List of 10 Native Trees recommended as substitutes for the Ash, Fraxinus species
by Diana Beresford-Kroeger
1. Oak, Quercus
Q. macrocarpa is called the Bur Oak. It is a native oak, an edible species of the landscape
of the City of Ottawa. This oak or the white oak, Q. alba, or the northern red oak, Q.
rubra, will grow rapidly and form large canopies. These trees require immense amounts
of atmospheric carbon dioxide to grow. They are local trees that will reverse climate
change, reduce pollution and skin cancers. They have the strength to withstand ice storms
and heavy snow. They are also extremely drought resistant.
2. Honey Locust, Gleditsia triacanthos
The natural form of honey locust is extremely healthy and hardy in city traffic conditions.
It is almost resistant to disease infestations. It is drought resistant and it fixes its own
nitrogen from the atmospheric nitrogen dioxide and from the soil. The locust will reverse
climate change. The canopy of which produces a high filtered light for city gardens. The
tree produces edible beans which can be ground as flour and added to other grains to
make flour in various proportions. The flowers of the locust feed beneficial insects which
in turn act as predators reducing the need for pesticides. The tree is also an 'Escape tree'
for birds from city cats and racoons.
3. American Basswood, Tilia americana
This local native tree has flowers in June to July which are immensely fragrant. The
lactone chemistry in the aerosols that are produced are beneficial to human health. The
tree is the greatest feeding tree in the entire world for beneficial insects. Basswood honey
is the best on the continent. This tree helps the bird populations to increase and produce
more viable eggs in the spring which in turn reduces the need for pesticides. The
Basswood leaves in its canopy combs the city air of its particulate pollution which is a
leading cause of heart disease in the asthmatic.
4. Eastern White Cedar, Thuja occidentalis
Ottawa is blessed with native populations of an evergreen tree called the cedar Thuja
occidentalis that the local native people called "The Tree of Life". There are golden, tall,
weeping and fastigate forms. The trees’ leaves have glands on the tips of the leaves that
can be easily seen by the naked eye. These glands in hot humid air release an aerosol
medicine into the air that regulates the beating heart and is antiviral. The tree is also
drought and fire resistant. It feeds birds and protects them in the winter adding 2 degrees
centigrade to their body heat within the shelter of this evergreen.
5. Black Walnut, Juglans nigra
The walnut tree is a medicinal tree. It produces anticancer bio-chemicals both in the
mature foliage and in the nuts themselves. Ottawa has a very high cancer rate. This tree
would act as a shield for this, most especially for the children of the city who are most
vulnerable because of their high metabolic rate when they are in growth spurts to
adulthood. Pound for pound, the flesh of the walnut is equal in protein to the best black
Angus t-bone steak. The tree is strong and wind resistant. It also has a wide canopy which
reduces summer cooling costs. The wood of this tree is one of the most valuable in the world. A well grown Juglans nigra ‘Thomas’ in the city will pay for a grandchild's
university education, quite easily. A full canopy of black walnut generates chemical
aerosols which will neutralize toxic benzene from the traffic.
6. Fir, Abies
All of the fir are drought resistant. They will withstand heavy snow loads and ice. The
conical form of anatomy of the tree helps them to stand straight, also, in high winds. The
branches have a special form of buttresses built into them. These trees guard all the
waterways, canals, lakes and river systems helping to purify potable water which is
increasingly an issue for cities and urban areas across the world. The chemistry from the
needles or leaves produces airborne aerosols that are antiseptic and antibiotic. These trees
act as air cleansers and as deodorants on a massive scale. This super clean air is a health
benefit to the city of Ottawa and to the surrounding area. There are two trees of choice,
the Abies balsamea, known as the balsam fir, balsam, Canada balsam or the eastern fir.
This tree is native to the city of Ottawa. The other is the Abies concolor known
commonly as the white fir or white balsam. This is a Canadian species, the best cultivar
for shape, form and drought resistance is A. c. ‘Candicans’. This tree is also a songbird
shelter and escape route for predation.
7. Spruce, Picea
The white spruce is the workhorse of Canada. It has a long and important history on the
landscape especially for Ottawa, where it grew on rocky areas overlooking the Ottawa
River. It was one of the trees with long tracheids that made pulp which made paper that
made money for the lumber barons. Their names can be found inscribed in Rideau Hall,
residence of the Governor General. The tree is famous for its pharmaceuticals, one of
which reduces blood pressure the other is anti-anginal and helps the heart itself to beat.
This is a medicinal tree. It is evergreen and can withstand snow loads and strong winds.
The resin of the tree helps all flying beneficial insects especially the honey bee. This tree
helps to stop Honey Bee Colony Collapse. The best spruce for Ottawa is the common,
native white spruce, Picea glauca. It is known as the skunk spruce. The latter is a
common name given when the science of the aerosol medicine was not appreciated by the
pioneers, but was used by the aboriginal medicine men for 40,000 years on this continent
as a medicine.
8. Catalpa, Catalpa speciosa
The catalpa is the most spectacular flowering tree for the city of Ottawa. The bloom
clusters are bigger than a man's head. The flowers are white and fluorescent purple. The
long beans hang in tassels into the fall and winter. They are the food of the red cardinal
birds who love to split open the bean and eat the seeds. This tree is suited to the
calcareous soils of the city of Ottawa. The tree can be easily grown, it is disease and
drought resistant. The horizontal limbs and main branches in the winter are flexible and
will withstand heavy ice and snow. The blooms are like orchids and attract butterflies.
The author, Diana Beresford-Kroeger would like to see these trees widely planted in the
downtown area as a tourist attraction for a festival of their flowering in June to July.
Such a tree allée would also help to maintain clean air as the huge leaf can comb air pollution of 2.5 micron sizes, reducing it for easy breathing. It is a North American tree.
Its origins are unknown on this continent.
9. Hickory, Carya ovata
The Hickory trees that were cut down for the building of the city of Ottawa were Carya
cordiformis. The tree is also known as the Bitternut Hickory, Bitternut, Swamp Hickory
and by the farming community as Pignut. It is not known if other members of this family
were present at the time. They may have been present because the aboriginal people often
planted nuts. These trees would have been Carya ovata, the Shagbark Hickory, the antifamine
trees. The Hickory is unique to the continent, except for China. It grew to
enormous proportions here. Fingerprint boles account for circumferences of 18 feet on
shallow soils. The Hickory is a feeding tree for birds, man and mammals. It is also a
butterfly tree, used in a butterfly’s continental migration. This tree can be planted for a
public park or a larger garden. In the last ice storm this Ottawa tree species was badly
damaged. It needs to be replaced, also.
10. Cucumber tree, Magnolia acuminate
The Cucumber tree and all the other species of trees that are endangered in Canada could
go on a long list. People who are interested in preserving the native heritage and stories
of Canada should grow this magnificent Canadian tree. The tree produces a unique
cucumber style fruit. From this fruit the frost opens the seed cases and dangles a red seed
by a white thread. Birds love these rich seeds. The flower is like a steel grey tulip which
is produced at the end of May. From this tree the aboriginal people made anti-malarial
medicine. They made dugout canoes for inland travel on their water highways and they
carved death masks from its sacred wood. These masks had an important ceremonial
function. The cucumber tree is almost extinct. The City could help in a recovery program
for its new World Heritage Site of its canal system. Then these trees could be enjoyed by
everyone again. They were a waterway tree.
Found on Ecology Ottawa website (October 2013)
P.S. Check out my latest "urban wild" nature blog: Wild. Here.