Lichens

[mrtree]

Be careful with the sampling. I have seen hatchets used to take samples from trees.

[David Humphries]

Theres a reason silver backs dont climb trees! take the hint! and remember trees are onlt 4times stronger than they need be for "usual circumstances" you might be considered an "unusual load":laugh1:

 

 

 

guess it's the added grey matter in me noggin, to which you refer

 

 

 

 

 

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[David Humphries]

Be careful with the sampling. I have seen hatchets used to take samples from trees.

 

have spoken to the prof already as to what I would find acceptable.

 

 

 

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[mrtree]

The natural history museum has an online lichens-on-twigs identification key

 

start here

 

A guide to lichens on twigs - The Natural History Museum

[BenR]

David, if that is the OPAL study, it is very similar to the method I used for my study.

 

Do you have the pdf? I think you can download it somewhere. I think that method just uses easily identified indicator species. If you can't find it online and you need/want it let me know and I can email it to you. When you get up the tree maybe consider sampling from different heights in the canopy. I tended to find that different species were at the top from the bottom of the tree. However, most of my sampling was done in woodlands, rather than on trees standing alone in full light where the same amount of light gets to the bottom as the top.

 

Sounds really interesting. My guess would be pollution tolerant lichens around the edges of the heath and perhaps slightly more tolerant ('intermediate species' I think they are called in the survey) towards the centre of the heath.

 

Please keep us updated!

[David Humphries]

Hi Ben, thanks for that.

 

But tbh, it's not really my gig, it's the local school & History Museums, I've just put some 'vertical' thought to it & offered our services.

 

Not entirely sure if they are going to take us up or not.

 

Have a hard copy of the Opal survey here in the office.

 

 

Will update for sure.

 

 

 

 

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[BenR]

Hi Ben, thanks for that.

 

But tbh, it's not really my gig, it's the local school & History Museums, I've just put some 'vertical' thought to it & offered our services.

 

Not entirely sure if they are going to take us up or not.

 

Have a hard copy of the Opal survey here in the office.

 

 

Will update for sure.

 

 

 

 

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Any updates on this little study David? Was that "unusual load" too much for the lichens to bear?

[David Humphries]

Any updates on this little study David? Was that "unusual load" too much for the lichens to bear?

 

Hasn't kicked off yet Ben.

 

Will update when I know more

 

 

 

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[Fungus]

Bark pH varies between tree species, ie. pines and oak are acidic and maples and elms are basic. Bark pH also varies with age and growing conditions (high rain fall can leach nutrients from bark and move pH towards basic). Lichens have certain preferences and pH is one preference we can easily identify.

 

And then there is the phenomenon of both "clean air" indicators and polluted air tolerant lichens on the same tree, where you find representatives of the indicators of clean air on the side of the tree out of the most dominant wind direction and the pollution (ammonia, nitrogen oxides, sulphur dioxide) tolerant lichens, such as Xanthoria's, on the side of the tree, which is most "hit" by winds from the prevailing wind direction.

[BenR]

And then there is the phenomenon of both "clean air" indicators and polluted air tolerant lichens on the same tree, where you find representatives of the indicators of clean air on the side of the tree out of the most dominant wind direction and the pollution (ammonia, nitrogen oxides, sulphur dioxide) tolerant lichens, such as Xanthoria's, on the side of the tree, which is most "hit" by winds from the prevailing wind direction.

 

I have also seen in certain lichen papers, the suggestion that the species composition on the trunk may be more representative of past pollution conditions and twig lichen communities on the same tree may be more representative of recent pollution conditions because the thalli are smaller thus started to grow later than some of (in some cases) the much larger thalli of lichens on the trunk. Interesting subject, studied it for my dissertation. They are so sensitive to so many variables and external influences. It makes it very difficult to explain why which lichens are where they are and why.