In Defense of Beech Trees

Beech (Fagus grandifolia) are one of my all time favorite trees. They are considered a climax tree species in this region along with maple and hemlock. They stand tall, they support a wide range of species as a food and shelter tree, they are long lived and, their trunks have a smooth, elephantine bark that really makes them stand out. Sadly, this smooth bark also makes them targets for dumb humans who need to proclaim love, peace, or the date in which they were there by carving it into the bark amongst other idiotic scribbles (Fig. 1).

Figure 1. Dumb Hippy Petroglyph

The bark of a tree is it's first line of defense from a wide range of fungi and diseases that would love to feast on tree tissues. There are two types of fungi present in North America that are particularly damaging to beech trees. The fungi are known collectively as beech bark disease but scientifically they are Neonectria faginata and Neonectria ditissima. Sources say these fungi were introduced from Europe and first made its appearance in Maine back in 1932. Beech bark disease is deadly in some circumstances and severely crippling in others. A few trees do show some genetic resistance to infection. The fungus works its way into the living tissue just under the thin bark of the beech and causes cankers to form. If enough tissue is killed, the tree is effectively girdled and it will die. In a majority of the cases the cankers zap enough energy from the tree that it no longer can sufficiently reproduce which has rippling effects through entire forests. As mentioned above, beech are a climax tree species which basically means they are a dominant species in maturing forests. They also a masting species which means that every few years they produce massive seed crops which provide food for numerous forest dwelling species like squirrels and turkey. If this food source is lost, it can spell disaster for forest biodiversity.

So how does the fungus get into the tree? Well, one of the most common ways is due to an invasive scale insect known as the beech scale (Cryptococcus fagisuga). This invasive insect pest was introduced to our forests back in 1985 in an arboretum in Ohio. The females penetrate the bark with their feeding tube and feed on the juices of the tree. They secrete a waxy substance so it is easy to see which trees are infested (Fig. 2).

Figure 2. Beech scale on a beech

Their feeding habits leave small wounds in the thin bark which then serve as infection sites for the fungal spores of beech bark disease. This is bad enough but of course humans add insult to injury every time carving is added to the bark of a beech tree. Carving opens up the bark far worse than the beech scale making infection inevitable. The beech in Fig. 1 is showing the characteristic cankers forming under the bark that are no doubt from the nice pot leaf petroglyph.

We have to be smarter in how we interact with our forests. We need them more than we will ever realize. We have already lost the American chestnut (Castanea dentata) and the American elm (Ulmus americana) as ecologically functional species thanks to other invasive fungi. We are currently losing our ash (Fraxinus sp.) species thanks to the emerald ash borer, hemlocks (Tsuga canadensis) to the hemlock wooly adelgid (also a scale insect) and now beech are in danger. These were all lost due to pests introduced via the horticultural trade. There is even evidence that sugar maple (Acer saccharum) are in decline though the causes of this are a little more difficult to pin down. Our forests are losing some of their most keystone tree species. Change is inevitable over time but at what cost?

Further Reading:

http://www.baycounty-mi.gov/Docs/Health/GypsyMoth/BeechBark.pdf

http://www.dnr.state.oh.us/tabid/5218/default.aspx

http://na.fs.fed.us/fhp/bbd/

http://en.wikipedia.org/wiki/Beech_bark_disease

Invasive Orchids?!

Orchids are notoriously finicky about where they will grow. The family with which they belong (Orchidaceae) is one of the most diverse plant families known along with Asteraceae. Because of this massive diversity, orchids have become quite specialized plants. Orchids hedge their reproductive success on production of millions upon millions of tiny, wind-blown seeds. With seeds so tiny there is not much room left to equip them with food in the form of nutrient packed endosperm (the stuff you are eating when you eat peanuts) and thus orchid seeds rely on very specific species of fungi in order to germinate. Some orchids take this relationship to the extreme but that is a post for another day. Because of all this specialization, orchids are a pretty vulnerable group of plants. Most species are threatened because of poaching and habitat loss and many are endangered. This is why coming across the plant I am writing about is so shocking.

