Wednesday, July 27, 2005
DC Arborist Selected for Society of Municipal Arborists Exchange Program
I) Urban Forestry
The urban forest in Vancouver consists of green roofs (most noticeable is an approximately 18” DBH conifer growing on the roof of a 10-story building), street trees, plantings in traffic circles and median strips, and old and second growth forests. The diversity of plants is tremendous: small trees, large trees, gigantic trees, shrubs, flowers, and herbaceous; bananas plants, palms, tree ferns, and the list goes on. The most common varieties of street tree species planted are: Prunus spp, Acer spp, Ulmus spp, Tilia cordata, Asculus hippocastanum, Liquidambar stirifura, Carpinus bekulus, and Betula pendula.
Challenges and Solutions
One unique challenge for the city of West Vancouver (a separate municipality) is the illegal topping and or killing of city trees by residents so to preserve vistas from their homes or apartments. Like most municipalities in the United States there is the challenge of reducing the mortality of newly planted street trees. Overhead utility lines and tree conflict on both private and public property trees is also a problem. Weed whacker damage is common to trees on planting strips and the city has addressed that problem through education and installing trunk guards. What was striking, especially in the downtown area of Vancouver, was the size of tree boxes, many as small as 18”x18” and the use of organic and inorganic mulch – woodchip and small gravel. What I found very desirable is that the Board has its own nursery and green houses located within the city. Here flowers, trees, and shrubs are grown in containers or in the ground.
II) Integrated Pest Management
Like many municipalities, exotic invasive plants are a challenge to manage or control. Invasives come in the form of vines, trees, herbaceous, or aquatic species. Examples of some problematic plants are morning glory, purple loosestrife, and giant hogweed. Insect and disease pests are also a problem – aphids, anthracnose, aerticillum, ainsliella, and buccarlatrix to name a few. To a lesser extent animals are a problem, mainly herons which tend to roost in a high-use section of Fraser Park, and the high volume of feces created has moved from being a nuisance to burning leaves and may ultimately result in the death of those trees.
