(Arboricultural-styled) 'Fact of the Day'

[tree-fancier123]

you answered my question about summer branch drop while I was typing it!

[Kveldssanger]

73 that's going back a bit

is cladoptosis connected with summer branch drop?

 

would be interested if you've found any literature on hazard beams, apart from Lonsdale

 

customer has a big split in white pop limb, suggested taking some weight off above, she said leave it for now, been like that for years. Still in leaf above, went through gales like it etc, but the hazard beam doesn't inspire confidence visually.

 

In regards to summer branch drop - maybe. See the part about Ohio. The source cited by the book is however from 1902 (see here)!

 

Hazard beams, as long as they remain 'moist' are less of a risk (by-and-large, though not always). If the wood dries out, the friction that builds up due to a lack of lubrication means failure is more of a risk.

 

Hazard beams also depend on wood properties. Willow or horse chestnut - get them down, if the target area is bad. On oak, I have observed hazard beams in huge limbs that appear to have originated some time ago.

 

Of course, ain internal fracture is exactly that, and that's not 'good' (from a safety perspective). Obviously one must weigh up the pros and cons of leaving it / removing it.

[tree-fancier123]

thanks for the reply, thought there must be plenty of trees that have had them for years, will try to remember about willow and horse chestnut if I come across any in them

[Kveldssanger]

I don't have a source for horse chestnut, though from speaking with a colleague he remarked that they a tendency to drop big limbs. I know in Lonsdale's book he used a HC in the example for hazard beams in one of the pictures.

 

I have seen a cracking (no pun) hazard beam in a willow and it has been there for years, however. It's flippin' wide, too. Considering the weight of the limb, I did laugh when, in a wind storm, another branch failed and not that one!

 

If you're interested, 'A Handbook of Hardwoods' has details regarding the wood properties of many trees. There is another edition for softwoods too, entitled 'A Handbook of Softwoods', though it's a lot smaller as it covers fewer species.

 

[ame=http://www.amazon.co.uk/gp/product/B00NQ6BN7E?keywords=a%20handbook%20of%20hardwoods&qid=1443868017&ref_=sr_1_12&sr=8-12]A Handbook of Hardwoods: Amazon.co.uk: HMSO: Books[/ame]

Edited October 3, 2015 by Kveldssanger

[Kveldssanger]

Links to past facts:

 

Fact 1 – A history of coppice woodlands

 

Fact 2 – Branch failures in wind storms

 

Fact 3 – What is bark?

 

Fact 4 – A history of man trying to afforest the Black Country, UK

 

Fact 5 – Mycorrhizae-facilitated communication between individuals

 

Fact 6 – Root severance and tree stability

 

Fact 7 – Development cycle of wood-decay fungi

 

Fact 7.5 – A brief history of Ancient Woodland in the UK

 

Fact 8 – Coal deposits of the past

 

Fact 8.5 – Europe's lack of tree diversity

 

Fact 8.75 – The resource demand of trees

 

Fact 9 – Endo- and ecto-mycorrhizal fungi

 

Fact 10 – An overview of cladoptosis

 

Fact 11 – Trees can help with human recovery

 

Fact 11.5 – Aborting fruit to improve tree vigour

 

Fact 12 – Vigour and vitality

 

Fact 13 – Photosynthesis

 

Fact 14 – How residents perceive trees

 

Fact 15 – Bid cherry-mediated competition between two of its principal herbivores

 

Fact 16 – Coppicing ability and suckering

 

Fact 17 – Concrete and asphalt as mulch?

Fact 18 – Root penetration of sewer pipes

 

Fact 19 – So exactly how small are micro-organisms?

 

Fact 19.5 – Bat-shaped soil amoebae

 

Fact 20 – Arbuscular mycorrhizae benefits

 

Fact 21 – What do plants need to grow?

 

Fact 22 – Utility installations and root pruning issues

 

Fact 23 – Seedlings and susceptibility to pathogens

 

Fact 24 – Bumblebees self-medicating!

 

Fact 25 – Doesn't exist because I cannot count above 24.

 

Fact 26 – Apical dominance

 

Fact 27 – Fertilisation – is it good or bad?

