(Arboricultural-styled) 'Fact of the Day'

[Kveldssanger]

02/09/15. Fact #21.

 

Nice and short one (plenty of room for thinking for those reading)...

 

Trees need eight things to survive:

 

1. energy

2. space to grow

3. water

4. essential elements

5. concentrations of factors

6. time

7. temperature

8. genetic code

 

As trees cannot just get up and walk away from a site and choose where they want to go, they must adapt or die.

 

When one of the eight factors is compromised, the others suffer too - to varying extents.

 

Source: Shigo, A. (1986) A New Tree Biology. USA: Shigo and Trees Associates.

[daltontrees]

I'm merely observing that beech 'can' regenerate, not that it can regenerate well/commercially.

 

.

 

David, excuse my clumsy delivery style, Gary is so much more diplomatic. But I will blunder on as I usually do, please don't be put off keeping up the debate.

 

Beech sprouts from wide stumps, but it (in my purely direct experience) doesn't last and so it doesn't regenerate into a viable tree. A bud popping out from behind the bark rather than through it might not have a complete bark cambium connection to the stool. I am working aeay form home these days and don't have access to my library or to the few local examples on beech stumps I know of, so I can't really research my amateur theory just now. Maybe someday soon...

[kevinjohnsonmbe]

02/09/15. Fact #21.

 

Nice and short one (plenty of room for thinking for those reading)...

 

Trees need eight things to survive:

 

1. energy

2. space to grow

3. water

4. essential elements

5. concentrations of factors

6. time

7. temperature

8. genetic code

 

As trees cannot just get up and walk away from a site and choose where they want to go, they must adapt or die.

 

When one of the eight factors is compromised, the others suffer too - to varying extents.

 

Source: Shigo, A. (1986) A New Tree Biology. USA: Shigo and Trees Associates.

 

 

What is meant by concentrations of factors?

[Kveldssanger]

I am not actually too sure. Perhaps it means it needs specific measures of all other 7 (or 5, sans time and genetic coding)? Shigo didn't seem to elaborate.

[Kveldssanger]

03/09/15. Fact #22.

 

When cable installation works were being undertaken in the London Borough of Havering during the early to mid nineties (started in 1991, and finished by winter of 1993/94 I believe), a survey was undertaken to ascertain damage caused by the trenching works.

 

As a precursor, the installation company (Bell Cable Ltd) stated they had a "tree protection policy". NJUG guidance states roots over 25mm diameter should be protected (as it is poor practice to not do so - unless there is absolutely no means of reconciling the root's presence, one would expect).

 

So when the 1,154 mature trees that could potentially have been impacted by the trenching were surveyed, the surveyors found that:

 

1. Over 90% of all trees had at least one root of greater than 25mm severed

2. Over 20% had one or more roots severed of 100mm+ diameter

3. The largest root severed was 0.5m in diameter

 

This meant that:

 

1. 6% (68) trees had to be felled due to the severe risk of retaining them

2. A further 17% (198) had to be crown reduced to lessen wind-throw potential - this number would have increased by another 300 had some trees not been pruned as part of the LA's cycle of maintenance at the time of cable installation

 

Following the presentation of results, Bell Cable Ltd (the company that installed the cables) agreed to pay "substantial compensation" to the LA, including full costs of the investigation, remedial pruning works, felling, three replacement trees for each tree lost, and aftercare costs due to "the loss in amenity value".

 

Conclusions (stated at the time):

 

1. utilise trenchless technology

2. hand-dig around larger roots if trenchless technology isn't an option

3. LAs should monitor the situation more closely

 

Source: Crane, B. (1997) Damage to Tree Roots by Cable Trenching: a Case Study. In Claridge, J. (ed.) Research for Amenity Trees No. 6: Arboricultural Practice – Present and Future. UK: HMSO.

Edited September 3, 2015 by Kveldssanger

[tree-fancier123]

What is meant by concentrations of factors?

 

could be Plant Growth Factors: Plant Hormones

[Gary Prentice]

 

I'm going to have to go and read a book to complete my daily CPD quota:thumbdown:

[Kveldssanger]

Hahaha steady on, it's not midnight yet!

