I am a 6th grade student from northwest Oregon and I am working on a science fair project. My project is to study why some types of mosses grow so heavily on big leaf and vine maple trees here in the Pacific Northwest. Based upon my observations, I have some ideas why this is but was wondering if anyone was aware of any research that has been done to determine WHY big leaf and vine maples seem to grow some species of mosses in such abundance where trees that are growing right next to them (such as alder, cherry, cottonwood, Douglas-fir, hemlock or cedar) have little or no moss growth. Thank you.
This sounds like a very interesting science fair project! Maybe if you were to google bryophytes you might find some sites that might offer some info?? I do hope that you will take images of the trees that do and the trees that do not have mosses that are side by side. There are a number of variables involved including the way in which mosses spread and the conditions that favor the survival of the sporophyte of the young moss. Please do post up your observations here as I, for one, would be very interested in learning what you have found out!
hmm. some random thoughts that may or may not help.. Moss spreads via moisture. Slick bark may stay moist longer and provide a better transport path than coarse / more porous bark. Big leaves provide lots of shade. vine maples are understory trees that grow inthe shade of others. some plants have partnerships with other organisms that benefit both. IE. Mycorhiza http://orissagov.nic.in/e-magazine/...hizaanditssignificanceinsustainableforest.pdf
Thank you. I have already done a Google search and could not find anything. I have also sent an email to Dr. Vitt, who is a professor at a college that wrote the book on mosses that I am using. He has so far not responded to my email, maybe because it is winter break. I have been studying the following variables: available light, nutrients in the tree bark, type of moss, roughness of the bark, and age of the tree.
Here's the search on Google you need as a starting point: Acer macrophyllum moss (using Google Scholar, not vanilla Google). The paper by Kenkel and Bradfield "Epiphytic vegetation on Acer macrophyllum: a multivariate study of species-habitat relationships" provides some hints in its abstract - and, as is often the way with scientific papers, if you use the references section, you can track down preceding papers on the topic.
Thak you very much! This is wonderful. It looks like this study was considering similar variables that I have thought of. I will go to the library to see if they can get this article for me.
Somene mentioned smooth or slick bark staying wet longer. My experience with trees seems to indicate otherwise. Tiny cracks and cavities in older coarse bark stay damp longer, being protected from wind and sun. The small cavities also provide lodging places. But there must be more to this, because it seems that other coarse bark trees don't get as much moss. The micro-climate and dampness of the area may have a lot to do with it. As you research this, why not walk in the woods, and look at trees that are just beginning to get moss. Where on the tree is the moss starting? Cracks? Where branches fell off? I was just hiking at the Oregon Caves a couple of weeks ago, and noticed a lot of moss on the lower trunks of some Madrone. You will probably find quite a few answers for your project. You probably will learn a lot from this, and remember quite a bit. My 6th grade project over 40 years ago was about Arthropods, and I still remember several things about the insects, crustaceans and arachnids that I learned back then. What city are you at in NW Oregon? We might be able to suggest some good parks for your parents to take you to. One fast afterthought about mosss on trees - I see it the most on decidous trees that don't shade the bark as much in the winter. Big evergreens block a lot of light and water with the foliage. That might affect things to some degree.
Thank you for your thoughts. As I have been observing in the woods, I have been thinking about similar things as well. I am thinking now that the bark has much to do with it.
I've also noticed that on mostly older Oregon/Big Leaf Maple that mosses are more prevalent, but not exclusively so. Some are abundant with moss in some areas, while not in others. I think the ones I've noticed with moss are in areas with moist roots nearly year round. Areas that routinely experience summer drought never seem to carry moss. As far as other genus as a moss host, the links above may help. Cheers, LPN.
