Thursday, January 3, 2013

Mistletoe: Former Demonized Plant Turns Out to be a Great Helper

Photo Credit: Duke University
Mistletoe is more easily identifiable in the Fall and Winter when deciduous trees have lost their leaves. Yet there are numerous other species of Mistletoe which exist on other evergreens, cactus, Chaparral, Eucalyptus, etc. Often demonized and used as an excuse for  timber harvesting and Control Burns, now it appears to be an actual Keystone species necessary for a health Vegetative system and it's occupants.

Wow, who knew it had other uses ? Well, Scientists should have known this all along. At least the ones who are in charge and trust of protecting the natural world and the authoritative control over official policies for responsible the land management. But as with other areas of Science back in the 20th Century, this hasn't always worked out well for the natural world. Government agencies with official oversight of Natural Resources have always managed the landscape from an exploitative money making venture perspective. Now that our natural world is so badly degraded at the start of the 21 Century, it is only now we see the real true value of things that have been either completely lost and not ONLY on the verge of  extinction, but now Science is actually taking a harder look at things assigned negative labels such as a disease, infectious, invasive, ugly, worthless, parasite and so forth. Ultimately, they now have to try to view various components of Earth's Ecosystems from a purposed perspective (something often considered by some as heretical in the past), just what benefits are derived from organisms like Mistletoe deemed worthless, evil or invasive.

Credit: US Forest Service
Words/Terms like these ones here  'invasive' - 'parasite' - 'infection' etc, have often in ignorance done more to hurt our understanding of some organism than to further it. To be honest, Mistletoe in my book isn't any of these and I'll conclude further on down as to why that is so. For more than a century, Mistletoe has been long thought to be a destructive trees murdering organism for which this great harm to human resources must be eradicated. I wanted to comment earlier when the research paper came out by David Watson, a researcher at Charles Sturt University in Albury of New South Wales in Australia, but I was delayed. I really wanted to document & reference for you some of the usual bad forest policies used in the past to eradicate or control what were considered infestations of Mistletoe in regards to Control or Prescribed Burns. But first, here is the latest article came out in the around December 17th 2012. Here is the link and Abstract and my comment after that. (by all means read the entire paper)
The Royal Society: "Mistletoe as a keystone resource: an experimental test"
"Various entities have been designated keystone resources, but few tests have been attempted and we are unaware of any experimental manipulations of purported keystone resources. Mistletoes (Loranthaceae) provide structural and nutritional resources within canopies, and their pervasive influence on diversity led to their designation as keystone resources. We quantified  the effect of Mistletoe on diversity with a woodland-scale experiment, comparing bird diversities before and after all Mistletoe plants were removed from 17 treatment sites, with those of 11 control sites and 12 sites in which Mistletoe was naturally absent. Three years after Mistletoe removal, treatment woodlands lost , on average, 20.9 percent of their total species richness, 26.5 percent of woodland-dependent bird species and 34.8 percent of their woodland-dependent residents, compared with moderate increases in controlled sites and no significant changes in Mistletoe-free sites. Treatment sites lost greater proportions of birds recorded nesting in Mistletoe, but changes in species recorded feeding on Mistletoe did not differ from control sites. Having confirmed the status of Mistletoe as a keystone resource, we suggest that nutrient enrichment via litter-fall is the main mechanism promoting species richness, driving small-scale heterogeneity in productivity and food availability for woodland animals. This explanation applies to other parasitic plants with high turnover of enriched leaves, and the community-scale influence of these plants is most apparent in low productivity systems."

What impact does the Dam
of a Keystone Species like a
Beaver play in an ecosystem ?
Mistletoe = Ecological Keystone Species ? This would be a living organism that has the biggest impact on life around it within an ecosystem. But who would have thought that of Mistletoe ? I mean it is often ugly, rangy looking, certainly poisonous. So what possible worth or value  is it ? It's funny, I was reflecting on this negative attitude on this plant and similar attitudes towards other species plants, animals, birds, etc (like various Chaparral Plant Community Species) from a Human perspective and realized that humans treat and judge other humans the very same way. Or is it the other way around ? Could it be that mankind's often inhuman treatment of other cultures, races, class distinctions etc has been transferred over from their abuse of the natural world's resources and that explains the sad state of affairs in our societies as well ? I do believe it's both that reflect the mirror image of each other. But let's get back to examples of other kinds of Foundation Species which will illustrate the importance of the role a Keystone species plays in any habitat and get a better than average understanding of what and how Mistletoe fits just such an important niche in nature. How about a Beaver's Dam ? A Beaver moves into a completely new area and then by his dam building, physically and dramatically changes an entire wide area even well beyond it's immediate shorelines. 