I am talking about the helleborine orchid (Epipactus helleborine) which originally hails from northern Eurasia. I first came across this plant down on some Nature Conservancy land in Gowanda, NY. This was a few years ago and I did not recognize it for what it was. This year however, I began seeing this plant in the strangest places including areas in the City of Buffalo with amazingly poor soil. I was lucky to have a few start growing in my girlfriend's garden so watching them develop was fun and easy. They are a very nice looking plant, standing about 7 to 8 inches high. The flowers are readily recognizable as belonging to an orchid and each plant produces a handful of them per season. The true awesomeness of this species comes from its life history.

In its immature stage this plant germinates and grows as an underground rhizome (underground stem) and is considered fully mycoheterotrophic which means it tricks mycohrrizal species of fungi to associate with it then feeds off of the nutrients that the fungi gain from trees. The orchid can stay in this state of growth for upwards of 10 years before it feels the need to flower. When the right conditions are present it then begins it's adult phase of growth. It throws up a stem, some leaves, and flower buds. At this point it can begin making its own food through photosynthesis but it still uses the fungi as well.

Once it begins to flower it then needs to call on the help of wasps for pollination. There has been some amazing research done on how it achieves this. Apparently the plant begins to release compounds called "green-leaf volatiles" or GLV's. Plants like cabbage produce GLV's when damaged by insects in order to attract wasps that will either lay eggs in/on the insects or use them to feed their young pick them off to bring back to their larvae. Well, when the orchid does produces GLV's, it's doing it for sex. Once the wasps get there they are "encouraged" to stick around a while because the flowers apparently have not evolved structurally sound methods for pollination. Orchids don't dust their pollinators with pollen. Instead they produce pollen sacs known as pollinia that stick to their pollinators via a glue-like substance. There are reports that the flowers produce narcotic drugs and alcohols that dope up the wasps and causes them to linger and stumble around the flower thus increasing the chance of picking up a pollinia. This process then gets repeated every time a wasp visits another flower.

Pretty fracking cool huh? Now, the title of this is a bit misleading. I would not consider this species as truly invasive in that I never see it in any abundance that would suggest it is crowding out native species or changing soil characteristics. I was only able to come across one account of a gardener who claims it grew so thick that he had to eventually rip it out of his garden bed. The jury could still be out though. Not all invasive plants act invasive initially. This plant was first described in Syracuse, NY back in 1879 so it has been here a while. Keep an eye out for it next summer. You will be surprised where you might find it! Also, check out my favorite podcast ever, Wild Ideas, to hear a fun discussion on the helleborine orchid.

Further reading:

http://www.sciencebuff.org/collections/research-collections/botany/helleborine-orchid/

http://link.springer.com/content/pdf/10.1007%2Fs00606-002-0197-x

http://blogs.discovermagazine.com/notrocketscience/2008/05/12/orchid-lures-in-pollinating-wasps-with-promise-of-fresh-meat/#.UOxdL7t0SQ0

http://www.cell.com/current-biology/retrieve/pii/S0960982208005265

An Intro

I grew up when blogging first came about in the world of the internets. I swore I would never be part of it. Alas here I am. I found that while working on Lookin' at It that I really enjoyed doing the research and posting interesting facts on our Facebook page. I am a firm believer that the more you know the more you care and the more you care the more you want to do. Well plants need our help. Our ever growing population coupled with short sighted land use ethics have landed too many plant species on the path to extinction. Plants are the foundation of most food chains, the exceptions being deep sea thermal vent communities that rely on chemosynthesis for an energy source. Plants are what take our closed-system planet and open it up by utilizing solar radiation along with CO2, water, and some trace nutrients to generate sugars. The byproducts of this process as many of you know, are water and oxygen; two chemicals we rely on quite heavily. So, long story short, I am starting this blog in order to share with the world why I fell in love with plants and why you should too... okay, maybe not fall in love but at least gain some awareness as to why plants are so important. If we are more conscious of their survival, we will benefit in the long run as well. The focus of this blog will mainly be plants of the Northeastern United States (where I live and play) but there will be tidbits thrown in from all over the world as I am also an avid gardener. I hope you decide to check back from time to time. I will try to make each post as understandable and coherent as possible. Thanks and be well!

-Matt