 

Fact 28 – The Black Poplar

 

Fact 29 – Sporophore (fungal bracket) formation

 

Fact 30 – Trees to regulate temperature

 

Fact 31 – Honey fungus sporulation

 

Fact 32 – Saproxylic insects

 

Fact 33 – A video on photosynthesis

 

Fact 34 – The pale tussock moth

 

Fact 35 - Białowieża National Park, Poland

 

Fact 36 – Reproductive growth in plants

 

Fact 37 – How plants detect light and the birth of pigments

 

Fact 38 – A more detailed look at light and photosynthesis

 

Fact 39 – Adaptive growth in response to mechanical stimuli

 

Fact 40 – Gravitropism / geotropism

 

Fact 41 – Telepathic plants

 

Fact 42 – Vernalisation

 

Fact 43 – Phenotypic variation as a means of compartmentalisation

 

Fact 44 – Responses by plants to herbivory

 

Fact 45 – Monoecious and dioicous trees

 

Fact 46 – Insects and flowers

 

Fact 47 – Trees and crime rates

 

Fact 48 – Branch shedding in more detail

 

Fact 49 – Factors that influence cladoptosis

 

Can a mod please edit my first post and permalink this post in the first post, so people can have easy access to this index? Cheers.

Edited October 3, 2015 by Kveldssanger

[Kveldssanger]

Turned out to be a busy day in the end - will get a fact done from The New Sylva tomorrow. So much text, I will have a hard time knowing where to look. I did spot a cool fact on oak breeding programmes, which I may write about.

[Paul Melarange]

Thanks for the facts on Cladoptosis Chris, really interesting 👍

[Kveldssanger]

5/10/15. Fact #50.

 

The effects of elevated ground-level ozone, CO2, and other gaseous compounds within the atmosphere are well-documented on the whole.

 

Perhaps a more obscure factoid regarding elevated ground-level ozone and CO2 is that of

elevated levels, but still levels that may occur naturally (and more readily as pollution continues), disrupting the 'communication' (chemical) between plants and insects.

 

For instance, elevated levels of CO2 (not ambient levels) adversely impacted upon plant communication (and subsequent recruitment) with carnivorous insects that predate upon herbivorous insects defoliating the plant. Elevated ground-level ozone, similarly, disrupted communication of plants with wasps, by rapidly oxidising chemical secretions (volatiles) by the plant before they could be adequately 'received' by the wasp.

 

Perhaps research into such changing atmospheric conditions should therefore more readily consider the impacts on plant volatile emissions, as we move into a more polluted future.

 

Sources:

 

Karban, R. (2015) Plant Sensing & Communication. USA: University of Chicago Press.

 

Pinto, D., Nerg, A., & Holopainen, J. (2007) The role of ozone-reactive compounds, terpenes, and green leaf volatiles (GLVs), in the orientation of Cotesia plutellae. Journal of Chemical Ecology. 33 (12). p2218-2228.

 

Vuorinen, T., Nerg, A., Ibrahim, M., Reddy, G., & Holopainen, J. (2004) Emission of Plutella xylostella-induced compounds from cabbages grown at elevated CO2 and orientation behavior of the natural enemies. Plant Physiology. 135 (4). p1984-1992.

[Kveldssanger]

5/10/15. Fact #51.

 

Locally-sourced hawthorn seed has shown, through a number of field trials, to flush later, be thornier, more resistant to mildew, and more vigorous on upland sites than seed sourced from the Continent - to the point that landowners, where new hedges are being created, should source from local specimens. This will help ensure the hawthorn remainds very hardy and prosperous, going forward.

 

The practice of local seed-sourcing also is highly important for associated wildlife. The approprite phenology and flowering habits of hawthorns, as well as their thorny character, provide insects and birds with viable habitat respectively.

 

Source: Hemery, G & Simblet, S. (2015). The New Sylva: A Disource of Forest & Orchard Trees for the Twinty-First Century. Spain: Bloomsbury.

[Kveldssanger]

6/10/15. Fact #52.

 

An earth-shattering fact for today. Didn't realise this myself...!

 

The plural of Sorbus is (at least for the English language) Sorbi. I am unsure whether in has any basis in general nomenclature, however.

 

Source: Watson, B. (2006) Trees - Their Use, Management, Cltivation, and Biology. India: Crowood Press.