RE: Pollen Allergies in winter? No way!

2018-01-11T19:04:52Z

Dear all,
We experienced record early start of flowering of hazel in the Netherlands. In a previous post I already told that the first hazel trees were very early. Now it is clear that the peak of the first flowering observations (the date when half of all hazel first flower observations have been sent in) took place before New Year! This never happened before in the Netherlands. 50 years ago the average peak flowering date was 15 February!

The most important reason for this record is the very high temperatures since October. The average temperature from October, November and December has been 8.5 degrees Celsius. 50 years ago that was 6.3 degrees, so more than 2 degrees Celsius higher this year. Only 2014, 2015 and 2006 had a higher temperature in these months. Different this year was that September has been relatively cold which could have triggered the trees that winter was approaching. Then the temperatures increased and the trees 'thought' spring was coming. An exiting start of the growing season in the Netherlands. Temperatures in January so far are still 2.2 degrees Celsius above normal. Last week the first daffodils started to flower! I was asked to explain the situation in front of the cameras of the main Dutch news channels.

I'm looking forward to what this year will bring with the GrowApp!

I wish you all a nice GrowApp year with the creation of beautiful and scientific relevant time-lapse videos!

Arnold van Vliet, Wageningen University, the Netherlands

Pollen Allergies in winter? No way!

2018-01-11T15:39:49Z

You may wonder what makes me talk about allergies in January. Trees start flowering in spring, everyone knows that, so why to be alerted now?

Listen to what the phenologist Lenka Hájková from Hydrometeorological Institute says about the onset of pollen episodes for this year:

“This winter air temperatures are so far 2 °C higher when compared to the long-term average. The forecast for following week only confirms that nothing much will change about the fact that we experience yet another warm winter, or more precisely: high-above-average-warm first half of winter.
The mild winter results in an early onset of flowering of hazel trees, and if the temperatures do not drop below zero soon, we can expect the alder tree to start flowering as well. Hazel and alder trees belong to the significant source of pollen allergens and what is even worse, these two are easy to wake up from winter slumber. Look at the hazel. The tree needs only couple of days with temperatures above zero to form the buds of male flowers that afterwards quickly progress to swelling, bud burst and flowering phase. Then you can observe bunches of hanging yellow flowers, with clearly visible anthers that release pollen.”

That was a report for Czech Republic. What about hazels in your garden?

Take a picture of a hazel tree with Grow App and add one more detail photo of the flowers. Don´t forget to keep a handkerchief in your pocket if you suffer from allergies! ;-)

The message for today:
NEVER STOP OBSERVING TREES. ALTHOUGH THEY SEEM TO BE DEEP ASLEEP, THEY CAN WAKE UP FAST.

And if you missed it, read the comment of Arnold van Vliet who spotted flowers of hazels in Netherlands even before Christmas:
https://www.globe.gov/web/european-phenology-campaign/overview/discussion-forums/-/message_boards/message/36437345