[CANUFNET] Tree Maintenance Cycles and the Effect on Growth and Rotation

[Ryan Senechal]

Picking up on Mark's sentiments, I would suggest doing some fact finding on
how the rubber meets the road with existing municipal cyclical pruning
programs in your region.  This means some observation of cyclical
maintenance artifacts sited at different levels of occupancy, and talking
with field staff/contractors and urban forestry operations planners.
Finding the right amount of plan to generate positive outcomes on public
trees including useful life expectancy, risk management and cost
effectiveness should give consideration to the depth of your operation's
resources and its ability to effectively introduce and meet targets.

Formulaic pruning prescriptions and cycles look great from a desk, and are
useful for reporting quantified outcomes.  Whether the reported cyclical
pruning outcomes are beneficial or not (as Mark Carroll described in
detail) in many cases is in question, and question them I will because
resources are precious.  Fixing criteria on pruning cycle treatments in
terms of live branches removed as a percentage, and in many cases
predetermining structural defect treatments are not reflective of the
conditional variances that should be considered across species/age/sites by
a competent field technician.  Many ops planners are determined to whip
field technicians into shape on pruning criteria that runs contrary to
industry standards and is counter-intuitive to the tech's arboricultural
training and experience (that being applying the appropriate amount of dose
for the condition).  Put more bluntly, field technicians are not wrong to
push back against cookie-cutter urban forest management.

Urban forest operations planners would be wise to create a detailed
cyclical pruning plan with a separate simplified field guideline that can
be used as a training and reference resource.
I would emphasize that the path to positive outcomes (given all the other
demands on your department's resources) is equal parts planning, training,
measurement, adjust, repeat.  If you're encountering repeating
frustrations, something is out of balance and it's probably originating
from the plan.  The field guidelines and effective training of everyone
involved is the step that is often missed.  Creating dozens of pages of
policy and procedures that no reasonable field technician will ever read
raises profound questions about modern urban forest management.  These
types of programs take skilled internal field technicians away from
important and diverse urban forestry functions to become box-ticking
contractor quality control robots.

Summarized, an effective cyclical pruning program establishes goals and
priorities, and evolves based on ongoing observations and technician
feedback rather than picking an interval out of thin air or from another
climatic region.  An inventory is helpful in planning an effective cyclical
pruning program as is having an understanding of public risk priorities
across different occupied areas.  Preventative cyclical pruning on young
trees through establishment on a short cycle is as important as managing
your aging stock with mitigation through end-of-life extension treatments.
Embedding local knowledge of species including typical response to pruning,
common defects, and failure profile for existing young and mature trees
would be worthwhile.

Hope this helps.

Ryan Senechal
Assistant Supervisor of Urban Forestry – Large Tree Specialty
Arboriculture and Natural Areas
Parks & Recreation
City of Victoria

*T* 250.361.0440    *F* 250.361.0615
rsenechal at victoria.ca





On Fri, Jan 17, 2020 at 6:54 AM Mark Carroll via CANUFNET <
canufnet at list.web.net> wrote:

