I am going to do a follow up of my last post regarding the pollen season of 2014 and the cold spring that occurred. First I would like to refer to this term that has been used this season called the pollen vortex. A vortex refers to weather, like the wind, and not to pollen. Our research has proven that pollen release is affected by temperature, sunshine, rain etc but the wind is just a vector by which the tree pollen are carried in the atmosphere.
In most parts of Canada the season was very slow to come. This is not unusual and it has happened in the past. Southern Ontario was particularly noticeable as to how late the season was in that area. This was unusual in all the years we have been collecting data.
So the spring came slowly which is a good thing for the trees. What affects them a great deal is if we have a long warm spell followed by a noticeable lengthy cold snap with temperatures below freezing. Since this did not happen the trees adapted quite well and continued on with their season.
What is happening is that some of the early pollinators, which I listed in my previous blog, came and went with a bit of a shorter season. The pollen levels were still high but for a shorter time. Now this is not true of all regions since the weather changes from the east to the west coast. Alberta is just finishing their very high poplar season. Poplar is one of the earlier trees so they are really late. Alberta does have Chinooks so this is how the trees adapt there.
We are now noticing the later trees like birch, ash and the oaks are now having their season with a slight overlap with the poplars. This is what happens in a season that has been delayed due to a late spring. All indications are that the later trees are having a bit of a slow start due to the temperatures at night still being quite cool. However they will likely have high seasons. Our data and research shows that the trees adapt to whatever the weather except for ice storms where the trees are totally demolished. Trees know how to preserve their energy and they have a mechanism that helps the species to survive.
Victoria is already into its grass season. This is early and also from the looks of the start of the season it may turn out to be a high season. Looking at our data the start of the season can be an indicator of what the rest of the season will be for that site. This applies to Vancouver and Kelowna as well. We use this as an indicator as well for what may happen with the grass season in the rest of our locations. A cool wet spring seems to be a factor in producing a higher season for the grasses.
The fungal spores are also starting and we are seeing moderate counts of Cladosporium at our sites in Saskatchewan. This fungal spore really likes the Prairies due to agriculture. Cladosporium likes to grow on dead material such as grain. It is also a very common fungal spore that is found in the remains or what people call poplar fluff. This organism is considered an allergen. This fluff, or remains of the structures of trees after the pollen season, is quite normal and happens in all species of trees. This is a normal phenomenon and it cannot be stopped since all trees do this in some form or other. Molds or fungal spores live on all decaying or dead matter. It’s nature. It is a good thing we cannot get rid of nature.
Looking forward to blogging more on the topic of Aerobiology and our study of airborne pollen and fungal spores
Written by Frances Coates from Aerobiology