(Arboricultural-styled) 'Fact of the Day'

[Kveldssanger]

05/09/15. Fact #26.

 

Yes, another one. Nice and short!

 

The terminal bud of the central leader of a tree will usually be the dominant one, and thus will extend to form a shoot (and eventually become a branch / continue the trunk). In some species however, this apical dominance is not as rife, and lateral buds will grow rapidly to form long lateral branches.

 

Take beech in a woodland setting, for instance. As it grows in the under-canopy, it will adopt such aforementioned characteristics, and develop a broad crown with long laterals. However, once canopy space is freed up (triggered by a mortality event to a former canopy tree(s) such as wind-throw, general old age, or otherwise), the 'leader' will grow rapidly and the tree will principally grow vertically in place of laterally.

 

Such long laterals are subsequently shed due to the lack of need in retention, and this brings about trunk defects around 1-4m above ground level. And so, decay may begin...

 

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

[Gary Prentice]

That seems counter-intuitive from an evolutionary perspective! A trait that brings about decay, potentially an early demise, doesn't seem like a good idea and I would have thought would have been 'bred out'.

 

Not disagreeing with the fact, just thinking about it.

[tree-fancier123]

That seems counter-intuitive from an evolutionary perspective! A trait that brings about decay, potentially an early demise, doesn't seem like a good idea and I would have thought would have been 'bred out'.

 

Not disagreeing with the fact, just thinking about it.

 

Or, the long laterals trait may have emerged and endured because it allows most of the beech etc to reach sexual maturity in conditions of sparse light. Those times when the surrounding canopy is lost in woodland could affect only a small percentage of the poplulation, so the wounds and consequent pathogen induced demise don't matter.

[Gary Prentice]

Sounds a reasonable explanation, thank you.

[Kveldssanger]

Gary, a few sources I linked here on beech a week or so ago explain this strategy somewhat.

 

Remember it may only potentially cause significant decay to ensue. Branch attachments usually have good 'barriers' at the base, within the protection zone. Proper cladoptosis processes for the lower branches would reduce risk, assuming specialised opportunists didn't latch-on to the senescing branch and assimilate into the branch structure.

[Gary Prentice]

Thanks, I think I downloaded them, but haven't got round to reading them yet.

[Kveldssanger]

06/09/15. Fact #27.

 

Increasingly, research is suggesting that fertilisation is, by-and-large, an unnecessary step in the transplanting process. Backfilling exclusively with native soil has shown to have no significant detraction in root growth over the two-year period following transplanting, when compared to soil that was amended with fertiliser. In the UK, fertilisation is in fact largely not required - soil conditions are typically of acceptable standards in their natural state.

 

Ideally-speaking, soil analyses should be a necessary step in the planning phase of the wider transplanting process. One must understand the current state of the soil before seeking to amend the very same soil, as present properties will influence the dosage (and frequency of applications) needed to bring the soil up to an acceptable standard; assuming it is not at an acceptable standard, of course. And even then, some research papers indicate that fertiliser application has no lasting (or significant) benefits.

 

Care must also be exercised in applying nitrogen-based fertilisers to soils, as application can disrupt the root-mycorrhizal fungi symbiosis; as is it critical that fertilisers are not applied after mid July (as a guideline) because the application will encourage soft, 'sappy' growth that will likely not have time to mature (lignify) before autumn, thus increasing the risk of frost damage if the oncoming winter is bitter.

 

Further to this, the application of fertiliser is mostly ineffective if irrigation is not regular and sufficient, due to the root system being largely unable able to uptake the additional nutrients until the root system has adequately developed into the surrounding soil. Research suggests that only 2-5% of nitrogen applied at the time of planting is ever taken up by the plant.

 

Sources:

 

Davis, M. (2015) A Dendrologist's Handbook. UK: The Dendrologist.

 

Day, S., Bassuk, N., & van Es, H. (1995) Effects of four compaction remediation methods for landscape trees on soil aeration, mechanical impedance and tree establishment. Journal of Environmental Horticulture. 13 (1). p64-71.

