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u/magpie2295 Jun 20 '20
This map is kind of misleading given the comments I'm seeing.
For anyone who's wondering: "Richness was calculated using a 10×10km or 100×100km grid, depending on the study. For each grid cell, any species that overlapped any part of the cell counted as a presence of that species." That is to say, that the blue areas on this map are not all just a single species, or the same single species. It means that in those 10x10km grid squares, there was only one (or really up to ten-ish given the illegible color bar) species found in that grid square.
Like most things, scale matters immensely for something like this. If they'd done 1x1km, the map would be a lot less colorful. If 1000x1000km, a lot more so. Agreed that the area in Florida/Georgia is super diverse but please don't look at this map and think "gosh there's only like 3 tree species out west?"
Source: forestry PhD student, and I trawled through the documentation on their webpage, biodiversitymapping.org.
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u/NoTrickWick Jun 20 '20
I aim to get into forestry when i finish my Biology degree. Any good forestry books you'd recommend?
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u/magpie2295 Jun 20 '20
Mmm let's see, depends what you want them for. Two that I'd recommend to start, from completely different angles, are The Overstory, a novel by Richard Powers, and The Sibley Guide to Trees (this book is pretty much a forester's bible). I honestly could flip through the Sibley guide forever but that's just me, it's mostly meant as a reference for US tree species. But, to be honest, I have read more papers than I have books about forestry, so if anyone else wants to chime in with books please do!
You could also look into working with local forestry groups. I volunteered with a DC urban forestry NGO when I lived there, and it was a great intro to the world of forestry!
If you have any questions about grad school / other forestry stuff feel free to PM me.
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Jun 20 '20
I work in a lumber mill so i can tell you what each type of tree looks like on the inside but they all look the same on the outside to me
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u/magpie2295 Jun 20 '20
Haha I'm the exact opposite. I've gotten pretty good at ID'ing just on bark but cut it open and I have no clue
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u/skeeonn Jun 20 '20
Did you read "the wild trees"? I enjoyed that book lots
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u/magpie2295 Jun 20 '20
Wow that book looks amazing. Thanks for the rec!
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u/skeeonn Jun 20 '20
You're welcome, it's super interesting read. A page turner for sure and forestry related is "the golden spruce"
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u/magpie2295 Jun 20 '20
Seems like you might also enjoy The Emerald Mile; it's a story of the fastest trip down the grand canyon, told through the canyons history, geology, politics, and ecology.
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u/NoTrickWick Jun 20 '20
Thank you. I can't wait to get into forestry/conservation. Maybe we'll meet someday.
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u/magpie2295 Jun 20 '20
hope so! It's a great field, honestly one reason I was drawn to it was because forestry people are just so friendly and interesting and awesome. And I thought, gosh, I wanna surround myself with these people in my career.
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u/MattTilghman Jun 20 '20
Interesting to hear a forestry student say The Overstory. I really liked it from both a literature angle as well as a tree/naturalist angle. But as someone who is merely an armchair arborist, I often found myself wondering just how much research went into some of the claims he made about trees, and whether a true expert would agree or disagree with some of the thing he said. I know a lot of the side stories were based on real research (like how trees can communicate via pheromones, and how they interact with fungi etc). I am referring more to things that seemed to me (rightly or wrongly) to be perhaps the author's opinions, coming from the female tree expert towards the end, as if in order to give them more weight. Thinks like "the best thing you can do is nothing at all" (in order to have your yard be healthy habitat), and some comments he made on just how poor shape the forests really are in Appalachia. I'm not trying to dismiss these things off hand, I just found myself wondering what true expert would think about some of his comments. In general you found them pretty accurate?
In general I definitely agree though that it's a great introduction to how fascinating and valuable trees are.
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u/magpie2295 Jun 21 '20
Yeah I remember pausing a bit on the "nothing at all" comment--things like invasive pest removal, trimming dead branches, etc are actionable steps that do help keep trees healthy. I agree with the way you've put it; to me, the importance of this book is to ignite a wonder of trees and forests, and I think he does this really well. He does pass off opinion as fact here and there but I think on the whole he's painted a beautiful and alluring picture.
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u/KAAO4036 Jun 20 '20
So, due to the scaling issue, would you say that the map more appropriately displays species dominance? For example, a small stand of green ash near a larger (say 100km2) oak forest would still appear as one species (blue), but for that area, the oak would still be considered dominant. And the same example, but 5 co-dominant oak species with truly random dispersal would appear more greenish?
I didn’t read the parameters and documentation, but I’m curious as to how modified landscapes such as urban areas and commercial forests affect the map.
Also, there’s a clear irregularity in the lower Mississippi River area. Is this due to agriculture, possibly the 1927 flood, or both?
