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Catkins In Common: Distinct Features Of Three Widespread European Trees

Catkins In Common: Distinct Features Of Three Widespread European Trees

The vibrant blossoms of spring are obvious, particularly when the blooms are shown off to their best in bright sunshine. The flowers of other trees are less obvious, especially when they are less obviously flowers.

The Betulaceae is a family of trees that derives its name from the genus Betula, more commonly known as the birches, which forms part of the family. The common and widespread Eurasian birch species that many people know is silver birch, Betula pendula, also known as European white birch. Downy birch, the UK’s other native birch, is Betula pubescens.

The male flowers of the Betulaceae are borne in long catkins, which once extended, become very noticeable. The female flowers are held on the same tree. Both of these flowers are very different to the archetypal cherry blossom. Moreover, the flowers of the Betulaceae often show themselves in late winter, yet often go unnoticed. Once you notice you the catkins, though, you notice the similarity between a number of common species. Further, once you have a closer look and compare the differences, these species are easy to tell apart.

Silver Birch, Betula pendula

Silver birch in unlikely to need any great introduction or description here. It is ubiquitous in many parts of northern Eurasia, from the UK eastwards. It’s easy to spot in the landscape due to its silvery-white bark and pendulous shoots.

white barked silver birch trees in spring sunshine
Silver birch is very easy to spot from a distance, even without leaves. East Sussex, late March. Photo: Paul Kirtley.

This tree is one of the outdoors-person’s true friends, providing many resources. Even so, many who are familiar with the tree perhaps have not taken much time to notice the flowers of this common species in the spring. I would recommend taking a look. It will help with understanding and recognising not only birches but also their cousins, including alders and hazels.

catkins of silver birch, Betula pendula, with emerging leaves against a blue sky
Silver birch flowers – male catkins hanging down, female catkins standing upright. Leaves just emerging. East Sussex, early April. Photo: Paul Kirtley.

Common Alder, Alnus glutinosa

Alders form the genus Alnus and also form part of the family Betulaceae. Alders are trees that impose themselves on your consciousness much less stridently than birches do. They are less showy and tend to congregate down in damp hollows, particularly in places boggy mud might ooze over the tops of your boots. So, maybe you don’t tend to tramp there as much as other places.

Alders are often found on the edges of streams and rivers and always like their roots in damp ground. As such, alders are a good water-indicating genus in the northern temperate zones. Dead standing wood from alder also makes a very decent bow-drill spindle and hearth board.

In leaf, Alnus glutinosa is easy to recognise with its shiny racquet-shaped leaf. In winter, its buds are a highly distinctive mauve colour. Before they expand, the catkins are also tinged with purple. Once extended they also have shades of yellow in between the purples.

puple-yellow catkins of common alder, Alnus glutinosa
The mauves and yellows of alder buds and catkins. Some cones also present. County Durham, early March. Photo: Paul Kirtley.

Alders are the only broadleaved deciduous trees that form woody cones. You can see these forming, green, on trees early in the year but you’ll also see dark brown, almost black, spent cones sticking around into the following year, still on the tree or having got caught up on their fall to the ground.

little woody corky brown-black cones of common alder, Alnus glutinosa
The woody cones of alder often remain from the previous year. County Durham, early March. Photo: Paul Kirtley.

Bring all the above features together and alders are not only fascinating to look at up close but also easy to differentiate from other species.

Common Hazel, Corylus avellana

Hazels were once treated as part of a separate family but latterly were joined into the enlarged birch family, Betulaceae. Certainly there are some similar traits, in particular the catkins. Indeed, if I were to wager which trees the average person would most associate with catkins in the spring, my money would be on hazels.

hazel catkins in spring sunshine
Hazel catkins starting to extend. Note also the buds. This is the species most people tend to associate with catkins. County Durham, early March. Photo: Paul Kirtley.

Again, hazel catkins hold the male flowers. Much smaller, but even more fascinating are the female flowers of common hazel. They put forth small but brightly pink structures that give the impression of some kind of alien tentacles. Combined with the bud from which these structures protrude, the overall impression resembles a funky hermit crab.

Corylus avellana - green bud with weird pink bits sticking out like tentacles
Hazel female flower. Like a hermit crab or a “weird alien”. London, early February. Photo: Paul Kirtley.

Hazel shoots are often coarsely hairy, with short stubbly hairs. The terminal buds tend to be fat, with noticeable bud scales and red-green colourations reminiscent of some popular apple cultivars.

common hazel hairy twig and fat green-red bud
Terminal bud and hairy twig of common hazel, Coryllus avellana. County Durham, early March. Photo: Paul Kirtley.

