Terminal velocity is a broadly a function of the size of an object, as small objects have more drag force at a given speed per kilo of mass. I suggest that most seeds have a terminal velocity of FAR less than 200mph. Bearing in mind they're designed to fall off trees anyway, I suggest that landing on unsuitable ground is a much more significant factor in whether or not they germinate. You could always test this by throwing some off a tall building onto some mud or grass. I bet they'd be fine.
2008/12/5 Alvia Gaskill <[EMAIL PROTECTED]>: > > I think you have the Geoengineering Google Group confused with the Discovery > Channel, unless your message was sent to them and you copied the group on > it. This is a discussion group for geoengineering and because of the delay > in the broadcasts of this series internationally, I volunteered to summarize > the programs for those who were not able to see them yet. I still have 5 to > do also! > > As for the Raining Forests program, I concluded that the black mangrove > seedlings failed to take root because they were planted in January at the > uppermost northern extent of their natural range, a consequence of the > filming schedule that impacted other programs in the series as well. > Another explanation could be as Hodges noted, due to soil conditions. He > found that some of them had begun sending out roots, meaning that the drop > from the helicopters had not destroyed them. In general, however, objects > dropped from aircraft attain a terminal velocity of over 200mph when they > impact the ground, rendering this method useless for all but the softest of > soil, which as it turned out was the case for the sand bar in Louisiana > where this study took place. I see no way this could be duplicated for > forests and saplings. > > Your proposal to instead drop seeds has also been used before, but primarily > to reseed hillsides with grass, not plant trees. Also, forests are complex > ecosystems, so one cannot "replant a forest," simply by dropping some seeds > from an aircraft. I would also question the extent to which such programs > would be effective in planting trees this way. That's why foresters plant > saplings and not seeds. > > You are correct in that the Discovery Channel program went overboard on > their concerns about the carbon footprint for this and the other programs as > well. I have no control over the comments from critics that they presented > on their website. You can check their website to see if there is some kind > of comment mechanism for these programs. I am not aware of one. > > Alvia Gaskill > TV Critic (sort of) > > > ----- Original Message ----- > From: "greenflight" <[EMAIL PROTECTED]> > To: "geoengineering" <[email protected]> > Sent: Thursday, December 04, 2008 4:38 PM > Subject: [geo] Aerial Reforestation is Nature's way! > > > > Comments to Mark Hodges "Raining Forests" > > I am writing to you because our NGO has also been working for the last > ten years in the same general idea I watched yesterday in the 'Raining > Forests' program at the Discovery Channel. First of all I want to > congratulate you and all of the people involved with the show for a > wonderfully entertaining and illustrative production. I am really > sorry you did not get the results you were expecting but I am certain > you are on the right track. > > Commenting your experiment outcome (and probably you already have > arrived at the same conclusion), l think you should revise the drop > altitude and type of container that were selected. At first look, it > seems that the chosen combination was fatal because of the resulting > mass, terminal velocity and consequent violent deceleration might have > crushed and destroyed the seeds cellular cytoskeleton, effectively > 'killing' them. > > We think a seeded hydro-mulch mix approach from a much lower altitude > could better replicate the natural aerial reforestation process that > has been successfully going-on since the beginning of time, yielding a > superior result. A bottleneck in this alternative would be getting a > large enough native seed stock to do the job with hydro-mulch on a > sufficient grand scale (only in Mexico, we are talking of more than > one hundred million acres). But we think it is not that difficult to > build the necessary scheme and infrastructure to solve that particular > problem in the same manner you propose, that is, by getting indigenous > communities to participate and benefit. > > Going straight to the point, I want to ask you if you could get in > touch with the Discovery Channel people and get them to change some of > the "Critics Voice's" assertions 'they' make on the corresponding Web > page for the 'Raining Forests' program, which are quite wrong and > could by-chance hamper arduous and longstanding lobbying efforts. > > In order of appearance, it is stated there that the necessary flights > carbon-footprint would be too large and, for that reason, subject to > condemnation. Well, that could probably be true if helicopters were > the chosen aircraft for the job but it's not the case for large Single- > Engine Air Tankers that can fly slow and low enough for an accurate > drop with very big loads. For instance a Bell 212 helicopter like the > ones I think are used on your experiment consume 115 GPH while a large > SEAT does 70 GPH. But that is not all; a SEAT can load almost 9000 > pounds of seeds while the Bell 212 could do only half that load > safely. So for that matter, a SEAT would "yield" 130 pounds of seed > per gallon of burned fuel, while the helicopter would only yield 40 > pounds of seeds per gallon. That is a 3.25 to 1 productivity ratio; > or, in this case, 70% less carbon-footprint per pound of seeds. > Furthermore, the same SEAT "fleet" might be utilized in a better > wildfire firefighting strategy during the fire season, effectively > offsetting any aerial reforestation carbon-footprint and much more. > > I think is futile to fight the senseless SOP argument and, most of > all, the people who defend it; so let that be. But what we cannot in > any way let pass is the bold, inaccurate and careless final statement > that "Aerial reforestation would, of course, be hugely expensive." If > anything, Ag-aviation has been demonstrating for the past 70 years to > the world and without contest that there is no cheaper way of sowing > seeds. The direct operation costs of aerial seeding, is in the cents > per acre figure. And there is no way that manual reforestation can > beat that. Seeds for aerial reforestation also are infinitely less > expensive to produce than the seedlings needed for manual > reforestation. > > Please help us by making sure that the Discovery Channel fixes those > substantial mistakes. We are not against debate nor do we run away > from a good honest polemic but in that tenure, if Discovery Channel is > going to publish those "Critic's Voice's", the least they could do is > give an equal opportunity for refutations. > > Fundación Vuelo Verde, A.C. > > > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
