Tree care: March 2008 Archives

The City of Los Angeles has the country's largest roadway and sidewalk system with 6,500 miles of streets and approximately 10,000 miles of sidewalks. And Los Angeles also has the largest urban forest with a population of nearly 700,000 street trees.

A successful sidewalk program includes tree planting. Trees shade sidewalks and the adjacent streets to reduce heat.  Urban areas can be as much as 10 degrees warmer than surrounding open areas, so every tree -- especially MATURE tree counts.

The overall goals of the program are to:

1. Provide safer and more accessible transit surfaces for pedestrians.
2. Improve street drainage.
3. Maintain a healthy, safe, and sustainable urban forest.

Los Angeles, CA has a longstanding policy of replacing every tree removed from sidewalk areas with a minimum 2 to 1 replacement ratio. The Bureau of Street Services uses every sidewalk retrofitting opportunity to expand the  future tree canopy coverage by planting every available site within the sidewalk repair area. Where there is no room to replant trees, vacant planting locations are identified on adjacent streets to plant more than the 2 to 1 replacement ratio.

In the City of Los Angeles, replacement street trees must be 15-gallon size containers or larger. Using larger trees minimizes the occurrences of vandalism and gives the trees a much better chance of surviving.

All trees are planted using root deflection devices, which will help reduce future sidewalk damage. However, the most critical decision for reducing future infrastructure damage is proper species selection.

A municipal arborist is invaluable in selecting species that are compatible with each site. Consider hiring an arborist that is knowledgeable with the trees in your area.

If you cannot plant a favorite tree with aggressive roots, such as a willow, because your sewer lines are old and  could be damaged roots...what are your options?

SOLUTION:  Plant the willow tree in a  large tub of earth -- 2-3 feet across and high enough for a good root ball.  Get a book on bonsai and use the same basic technique to grow trees in pots or tubs.  The care of bonsai trees entails pruning, wiring, fertilizing, repotting and watering properly, and of course -- proper seasonal timing!

• Junipers and Maples, are hardy enough for growing outside
• Ficus and Norfolk Island pine make good indoor bonsai or plants for moderate climates (like Southern California)

I've heard from one gardener that she has a 20 year old redwood that is only 6' tall that she's been bonsai-ing for years.

Some sources of basic bonsai information:

www.wikihow.com/Create-a-Bonsai-Tree

www.bonsaigardener.org/

www.bonsaiforbeginners.com

Here's your chance to take part in the "growing" TreeVitalize movement,
a program designed by Pennsylvania's Department of Conservation and
Natural Resources (DCNR) to increase Southeast Pennsylvania's tree cover
and the benefits that trees offer us all. Join us for 9 hours of
hands-on training that will cover tree biology, identification,
planting, proper care and working within your community.

The course is being offered on weekday evenings at five different
locations, and is designed for lay people and experts alike. The course
is free but registration is required. Pennsylvania Landscape
Architecture, PLNA, ISA Certified Arborist, and Act 48 CEUS are offered.

There are several ways to register. See below for a registration form
which could be faxed to 215-988-8810 or mailed in. You can also register
online, by going to www.pennsylvaniahorticulturalsociety.org, and
choosing "Tree Tenders Training".

Tree Awareness:
* Tree Biology
* Urban Stresses on Trees
* Tree Identification
* Basic Tree Pruning and Root Care
* Tree Planting

Community Organizing:
* Fundraising and Identifying Resources
* Working with Local Government
* Organization Building

The three-part series is FREE

For more information contact:
* Julianne Schieffer, 610-489-4315 or jxs51@psu.edu
* Mindy Maslin, 215-988-8844 or mmaslin@pennhort.org

Alex Shigo, a New Hampshire-­based plant pathologist  made his name in the 1970s by dissecting an estimated 15,000 trees and debunking the myth of "topping" -- hacking off the tops of branches -- which he believes is at the root of all bad tree care. He is widely considered the father of modern arboriculture.

In the early 1990s he helped persuade the City of Los Angeles to take tree  topping off its list of accepted trimming practices. Dr. Shigo served 15 years as the Chief Scientist in the US Forest Service.

Dr. Alex Shigo wrote:

Tree Pruning: A Worldwide Photo Guide
A Tree Hurts Too
A New Tree Biology: Facts , Photos and
A New Tree Biology and Dictionary
Tree Pruning Basics
Tree Pithy Points
100 Tree Myths
Tree Pruning
Tree Anatomy


More information is available at www.shigoandtrees.com