 

Day, S. & Harris, J. (2007) Fertilization of red maple (Acer rubrum) and littleleaf linden (Tilia cordata) trees at recommended rates does not aid tree establishment. Arboriculture & Urban Forestry. 33 (2). p113-121.

 

Ferrini, F. & Baietto, M. (2006) Response to fertilization of different tree species in the urban environment. Arboriculture & Urban Forestry. 32 (3). p93-99.

 

Ferrini, F., Giuntoli, A., Nicese, F., Pellegrini, S., & Vignozzi, N. (2005) Effect of Fertilization and Backfill Amendments on Soil Characteristics, Growth, and Leaf Gas Exchange of English Oak (Quercus robus L.). Journal of Arboriculture. 31 (4). p182-190.

 

Gilman, E. (2004) Effects of amendments, soil additives, and irrigation on tree survival and growth. Journal of Arboriculture. 30 (5). p301-310.

 

Harris, J., Day, S., & Kane, B. (2008) Nitrogen fertilization during planting and establishment of the urban forest: a collection of five studies. Urban Forestry & Urban Greening. 7 (3). p195-206.

 

Hipps, N. & Nicoll, F. (1997) Preconditioning Trees to Improve Outplanting Performance. In Claridge, J. (ed.) Research for Amenity Trees No. 6: Arboricultural Practice – Present and Future. UK: HMSO.

 

Rivenshield, A. & Bassuk, N. (2007) Using organic amendments to decrease bulk density and increase macroporosity in compacted soils. Arboriculture & Urban Forestry. 33 (2). p140-146.

 

Smalley, T. & Wood, C. (1995) Effect of backfill amendment on growth of red maple. Journal of Arboriculture. 21 (5). p247-250.

 

Watson, G. & Himelick, E. (2013) The Practical Science of Planting Trees. USA: International Society of Arboriculture.

[daltontrees]

Without reading all the papers cited in this fact of the day, I am tempted to suggest that there is a good reason to fertilise with mulch or manure that hasn't been mentioned. I am speaking now from direct and real experience of a current situation.

 

The improvement of soil by adding organic material is beneficial for worms. They feed on this material and their daily vertical travel through soil is immeasurably beneficial for most plants including trees. Drainage, gas exchange and porosity for root development a re a few of the direct immediate benefits. The creation of a good humic content is less direct but very valuable. Within a year or two the tree can through leaf shedding and natural mulching and the normal recycling of short-term rootlet develop a steady equilibrium of worms and worm food, but unless the soil used for backfilling already contains worms and enough organic material to sustain them for a couple of years then the tree will lose all the benefits of wormy soil.

 

So it's nothing to do with fertilising to feed the tree, it's to do with feeding the things that help the tree until it settles in. Soil without happy worms is almost dead, and that's not good for trees in it.

 

Good point about fertilising late in the season. I'm not a fan of chemical fertilisers any time of year unless the environs of the tree are cheating it of recycling its own nitrates. In particular removing fallen leaves. The ideal seems to be to fertilise at the very time when last-year's leaf falll will have degraded and gone into the soil for uptake in early spring.

[Kveldssanger]

Great shout - absolutely agree.

 

For the worms!

 

(seriously)

 

I also considered, when reading about planting on old landfill sites with compacted ground, whether 'inoculating' an area with a huge mass of worms would be feasible. Subsoil / rip the area, add some manure, and quite literally ferry in a load of earthworms in boxes.

[daltontrees]

Great shout - absolutely agree.

 

For the worms!

 

(seriously)

 

I also considered, when reading about planting on old landfill sites with compacted ground, whether 'inoculating' an area with a huge mass of worms would be feasible. Subsoil / rip the area, add some manure, and quite literally ferry in a load of earthworms in boxes.

 

Make sure you are using Lumbricus terrestris, the compost worms only eat decaying vegetation but Lumbricus eats soil. They reproduce every 3 months, a handful every few square metres is all you need. It's a start, but sounds like decompaction and organic matter will be needed too. Possibly overseeding with clover for a season then turn it in when prepping the site, the nitrates and porosity are really beneficial.