Saturday, July 27, 2013

Eucalyptus Globulus Exacerbates Drought Conditions.


Stunted native trees, deprived of light and water by the eucalyptus.

Our friend on the North Hills Forum, who goes by a pseudonym  Remsen Belvedere, because he doesn't want to associate his real name with his troll persona, challenged my conclusions that:

  1.  If a tree does not regulate it's stomata to slow water loss through transpiration during drought, it will dissipate more moisture into the atmosphere than trees that do close their stomata during droughts. 
  2. If the same tree, also has a predominately lateral root system extending out 100 feet from the trunk, one that is also very efficient at extracting moisture from the soil, even under high soil moisture tensions, the result will be less moisture in the soil, especially during the dry the season, within 100 feet of each mature tree.
So here is the comment by our anonymous friend. Let's dissect it. Light red is Remsen Belvedere, light blue is wiki.bugwood.org.

Actually, you provided a source, but it in no ways backs up your conclusion.
My source does support my conclusion, as anyone with a capacity for critical thought can attest.
Read what your source says and then read what you concluded. In your mind the source may support your bizarre conclusion, but there is no actual link there.
This is called psychological projection, where he is projecting his own behavior onto me.
Your source stated that studies show that eucs are able to find water in drought conditions and thus are able to survive where other trees aren't able to survive. That's all your source stated.
Clearly, that is not all my source states:
They do not economize in the use of water but have wide-ranging root systems and an ability to extract water from the soil at even higher soil moisture tensions than most mesophytic plants. Transpiration rates remain high even when water supply from the soil is dwindling. 
My source also states:
Phytotoxins exuded through the pores on the leaf surfaces are transported by condensation, fog drip, and rain creating a ring around the base of an individual tree with a relative paucity of herbs. It was also proposed by Dr. Leisner, of the Department of Environmental Horticulture at the University of California, Davis, that another reason for the absence of other plant life beneath the trees might be the strong competition for water exerted by the trees, which outcompete other plants (Brown 1983). 
And then there is this description of the root system:
The root system of E. globulus consists mostly of strong lateral roots. An abundant supply of moisture is demanded. Since the roots grow quickly toward water, E. globulus should never be planted near wells, cisterns, water pipes, irrigation ditches, sandy or gravelly soils. Large roots have been discovered at a depth of 45 feet below the surface, and surface roots frequently spread over 100 feet away from the trunk (Sellers 1910). 
Obviously, my source states much more than his cognitively challenged mind comprehends.
You, however, jumped to the conclusion that since the eucs are able to find water, they must necessarily be depriving all other trees of water. Your source in no way stated that. You claim that it's logical to assume that, but that is exactly my point...it's an assumption, not a fact.
As  we can all see from the wiki.bugwood.org snippets, my conclusions are clearly shared by the published biology and supported by the facts.
And it's a bizarre assumption. Just because one tree can find water to survive doesn't mean that it is preventing all other trees from finding water. This is why I asked for your source, and you have admitted that you're just assuming that it's the case. Unless you show a study where it was shown that eucs water use in a drought actually deprives other trees of water and causes them to die, your assumption remains nothing more than unsupported and illogical speculation.
Why is it illogical to agree with what is clearly stated?
Eucalyptus globulus out-competes native vegetation for space, light and nutrients.
Water being one of the nutrients that eucalyptus deprive the natives of.
Let me remind everyone of what you claimed: "[Eucs]  exacerbate drought
conditions, making the local forests drier and more fire prone by their
mere presence."
Yes, I did make that claim. And the facts clearly bear out that conclusion.
All your source said is that eucs are able to find water in a drought where other trees have already died. In other words, your source says that eucs are able to survive droughts better than other trees, but in no way is that source saying that eucs "exacerbate" drought and, in fact, the source says that where other trees die from drought, eucs can survive, and that logically means that the forest with eucs in it is less prone to fire, not more prone.
My source said nothing about finding water where other trees have died. In fact, it states that eucalypti outcompete, IE kill the other trees by sucking up all the moisture, until everything wilts. Then, because of their nature:
Eucalypts develop an abundance of hard tissue called sclerenchyma which gives them the ability to endure severe wilting without lasting damage (Pryor 1976). 
They suck the moisture from the soil, worsening drought conditions for nearby flora. When everything including the eucalypti wilt, the eucalypti survive and are the first to come back after the drought is over. Meanwhile, much of the rest of the forest is dead.

Eucalypti also take advantage of fire to eliminate competition from other flora. They supply enormous amounts of ground fuel while sucking the moisture out of the ground and dissipating it into the atmosphere, creating favorable conditions for wildfires. Eucalypti are able to survive fires. They are the first species to resprout after a fire, and given their other allelopathic characteristics, they have the enormous advantage over the native flora.
Again, until you find a source that says that the eucs actually deprive other trees of water in a drought your conclusion is as illogical and unfounded as most other things you say.
Here again he is projecting his own cognitive dysfunctions onto me. it is obvious that if eucalyptus outcompete other trees for water, and don't economize, they will deprive other trees of water during drought conditions. 

Eucalyptus are like the rich people with million dollar, water intensive landscapes, who refuse to economize during drought. They don't turn off the faucet until the last drop is used up.

The roots extend 100 feet from the base of the trunk.

With the eucalypti gone, the natives would take over, keeping the whole forest moister and less fire prone.

Stunted natives that would quickly fill the open spaces left after eradication.