Mast Year 2018

I mentioned in a post recently that we have a lot of pollen this spring. (Understatement of the year!) Well, I have since learned that not only has everything flowered at once due to our warm April – the warmest on record since 1881 in Germany – but it is also a so-called mast year for birches, spruce and firs in our region.

A mast year is basically a year when certain types of tree in a whole region produce much more pollen and thus far more seeds than in a normal year. Birches do this regularly – every second year – while other trees such as oak or spruce only do this every 4-8 years.

Our silver birches, swaying in the wind

Trees generally use their energy for putting on growth in non-mast years. But in a mast year something triggers them to put all their strength into preserving themselves and to produce as much seed (and hence pollen in spring) as possible. This can apparently be seen in the rings when a tree is cut, with intermittent rings of very little growth. The trigger may be a warm spring, drought or other factors such as the North Atlantic oscillation. In other words, climate change affects tree ‘behaviour’. But what fascinates me is that, for example, practically every Spruce tree in the whole of Germany has started pumping out the pollen, whether in the far north, the Alps, the Black Forest or the Bavarian Forest. Clever. 😉

Spruce, only just showing signs of fresh green

Just looking across our valley at the hillsides around us recently it suddenly became clear to me that the Spruce, Firs, and probably many other conifers have joined the birch this year – the trees are gold and brown instead of green, with little fresh growth and millions of flowers and cones forming on their branches. Perhaps you can see what I mean from this photo taken yesterday where the conifers are all much darker than the fresh deciduous trees in full leaf…

In fact, when I walked around the garden and took a closer look I could see our Norway Spruce, Douglas Fir, Silver Fir, Austrian Pine and other conifers I cannot identify are all going mad this spring!

Douglas Fir, with fresh shoots just beginning to show

One article I read quoted a botanist suggesting the conifers are suffering from several dry years in a row, and this is a self-preservation measure should they die. A grim thought. While looking for more information on this phenomena I found myself engulfed in the technical jargon of meteorologists and botanists. But it was interesting to find out just why we are experiencing so much pollen this spring!

Have you ever heard of mast years or experienced the same where you live?

46 thoughts on “Mast Year 2018

    • I hadn’t made the connection between massive seed production in autumn and the excess of pollen in spring, but this year is so extreme due to the dry weather too that I got thinking about it more. (By the way, we had some heavy rain tonight at last… not enough but better than nothing!)

  1. I have never heard the term ‘Mast Year’ but I have noticed that after a very dry summer that the trees make many more seeds.

    • The must recognize climate patterns in advance in order to produce more flowers than usual earlier in the year too. I would love to know how they know!

  2. That’s fascinating! I’ve heard that native trees here in Australia flower much more prolifically when there’s a drought for preservation of the species, and in fact flowering has been abundant this year.

    • Hi Jane! I suppose mast years will become more frequent occurrences in many parts of the world as our climates experience more extreme weather patterns. And the effect on the wildlife is another factor too…

  3. The TV news here has been playing a video of a tree in New Jersey that was hit by a backhoe and sent out a huge cloud of pollen. A Mast Year does make sense when the trees are stressed.

  4. Cathy, I congratulate you on your wonderful and informative blog. I already told you the first time you talked about the mast years in passing that I did not know anything about it. Thanks to this blog now I know that they speak to me and also of the maximum years .. In short, Nature is defending itself from Climate Change, especially the spruces that take longer to grow. I went out to the garden before writing this. My neighbor has 7 Himalayan firs and they are less green than last year. I have a mini Birch that was born alone and has not yet done all the leaves, it has half done, and they are green but at this moment not as much as last year. Even when I finish throwing them they get more green. You have raised me the desire to investigate. Cathy congratulations on your blog and thank you very much. Greetings from Margarita.

    • I am glad this has got you thinking too, Margarita! I have since found out that the bark beetles which attack conifers here are also causing the fir trees to produce more seed as a desperate attempt to sustain the species. I can forgive them for all the pollen as they are only acting in self-defence! Have a good weekend Margarita!

      • I am glad this has got you thinking too, Margarita! I have since found out that the bark beetles which attack conifers here are also causing the fir trees to produce more seed as a desperate attempt to sustain the species. I can forgive them for all the pollen as they are only acting in self-defence! Have a good weekend Margarita!

  5. Yes Cathy, here in New Zealand I’m well aware of “mast” years when the native beech trees provide a lot more food and the native birds are then at risk because of the explosion of the pest population due to the abundance of food, especially when that food eventually starts running out.

  6. We mostly notice mast years with oaks when there are a ton of acorns in the yard to clean up. Last year must have been a mast year for maples because there are now a LOT of maple seedlings everywhere. Last year it was ash. It seems there are always some form of tree seedling to weed out of the gardens!

  7. I have only heard of it in connection with beech trees but only in the autumn when there are far more beech nuts than usual which provide food for the wildlife. But then, thinking about it, there must have been more flowers and pollen to make the beech nuts in the first place.

  8. A very interesting post, Cathy, thank you! We experience mast years as well in our woods which are full of chestnut and oak, much to the delight of wild boar of course. The past few years those trees have produced a tremendous amount of nuts, I sometimes worry they’ll exhaust themselves. The other day I had to weed in Pompeii as millions of oaks have seeded in my new borders…oh dear! Monsieur suggested to let the wild boar in but this is out of the question ;), have a good w-e, xx

    • 😉 The problem is they would eat – or at least dig up – EVERYTHING! Maybe when you want a new bed digging over you could invite them in! LOL! We get lots of sycamore seedlings – but when the ground is this dry I can’t even weed them out!

  9. Yikes! All that pollen 😦
    I’ve heard of mast years around here in the NE US as well. I always thought it depended on dry weather and good pollination, I didn’t know that the trees were already planning ahead and putting out even more flowers than usual. Based on my allergies I suspect we are having a mast year as well 😉

    • Oh dear, hope your allergies are bearable. We finally had a downpour yesterday which seems to have cleared the air a bit and washed a lot of it away. I think the worst is over now anyway. Have a good weekend Frank!

  10. This is absolutely fascinating information, Cathy! I have never heard of a mast year, but I’m going to do a little research to see if there’s anything similar in our region. My granddaughters’ allergies have been really awful this year, and I was sitting outdoors one day and watched pollen, thicker than I’ve ever noticed it before, streaming from a huge deodor a few houses up the block. It’s a massive tree, and it was raining pollen in quantities I’ve never seen before. I’m now so curious. Nature is never still!

    • Yes, we have seen clouds of it from our fir trees too. Terrible for allergy sufferers. You are right, nature is at work where we often don’t even realise it.

  11. Some specie of oaks do this supposedly to sometimes overwhelm squirrels. If they always produce the save volumes acorns, it helps to keep the squirrel population stable. However, if they occasionally produce too many acorns, there are not enough squirrels to eat them all. They do not do it often enough for the squirrel population to really get overwhelming.

    • That is certainly a different perspective on it Tony and makes sense. It is wild boar in this country that like the masses of acorns produced in a mast year. 🙂

  12. Absolutely fascinating, Cathy, and nit sonething I have heard of – I will look into it for more info. Must be a nightmare for hay fever sufferers thougj… 😑

  13. A very interesting post Cathy. I have always known that the tree pollen starts my hay fever symptoms, this explains why some years are worse than others. While it affects me , isn’t nature wonderful.

  14. Oh a mast year is a new to me piece of information Cathy and a most interesting one. Now on my list of things to find out more about. Thank you.

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