[Kveldssanger]

04/09/15. Fact #23.

 

Dedicated to Gary (impatience is a virtue!).

 

One of my previous facts detailed the life processes of wood-decay fungi, though I'm interested in moving off at a slight tangent with that train of thought to explore the periphery of unspecialised parasites and their relationship with very young seedlings.

 

Seedlings, until a certain age (species-specific, in part, though also driven by environmental conditions - may be from 5 days to 2+ weeks), lack the 'mature' tissue and resistance to pathogens that established ones have (this occurs when pectin begins to convert to calcium pectate within cell walls). This means seedlings are susceptible to unspecialised opportunists, particularly those within the soil.

 

Depending upon the extent of soil-based inoculum, seedlings may in fact be killed before they even emerge from the soil (high inoculum potential). If the inoculum base is lower, seedlings may instead be killed post-emergence. In such instances, where localised humidity is high due to an abundance of seedlings creating a humid micro-climate and high rainfall (or artificial watering), fungal mycelium may spread across the surface from hypocotyl to hypocotyl - such rapid spread is aided by better aeration when compared to soil aeration. Such a concept is termed 'damping-off' disease.

 

Source: Garrett, S. (1970) Pathogenic Root-Infecting Fungi. UK: Cambridge University Press.

[Kveldssanger]

05/09/15. Fact 24.

 

This one isn't wholly arb' related, though is to some extent (with regards to trees that flower and provide a nectar source for insects, including bees). I think it is absolutely worth the mention though, given how important ecosystem health is on the whole, and how the arb' industry and related industries can directly aid with insect population levels in particular.

 

The paper being referenced is currently in press, and the source I used for this was Russia Today's website (linked here). Instead of paraphrasing the article, I will quote it all below - the message is short and clear, already.

 

Bumblebees sickened by an intestinal parasite are apt to visit flowers containing nectar and pollen that have a medicinal effect, a new study reports, indicating the current decline in the bee population could be abated through beneficial plants.

 

Iridoid glycosides, or secondary metabloites found in floral nectar, reduce common parasites in bees, previous research has found. In this case, scientists from the University of Vermont, Dartmouth College, and the University of Colorado-Boulder increased concentrations of two iridoid glycosides – aucubin and catalpol – in turtlehead, a wetland plant frequented by bees in eastern North America. Some plants were given high volumes of iridoid glycosides, while the other half's iridoid glycosides were diluted with sugar water.

 

Parasitized bees -- afflicted with reproduction and foraging complications -- preferred the flower with the highest iridoid glycoside concentrations, the researchers found. Their results are being published in the journal Ecology.

 

"We show that bees might be able to self-medicate, altering their foraging behavior when parasitized so as to maximize their consumption of beneficial plant secondary metabolite compounds," said senior author of the study, Rebecca Irwin, a faculty member at North Carolina State University who was formerly with Dartmouth, according to phys.org.

 

The research team also found that bees would carry more pollen to other flowers from plants with the highest concentrations of nectar iridoid glycosides.

 

"Secondary metabolites are commonly present in floral nectar and pollen, yet their functions are not well understood," said the study's lead author Leif Richardson, a former Dartmouth student now with the University of Vermont. "In this study, we show that these compounds could influence plant reproduction via complex suites of interactions involving not only pollinators but also their natural enemies."

 

The numbers of bees, vital to the pollination process, are dwindling across the world thanks to habitat destruction, pesticide use, and disease. In May, the US Environmental Protection Agency announced new regulations on pesticide use that seek to protect managed bee populations during certain periods of the year.

 

The proposal is part of the Obama administration's National Strategy to Promote the Health of Honey Bees and Other Pollinators. The administration wants to spend upwards of $82.5 million on honeybee research in the upcoming budget year, more than double the current allocation of $34 million.

 

Source: Richardson, L., Bowers, M., & Irwin, R. (2015) Nectar chemistry mediates the behavior of parasitized bees: consequences for plant fitness. Ecology. In press.