This impact of a Beaver's Dam building in create a lake or even small pond are huge indeed. Clearly as illustrated above, there are the obvious reasons. But even still, more so even far away from beyond the immediate vicinity of the pond or lake. Underground water tables are raised. Riparian woodlands which will be extensive around the banks will not only provide shelter and other habitat and food resources, but also the fact that their specific nature with regards their root systems in being both Endo & Ecto Mycorrhizal make them perfect water shunts or hydraulic transporters to other species of forest trees and chaparral far away from the water source. That in turn creates further life opportunities elsewhere.

I truly enjoyed reading from the study here, about some of the benefits that Mistletoe actually provides in the plant communities. I've always known about the benefits to birds as far as food and nesting, but the intriguing benefits of Mistletoe leaves to the forest floor was very interesting. Again, who knew ? Who would have thought Mistletoe leaf litter contained further richness for which to effect other life on the forest floor ? So the Mistletoe actually provides more richness in nutrient drop debris, than simply it's own leaf litter. And as far as that label "Parasite", I hate it !!! Why ?  Because the reason is, it's inaccurate of what I would consider a true parasite, you know, one that sucks almost all the life from it's host and gives nothing back ? But Mistletoe is different. scroll back up and look at the colour of that Mistletoe at the top of the page. Notice all the green ? That is Chlorophyll and for what purpose is Chlorophyll used for ? The manufacturing of food. So it's doesn't exactly draw from the tree's carbon stores what it needs, it manufactures it's own.  What it does do is create roots within the tree's branches and trunk and draw water and nutrients. Mycorrhizae however does draw from the plant carbon sugar stores and yet we don't consider it a parasite. Why ? Because it actually increases nutrient and water uptake by the plant by 200% and you can actually see improvement. It actually makes the plant work harder, but more efficiently. So one has to wonder what other things Mistletoe may be giving back to the tree in the way of beneficial Chemical exchanges. We do know that through the mycorrhizal network that plants can make chemical exchange between all sorts of trees and shrubs. So mycorrhizae gets a much nicer word of association through Symbiosis

Dwarf mistletoe on black spruce in
northern Minnesota, USA
There is no doubt that under specific circumstances, the over abundance of Mistletoe in a tree which may be in a weakened state,  can overwhelm and even kill the tree. Some like the Dwarf Mistletoe which are perhaps not of the Greener variety and colonize pines, maybe have more of a parasitizing nature when out of control caused by imbalances. However, if there is one thing we all do know NOW, the natural world when it's left in a pristine healthy state with all it's various living components for which we NOW know all cooperate and help one another as opposed to the mistaken dogma or doctrine of "Survival of the Fittest", doesn't normally work against itself, UNLESS something gets out of balance. Mostly, if it does, it has a human stain of ignorance shackled by greed and selfishness as a motivational factor. The same could be true, and there is evidence that it is, with much of the mistletoe degradation of forested ecosystems around some places on Earth. At times however, out of control mistletoe can leave clues behind as to why conditions were so favourable for it's excessive spread which has been a result of human mismanagement of the land.  Take for example this photo below. 

