Neighbourwoods Fall Tree Talk – Review

This fascinating talk was
presented on Oct 17, 2019 by arborist Kyle McLoughlin.
Fungi are
not plants – they belong to their own kingdom. In fact, they are more
closely related to animals than plants. If you felt there was a lot to absorb
at this talk, think about it this way: imagine you knew very little about
plants, and a friendly and knowledgeable presenter gave you a 60 minute talk
about the plant kingdom – there would be a lot to tell! The world of fungi
is similarly complex, and Kyle was a veritable encyclopedia.

Here are a few of the main ideas Kyle covered:

• Never eat a mushroom unless you are 100% sure
  what it is! This was an important point to make right off the
  top.
• An arborist looks for fungi on and around a tree,
  as part of a tree risk assessment.
• If fungi are present
  on a tree, it indicates a situation that needs to be addressed. It doesn’t
  automatically mean the tree must be cut down; there are other
  options.
• Fungi, like any organism, are looking for a
  place to live, eat, and reproduce. The leaves, wood, and roots of trees are
  all suitable environments for fungi to grow.
• Some fungi
  (the mycorrhizal fungi) are beneficial to trees. They grow underground among
  tree roots, and enable the roots to take up naturally-occurring phosphorus
  from the soil, an essential nutrient. In return the fungi receive needed
  sugars from the tree roots.
  • The loss of these underground
    fungal networks due to urban construction projects is a big loss to the
    trees. Adding artificial phosphorus fertilizer is a poor replacement.
    Preserving these symbiotic relationships between trees and fungi needs to be
    a priority.
• Other types of fungi
  can damage trees. Effects can range from the mild (leaf tar spots) to the
  serious (decay within the tree).
• Fungi get into the
  interior of trees via wounds to the tree, for example those caused by
  incorrect pruning, storm damage, or lawnmowers and
  weed-whackers.
  • Trees don’t heal from wounds; they react
    by compartmentalizing, or sealing off the area.
  • The tree
    creates a ‘barrier zone’ to prevent the invading fungi from
    spreading.
• A tree’s environment
  affects its health and ability to defend itself against invading
  microorganisms. The urban environment is generally unhealthy, with
  nutrient-poor, compacted soil; air pollution; construction damage; root
  constriction; and proximity to buildings, roads, and other
  infrastructure.
• Some trees eventually fail due to
  accumulated defects, which causes risk to property and human safety. Our goal
  is to keep trees healthy and flourishing for as long as possible, to avoid
  damage or loss, and maximize the benefits they provide.

Some
ways of reducing the risks posed by weakened trees
include:

• Starting off right at the planting
  stage (e.g. right species suitable for conditions; in good soil; not too
  close to buildings, sidewalks, hydro wires, etc);
• Maintaining a variety of native species, of different ages, in the urban
  forest; mulching, watering, and pruning proactively; protection from
  construction damage (especially to roots); pruning off dead branches and
  reducing the weight of living
  branches.

Tree
Walk

On the Saturday morning following the
talk, Kyle took 17 of us on a hike to view a large variety of fungi in the
forest. We were amazed at how much there was to see, and just how much there
is to learn about the world of
fungi.

Suggestions for further
reading:

• Journal of Urban
  Forestry and Arboriculture
  • http://joa.isa-arbor.com
  • (scholarly
    publication)
• Tree risk assessment
  manual, geared toward interested community members – here is one
  example:
  • https://www.fs.usda.gov/treesearch/pubs/11070
• Lone Pine Field Guide, Mushrooms of Ontario and Eastern Canada (may be out of
  print – check the library)
• Peterson Field Guide to
  Mushrooms, North America
• Timber Press Field Guide,
  Mushrooms of the Northeastern United States and Eastern
  Canada