(Arboricultural-styled) 'Fact of the Day'

[Kveldssanger]

07/12/15. Fact #95.

 

Found something cool, so there is a fact today.

 

In a new study looking at the inter-connectedness of Pseudotsuga menziesii in an ectomycorrhizal sense, it was found that older trees had a discernible role in facilitating the growth of younger specimens via the shuttling of nutrients (sugars, etc), via the ectomycorrhizal network of, in this instance Rhizopogon vesiculosus and Rhizopogon vinicolor (more research is needed into links via other fungal species). The mycorrhizal network from these two species was found to, in one tree, provide links to 19 other trees of the same species - all within a 30m x 30m survey zone.

 

The interesting thing about this, the study states, is not only that it adds serious weight to the concept of a forest being an inter-connected cohort of trees that form, as Shgio put it, one 'larger' tree, but also the fact that this research identified connections via only a select few ecotmycorrhizal species. When one considers that there are many species of ectomycorrhizal fungi within an ecosystem, the fact that there are also many different species of tree and plant within an ecosystem, and the fact that ectomycorrhizae may shuttle resources between different species at different times of the year and under different circumstances, a seriously complex ecological matrix is born, by where removing or stressing one tree (particularly a larger, older one) will have identifiable impacts upon trees connected to it. The study also shows that ectomycorrhizal species massively benefit from this relationship, as much as the trees do, as their diversity across large age ranges means that they always have a role to play and will never become obsolete, assuming the ecosystem remains healthy and functional as is currently.

 

The below image, taken from the study paper, really drives the above points home. This is in the 30m x 30m zone surveyed. Now add in all other trees species, ectomycorrhizal species, and pan out to forest-level, and bask in the mental image produced. The intricacies of the natural world, and it's all going on right beneath our feet. Fascinating!

 

 

Source: Beiler, K., Durall, D., Simard, S., Maxwell, S., & Kretzer, A. (2010) Architecture of the wood‐wide web: Rhizopogon spp. genets link multiple Douglas‐fir cohorts. New Phytologist. 185 (2). p543-553.

Edited December 7, 2015 by Kveldssanger

[sloth]

I like this latest fact/post a lot

[Kveldssanger]

Same. That sort of stuff always leaves me in a state of awe. We're really just scraping the surface of how plant communicate, and what we're essentially seeing here is a peer-to-peer economy between plants. Take the following extract for example, with sources attached, from Simard (2009).

 

"In a study examining carbon transfer in mixed Douglas-fir plantations, Simard et al. (1997) showed that summer shading of Douglas-fir increased its sink strength and net carbon gain from carbon- and nutrient-rich paper birch source trees. The amount Douglas-fir received in deep shade was equivalent to 10% of its total carbon budget, an amount comparable to carbon investments in seed production. In a later study, Philip (2006) showed that shifts in interspecific source–sink relations over the growing season

reversed the direction of net transfer in spring and fall; that is, it occurred from Douglas-fir to leafless birch. She also found that the amount of two-way transfer increased over the growing season, when root and ECM fungus development were greatest (Philip, 2006), agreeing with an earlier study in maple forests by Lerat et al. (2002)"

 

So basically: trees take ('borrow') resources - and return the favour - when their donors need resources back. Quite literally a community of trees.

 

Sources:

 

Lerat, S., Gauci, R., Catford, J.G., Vierheilig, H., Piche, Y., & Lapointe, L. (2002) 14C transfer between the spring ephemeral Erythronium americanum

and sugar maple saplings via arbuscular mycorrhizal fungi in natural stands. Oecologia. 132, 181–187.

 

Philip, L. (2006) The role of ectomycorrhizal fungi in carbon transfer within

common mycorrhizal networks. PhD thesis, The University of British Columbia,

Vancouver, BC, Canada.

 

Simard, S. (2009) The foundational role of mycorrhizal networks in self-organization of interior Douglas-fir forests. Forest Ecology and Management. 258. S95-S107.

 

Simard, S., Perry, D., Jones, M., Myrold, D., Durall, D., & Molina, R. (1997).

Net transfer of carbon between ectomycorrhizal tree species in the field. Nature. 388. p579–582.

[Kveldssanger]

09/12/15. Fact #96.

 

The accumulation of toxic heavy metal ions within the soil, which may be brought about by acid rain, industrial pollution, or otherwise, is known to have negative impacts upon the ability for decomposers (fungi and insects) of an ecosystem to function properly. This leads to imbalances in nutrient cycling, litter decomposition, and productivity of the ecosystem, which in turn can impact upon vegetation life, and may lead to stresses developing that can increase in severity over the years.

 

Source: Pennanen, T., Perkiömäki, J., Kiikkilä, O., Vanhala, P., Neuvonen, S., & Fritze, H. (1998) Prolonged, simulated acid rain and heavy metal deposition: separated and combined effects on forest soil microbial community structure. FEMS Microbiology Ecology. 27 (3). p291-300.

[Kveldssanger]

11/12/15. Fact #97.

