Input from Save the Urban Trees to Mayor of Technical and Environmental Affairs

Focus areas.

For the protection and preservation of the urban street trees.

Street trees


Street trees should be protected from traffic, with iron structures. The bark damages on a tree that has been hit by a car, is an open wound and an invitation to rot and fungus, which kills large parts of the tree, causing branches to drop and eventually the tree is cut down. A driver is more likely to pay attention to iron than tree. On squares and open spaces protective measures could be combined with the need for benches and bike parking. For example, circular parking structures around the tree.

Road engineers


Road engineers must be told not to suffocate the planting hole with asphalt. This practice will only make the surface bulge, as the roots seek upwards for oxygen, and eventually kill off the tree. Improved dialogue with the park administration is a must. Road engineers must be instructed to preserve existing trees, and make space for new trees.
  

Salt

Salting of the roads is the big killer. Funds must be set aside to protect street trees from salt, and more urgently an alternative to salt must be implemented. As a start the green stretches/green bike lanes should be spared from salt.

Supervision and enforcement

Damage of public trees should be punishable. Over and over again we see trees being hit by trucks and cars, with zero consequence. The city should send a clear signal that the health of our trees is a serious matter.


Construction

During construction work the trees should be protected with a set of clear instructions. It is important that the language is clear and not open to interpretations, no "should" and "recommended". The drip zone (area directly below the canopy) should be free, and things are not to be leaned against the trunk, nor should heavy objects be placed in the root zone. At the present no rules are set and entrepreneurs are frustrated that one spends time and energy preserving trees on constructions sites, when the next just goes on to fell, immediately after. There is an urgent need for clear rules and enforcement thereof.

In public projects it should be a given that existing trees deemed worth preserving, if at all possible, are incorporated in the project from the beginning, and not just replaced. Even if it comes at an additional cost.

In Amsterdam the park administration have cooperated with the road planners to come up with a special surface for bike lanes, giving the impression of floating on air. It is gentle on the roots, more flexible and less porous than regular asphalt. Copenhagen should test this solution.


Urban planning
There must be an understanding that "breathing holes", like the airy spaces between houses,  or fenced off green areas, are not necessarily unused areas. The urban development team is quick to label these spots ready for development, not recognizing their great value and importance to the citizens. Breathing holes are zones free of construction and re-thinking, where trees and nature are allowed to stay. Their function are among others to lower the temperature, preserve the biodiversity, absorb water and noise, clean the soil and air, catch the lethal particles from air pollution, bring peace to- and enhance the quality of life to the citizens.

Boroughs should be divided in zones, where areas with a documented low percentage of green per citizen, should be treated with extra care during urban planning. There should be a minimum limit of nature pr m2. The city already have a clear idea of what is left (measured in 2009), and as such know how to locate the most nature deprived areas.

Trees should to a higher degree be mentioned in local plans and urban statues.

Assessment of worth/recognition of value

Trees must be valued, and their many benefits recognized. Among other things the value of trees ability to filter particles in heavily polluted areas should count, and be part of the planning. Old and viable road trees on stretches that exceed the established value for air pollution, should under no circumstances be felled. The calculation should be used in the planning stages of projects and fellings.

Scale for replacing trees
Measuring trees in a scale of 1:1 is not valid. If the tree in question is healthy, it should be measured by canopy cover. A 100 year old tree is not the same as a twig. Not to our quality of air or life, and not to biodiversity and animal life.

Another reason 1:1 is invalid: newly planted street trees have worse growth conditions than the ones planted only 30 years ago, the soil is more compressed and packed with cables, fibres and pipes. And the trees are being hit by cars and salted to death before they develop any resistance.


Healthy urban trees are irreplacable and should not be felled under any circumstances. Experience shows that new trees will not resurface at the same spot again. The city should work hard to protect the huge investment that the existing street trees represents. Currently, there are not enough means set aside to protect the big street trees, the limited budget goes toward protecting the newly planted for the first years.



The overview
There must be a place where all information about the urban trees are stored, and every time a tree affected by plans, it should be approved from this place.

The urban trees must be mapped, to stay informed on exactly which are involved during road work and construction, and which should be incorporated into new projects. We also urgently need to know exactly how many are felled and why. To learn how we prevent the irreplaceable, but often avoidable loss of trees.

Criteria for the preservation of trees

The criteria for what is considered a tree worth preserving, should be reevaluated. Current rules state that a major canopy reduction is not acceptable, but if that is what it takes to make an old tree survive, it should be considered an option. The way we treat street trees today, few measure up to the current criteria for trees worth preserving. Revised criteria for trees worth preserving should also include input from biologists, who highlight the dead parts of a tree (to the extent they don't pose danger to people), as useful to animal life and biodiversity.

Copenhagen should have more tree specialists involved in the management of the trees. As a supplement to landscape architects, there should be a higher percentage of biologists and arborists. When a tree is evaluated, it should as a rule be inspected by a biologist or arborist.


A tree policy

As is the case on Frederiksberg: it should be illegal to fell a tree over the age of 25, without city approval.

In Berlin every street tree is numbered, mapped and registered by age and species. And all trees are inspected in intervals of 18 months. If one is felled without approval, or if a homeowner use salt, it is punished with massive fines. In Berlin road engineers and park administration have come up with an alternative to the all destructive salt, which they would be happy to elaborate on.

Trees should be eligible for landmark status, individually.

All trees should have a health report, and as a minimum no tree in the city should be felled without one.



Input from Save the Urban Trees, February 2016