(Arboricultural-styled) 'Fact of the Day'

[Kveldssanger]

...so it's that time of year again when pollen starts getting everyone annoyed - noses clog up more readily than the junctions around the M25 at 8.30AM, eyes eject enough liquid to flood the Mississippi basin, and you could power the country on anger alone for a good two weeks...

 

...yeah no it's not that time of year, but alas.

 

09/11/15. Fact #74.

 

Some people suffer from asthma or react otherwise adversely to tree pollen, which can lead to increased hospitalisation and medical care bills. The ill-health brought about by tree pollen can also bring about a drop in productivity of those affected, given time off of work may be necessary. In addition to this, the principal problem for urban residents during a survey undertaken on urban street trees was that of allergies, which indicates the potential scale of the issue.

 

Sources:

 

Alcázar, P., Cariñanos, P., De Castro, C., Guerra, F., Moreno, C., Domínguez-Vilches, E., & Galán, C. (2004) Airbone plane-tree (Platanus hispanica) pollen distribution in the city of Cordoba, South-western Spain, and possible implications on pollen allergy. Journal of Investigational Allergology and Clinical Immunology. 14 (3). p238-243.

 

Dales, R., Cakmak, S., Judek, S., & Coates, F. (2008) Tree pollen and hospitalization for asthma in urban Canada. International Archives of Allergy and Immunology. 146 (3). p241-247.

 

Lohr, V., Pearson-Mims, C., Tarnai, J., & Dillman, D. (2004) How urban residents rate and rank the benefits and problems associated with trees in cities. Journal of Arboriculture. 30 (1). p28-35.

 

Lovasi, G., O’Neil-Dunne, J., Lu, J., Sheehan, D., Perzanowski, M., MacFaden, S., King, K., Matte, T., Miller, R., Hoepner, L., Perera, F., & Rundle, A. (2013) Urban tree canopy and asthma, wheeze, rhinitis, and allergic sensitization to tree pollen in a New York City birth cohort. Environmental Health Perspectives. 121 (4). p494-500.

Edited November 9, 2015 by Kveldssanger

[Gary Prentice]

 

Gary, I couldn't understand your equation "variable fluorescence- Fv= Fm¬-F0". Is there wrong symbol in there? Should it be "variable fluorescence- Fv= Fm-F0"?

 

I'll look up my original work to see if something went wrong in the copying and pasting, although I suspect that it was typo in that work.

 

I've an awful feeling that I'm also going to have to go back and read everything I read to write the assignment to clarify this:sneaky2:

[Kveldssanger]

I had a fact posted but there was a 'database error' and the post didn't save. Will post it tomorrow!

[Steve Bullman]

sorry about that

[daltontrees]

I had a fact posted but there was a 'database error' and the post didn't save. Will post it tomorrow!

 

Must have been too long! Keep 'em bite-sized if you will.

[tree-fancier123]

pollen seems to make my asthma worse, fine with inhalers most of the year, then end of June through July wheezing like an old man, steroids seem to be the most effective thing for those type of allergies at the moment, other than avoidance.

 

Quote from Bob Watson's book, 'The longest time an evergreen leaf could potentially live is four to five years, as this is the maximum life span of leaf cells'

 

So if a yew etc can live for a thousand years or more, a single leaf cell in the tree won't have been around since the early days.

[Kveldssanger]

12/11/15. Fact #75.

 

In temperate regions of the world, the fruits and seeds of most tree species will ripen during the autumn and early winter, and this is down to, principally, the fact that the growing season is limited to only particular months of the year. Tropical regions do however also demonstrate seasonality, with regards to the ripening of fruits and seeds of constituent species. Ultimately, the phenology of each particular species, and variations also between a single spcies, determines exactly when ripening will take place.

 

Interestingly, the manner in which a species will disperse its seed, in part, determines when the fruit and seeds will ripen. For example, deciduous trees that rely on wind dispersal will have their seeds ripen during very dry periods of the growing season, as the desiccation of seed and its subsequent 'mobility' is optimal under such dry conditions.

 

Conversely, tree species that rely on animals to consume their fruits and then disperse the seeds elsewhere will have their fruits ripen during the wetter months of the growing season. In fact, plants in the USA that produce fruits will normally have their fruits ripen during the period where mass bird migration is taking place (during autumn). Of course, this trend is not necessarily true across the board, as Amelanchier spp. and Prunus serotina will ripen during the summer, though their means of seed dispersal is reliant upon mammals and non-migratory birds.

 

Fruits that ripen during autumn are normally of high nutritional value, and are eaten in abundance by migratory birds as a result. This increases the chance of successful seed dispersal.

 

Source: Sedgley, M. & Griffin, A. (1989) Sexual reproduction of tree crops. UK: Academic Press.

[Kveldssanger]

pollen seems to make my asthma worse, fine with inhalers most of the year, then end of June through July wheezing like an old man, steroids seem to be the most effective thing for those type of allergies at the moment, other than avoidance.

 

Quote from Bob Watson's book, 'The longest time an evergreen leaf could potentially live is four to five years, as this is the maximum life span of leaf cells'

 

So if a yew etc can live for a thousand years or more, a single leaf cell in the tree won't have been around since the early days.

 

Thanks for this. I knew I read that leaf factoid somewhere before! Forgot where, but now I know.

 

A lot of people suffer from grasses with regards to asthma and hayfever.

[Kveldssanger]

12/11/15. Fact #76.

 

Adventitious buds are capable of forming on many woody plant species, and are borne from parenchyma tissues not directly associated with the apical meristems, nor is their formation dictated by the prevailing 'phyllotactic' qualities of the woody plant (phyllotactic = leaf arrangement).

 

When pruning, we may often state that many of the subsequent sprouts are adventitous in nature. Zimmerman & Brown suggest the opposite, and suggest that many of the sprouts are borne of pre-formed but suppressed buds that track just beneath the periderm.

 

Most adventitious buds, they also state, are formed in the bark cambium (or cork cambium / phellogen, as it is otherwise called).

 

Of course, once the adventitious sprouts are borne, they must make contact with the tree's vascular system, else they will die.

 

Source: Zimmerman, M. & Brown, C. (1971) Trees: Structure and Function. USA: Springer.

[Kveldssanger]

14/11/15. Fact #77.

 

When we think of hollowing (or hollow) veteran or ancient trees, oft is it suggested that aerial roots will utilise the mineralised nutrients, provided through the decay of the tree's own heartwood structure by fungi and bacteria, to aid with life processes. However, the presence of aerial roots may be over-stated.

 

The author here suggests that aerial root formation (from undifferentiated cambial cells) requires specific conditions - namely, poor light conditions and high levels of localised humidity. Therefore, where these conditons are not present, internal aerial root formation is unlikely to occur. This almost certaily means the tree, where such conditions are lacking, will be unable to re-uptake such mineralised nutrients, as to do so it would need to grow fibrous roots from the periphery of the root crown (where roots are not covered by a corky bark layer) all the way to the centre of itself.

 

Perhaps, therefore, the mineralised matter is more likely to become useful to future generations, with the veteran / ancient tree acting as a 'nurse' through the provision of its own nutrients to younger, more vigorous, individuals of the future.

 

Source: Watson, B. (2006) Trees: their use, management, cultivation, and biology. India: The Crowood Press.