I was hiking today at Cook and Green trail. (making page at this moment - link below will work after 5pm tonight 12/27) http://www.mdvaden.com/cook_green.shtml Anyhow, I was looking at the moss. Maybe equally as important as why moss grows on a tree, is why it doesn't grow on other trees. I was wondering if some trees produce chemicals that inhibit moss growth. Madrone trees had virtually no moss at all. But many older ones had some moss on the lower one to two feet of the trunk - rarely on smooth bark, because the bark near the ground was not smooth. Not sure if the roughness makes a difference. Most of the live oak had moss. A lot on the older ones, and up quite high. Basically, no moss grew on the Pacific wax myrtle trees. Nothing on sugar pine, Douglas fir or ponderosa pine - not even the bottom couple of feet. Moss was all over bare rocks - like all over the place. I don't know if it was the same moss as on the live oaks and big leaf maples because they mosses looked a bit different. But what seemed noteworthy, is that whatever the moss on the rocks was, it was not on the bark of the pines at all.
If you are interested in learning what mosses occur in Oregon here is a link that lists the names of the mosses. http://darkwing.uoregon.edu/~fieldbot/ormoss.html While the majority may not have images on the net you may want to check them out as surely some do and perhaps will provide some clue to genera as to the ones that you may be viewing on your hikes. By the way what kind of rocks are the mosses growing on? Granite, limestone, shale, ?? According to Dr. Norris, UCB, who is one of the leading bryologists on California mosses he has reported seeing no mosses on any conifer in the state. A reason may be due to the fact that they discard a great deal of leaves and that those leaves can produce an acidic soil condition which could be lethal to any gametophytes of the mosses or is the simple leaf fall such that so much accumulates that the young mosses are simply shaded out of existence??? Also there is the fact of the distribution of mosses in relationship to geologic history and the co-evolution of "host" type plants that they can grow on, or rather the specific species of moss can grow on?? Lots of questions!
I'll check the link out. One thing I noticed today, trees like live oak underneath the conifers, did have moss on them, even though needles were all over the ground. And the bark of the conifers was not trapping needles in the bark; especially the sugar pines. The moss was growing on several kinds of rock in the hills where I was at today, including some granite and some marble. I liked this particular thread, because it's actually interesting - something I'd like to study myself. I swapped out images in the page I linked to before: http://www.mdvaden.com/cook_green.shtml Removing a mossy rock wall and adding a photo of trees by the trail. It clearly shows no moss on the madrone, and plenty on the live oaks. Older Madrones with trunks in more shade were the ones with like 1' of moss near the base. The moss did not grow on any decayed cavities that I looked at today - just on the bark. Now I did find a photo of Manzanita uphill from the Oregon Caves National Monument, and that plant had a little bit of moss in the little pockets where dead decayed limbs popped loose. But one difference, this Manzanita limb was somewhat horizontal allowing moisture and particles to become trapped differently than openings on vertical trunks. I did not see moss growing on bark of any Manzanita on today's hike. My images may be limited on forest trees, but I seem to recall seeing a little bit of moss on spruce.
Scraping for images !! I noticed that moss grows on old stumps of hemlock, spruce and Douglas fir. That seems to indicate that the living trees exude something that prevents moss, because it certainly shows up after the trees die. Here's an image of the largest spruce in Oregon; in fact, it was in the news lately because it has a bit of damage. It's future is uncertain. It has moss on it's trunk, but, it's also quite old too. Anyway, it's living and it's a conifer.
Now here is none on this coastal redwood. But check out the poison oak vine. The poison oak is impressive too. It has a 4" to 5" diameter trunk, and is at least 150 tall - I expect even higher. I would not have known what it was, but it's red fall color made the leaves show up high in the canopy. It's hard to see in the photo, but it looks like the moss stops growing right where the poison oak trunk meets the redwood trunk.
I go on a number of moss and lichen field trips with the most experianced guy here in Victoria. You could perhaps e.mail him. Gerry Ansell, E-mail him: gansell@shaw.ca
Found a Douglas fir image with moss - Oregon coast range I think. Looks like a 80 - 120 year old tree size.
Another image of moss on maple? Vancouver maple that we moved to Okanagan 30 yrs.ago. Adjacent pines and fir show no evidence of moss. Just noticed the fungus on birch!