High Elevation light intensity with CPs

[kulamauiman]

Aloha everyone,
Was wondering about how elevation affects light intensity? It was my understanding at higher elevations less stuff in the air to deflect/filter out some of the sun light. If this is the case In Hawaii at a higher elevation (cool air) but more chance of sunburn? Has anyone else looking into this? I have noticed some of the green VFT clones do not seem to appreciate full morning sun. If this is the case could a simple shade cloth of 25-50% shade reduce the problems?

We are not that high in elevation (4000 feet) but might be interactions with our southern latitudes in addition to most of the time clear skys.

Mahalo,
MTF

[ICPS-bob]

This is an interesting and complicated question.
I do not know the answer, but here are a few relevant papers

www.answers.com/topic/altitudinal-vegetation-zone?cat=technology

Plants and Altitude — Revisited
J. Gale
Annals of Botany 2004 94(2):199
aob.oxfordjournals.org/cgi/content/full/94/2/199

Solar Ultraviolet on Tropical Mountains: Can It Affect Plant Speciation?
David W. Lee and J. Brian Lowry
The American Naturalist, Vol. 115, No. 6 (Jun., 1980), pp. 880-883
www.jstor.org/sici?sici=0003-0147(198006)115%3A6%3C880%3ASUOTMC%3E2.0.CO%3B2-V

Phenolics and condensed tannins of high altitude Pteridium arachnoideum in relation to sunlight exposure, elevation, and rain regime.
Miguel E. Alonso-Amelot, Alberto Oliveros-Bastidasa and Maria Pía Calcagno-Pisarellia
Biochemical Systematics and Ecology Volume 35, Issue 1, January 2007, Pages 1-10
linkinghub.elsevier.com/retrieve/pii/S0305197806001839

UV-B radiation and acclimation in timberline plants.
Minna Turunena and Kirsi Latolab
Environmental Pollution Volume 137, Issue 3, October 2005, Pages 390-403
linkinghub.elsevier.com/retrieve/pii/S0269749105001144

[kulamauiman]

A minor update:
Finding the obligate shade loving plants (i.e. D. adelea) seem to burn even under 50% shade cloth. They were looking like the over cooked tourists I see here including tan lines where insects were caught on the leaves. They went back into the terrarium (70-90F over the course of a 24 hour period and very high humidity, two 55Watt compact fluorescent lights, but I guess compared to the sun not too bright.

Thanks Bob for the leads. Will keep looking and see what can find. May have to do some trials with various levels of light via different shade cloth.

MTF

[Clint]

Have you even seen D. adelae grown in very strong light? I've burnt plants outside (instead of just throwing them away, I put them with the Sarracenia) to have them return as much smaller plants but are DEEP brilliant red with more mucilage.

[kulamauiman]

can try that. Just don't want to kill off my mother plants before I have some redundant back ups just in case.

Also can report that D. capensis is not the least bit bothered by my sunlight. In fact by the way they are stretching they seem to want more. Will try to move some to a place with a full day of sun to see.

MTF

[kulamauiman]

After reading some lit and chatting with some people, found that the problem may be UV more than just light. Working on trying to find a way to measure. Also reading that some plants can adapt but there are costs in terms of vigor, size, etc.

I am not sure if the shade cloth blocks UV very well, which is why the plants under 50% shade cloth still fried. Any way to block UV on plants that I could test?


mahalo,
MTF

[Not a Number]

You can buy UV blocking film but it has to be applied to glass or plexiglass.

Hold on, someone does make UV blocking shade cloth:

www.ultra-shade.com/

[kby]

Jul 9, 2008 12:12:15 GMT Not a Number said:

You can buy UV blocking film but it has to be applied to glass or plexiglass.

That sound a little like snake oil unless there are more specifics (like particular wavelength range of UV). Normal glass blocks a fair amount of at least some (a lot?) of the UV spectrum anyway.

As far a shade cloth I'd think most plastics like that are opaque to UV, but of course if the UV content is exceptionally high the remaining 50% would be a larger number than if it weren't that high.

In the absence of having read Bob Z's references, I would say that higher altitude should lead to perhaps higher percentages of UV content as the atmosphere is responsible for a lot of the screening effect of UV.-kby

[Not a Number]

The amount of UV that glass blocks depends on the composition of the glass. Quartz coatings or plastic laminations absorb the most UV.

UV blocking films block 95 to 99.9 percent of UV light and are used extensively for museum and archival displays.

You won't know how much UV a pane of glass will block unless you measure the UV transmission or buy glass manufactured to block UV.

If glass blocked all UV light then UV light bulbs wouldn't work, stuff in store windows would fade less, and your curtains would last longer.

[kulamauiman]

Aloha Everyone,
just wanted to post an update. I put up a small polycarbonate covered greenhouse. It is well ventilated to prevent overheating. The products literature suggested that it could reduce about 97% of the UV , while still being able to transmit 90% of the sunlight. A few of the obligate shade loving species may need more shade or might go under benches. I used one of the forums members suggestions of using the plastic shelving units, I think can put on a lower shelf and have the upper ones provide shade. have some shade cloth to put over sides to add more if needed. Will try to post pics soon on this on going experiment. I have a few D. adelea to try and test things. However, I am using D. capensis "Red" as an indicator. The ones in the greenhouse are not as red as the ones grown outside in full sun. Will also test on other Drosera species that have this turns red in the sun response. Will also put the pics online for these experiments.
Mahalo,
Mach Fukada

[kulamauiman]

Update:

Based on lit the polycarbonate should be blocking about 90% of the UV while allowing 90% light transmission. I have built this thing to be well ventilated and cool.

this is what me and the wife built. My neighbors were shocked at how quickly it came up. My wife was a bit leery of my building an all glass structure like the one that Bob has as we get earthquakes just like California.





So far I can see some indications of the effects of reduced UV via the plants that are supposed to be red not turning red.

here is a side by side comparison of D. capensis "red" left side was grown outside in full sun and right side in the greenhouse.



I am starting come D.capillaris seeds and will try similar sort of side by side comparison. Preliminarily things look good. I have not fried my D. regia or D. prolifera.

On a side note. All my D. capensis seeds were started the same time. The albino and narrow leaf are blooming profusely. The reds have not. Could this be another phenomenon related to the high UV light intensity? Perhaps these plants are spending so much time making red pigment in response to UV light that they are not able to store up resources to produce a flowering spike. Any ideas?