How do you tell the difference between coniferous trees ?
I should probably title this trying to understand conifers. What a minefield! For the last year or so I have attempted to get to grips with conifers. What is the difference between a fir and spruce, a tsuga and pseudotsuga, a cedar and larch and then pines, cypress, juniper and yew ….. Yikes! So how do you tell the difference between coniferous trees ?
Although only three native conifers in the UK, Scot’s pine, juniper and yew, there are tons throughout Europe. Of course, our three native conifers have all been used medicinally. Many of the European, and indeed worldwide, conifers are medicinal too. Naturally I am keen to learn more about them but first of all it would help to be able to identify them.
So … how do you tell the difference between coniferous trees ?
Tsuga sp. – hemlocks
First up I’ll have a look at the Tsuga species. More commonly known as hemlocks. To my knowledge they are all native of North America. I don’t believe any are European. However, I may be wrong there.
My little Collins British Tree Guide tells me there are ten species. I certainly haven’t actually met ten Tsuga species. They are in the Pinaceae family which includes cedars, firs, spruces, larches and of course, pines.
The photos of the Tsuga canadensis here were taken at the Aude arboretum. T. canadensis is more commonly known as eastern hemlock. I’ll use this species for descriptions.
What do I know or what have I learnt?
My little book recommends one should look at shape, shoots, colour and leaves to identify.
Tsuga species have a prominent peg. So what does that mean?
Well if we have a look at the close up of my photo of Tsuga canadensis you can, hopefully, see the leaves are coming out from a little sort of perch, or peg. The leaves also have a small stem, or petiole.
The leaves are short and flat. Dark green and shiny, or glossy, on the top. On the underside (see close-up) they are light green with two very visible white lines.
Leaves of this particular species are mostly pectinate. This means they are comblike. On the close up where they are nearer the tip they are less comblike. In the other image above you can see the lower leaves (needles) are indeed more comblike than those nearer the tip.
so … how do you tell the difference between coniferous trees within the hemlock species ?
As I said I don’t know many of the hemlock species but I have learnt a little about identification. If trying to differentiate between eastern hemlock and western hemlock (T. heterophylla) apparently the leaves of the western variety are less pectinate (comblike). Also the eastern hemlock twig is described pubescent. This means the twig has sort of short soft hair. Whereas the western hemlock twig is described wooly.
In addition, the western hemlock smells sour like the poisonous hemlock plant. The eastern hemlock is much fresher some suggest a pine or lemony aroma. Crush a leave to check.
Furthermore western hemlock is generally a taller tree with a single trunk and low sweeping branches. Other Tsuga species tend to have multi-trunks.
Finally the cones of Tsuga species are small, never more than 3cm. The eastern hemlock usually no larger than 1.8cm and the western hemlock around 2.5cm. The image of the cones shown here I took last year. It is a Tsuga species but I am unsure which species.
I have never used a Tsuga species medicinally and know little of its medicinal value. However, native American Indians apparently utilised it for its astringent and antiseptic properties.
Pseudotsuga menziesii – Douglas fir
Next up the Douglas fir. I love the cones of this tree. The foliage is described similar to a fir (Abies sp.). Commonly it is called Douglas fir but it is not a fir tree. Nor is it a hemlock (Tsuga sp.) hence the Pseudotsuga. Confused? Me too.
So … how do you tell the difference between coniferous trees that are not firs or hemlocks but have similarities to them ?
My little Collins book states there are 5 species of Pseudotsuga. It is evergreen like the hemlocks and firs. Native to North America.
However, whereas the Tsuga species have a prominent peg, neither Douglas fir (Pseudotsuga sp.) or indeed, actual firs (Abies sp.) do. So, no peg!
Leaves are soft, flexible and slender, unlike fir tree leaves (or needles). They have narrow white-green bands on the underside. Hence, Pseudotsuga. The French description above also describes them soft in addition to light green and shiny.
the cones …
And so to my favourite part, the cones. The cones of both the fir (Abies sp.) and the Douglas fir (Pseudotsuga sp.) are both larger than 3cm so larger than those found on a hemlock species.If you have a cone it is fairly easy to recognise it as a Pseudotsuga. First of all, if on the tree, cones are pendent i.e. they are hanging down. On a fir tree (Abies sp.) they are erect.
If you look at the photo I took of a cone at the Aude Arboretum you will see prongs protruding out. The French description at the top describes the cones as medium sized with thin scales between which are bracts.
My little Collins book describes this a three pronged snake’s tongue. Not liking snakes very much myself I prefer to think it is a friendly little critter trying to hide but his tail and two back legs are sticking out.
I have used Douglas fir essential oil. It has a pleasing crisp, fresh and uplifting aroma. As you might think it is useful for colds and sniffles. The freshness provides clarity.
I do remember reading that native American Indians utilised the tree medicinally by infusing young leaves. Occasionally resin was utilised. One action in particular springs to mind…. younger shoots worn in footwear apparently stops sweating feet and prevents athletes foot!
Finally a Douglas fir was at one time listed as the tallest tree in the UK. The tree was in the Caledonian forest in Scotland. Whether it is still the tallest tree I know not.
I guess the fir and the spruce, the cedar and larch and the rest of the coniferous trees will need to wait another day…