Large clearcut in mistletoe infected jack pine stand in Manitoba. Cut boundaries located well beyond extent of infection. Site chained afterward to eliminate infected understory trees.
 When I hear of certain specific reasons (excuses) made for why trees needed to be harvested to eradicate something or even plans for a prescribed or control burn to eradicate something, I know that as a general rule, some other motive is behind it. While there may be real circumstances where there could be a real need, how or why did such an overwhelming outbreak occur in the first place ? Take a clue from the photo above of the clearcut forest. They said on the forestry link that it had to be done because of the invasive Mistletoe. Really ? See anything odd or unnatural about that photo ? Yes, of course, it's a dead give away. It's not a normal occurrence for Jack Pine or any other species of tree to grow in a monoculture setting which looks more like row crops of a corn field somewhere in Iowa. Clearly, the unnatural circumstance of the Industrial Forestry created in the first place by humans is to blame, but that is not what gets the blame. Mistletoe is the evil villain. The above circumstance also justified taking out non-infected areas also. Open this link below here from the Warnell School of Forestry in Georgia and scroll on down to page 20 view the survey chart which shows the results of three Surveys taken in the U.S. states of Kentucky/Tennessee hardwood forests. The percentages shown for the majority of Mistletoe colonization are mostly tiny to none per species and yet the four highest percentage species listed certainly are not life threatening to the woodlands either. This is because the forest is extremely biodiverse and not monocropped like the Industrial Tree Farm of Jack Pine in the above photo. 
Juglans nigra 35%Ulmus americana 21%Ulmus rubra 16%Robinia pseudoacacia 11%Prunus serotina   9%Fraxinus americana   7%Acer saccharinum   4%Celtis laevigata   4%Gleditsia triacanthos   4%Ulmus serotina   3%Ulmus thomasi   3%Acer rubrum   2%Carya ovata   2%Celtis occidentalis   2%Maclura pomifera   2%Fraxinus pennsylvanica   1%Liriodendron tulipifera   1%Nyssa sylvatica   1%Quercus alba   1%Castanea dentata   0.6%Platanus occidentalis   0.6%Acer saccharum   0.3%Fagus grandifolia   0.3%Liquidambar styraciflua   0.3%Ostrya virginiana   0.3%Quercus prinus   0.3%Sassafrass albidum   0.3%Ulmus alata   0.3%Quercus muhlenbergii   0.1%
There are numerous Mistletoe species and many of them host specific, which means they prefer one or two kinds of tree. The more biodiverse, the far less problem of an entire wipe out of an ecosystem. BTW, read that entire link. There are some fascinating educational information on Mistletoe life cycle and construct on that paper. Below is a photo of the use of prescribed burns for control. 

Cut, felled and 'prescribe burn' of supposedly Mistletoe 
infested Lodgepole pine in the United States.
Recently I wrote about the Santa Rosa Mountains which are above overlooking Palm Springs. Sometime back in the 1930s, a switched back trail called the Sawmill Trail was constructed to allow Logging companies back in the 1930s to harvest Jeffrey Pine trees. Talking with the man who built the road, Jay Dee McGaugh, he said the excuse the Forestry gave them for clear cutting the Jeffrey Pines  was that they were all "Bug Trees", which I took to mean they were all infested with some species of Pine Beetle. Knowing the way politics was and has been, one has to wonder if the real truth of the matter was more of a money making venture as opposed to any ecology. Guess we'll never know for sure, but no replanting effort was made and the forest tree line no longer extends lower down Santa Rosa as it once did. Recently another similar Science report has come out and exposed the cause for the global increase of an explosion of Jellyfish populations everywhere around the entire earth. Of course the report doesn't blame the Jellyfish, but does expose the human cause of pollution throughout our planet's oceans for the favourable conditions which facilitate & trigger their rapid increase. My point here is this. There are all sorts of living organism on this planet that are out of balance. Some of the out of balance circumstances even in your own yard's landscape like insect pests, weeds or whatever may be a fault of your own, but unknown to you. Before applying some irresponsible damage control measure by use of other science based innovations like chemicals, should be avoided to see if there is a more ecological solution which would be more viable.
Common scene of Japanese Fishermen fighting to keep Jellyfish from their nets. These creatures are also consuming the fish they may catch. But will the Fishermen blame government and big business for the off balanced abnormal conditions created by industrial pollution and demand something be done about it ? Or will yet apply another negative label to be attached to a creature who simply responds to genetic instructional instincts as triggered by it's environment for which humans are responsible ?

These two links here are of some of the negative uninformed mentality which rules. Further below are some more interesting links. You can actually Google more info and obtain 100s of other informative links with the same bad science viewpoint towards Mistletoe. In the mean time, when you next go walking on a nature hike, give consideration to those darker green lush patches high up in the tree's branches and give some thought to all the other biodiverse richness of life they provide to the entire system
Further Reading References on the importance of Mistletoe
University of Adelaide: "Could mistletoe give the kiss of death to cancer?"
"Beyond pills: Cardiologists examine alternatives to halt high blood pressure" (Mistletoe Extract Used in Chinese Medicine)
Charles Sturt University: "Passions meet in mistletoe book" (2011) - "MISTLETOE: FRIEND OR FOE?"

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