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Several British news reports (including the BBC "Bleeding trees") describe trees issuing red blood-like liquid when cut.

Once the stuff of myth and legend, modern day eye-witnesses now catch on camera blood pumping from the trunks of trees.

This is linked to biblical accounts (Book of Ezra).

Have any of these instances been validated? Examined by reputable botanists and established as not likely to be hoaxes? I wouldn't expect tabloid speculation from the BBC, but have not found any corroborating sources.

Edit:

Rjzi helpfully points out that dragon trees are known for red sap. However, but the video is not exclusively about dragon trees (indeed, they're not mentioned). Yews are specifically mentioned, and unnamed trees in Australia with rough bark that does not seem to match the dragon tree. My question is, are there reputable accounts of trees not known for having red sap nevertheless appearing to bleed. E.g., perhaps there's a fungus known to gives tree sap a red color?

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    The only Book of Ezra that refers to a bleeding tree of any sort is "The Fourth Book of Ezra". This is not part of the Bible canon but an old apocryphal book.
    – user100487
    Feb 12, 2015 at 23:09
  • @user100487 In addition to being non-canonical it is a work of the apocalyptic genre, where it is typical to vest historical events with cosmic significance with hyperbolic symbols of destruction and recreation. Feb 14, 2015 at 18:52

2 Answers 2

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The Dracaena cinnabari (Socotra dragon tree or dragon blood tree) is well known for having a distinct red sap or resin and there are a number of other plants that also exhibit similar "Dragons's Blood". As noted in the Wikipedia article on Dragon's Blood:

The dragon's blood known to the ancient Romans was mostly collected from D. cinnabari, and is mentioned in the 1st century Periplus (30: 10. 17) as one of the products of Socotra. Socotra had been an important trading centre since at least the time of the Ptolemies. Dragon's blood was used as a dye, painting pigment, and medicine (respiratory and gastrointestinal problems) in the Mediterranean basin, and was held by early Greeks, Romans, and Arabs to have medicinal properties. Dioscorides and other early Greek writers described its medicinal uses.[3]

[3]: Casson, L. 1989. The Periplus Maris Erythraei. Princeton University Press, pp. 69, 168-170. ISBN 0-691-04060-5.

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  • But what about the biblical claim in the Book of Ezra? I figure it's bronze age goat herders not knowing crapola, so they made something up to explain an unusual phenomenon, but would be nice to see that addressed in your answer. :)
    – JasonR
    Feb 12, 2015 at 17:04
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    @user19555 Biblical claims are tough to address here since there is a degree of interpretation to the readings. Your best bet might be to try over Biblical Hermeneutics since if the Romans were aware of D. cinnabari it was likely known in biblical times as well. That doesn't mean they would have been referring to D. cinnabari in the relevant passages though.
    – rjzii
    Feb 12, 2015 at 17:09
  • That "resin" doesn't look like the red liquid which was pulsing/pumping out, in the video posted in the OP.
    – ChrisW
    Feb 12, 2015 at 17:13
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    i found some "sketchy" sites that say that trees that have alot of sap in them, can have their sap turn red if the water supply they are feeding off of has alot of rust/iron in it. so a normal tree could theoretically have red sap(i cant find any trees that gush though) also there havnt been any sources to confirm this.
    – Himarm
    Feb 12, 2015 at 17:22
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    @ChrisW: I agree that this tree does not appear to be the same species of tree as any of the examples shown in the video. However, the sap in the video appeared to be leaking out, not pumping out. The use of the term "pumping" seems to be hyperbole by the narrator, and I don't think it should be required of an answer.
    – Oddthinking
    Feb 13, 2015 at 0:50
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You can see quite a few videos on YouTube which show trees pumping out blood-coloured sap. They include videos cited by the BBC programme (Nature’s Weirdest Events) in the OP's question. However, from the looks of this report, the programme, after some generous speculation goes on to offer the following explanation:

And presenter Chris Packham added that it was by no means an isolated incident, with reports of ‘bleeding trees’ occurring across the world and everything from disease to ‘the supernatural’ being blamed.

The good news is that there does seem to be an explanation for the weird goings-on – with rising sap in the springtime apparently responsible.

‘The sap is at high pressure until the leaves open and begin to evaporate the water, any injury releases this pressure,’ Packham explained.

‘This apparent ‘bleeding’ can look distressing, but it may be the tree';s way of trying to heal.’

Here are some people of a scientific bent confirming that trees release sap to heal. As rjzii's answer notes, trees do exist with blood red sap.

Here is an image of the Marri tree of Australia leaking a red blood-like gum named Kino: Copious flow of kino from a wound near the base of the trunk of a Corymbia calophylla (Marri)

Here's a report in an Australian paper on a gum tree in NSW "bleeding" due to an attack by borers.

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  • The act of "bleeding" sap makes perfect sense; it's a liquid in the tree, cut it and it'll doubtlessly leak. It's the bloodlike redness of the sap which is striking. Is there any explanation for why trees would issue red sap, (other than the dragon tree, for which red sap is normal)?
    – user3150
    Feb 13, 2015 at 13:44
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    @JonofAllTrades It isn't only the Dragon Blood tree that leaks red sap. According to the linked article on 'Kino', the Eucalyptus genus of trees does the same. The article also states that the red colour is due to the presence of Phlobaphene in the gum.
    – user7920
    Feb 13, 2015 at 13:54

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