> To All,
> Thought I would send a couple thoughts for scheduled tree pruning to the
> forum,
> This may not help but here it is...
>
> In regards to tree pruning, is a schedule an accurate way of determining
> the proper way to look after one of our natural heritage assets.
>
> It seems we look after our trees completely different from our other
> assets. We inspect our roads, we inspect our play ground equipment, and we
> inspect our buildings and so on and make the necessary repairs or
> preventative maintenance as needed. With trees we seem to have the need to
> just send crews out to prune. Do our crews have the knowledge, do our crews
> care enough, and do our crews have enough experience? If you use a
> contractor, we use the low bid. Will these contractors send us their best
> to prune, highly unlikely? They send their cheapest crew so they can cover
> the low bid.
>
> Structural pruning is what I would call “subjective to the individual
> doing the work”. Pruning a tree every 5, 7 years just because it is part of
> the rotation can have devastating effects on trees. Remember “the best
> thing you can do to a tree is prune it, the worst thing you can do to a
> tree is prune it”.
>
> Boulevard trees are subjected to a multitude of deceases, hardships, and
> pests. Salt, heat, vehicle damage, lack of habitat, lack of nutrients, lack
> of soils and the list can go on. It’s a wonder we have trees at all these
> days. Add to this the unnecessary pruning and you now have a tree that may
> not survive or at best be under constant stress.
>
> Extensive structural pruning in warmer climates may be beneficial to some
> trees. Longer growing seasons and better habitats will afford the tree
> better conditions to heal quicker without putting stress on the tree. Ed
> Gilman, a well known expert in structural pruning will not hesitate to
> remove more than 50% of a tree to prune it for proper structure. My opinion
> is that this may be ok for a tree in Florida where the growing season is
> almost 12 months of the year, but will it work in Ontario where we only
> have 6 to 7 months of a growing season. Will 50% be too much for a tree to
> handle here and will it take longer to heal? This may leave it exposed to
> deceases and pests for a longer period of time with wounds leading to
> cavities and weakened structures.
>
> When we look at pruning schedules, what do we want? Structural pruning?
> 2.5 to 3 meters over the sidewalk? 4 to 6 meters over the road for safe
> vehicle passage? How big will branches be when removed? No larger than 8 to
> 10 cm? No main trunk cuts? Do you thin out the Tree? Do you do reduction
> cuts? Do you have to climb each tree? Is each cut made from the ground?
> What is your budget? How many trees do you have to do?
>
> What about basing the pruning on the type of tree? Does a Locust need as
> much pruning as a Linden, or vise versa? Locust are over used, as are
> Lindens along our municipal street-scapes. Are they the best trees to be
> planting? Lindens are notorious for over growing on the lower branches and
> will need to be drastically elevated once they have reached 10 to 15 years
> of age or older. This will encourage epicormic shoots to grow and now we
> are back removing these shoots in a few short years. Lindens often have the
> co-dominant leaders that will present a problem when they are mature. Do
> you remove one whole leader all at once leaving the tree looking lopsided
> with a large open wound, or do you remove one leader slowly over a period
> of time.  Locust have a bad habit of shutting down branches, which leaves
> deadwood throughout the tree. Locust too, can have long straggly branches,
> small leaves and insect infestations that residents have trouble with
> leading to many visits for pruning. How do you manage this if you are on a
> 7 year pruning cycle?
>
> Trying to get developers, consultants, landscape architects, engineers and
> planners to diversify our tree canopy is a struggle, more like pulling
> teeth. Who doesn’t like the Freemanii Maple? They are planted everywhere.
> How much pruning will these trees need? They have the structure and growth
> pattern of a Silver Maple and it is the fall colour of the Red Maple that
> makes them so utilized. Usually multiple co-dominant stems and lateral
> branching wherever the sun seems to hit it the most. Locust, Lindens and
> some sort of Maple cultivar is the average species list that come with any
> sort of subdivision agreement. Trees are never planted correctly, so when
> municipalities assume boulevard trees they are usually under stress from
> being dug in too deep, the worst nursery stalk and planted with ropes and
> burlap not completely removed. We assume thousands of trees each year and
> may never get to see each tree until years later and then it will be some
> time after that before we can actually prune all of them. By this time it
> may be too late to properly prune a tree.
>
> I would recommend a species determined schedule for pruning. (Does that
> make sense?) Hopefully we are now looking at diversity for tree planting
> along our boulevards. Pick species that will do well, show better
> structural growth patterns, fit the habitat that they are growing and
> withstand the harsh growing medium that they will be presented with. This
> may lead to a better option for pruning schedules. Training methods must be
> improved and staff must have the passion for preserving our trees and doing
> what should be done, this includes pruning practices.
>
> So as a summary to scheduled pruning??? Yes, if done properly! If a tree
> does not need to be pruned, don’t prune it. I don’t think you can write a
> tender that will cover proper pruning of a tree. Pruning is too subjective.
> No 2 trees are ever alike, they never need the same type of pruning.
> Training methods and opinions are too diverse. If we ever get to the point
> where we can actually engineer a tree that is the day when we can schedule
> pruning. We also need to well staff Urban Forestry Departments. If we can
> fully train and control pruning methods, that will help us with scheduling.
> Urban Forestry Departments are always under funded and under staffed. We
> rely on the “Request for Tender” for outside crews to the majority of work.
> Do we get the best? Again “maybe” most likely not.
>
> I always say” we all know we need trees, we just don’t want trees”. How
> often have you heard somebody say that they do not want a tree at or around
> their home? NIMBY!!! “Leaves get in my eaves trough, I have to rake too
> many leaves, there is too much shade for my grass grow” etc. But that same
> person will go to a park and sit under a tree to watch their family members
> play a sport or go to the playground and splash pad. Trees are often an
> after thought. Not really looked upon as an essential asset. Municipalities
> will often have more staff cutting grass, filling pot holes, doing snow
> removal, controlling water-waste water, than looking after their trees.
> This thought may be changing since there has been more concern for our
> natural environment all over the world. It will take time and money to do
> the right thing for our trees. I hope I see it in my life time.
> I hope this helps with “Tree Pruning Scheduling”. Most likely not, but I
> thought I would send my 2 cents worth anyways.
>
> [image: signature-TWS]
> *Mark Carroll *ISA Certified Arborist/Qualified Arborist Tech/Lead Hand |
> Public Works, Town of Whitchurch-Stouffville
> 111 Sandiford Dr., Stouffville ON | L4A 0Z8
> 905-640-1910 Ext. 4249| Cell; 416-791-1040 | mark.carroll at townofws.ca
> <http://www.townofws.ca/>
>
>
>
>
>
>
> On Tuesday, January 14, 2020, 09:49:19 a.m. EST, Hettmann, Joerg via
> CANUFNET <canufnet at list.web.net> wrote:
>
>
> Hello All;
>
> We are in the process of developing a long-term tree maintenance strategy
> for the City of Vaughan, including a tree pruning rotation.  While we
> preliminarily have considered a seven year cycle, we would appreciate any
> information from other municipalities on their strategies.
>
> We are also looking for information to what degree proper tree pruning
> enhances tree growth(yield), resistance, and age.  This information would
> be very helpful in our valuation of the investment into tree maintenance.
>
>
>
> Thank you for any information you may be able to share.
>
>
>
>
>
> *Joerg Hettmann, R.P.F. *
>
> *Manager of Forestry and Horticulture*
>
> 905-832-8577 ext. 6139  I joerg.hettmann at vaughan.ca
>
>
>
> *City of Vaughan I Parks Forestry and Horticulture Operations*
>
> 2141 Major mackenzie Dr., Vaughan, ON L6A 1T1
>
> *vaughan.ca <http://vaughan.ca>*
>
>
>
>
>
> [image: cid:image001.jpg at 01D567F3.E6C37260]
>
>
>
>
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-- 
Ryan Senechal
Municipal Field Arborist/Arboriculture Instructor/Arboriculture Health &
Safety Professional
ryansenechal at gmail.com - 250 818 7139 <(250)%20818-7139>
ISA TRAQ - ISA Certified Arborist/Tree Worker ON1272AT
ITA BC Climbing Arborist #6-TB-14 - HEBC Falling & Bucking Endorsement #156
BC Landscape Pesticide Applicator #198560 - TCIA Certified Tree Care Safety
Professional #931
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