Jenny- One of the interesting things about lichens in the Southwest (elsewhere too!), is that they serve as good indicators of air quality...of course, here in ALaska they are one of the primary food sources for caribou. -Don
> Date: Fri, 13 Mar 2009 11:56:26 -0700 > Subject: [ENTS] Re: Roots? > From: [email protected] > To: [email protected] > > > Gary, > > Sorry to be completely unintellectual - but Lichens are SO COOL! > Trying to narrow down a paper topic for Botany class- one idea is gap > dynamics in the NYBG forest and the other is Lichens....I think I'm > going for the lichens. I have amazing lichen photos from Maine and > Arizona, mostly on rocks (because rocks are SO COOL too....! - I'll > try not to use this expression in paper...) > > Thanks for your info, > Jenny > > On Mar 12, 5:46 pm, [email protected] wrote: > > One interesting hypothesis is that early. Plants were an "inverted lichen", > > algae left the aquatic environment with the help of protofungi in a > > symbiotic relationship. The fungi provided the protection from dissication > > and also served as the interface between the macroscopic algae and soil. > > Symbiotic (both ecto and endo symbionts) relationships are probably > > underestimated in the functioning of terrestrial ecosystems. > > > > Gary > > Sent via BlackBerry from T-Mobile > > > > -----Original Message----- > > From: Lee Frelich <[email protected]> > > > > Date: Thu, 12 Mar 2009 11:23:54 > > To: <[email protected]> > > Subject: [ENTS] Re: Roots? > > > > Jenny: > > > > Regarding mycorrhizae, its one of those interesting questions where the > > answer is yes and no. With very high soil fertility, trees can survive > > and grow without them, and in isolation, they can often grow without > > them. However, under most field conditions, and with the competition > > from numerous other trees, they are necessary for an individual tree to > > survive and grow, as well as for the function of the entire ecosystem. > > > > Regarding nitrogen fixation--its another case where both answers are > > correct. Free living bacteria (Azotobacter and Clostridium, some > > blue-green algae, and others) fix a small amount of nitrogen in the > > soil. Rhizobium bacteria form a symbiotic relationship with roots, in a > > nodule, which can easily be seen if you pull up a clover plant. This > > occurs mainly in legumes (locust), but also in some other trees (via > > other genera of microorganisms) such as alder, and shrubs such as Myrica > > (sweet gale), and Shepherdia (buffaloberry). The presence of nitrogen > > fixing plant species can fertilize the soils, thereby increasing the > > growth of tree species that cannot form nitrogen fixing nodules. > > > > Whether the nodule forming microorganisms are considered part of the > > tree depends on your point of view. They are halfway between ancient > > microorganisms such as certain algae and bacteria that have become > > chloroplasts in leaves, and mitochondria in cells of plants and animals > > (which are clearly part of the organisms, and cannot live by > > themselves), and microorganisms that cannot form a symbiotic > > relationships with plants at all. Its a continuum, and where you make a > > distincion along that continuum depends on the individual > > > > Lee > > > > JennyNYC wrote: > > > Lee, et. al., > > > > > I would love to see one of these "rhizotrons". Fascinating. > > > > > I have questions if anyone can help me out: > > > > > 1. Are mycorrizae absolutely essential for young tree roots to grow > > > and do trees have mycorrizae associations throughout their lives? > > > > > 2. I'm confused about the exact relationship between the bacteria in > > > the soil that fix nitrogen and the tree root itself. I know this is > > > a broad and vague question....just wondering it those bacteria are > > > considered part of the tree organism? > > > > > Thanks, > > > > > Jenny > > > > > On Mar 12, 8:54 am, Lee Frelich <[email protected]> wrote: > > > > >> Ed et al.: > > > > >> We usually measure root biomass by taking soil cores (usually 2-4 inches > > >> in dimeter, from 1-3 feet deep, depending on the purpose of the study), > > >> and separating the roots so they can be dried and weighed. By taking a > > >> number of such samples, we can estimate the biomass of roots per acre in > > >> the forest. Roots are also studied in rhizotrons (underground rooms with > > >> large windows all around). One can observe the root growth against the > > >> windows, study how earthworms move, and how the soil zonation changes > > >> over time, etc. The University of Michigan Biological Station and > > >> Michigan Tech have rhizotrons that I have visited. There are also mini > > >> rhizotrons that can be placed throughout the forest. > > > > >> Of course, these do not give you an estimate of the roots of one tree. > > >> I have seen that done by blasting away the soil with high pressure > > >> hoses, so that the root system can be mapped and measured. This is done > > >> in a stand that is planned to be clearcut, or perhaps a few trees in an > > >> experimental forest, and it only works in ecosystems with shallow soils > > >> and/or rooting depths. > > > > >> Lee > > > > >> Edward Frank wrote: > > > > >>> Jenny > > > > >>> I am sure if there was some practical and non-destructive method of > > >>> measuring the roots underground, we would give it a try. Ground > > >>> Penetrating > > >>> Radar is still a little expensive at the moment. > > > > >>> Ed > > >>> ----- Original Message ----- > > >>> From: "Jennynyc" <[email protected]> > > >>> To: "ENTSTrees" <[email protected]> > > >>> Sent: Wednesday, March 11, 2009 8:06 PM > > >>> Subject: [ENTS] Re: Roots? > > > > >>> Russ, > > > > >>> Thanks for letting me know about this. > > > > >>> Jenny > > > > >>> On Mar 11, 2:27 pm, [email protected] wrote: > > > > >>>> Jen: > > > > >>>> No. That type of work is usually done by researchers looking for a > > >>>> specific > > >>>> piece of information about a tree or group of trees. > > > > >>>> Russ > > >>>> **************Need a job? Find employment help in your area. > > >>>> (http://yellowpages.aol.com/search?query=employment_agencies&ncid=emlc...) > > _________________________________________________________________ Express your personality in color! 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