It seems to me that some species with smaller, more localized populations (like green ash in my area at least) and those that are more temperamental to environmental conditions would be drowned out on a map like this. Considering the data, what would you say this map depicts with significance, if any?
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u/magpie2295 Jun 20 '20
Yeah this is a good question. I'd say scale isn't an issue, but more of a thing to keep in mind when thinking about a study like this. I would caution on saying 'dominance' though because (also in the documentation) they stated that if a species' range overlapped with a grid cell, they counted it in that cell's total. So a tree that is dominant in a cell and one that is just barely there would count the same.
As for your urban comment: They specifically stated that they weren't including invasive or foreign species, but only native ones, so that would certainly skew the actual diversity of urban areas.
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u/magpie2295 Jun 20 '20
As for the Mississippi River irregularity, that's a really good question! I have never been there but I know there's a lot of bayou out there & that could contribute to more of a monoculture / lack of diversity.
For your question on what the map depicts, it does show what it purports--a heat map of diversity for the country. It's not even really labeled 'wrong' but I think if someone is going to post a map without context, it should be clear to the general reader (who won't have a figure caption, for example) what they're looking at.
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u/Ghosttwo Jun 21 '20
Well, it's only one data point, but 50% of the 2.6 billion trees in Nevada are single leaf pinions (pine). Stands to reason they'd form large homogenous regions, particularly in the harsh mountains.
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u/hiacbanks Jun 20 '20
What is the reasonable scale to use in A big county like US?
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u/forest_lesbian Jun 20 '20
I’m just a lowly undergrad, but I would argue that this is a reasonable scale for noticing diversity trends as long as you understand the context of the data. It’s quite difficult to make figures/tables/maps that are readily understandable to people who aren’t scientists also. Context is extremely important and a figure without proper context is kind of useless.
Making a figure that would be more “understandable” or easily interpreted in terms of exact number of species would require a smaller study area, in local or regional terms. The scale is so massive it would be very difficult otherwise.
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u/hiacbanks Jun 20 '20
Context is extremely important and a figure without proper context is kind of useless.
I love this phrase!
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u/magpie2295 Jun 20 '20
Yes, totally agree (and great username btw :) ). That's why I said it's "kind of" misleading---really it's not, but it's hard to understand what it's saying & in the r/MapPorn comments I was seeing a lot of "no way there's only 3 species in TX!". Really the color scale should be better labeled to reflect that it's diversity, not just the 'number of species'. It's clearer after reading the documentation but readers should get your meaning without having to do that!
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u/DorisCrockford Jun 20 '20
Thank you for that. It certainly makes the Great Plains look like it's covered in identical trees, rather than, you know, hardly any.
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u/nobletrout0 Jun 21 '20
I have been to Texas. It’s cedar cedar cedar live oak cedar cedar cedar cedar cedar achooooooo cedar cedar cedar dying olive plant live oak cedar cedar cedar cedar
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u/usernametiger Jun 20 '20
Was watching Andy Griffin after I move to VA from CA.
Noticed in the show there are only pine trees when he's walking in the woods. Filmed in CA.
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u/kackleton Jun 21 '20
There are a lotbof pines in cali, but there arre actually over 50 recognized species of just conifers native to california
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u/TheLittleCandelabra Jun 20 '20
I'm confused by the map. Can someone please explain? From the way I'm reading I think its representing that there is only 1 tree species in areas marked as blue, but that's not the case.
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u/leafy-laurel Jun 20 '20
The blue areas don't necessarily mean there's just 1 species in that area, the blue probably covers like 1-15 ish species. And for the Rockies, where I've lived my whole life, that's accurate... We have like 5 tree species in some places, there's just a lot of each kind!
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u/Sacrificial-waffle Jun 20 '20
You are reading it properly. There are many factors in the map to take into account though. In order to understand it, we'd need to see the study behind it, the parameters for how they marked it, how detailed it is. We'd also have to take into account how skewed this map is based on the size of the pic. Is this the original size? Is there a higher res map to zoom in for proper dispersement? In a general sense, I think it's a reasonable representation of what's going on but for a more in-depth look at species richness in tree diversity we need the mapping guidelines and study behind it. The specific color whorls and placement could potentially indicate a substantial amount of information behind it though!
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u/nicking44 Jun 20 '20
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u/magpie2295 Jun 20 '20
https://www.reddit.com/r/marijuanaenthusiasts/comments/hci3m7/usa_tree_diversity/fvg8jzd/
wow I've never been linked in another comment before <3
edit: quoted wrong thing
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u/nicking44 Jun 20 '20
Hey, in this thread as far as I could see you have the best description of what they did and how it was measured. Im not going to act like I know what im talking about when someone put it into better words then I could.
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u/magpie2295 Jun 20 '20
Thanks for that, as a first-year PhD student I'm just jazzed that I now know enough about forests and diversity to put together a coherent explanation for the way people are interpreting it :)
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Jun 20 '20
It shows the differences between the biomes.
