Big Leaf Maple = Future Big Problem as a Street Tree

7 February 2013 (I have sent the below mentioned comments as an email to every media outlet I could find, many arborists in multiple municipalities, municipal politicians, The Mayor of Vancouver, City Counsillors, etc)

Recently I received a press release (above) from Mole Hill Community Housing Society, my landlord, that the City of Vancouver has approved Big Leaf Maple Trees as a replacement tree for dying Cherry trees along the 1100 block of Pendrell Street in downtown Vancouver. The boulevard is under 2 metres in width between the curb and the sidewalk. Having been an admirer of this fine native species of Maple, with the largest leaf of any maple, I am troubled by this choice of tree as a street tree in the city core.

Acer macrophyllum (Big Leaf Maple) can grow to over 45 metres in height, have a trunk with a circumference of up to 3 metres and a significant surface root system (Mature Tree). My further concern for this Friday, 8^th February, planting by the Vancouver City Street Tree Program on Pendrell Street brought me to a Seattle City Ordinance, No. 90047, prohibiting the planting of this species in the City of Seattle on boulevards. In reviewing background on the use of this tree in Seattle, I found reference in “Trees of Seattle” by Arthur Lee Jacobson which states, “Around 1900, it was our most widely planted street-tree, but due to the ruinous effects of root-heaving on adjacent sidewalks, its use as a street-tree is now illegal by City ordinance.” Most municipalities I spoke to shy away from this magnificent tree due to its over-all size, wide and damaging root system, and tendencies to break large limbs during wind storms. Additional problems with this species include excessive seed production and excellent seed germination, powdery mildew and internal trunk rot. The City of Bellingham requires a planting strip with a minimum width of 30’+ for this species to be utilized in the city. Arborists for other municipalities stated that it was not a species they’d consider or had in their approved street tree lists. Don’t get me wrong – I find this tree to be a magnificent native maple with excellent fall colour, large leaves and a prominent trunk, but, it belongs in a suitable growing situation such as a park.

I spoke to Bill Steven, Acting City Arborist and Brad from the Vancouver Street Tree Program regarding the use of this tree and whether Mole Hill will be held responsible for future maintenance and repair costs, and their response was, “40 years and we will see sidewalk repair crews there and taxpayers will be responsible for paying for it.” It will, no doubt, be more like 30 years or less when roots will heave sidewalks and cause street damage with the potential of falling limbs and person/property damage. I’d imagine the city has good liability insurance. It was only little more than a year ago that a mature Big Leaf Maple in Nelson Park, only a block away, dropped a large limb during a wind storm. This tree is situated at the north-west corner of the school playground. The tree had become dangerous and was heavily pruned, no doubt at significant cost to tax payers. The expression, right plant-right place, wrong plant-potentially costly disaster applies to this situation. The City of Vancouver may be creating a costly future problem due to Mole Hill’s insistence for a native tree, namely the Big Leaf Maple. A native plant does not mean it is better than non-native plants. I outright stated to Bill Stevens & Brad, “…so what you are saying is that politics weighs stronger than common sense by planting this tree and taxpayers will end up paying for the end result of this decision?” I was dismayed that little regard for tax payers was expressed in the making of this decision. A street tree decision should be based on what is best for the tree, the city, tax payers and the environment. Just because this tree was planted extensively 100 years ago as a street tree does not mean it was a good choice, then or now, and probably explains the lack of seeing this tree currently as a common street tree. Brad mentioned that he had a hard time finding this tree, and for good reason. It is not a tree utilized in urban forestry for street tree use because of the aforementioned problems. Mole Hill Community Housing Society has long pushed for “native-only” plantings in the heritage block and ostracised those that appreciate non-native plants. Having had the front garden sprayed with herbicide a few times and killed and mob bullying has re-iterated this “native-only” drive. The overplanted and poorly kept native plant walk-through at Mole Hill has created a dangerous environment of drug dealing and criminal activity. With this commentary, I smell an eviction in my future!

What it really boils down to for the tree’s sake is I am asking for anyone’s assistance to prevent “Street Tree Abuse” that starts on Friday of this week. I am a plantsman and I care about plants. This, to me, is the same misguided environmentalist-type of action that Grant Hadwin bestowed on the Golden Spruce. If the City of Vancouver is vying for the “Greenest City” status, it should be done smartly, with the future in mind and without political motives at the forefront. If planting this tree is considered illegal in Seattle and punishable by a fine, wouldn’t the City of Vancouver take heed to this warning? Bill Stephen stated they will go ahead with this planting, despite my concerns. I’m encouraged that Drew Gilchrist, Superintendent of Arboriculture, Bill Stephen, Acting Vancouver City Arborist, Vancouver Parks Board, Donald Luxton, President of Heritage Vancouver Society, Sean McEwen, architect and Blair Petrie, Mole Hill founder and native plant person have vested interest in the community and I trust a sound resolution to this predicament will be found. None of us would want to end up paying for a poorly thought-out decision down the road. It would probably be best that Mole Hill Community Housing Society leave tree choices to the experts. After all, it would be an embarrassment for the Vancouver City Street Tree program, which I have held in high regard for tree diversity, arborists and urban foresters to make decisions based on politics instead of tree sense.

“I am the Lorax. I speak for the trees. I speak for the trees, for the trees have no tongues.” Dr. Seuss – The Lorax (1972)

Update 9 February, 2013

The trees were planted on the 8th February, 2013 as promised by the Vancouver City Street Tree Program. One could easily surmise that tree sense and common sense have been superseded by politics and misguided environmentalism. Out of curiosity I looked through several of my books to see what they said. The Western Garden Book, which is often considered the gardening "bible" of the west, states under Acer macrophyllum, "...Dense shade tree 30-75 ft. tall, 30-50 ft wide - too big for a small garden or a street tree." In Maples, by Rosemary Barrett, "There are other maples that call North America home, such as Acer macrophyllum (Big leaf Maple, Oregon Maple) and A. spicatum (Mountain Maple), but these are not suitable garden subjects nor are they readily available. This should not be of concern as the maples that have been described are so beautiful that we should not want for more." In An Illustrated Guide to Maples, by Antoine Le Hardÿ de Beaulieu, which is a marvelous book, it states, "...The tree's root system has adapted to these conditions and is very broad and superfial." I also found this Seattle Times article (October 21, 2002) regarding the tree which states,

"The tree is banned in Seattle for planting as a street tree because of its sidewalk-bursting roots and widow-making branches.
Plagued by compacted soil from parked cars and foot traffic, pavement and construction, the bigleaf is prone to root rot, said Linda Chalker-Scott, associate professor at the Center for Urban Horticulture.
Rot can make it more vulnerable to shattering in stormy weather.
The trees are also just too big to fit into street tree-planting strips, said Nolan Rundquist, city arborist for Seattle.
He has cut many a chunk of sidewalk out to make room for burgeoning bigleafs, and Rundquist remembers one sidewalk muscled up 18 inches by bigleaf roots.
"You had to just kind of fly over that part."
It's a tree for wild, open places, not the straitjacket life of a street tree. "Everything has its place," Rundquist said. "It's place just isn't between the sidewalk and the street."

I also wonder if the Cherry Trees (Prunus sp.) were suffering from honey fungus as almost all Maples (Acer) are susceptible species to this disease. I also noticed in the original Press Release that Acer macrophyllum is pluralized, which I don't even think is legal.

Fate

The supporting evidence is everywhere and experience with this species has taught some arborists but it seems others have forgotten or don't care. I guess some must error repeatedly to learn...or maybe not. It really comes down to understanding plants. Their characteristics, requirements, habits, negative and positive attributes and practical applications.