruning when trees are young; this defect, however, can be addressed at any point in a tree’s life by using proper pruning techniques.

Whole-tree failure due to root decay or saturated soils also occurs commonly in winter weather. Inspection of the base of trees, their major structural roots, and the root zone will help identify potential problems or decay. The foregoing are common areas of tree failure and among the most difficult places to identify problems, given that many tree failure problems originate belowground.

Finally, coast live oaks and other tree species that are susceptible to the Sudden Oak Death pathogen should be treated prior to the onset of wet weather. This disease spreads during rainy weather, and prevention is always better than trying to treat already infected trees therapeutically.

Vista pruning by Tom Smiley, PhD

With high amounts of rain this spring, many trees are growing very quickly this year. Generally we consider this a good thing, but if those trees are between your deck or windows and block a great view, you may not appreciate it.

Rather than removing or reducing those trees, we often recommend vista pruning. This involves removing live branches that are blocking the view, and retaining the rest of the tree for screening. The number and size of the branches to prune will depend on the type of view you want and the amount of screening you prefer. We often station an arborist with you on the ground while another one is pruning in the tree. They communicate about each branch, and you decide if it should be removed or retained.

Vista pruning is an excellent way to improve your view while maintaining your privacy and the beauty of your property. Ask your Arborist Representative for more information.

TREE & SHRUB CARE FROM BARTLETT TREE EXPERTSTREE TIPS

Autumn is a good time to have your trees inspected before the onset of winter wind and rain.

Managing tree root diseases by Drew Zwart, PhD

Two common causes of root disease in California are species of the fungus Armillaria and species of Phytophthora, which are fungus-like organisms. There are many differences between the two pathogens, but effective management of both involves creating growing conditions that favor plant vigor and that inhibit the pathogen.

Phytophthora species, once classified as ‘water molds’, are dependent on soil moisture to create disease. Phytophthora species produce spores that literally swim through saturated soils, finding and attacking fine roots. The potential for Phytophthora disease is greatly reduced by avoiding saturated soils through improved drainage and/or irrigation management. Organic matter additives to soil will also help to suppress the pathogen. Fungicide treatments are available for short-term management, but in the long term, creating the right growing environment is the best management practice.

Armillaria disease is often considered secondary, causing decline and mortality only in plants that are already suffering some physiological stress. Avoiding plant stress in general is the best preventive management. Exposure of root collar/flare area, avoiding drought stress, and maintaining appropriate soil nutrients and pH will help prevent Armillaria infection. Once infected, there is no chemical treatment for Armillaria, though treatments are available to improve plant vigor and increase resistance.

SEPTEMBERMonitor/Treat tuliptree scale on tuliptree and deciduous magnolias

Check organic mulch depth around all trees and shrubs and add as needed for a depth of 2 to 4 inches

Preventative applications for bark beetles on oaks and pines

OCTOBER Start pruning pine trees as bark beetles go into dormancy

Inspect trees for structural issues prior to rainy season

NOVEMBER Sudden Oak Death (SOD) applications

Phytophthora root disease treatment

Continue pruning pines and other conifers

Root Invigoration, if rains have started

DECEMBER Continue pruning pine trees

Root Invigoration

Continue SOD applications

Protect citrus and other cold-sensitive species if frost is likely

TREE & SHRUB MAINTENANCE CALENDAR

The faded leaves are a sign this shrub is suffering from Phytophthora disease.

The fungus on the base of this tree is a sign of Armillaria infection.

To avoid root disease, the best practice is to create and maintain good growing conditions.

Fun with treesGetting crafty with branchesPick up some branches on your next autumn walk and come home ready for a craft project! Armed with a few tools and some long nails, you can make rustic coat hooks. You’ll need five branch pieces—three with a fork and two straight ones.

First snip the forks to create hooks. Line up the ‘hooks’, mark and then saw each branch four inches above its hook. Next, saw one branch four inches below its hook. Use it as a guide to saw the other two hook branches to the same length.

Cut two straight branch pieces to be the top and bottom of your coat-hook rack. Finally, drill through the cross branches, insert nail, and hammer to fasten the hooks to the frame.

HistoryAn iconic tree of coastal California, redwoods are native to a thin coastal band from Oregon south through the Big Sur region of California, but are planted widely beyond that range also. Coast redwoods are the tallest trees in North America. The lumber is highly valued for its beauty, is light weight and resistant to decay. Its lack of resin makes it resistant to fire, so it is used extensively as building material. During the great fire in San Francisco in 1906, the use of redwood lumber in framing rendered some buildings fire resistant. In the past, railroad ties and trestles were made of redwood. While there remain pockets of old-growth trees, ancient coast redwoods are rarely found near urban areas.

Culture77 Performs best in deep organic soil with continuous

summer moisture supplied by coastal fog. Despite being native to a Mediterranean climate, this is a high-water-use species

77 Canopy appearance is normally thinner in more southern and inland areas

77 Very sensitive to salt spray, as well as to salt or boron in irrigation water – results in marginal scorching

Concerns77 Often topped and so may need redevelopment

of leader 77 Sensitive to soil moisture and heat stress 77 Stressed trees often infested with spider mites

and/or redwood scale; may show branch death due to Botryosphaeria canker

Bartlett Management Practices77 Prune to reduce the end-weight of extended branches 77 Avoid raising the canopy; the root zone should be

shaded and cool 77 Creating ‘windows’ in the canopy to reduce

wind resistance not recommended 77 Provide 4" to 6" layer of organic mulch 77 Ideal candidate for Root Invigoration

process 77 Irrigation and phosphite soil

treatments during dry periods 77 Mite treatments may be

warranted for management of heavy infestations

TREE FOCUS:Coast redwood (Sequoia sempervirens)

This elm is popular because it is tolerant of urban conditions.

WONDERS OF NATURE Dendrochronology – the past revealed by trees

Many people know that counting tree rings can reveal the age of a tree. Collectively, tree rings can also tell us much more. Dendrochronology is the scientific method of tree-ring dating.

By recording the pattern of rings in individual trees and then putting hundreds and thousands of tree-ring records together, scientists can tell what time period a tree is from and can learn about environmental conditions in the past. This information from trees also helps

archeologists to date wood artifacts and chemists to calibrate radiocarbon dates.

In case you were wondering, it isn’t necessary to cut down trees; small drills are used to access tree-ring information.

published by THE F. A. BARTLETT TREE EXPERT COMPANY(877) BARTLETT (877-227-8538) in U.S. and Canada • www.bartlett.com

For Tree Tips information contact smurdock@bartlett.com© 2017 The F. A. Bartlett Tree Expert CompanyCA3

Established to preserve 805 acres of coast redwoods, Armstrong Redwoods State Natural Reserve is just north of Guerneville, in Sonoma County. It is a living reminder of the primeval redwood forest that covered much of this area before logging began in the 1800s. Rainfall in Armstrong Redwoods averages 55 inches per year and the trees are often shrouded in a mystical fog that helps to maintain the moist conditions needed for the redwoods to survive.

The Reserve includes a visitor center, large outdoor amphitheater, self-guided nature trails, and a variety of picnic facilities. The main noted features in the park are along the Pioneer Nature Trail that is ADA accessible, mostly flat and level, and only 1.5 miles round trip.

To plan a visit or to learn more, search for Armstrong Redwoods on www.parks.ca.gov/ParkIndex.

Armstrong Redwoods State Natural Reserve – Plan a trip!

Compliments of

Your Arborist Representative

With the changing season trees are preparing for winter. Let us help them get ready!