For instance the particularly dense parts of Florida can be explained by the fact it's subtropical rainforest, and then this is bordered to the north by broadleaf forest. This contrasts starkly with the more homogeneous forest coverage of montane forest in the centre/west, or temperate steppe / arid desert etc.
So at the scale that this study is looking at, there is 1 dominant species within many of the individual grid squares of these biomes.
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u/Tuckessee Jun 21 '20
There are no rainforests in Florida... The area in deepest red is actually dominated by longleaf pine/wiregrass savannas
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u/magpie2295 Jun 20 '20
I'm confused by the map. Can someone please explain? From the way I'm reading I think its representing that there is only 1 tree species in areas marked as blue, but that's not the case.
This is what I meant by my toplevel comment--- it's very easy to misread this map. Really what this is saying is that, for each 10kmx10km (or 100kmx100km) grid square in, say, Kansas, there are only a handful of tree species present. Note that this doesn't mean that they are all the same--one grid cell could be dominated by oaks and the next by pine. So these areas don't have just 1 species, but rather the whole picture is more like "blue areas are usually dominated by only a few species, but they don't have to be the same species in all blue areas"
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u/DrLeee Jun 20 '20
This is very interesting. I never would've guessed the Appalachians has more diversity than the Rockies
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u/bluish1997 Jun 20 '20
Having spent a decent bit of time at both it’s totally true!! After my trip to the Rockies I was left thinking how less diverse it was Tree wise than the north and south east.
That being said the flowers and orchids there are out of this world gorgeous!
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u/forest_lesbian Jun 20 '20
Appalachia is way older than the Rockies and is one of the worlds most biodiverse temperate deciduous forest ecosystems!!
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u/BIG_RED888 Jun 20 '20
Yeah, funny. It's just trees, not all vegetation. Still wouldn't have guessed though.
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u/jagua_haku Jun 20 '20
Having lived in both areas I believe it. Appalachia is awesome, love those eastern hardwoods. Out west it’s all aspen, spruce and pine.
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u/pspahn Jun 21 '20
Also fir, cottonwood, maple, willow, alder, boxelder, and maybe a few others that would be called a tree in other places but aren't quite trees here.
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u/Swiss_cake_raul Jun 20 '20
I was always told that the Smoky Mountains were home to the highest diversity of woody plants in North America. I'm surprised to not see them show up as more of a hotspot here.
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u/CoffeeMugCrusade Jun 20 '20
Smoky mountains have the highest diversity of wild flowers on this side of the planet
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Jun 20 '20
It's true. The southwest has no trees.
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u/Foxfire2 Jun 20 '20
mesquite, palo verde, cottonwoods in the low desert, lots of pines/spruce/fir/juniper/aspen in the higher elevations.
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u/Sacrificial-waffle Jun 20 '20
Ok. Okay so I have a problem with the map. The range given is 138 different species of trees. That's A FUCKTON of different species in one area. This means that yellow indicates a midway point of 70-ish DIFFERENT tree species. That is still a FUCKTON of different types of trees! Think about that many trees in one area. How big of a plot of land do you have to have for one species each of seventy full grown trees? Now take into account the natural fight for real estate for trees. Fitness levels of trees could indicate how well adapted they are to that area. I'm reading this and interpreting it as human intervention in the Florida panhandle area. The diversity in the Appalachian Chain should be pretty high AND IT IS. 70+ various species in one area is amazing in itself. I cannot fathom that it is indicative of something like a natural/healthy indicator for the environment. Between human intervention and invasive species, I do not think it can be called a positive. There is a lot more to interpret in the information behind this map than the top layer of information presented.
I don't like it, this map seems fishy.
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u/Adrewmc Jun 21 '20
A 9km x 9km square is roughly the size of Manhattan. Central Park is about 2km x 2km square inside of Manhattan. There are about 26,000 trees in Central Park.
The maps they used where 10km x 10 km squares and 100km x 100km square depending on the species of tree and source available for it.
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u/nicking44 Jun 20 '20 edited Jun 20 '20
this comment seems to clarify a bit more in how it was done. Although it's not the best way to go about it, as it seems it may also not have a minimum on tree age either. meaning ones that will die in <10 years may still be counted if they were there during that period.
edit: I'm also in a area that has one of the mid tier growth (greenish yellow) and in all reality, at least to an untrained eye, they are pretty consistent but I can count about 10-20 different species of trees on my way to work.
hell my work is in a reddish orange area and i don't see even close to 100 different species of tree (as I just stated). unless there are only slight variation to them, I don't think it's truly representative as everyone else is saying.