Similarities And Differences

Despite these members of the Betulaceae having catkins in common, and while these flower stuctures provide recognisable family traits, it is not difficult to tell these species apart. Indeed we can use the catkins, buds and other local detail to help us pinpoint which species we are looking at.

Remember these identification features are going to be present before the leaves emerge and so help us with identifying species in the winter and early spring, when the easiest ID features (the leaves) are absent. I’m confident that in drawing your attention to the features highlighted above, you will be better equipped to identify these species of trees.

In the comments section below, let me know what was the stand-out piece of information you took away from reading this article.

If you’d like to learn more about the identification of trees and plants that are useful for bushcraft and survival, you can request information on my Tree and Plant Identification Masterclass online course by clicking here.

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22 thoughts on “Catkins In Common: Distinct Features Of Three Widespread European Trees

  1. Hi Paul,
    Yet another great post, very informative as always, appreciate the extra information about alder being good for bowdrill, will have to try and find some to give it a go.
    Many thanks.
    Nige.

    1. Hi Nigel,

      It’s good to hear from you again. Thanks for your comments on this post. I’m glad you liked it and found it informative.

      Let me know how you get on with the alder for bow-drill.

      Warm regards,

      Paul

  2. For me, the biggest standout (and useful) piece of information was the Alder being the only deciduous tree to bear woody cones. Made me realise just how many I have seen.
    Great article, succinct and informative. Thanks Paul for sharing.

    1. Hi Nigel,

      Thanks for your comment. I’m glad it helped with the alders. There are certainly plenty of them around once get your eye in. Thanks also for your feedback on the style of the article.

      Warm regards,

      Paul

  3. Hi Paul,
    The characteristics of the female flower of the common Hazel tree stood out to me.
    Thank You,
    Matt

  4. It has to be the funky hermit crap of course! 🙂 I have never notice the female have flowers. Also, like a previous commenter, I didn’t realise how many alders I have seen. Thanks.

    1. Hi Katy, I’m glad I brought your attention to a new aspect of a familiar species as well as bringing the alders more into focus. Thanks for the feedback .

      Warm regards,

      Paul

  5. Great post, Paul! I like these funky hermit crab of hazel. Never looked at them like this. I’ll go out and have a look myself to see this since we do have lots of hazel here.
    Thanks!

  6. Thanks Paul, you learn something new every day. I didn’t know that Alder is a member of the birch family. Alder is a little scarce in the Trent valley, aggregate extraction has decimated the tree population.

    1. Hi Howard, thanks for your comments. I’m glad you learned something from this article but sad it’s becoming harder to observe these trees near to where you live.

      Warm regards,

      Paul

  7. Great article, from top to bottom. Especially for a beginner like myself starting to get interested in trees in the middle of winter. Standout piece of info is the paragraph on Alder’s being a good indication of water. Thanks for putting out great content Paul.

    1. Hi Angel,

      Thanks for your feedback and I’m very glad this was useful to you, especially the practical take-aways.

      Warm regards,

      Paul

  8. Many thanks Paul.

    This, like all your material, was really useful. Look forward to my next walk and looking for some alder.

    In my ignorance and inexperience, I just assumed catkins just appeared on Hazel.

    Thanks again.

    1. Hi Alex,

      Thanks for your comments and your honesty. I’m glad I added a little incremental knowledge with this piece.

      Enjoy your next walk 🙂

      Warm regards,

      Paul

  9. Great images, not much hazel around here, still great information when I travel.
    sadly not even close to spring up here yet, I live more or less long stones throw from arctic circle, spring is approaching but still about 1m snow, snow is starting to thaw inn southern slopes…

  10. Hi Paul,

    Thanks for the post, I had never realised all these trees were betulacea. It was really interesting to see 3 trees which are stand alone in their own right descend from the same “branch” 🙂 I have each of these on the site I work, but had always steered towards the Hazel when doing bow drills, the recent wind brought down some alder so I shall be working a few sets out of there.

    As an aside, why is it trees with a preference to wet areas tend to be so useful for firelighting?

    Thanks again for the quality content.

    Chris

  11. Great read as always Paul,i find the photographs really useful when in the woods.Well done and thanks for all your efforts.

    1. Thanks Andy. Glad this was useful and you appreciate the photos. I appreciate the feedback.

      Warm regards,

      Paul

  12. Hi Paul
    Nought to add to the other comments already made, again a useful article to get my head around … so much information to be taken in you realise how complex and deep nature is and so much to be learnt, nothing better than standing under a tree or a forest canopy, you notice difference in the micro climate

    1. Thanks for your comments Keith. Agreed – nothing better than standing under a forest canopy.

      Glad you found this article useful.

      Warm regards,

      Paul

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