Ecolog: [Note: I, for one, like this way of responding to initial posts, with the original subject-line and the string of subsequent comments preserved, rather than individual responses to the initial post. I know it is not possible for this to remain uniform, because some will post before one or more other responses are posted, (ships will pass in the night) but it is nice to have the thread in a sequence. I also appreciate it a lot when tangential posts preserve the original subject line whilst adding an appropriate subject label ahead of the initial one so that I, the reader, can follow all of the branches of all the tangents back to their source.]
I share Rose's comment about the Hernandez post, which I agree is "right on." I am not opposed to Rose's comments, but they do strike some complex chords for me. Rose is right on when she mentions resilience, and I would add that not only diversity in species is important, but diversity of age classes and genetic variation also is important--yea, more important than species diversity in some contexts. One thing troubles me a bit however. Well, maybe it troubles me a lot. The implication of Rose's and Johnson's remarks seems to be that one can decide to plant all kinds of different species without regard to the suitability of the site for the species, although they perhaps believe that such goes without saying. In my days in the U.S. Forest Service, for example, we were careful, perhaps absurdly so, about the provenance of the seeds collected, taking care to note the elevation, orientation, slope aspect, etc. so that the resulting saplings could be planted in comparable circumstances, believing that a good match of the genes to the site would maximize the potential for survival (e.g., temperature tolerance range, etc.) and result in optimum growth potential. I know that forest science has undoubtedly come a long way since then, so I look forward to those more advanced to bring me up to date. But what disturbs me even more is the unstated possibility that various sorcerer's apprentices might loose designer-trees based upon some marginal, perhaps largely fictional, increased ability to provide a single "ecosystem service." (For some reason the Irish potato famine comes to mind . . .) The request also strikes me as more horticultural than ecological, and Rose and Johnson seem to imply that planting trees in South-Central Iowa (or any other location) can be done without regard to ecological context. While all the things Rose mentions are "good," and can be part of the ecological context, I often hear/read/see similar tree boosterism overriding ecosystem concerns as well-intentioned prescriptions without regard to context. Also (almost?) never mentioned are the supposedly tangential but real factors in the net-energy and carbon-balance equations that include energy consumption and carbon-release numbers associated with the production, transportation, and planting of growing trees. I stand ready to be further enlightened on this subject as well. WT ----- Original Message ----- From: "Katie Rose" <[email protected]> To: <[email protected]> Sent: Sunday, February 26, 2012 4:14 PM Subject: Re: [ECOLOG-L] best tree species for carbon sequestration Hello Dr. Johnson, I'd like to supplement some of the points made by Jason Hernandez, which are all right on. The best way to promote carbon sequestration is to plant a resilient forest: one that has a combination of tree species so you are buffered against pests and diseases, and then plan for what you will do with the trees after they die. If you plant trees which can be used to create furniture, such as cherry, oaks or pines, you will be creating a more permanent carbon sink. Also you can direct dead trees to a facility which will burn them for fuel: this will not only produce "carbon neutral" power, but will prevent more fossil fuels from being used. Finally, you can compost tree matter (leaves, pruned branches, etc). Although much of the carbon will be released, some will remain in the soil, which is actually a very under appreciated "carbon sink". An aside: besides providing for carbon storage, trees help cities in a huge variety of ways. They improve urban streams by intercepting storm water (prevent flooding), stabilizing and creating soil, contributing organic matter, and cooling stream water. Trees cool streets and buildings, reducing air conditioning costs (and therefor lessening the electricity needed to climate control the building). They remove pollutants from the air, and provide habitats for birds, bugs, squirrels, and other wildlife. Katie Rose On Sun, Feb 26, 2012 at 11:52 AM, Jason Hernandez <[email protected]> wrote: > Your criteria are shared by countless homeowners wanting to landscape their > yards (fast growing, long-lived, low maintenance). Unfortunately, there are > physiological tradeoffs involved, whereby fast growing trees tend to "live > fast" in other ways, too, and hence are as a general rule not long-lived. > Think about the way forest succession works: fast growing trees fill in gaps > quickly, reproducing before the competition catches up; slow growing trees > are the shade tolerant ones, coming up underneath the fast growing pioneers > and eventually supplanting them. > > > From what I have read of carbon sequestration (as it is not my primary area > of knowledge), old-growth forests hold a lot of carbon, but do not take it up > quickly; the decomposition of old trees and the carbon uptake of growing > trees about cancel out, making the old-growth forest approximately > carbon-neutral. Young forests take up carbon quickly, but as they age, the > uptake rate slows down. When a tree decomposes, all the carbon sequestered in > its biomass is re-released. So to have effective sequestration, you would > have to have a steady supply of young trees taking up carbon, without a > concurrent stream of decomposing trees. Net growth would have to exceed net > decomposition. In other words, the only long-term way to counteract > ever-increasing CO2 emissions, is to have ever-increasing acreage of forest. > > Jason Hernandez > > > ________________________________ > > Date: Sat, 25 Feb 2012 11:59:02 -0800 > From: Stephen Johnson <[email protected]> > Subject: best tree species for carbon sequestration > > dear Ecolog-ers, > > I am designing a tree planting-planting project designed to counter CO2 > production at a college in south central Iowa. Students will be involved in > planting. I have heard that Tulip tree (Liriodendron tulipifera) and sweetgum > (Liquidambar styraciflua) are both good candidates for carbon sequestration > an I wonder if there is any primary literature that backs the claim. Also are > there any other tree species with high rates of carbon uptake and biomass > accumulation, fast growing and long-lived and with low maintenance and > perhaps with any or all of these properties reflected in any scientific > studies. > > Dr. Stephen R. Johnson > Freelance Plant Ecologist/Botanist > [email protected] -- Katie Rose Levin Duke University, Nicholas School of The Environment Masters of Environmental Management Candidate, 2012 Masters of Forestry Candidate, 2012 Environmental Professional, National and North Carolina Association of Environmental Professionals Wilderness First Responder, National Outdoors Leadership School The true meaning of life is to plant trees, under whose shade you do not expect to sit. ~Nelson Henderson ----- No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1424 / Virus Database: 2113/4833 - Release Date: 02/26/12