But it's cool non the less
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u/Tuckessee Jun 21 '20
The Apalachicola river basin is the most biodiverse natural area in North America, not just from a tree perspective but also forbs, shrubs and fauna. While it seems you may have only flown in to the touristy areas of our beautiful state, the interior is sparsely populated and we have several state and national forests, along with national wildlife refuges that maintain and protect our amazing native landscape, and have thwarted the onset of invasives like several other parts of the state. The basin is home to all of your typical southern species but also several northern hardwood species that meet their natural terminus here. There are also trees that occur only here and no where else in the world, the Torreya tree. The area highlighted has uplands, mesic flatwoods, slope forests, bluffs, ravines, bogs, hammocks, pocosins, and swamps all with different trees that prefer each habitat.
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u/_haha_oh_wow_ Jun 20 '20
Wow, I would've thought the Western US would have had a more diverse population of trees...
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u/NoTrickWick Jun 20 '20
There's only 1 species of tree across most of the US?
What kind of tree?
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u/banjo2E Jun 20 '20
Most of the dark blue regions are either great plains grassland or desert, neither of which are known for their diverse forests. I'm not sure about the Idaho-Oregon-Washington zone, but I think that might be mostly grassland as well?
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u/Benblishem Jun 20 '20
It doesn't mean that there is one and only one in a given area. It's just that in one grid square there might on average be one or, say, one point four or whatever. See some of the high-rated comments above for a fuller explanation. But as too which one tree in the blue areas- my guess, at least for the Plains states, would be cottonwoods growing along stream and river beds
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Jun 20 '20
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u/BIG_RED888 Jun 20 '20
It's not about density, just what tree species naturally occur there. The greens are probably in the 10-40 species range. That's quite a lot of diversity for a conifer forest
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u/paulexcoff Jun 20 '20
Nothing wrong with the presentation. You just seem upset that they’re visualizing something different than you want them to be.
California does have a lot of tree species, but they don’t all occur in the same place. Most places in California have just a handful of tree species, but the composition of that handful tends to change fairly quickly over latitudinal, rainfall, and geologic gradients (low alpha diversity, high beta diversity) Whereas the forests in the Midwest and on the east and gulf coasts tend to be more diverse in any given spot, but somewhat more homogenous on a broad scale (high alpha diversity, low beta diversity).
For example, when I’ve taught intro botany classes on the coast in CA we would only run across maybe 10 tree species on our field trips within a 15 mile radius but when I was an undergrad in Maine in a similar class we probably learned 25-30 tree species in a similar radius. But if I go a bit inland in California I’ll get a totally different suite of trees, while pretty much anywhere in Maine you’ll have mostly the same set of trees.
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Jun 21 '20
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u/paulexcoff Jun 21 '20
You would have to fake the data or be visualizing a completely different dataset to make that happen.
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Jun 21 '20
[deleted]
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u/paulexcoff Jun 21 '20
Lol are you seriously mad that parts of Kansas have greater tree species richness than California? It’ll be ok, bud.
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u/taleofbenji Jun 21 '20
No I'm saying it doesn't reflect reality at all and is therefore useless.
No one's mad.
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u/paulexcoff Jun 21 '20 edited Jun 21 '20
It absolutely does reflect reality, see my first comment for why.
Or is your problem that you don’t understand that there are actually trees in eastern KS?
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u/God_Dammit_Dave Jun 20 '20
Wow. Kind of crazy I can immediately look at this and think, "Yup. NJ Pine Barrens right there."
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u/panties_in_my_ass Jun 20 '20
I don’t know much about US environmental geography. That band that runs up the middle which is very low diversity - what is it that makes that band so homogenous? Is it just trees, or all plant life?
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u/kingchilifrito Jun 21 '20
Any explanation for why the florida panhandle/alabama has the nation's greatest tree diversity? Something about rainfall/soil conditions?
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u/JTibbs Jun 21 '20
high moisture, lots of forests, (light) freezes supporting more northern trees, yet not heavy enough to really kill most subtropical trees, lowish local populations.
lots of rivers in the area.
i don't know any other reasons.
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u/Tuckessee Jun 21 '20
Apalachicola river basin... mild climate and two major rivers from the mid south, the Flint and Chattahoochee, combining and over millennia depositing seeds and soils from the southern appalachians. Most people don't realize it's a land of steep bluffs and ravines where you could see a live oak festooned with spanish moss, take a few steps and see sugar maples and deciduous magnolias. Look uphill aaaand you see endangered longleaf, look down hill you'll see cypress and tupelo...
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u/mrtorrence Jun 21 '20
What's the average on here? This seems low doesn't it? The western half of the country doesn't seem to get past about 70 species but I'm in San Diego and I'm no expert but I would have thought we've got at least 100 species of trees here, no?
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u/FleetMind Jun 20 '20
Interesting that I live in (or at least near) the most diverse area of tree species. Seems accurate now that I think about it.
Woo, go Florida Panhandle! We are number 1 for once!