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Tom Ogren


   Tom Ogren
    Author, Speaker, Pollen-Allergy Researcher,
    Creator of OPALS, USA

Short biography

Thomas Leo Ogren is the author of six published books. His work on allergy-asthma reduction is used in many countries. He is the creator of OPALS® (the Ogren Plant Allergy Scale) that ranks all landscape plants from 1 to 10, where 1 is best, most allergy-free; and where 10 is worst, very allergenic. Tom’s newest book, The Allergy-Fighting Garden, is published by Ten Speed Press and Random House Publishers. 

Conference session presentation – Allergy-Friendly Parks, Schools, and Urban Forests for Australia 

Allergy rates in Australia are high, and are getting worse. Australia is home to some of the highest asthma rates in the entire world. There have been other Australian episodes before of thunderstorm asthma, but the most recent outbreak (in which thousands rushed to hospital, and some died) was the worst ever seen anywhere in the world.

Clearly allergy/asthma is a growing concern in the cities of Australia, and with ever increasing carbon dioxide and climate change, if we do nothing, things will only get worse.

Modern allergy/Asthma is mostly an urban problem; both allergy and asthma are worst in our cities. Phenomena such as thunderstorm asthma cannot happen unless there is considerable pollen in the air, and considerable air pollution, generally caused by heavy vehicular traffic. 

Certain popular city trees cause way more than their share of human health problems. In almost any species there are some individuals that are either pollen-free or low-pollen, and these can be selected, cloned and used to great advantage. 

Some cities have already enacted pollen-control ordinances that ban the sale or planting of any more of the most allergenic trees/shrubs. These ordinances help, but a much more aggressive approach is needed if we are to be successful.  In many cities there is an overabundance of cloned male trees/shrubs, and these all contribute to allergy/asthma. It is necessary that we plant many more female selections of these same species, in order to achieve any sort of gender balance in our urban forests.

Keep in mind that for every single highly allergenic city tree, there is a suitable substitute that is not allergenic. This is true also of perennials, vines, and certainly of both lawn and pasture grasses.  We can have an urban forest that is exceptionally allergy-friendly, but we must understand what we must do, and then we must have the will to make it happen.

For three decades now I have been working to better understand the connections between human health and urban forests and landscaping. Many prominent MDs, allergists, and others from the medical profession have enthusiastically endorsed this work. Arborists and other professionals who have read my books are already applying their knowledge toward improving the health of the city. Unfortunately there has been a lag in the participation of enough growers, nurserymen, resulting in a situation where it is often difficult to find and buy the most allergy-friendly plant materials. We all need to work together if we’re to be successful, and we need to put pressure on the wholesale growers to grow far more of the best materials.

To all Arborists, Landscapers, Landscape Architects, Landscape Designers, professional gardeners, nursery people, professors, horticulturists: Our aim is to make the world a better place; to make our cities more beautiful, safer, and friendlier.

But what if a tree we plant today grows up to be something that produces large amounts of highly allergenic pollen each year? What if that same tree we planted ends up triggering both allergies and asthma for people who live or work close to that tree? Is this really something we’re okay with?

Every single time we plant a tree we must consider all of our environmental responsibilities. It is always important and a worthy goal to increase tree canopy in our cities, but we have a responsibility to do more than just increase canopy; we must increase canopy in a way that improves the health and the lives of those who live in the midst of our urban forests. 

In my talk(s) I will first explain in some detail the science behind allergy-friendly plantings. We will explore the most important plant flowering systems, perfect, monoecious, and dioecious and how each relates to human health. We will explore the concepts of proximity pollinosis, and will examine the findings of pollen dispersal tests. We will explore practical methods for implementing this work.  In short, we will set the stage for many future allergy-friendly city parks, schoolyards, and other public places all across Australia.


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