Guy Meilleur
Addicted to ArboristSite
Just got this recent issue, which had less arb content than the last. I liked Shigo's article on lichens; I always tell clients they are not parasitic but mutualistic or even symbiotic, as they may be able to transfer photosynthate to trees. I don't understand a few of his points:
1. If "There are no data that shows (sic) lichens cause tree or rock diseases", then how is it that "Lichens also produce acids and other chemicals that break down rocks and other materials" (including wood?) Their interaction with trees is poorly understood but since they're green plants that have been around a long time I think the odds are they do much more good than potential harm.
2. Can anyone make sense of the second photo? The branch piece on the left has stereum fungus, but the one on the right has green stuff that clearly looks like lichen to me. Is stereum the mycobiont? Can algae just float around and latch onto fungus, creating a lichen? Hard to say; a caption would've helped.
3. "Whether the (long beard-moss) lichens help...or limit photosynthsis, nobody knows." Sure we do! Anything that shades a leaf inhibits photosynthesis. That's not to say all growth that competes for sunlight should be stripped, but if you don't want bare middles in your trees you need to thin the outsides.
Three letters came in in response to the dropcrotching article in the last ish. The first I think speaks for itself
, while the second contains a very typical reaction from the diehard academic point of view. Saying that scientists should know better than practitioners is just one example of the writer's ivory-tower arrogance. Demanding research data to support every recommendation limits us to drawing from a small pool of learning.
There is good science that is based on observation and measuring alone that can be the basis for the art of tree care.
More rigorous experimentation would be great to do, but in the meantime we can work based on our understanding of the available science, in areas where research has not yet been able to explore.
The third letter echoes Turnbull's assertion that any tree with a "compromised" future should be removed. What tree's future isn't compromised, by epidemics, insects, or the worsening air and glare and soil and everything else humans are messing up? Once an arborist adopts the philosophy of preventive removal, where does it stop?
30+ years ago I was a utility climber, with a can of paint on my hip and the foreman filling my ears with "when in doubt, cut it out". It's 2004 now, so it's really disturbing to hear alleged advocates of trees say they should be cut down if they are "compromised".
Finally, I don't know why the author didn't respond to the critiques to her article. In most magazines, authors are given that chance.
1. If "There are no data that shows (sic) lichens cause tree or rock diseases", then how is it that "Lichens also produce acids and other chemicals that break down rocks and other materials" (including wood?) Their interaction with trees is poorly understood but since they're green plants that have been around a long time I think the odds are they do much more good than potential harm.
2. Can anyone make sense of the second photo? The branch piece on the left has stereum fungus, but the one on the right has green stuff that clearly looks like lichen to me. Is stereum the mycobiont? Can algae just float around and latch onto fungus, creating a lichen? Hard to say; a caption would've helped.
3. "Whether the (long beard-moss) lichens help...or limit photosynthsis, nobody knows." Sure we do! Anything that shades a leaf inhibits photosynthesis. That's not to say all growth that competes for sunlight should be stripped, but if you don't want bare middles in your trees you need to thin the outsides.
Three letters came in in response to the dropcrotching article in the last ish. The first I think speaks for itself
, while the second contains a very typical reaction from the diehard academic point of view. Saying that scientists should know better than practitioners is just one example of the writer's ivory-tower arrogance. Demanding research data to support every recommendation limits us to drawing from a small pool of learning. There is good science that is based on observation and measuring alone that can be the basis for the art of tree care.
More rigorous experimentation would be great to do, but in the meantime we can work based on our understanding of the available science, in areas where research has not yet been able to explore.
The third letter echoes Turnbull's assertion that any tree with a "compromised" future should be removed. What tree's future isn't compromised, by epidemics, insects, or the worsening air and glare and soil and everything else humans are messing up? Once an arborist adopts the philosophy of preventive removal, where does it stop?
30+ years ago I was a utility climber, with a can of paint on my hip and the foreman filling my ears with "when in doubt, cut it out". It's 2004 now, so it's really disturbing to hear alleged advocates of trees say they should be cut down if they are "compromised".
Finally, I don't know why the author didn't respond to the critiques to her article. In most magazines, authors are given that chance.