 

Juglans spp. will secrete a chemical called juglone, which impacts upon the growth of other constituent plant species of the rooting environment local to the walnut tree(s). This secretion of juglone is known as an allellopathic effect.

 

In a study that examined sensitivity of juglone by 16 different species of plant seedling, it was concluded that all 16 species tested suffered negatively as a result of the juglone. Shoot elongation and dry weight mass accumulation were impacted in all seedlings, whilst seed germination rate and radicle extension growth were impacted in only 6 species and 11 species, respectively. The greater the concentration of the juglone, the more marked the impacts - to the point that seedling death would occur when juglone concentrations reached high levels.

 

It was also determined that the impacts of allelopathy were greatest (adverse growth rate and other issues may manifest after only a few years) when young trees were located within the rooting environment of a mature walnut tree, and least impactful when seedlings grew up alongside walnut seedlings (where impacts may manifest only once the walnut trees reach a greater age - typically 12-25 years, according to a study of 41 different sites). It must be noted however that as the study only looked at visible impacts of juglone upon growth, there may be a period of many years prior where the impacts of juglone are apparent but simply not manifesting visually.

 

Soil quality may also impact upon the efficacy of allellopathic chemicals, such as juglone. Where soils drain poorly, and are of generally poor condition, allellopathic effects are more significant and occur more rapidly. On well-drained soils, the effects of juglone may not even manifest at any point.

 

Source: Rietveld, W. (1983) Allelopathic effects of juglone on germination and growth of several herbaceous and woody species. Journal of Chemical Ecology. 9 (2). p295-308.

[Kveldssanger]

13/11/15. Fact #98.

 

Been a little busy these last few days with assignments, though here's an interestic little one I first heard about earlier this year at Barcham.

 

When a horse chestnut is host (when is it not!?) to leaf miner (C. ohridella), injecting the tree with Emamectin benzoate, an insecticide, has shown to be nearly 100% effective after two seasons, and was done with full success in London during the Olympic Games 2012 preparations (trees were injected in place of being felled, and the leaf miner presence completely went away). Typically, only one injection is required no more than once every three years, in small dosages that are fast-acting.

 

Ultimately, an integrated pest management (IPM) approach, including biochar application, Emamectin benzoate root flare injections, and application of Agri-Fos (or other Potassium phosphate fertiliser) can nullify HCLM presence, as well as having theraputic effects for the tree (such as reducing stress levels); this is critical as it has been found that HCLM causes hosts to lose 40%, year on year, of its energy reserves. It is not a cosmetic problem.

 

Could this chemical therefore be utilised in the future more readily, or should be not be opting for chemical controls? Something worth considering.

 

Sources:

 

Burkhard, R., Binz, H., Roux, C., Brunner, M., Ruesch, O., & Wyss, P. (2015) Environmental fate of emamectin benzoate after tree micro injection of horse chestnut trees. Environmental Toxicology and Chemistry. 34 (2). p297-302.

 

Percival, G., Banks, J., & Keary, I. (2012) Evaluation of organic, synthetic and physical insecticides for the control of horse chestnut leaf miner (Cameraria ohridella). Urban Forestry & Urban Greening. 11 (4). p426-431.

 

Percival, G. & O'Callaghan, D. (2015) Pest and Disease Control [seminar]. Barcham. 1st July.

[daltontrees]

13/11/15. Fact #98.

 

When a horse chestnut is host (when is it not!?) to leaf miner (C. ohridella), injecting the tree with Emamectin benzoate, an insecticide, has shown to be nearly 100% effective after two seasons, and was done with full success in London during the Olympic Games 2012 preparations (trees were injected in place of being felled, and the leaf miner presence completely went away). Typically, only one injection is required no more than once every three years, in small dosages that are fast-acting.

 

 

Impressive, I wonder how much it costs?

[daltontrees]

Marketed as Tree-age in the states it is "Effective Treatment For: Pine Coneworm, Pine Cone Seed Bug, Tent Caterpillars, Western Spruce Budworm, Winter Moth, Bagworm, Fall Webworm, Gypsy Moth, Mimosa Webworm, Oak Worm, Tussock Moth, Leafminers, Honeylocust Plant Bug, Pine Needle Scale, Red Palm Mite, Sawfly, Clearwing Borers, Flat-headed Borers (including adult and larvae of Emerald Ash Borer), Roundheaded Borers (excluding Asian longhorn Borer), Scolytids, Ips Engraver Beetles, Mountain Pine Beetle, Southern Pine Beetle, Spruce Beetle, Western Pine Beetle, Pinewood Nematode."

 

We should spray the whole country from a giant helicopter.

[David Humphries]

......

 

We should spray the whole country from a giant helicopter.

 

the birds that rely on the wee crawly things in trees would love that

 

 

 

.

[daltontrees]

the birds that rely on the wee crawly things in trees would love that

 

.

 

I was only kidding. In the States when DDT was developed to kill mosquitoes, they sprayed vast areas and lakes, nearly killed everything directly and indirectly. Then it all came back. There's no such thing as a magic wand.