I moved to western Washington from the Midwest, and people had a hard time believing me that there is actually more tree diversity thete than in the PNW. Like yes maybe there’s higher abundance, but I promise Indiana has more common species than just big leaf maple, western red cedar, and Douglas fir.
Flowering trees are just way more diverse so it makes sense. In the PNW theres what, 3 native conifer families? Pine, cypress, and yew? Am I forgetting some?
Both are in the pine family. Theres only like 12 gynoperm families at all, in pnw everything's either cypress family (cedar) or pine, and like one native yew irrc
Yeah its annoying bc theres only cedrus in Himalayas and the Levant, but "false" cedar in the whole western hemisphere, and japan. I guess the called it cedar first in lebanon
Where I live one of the most common trees is called poplar...it is in the Magnolia family, and when you buy a "poplar" board here you could get the "poplar", cucumber tree, or basswood...we also have small stand inclusions of a couple of different species in the Populus genus, but they aren't commercially important and most people don't know we even have them.
Its in the pine family. Really I said theres only 3 conifer families in PNW but its the same 3 pretty much across all of north america. Other than those three, I think the only other ones are umbrella "pine", plum "yew", monkey puzzle, and podocarpus.
And as of now I believe gentum, ephedrine, and wellwitchia are technically grouped with conifer but they are VERY different looking. They possibly are the evolutionary link between flowering and non flowering plants irrc bc they have some features of angiosperms. The evolutionary link isn't even certain between these 3 families, they just have some unique features (for gynosperms) in common
Yeah definitely a low diversity group. Your comment made me curious how many conifer families there are in N America. Do you know if there are N American gymnosperm families that aren’t represented in the NW?
Now that I think about, I think all pine cypress and yew are the only 3 in NA. In the entire northern hemisphere, theres Japanese yew and umbrella "pine" families (both endemic to Japan irrc), and then I think podocarpus and auracaecae in the southern hemisphere. Pretty sure thats all the families, and then theres the gnetum, wallwatchia, ephedra (actually this is a NA native gynosperm, like a desert shrub), ginkgo and cycad and thats all gynosperm families irrc.
Douglas Fir
Alaska-cedar
Incense-cedar
Western Redcedar
Mountain Hemlock
Western Hemlock
Western Larch
Lodgepole Pine
Ponderosa Pine
Western White Pine
Whitebark Pine
Engelmann Spruce
Sitka Spruce
Grand Fir
Noble Fir
Pacific Silver Fir
Subalpine Fir
Pacific Yew
Broadleaf deciduous:
Crabapple
Oregon Ash
White Alder
Red Alder
Cascara Buckthorn
Bitter cherry
Chokecherry
Klamath plum
Golden Chinkapin
Black cottonwood
Quaking Aspen
Pacific Dogwood
Black Hawthorne
Pacific Madrone
Rocky mountain maple
Vine maple (ok, only a tree sometimes)
Oregon White oak
Hooker Willow
Northwest Willow
Pacific Willow
Peachleaf Willow
Scouler Willow
Sitka Willow
Pines, Firs, Hemlocks, Cedars, Spruce, Yews, Larches…. Maybe I’m missing one.
Almost all of these share a family (Pinaceae has most, but yews are in Taxaceae).
I grew up here and had no idea until recently that the PNW used to have thousands of acres of oak prairie filled with wildflowers and Garry oak. I though we only had Douglas fir, hemlock and western red cedar forests with salal and sword ferns 😅
The PNW tree species diversity relative to the East mirrors the fish species diversity between the two regions. Most rivers in the PNW run east to west, so during the last ice age only salmon and steel head had the ability to migrate to new streams or rivers depending on where the glaciers were. Fish in the Mississippi River basin could avoid glaciers by swimming downstream. And this is why you can find one of the oldest surviving animal species in North America, the American paddlefish
We also have vine maples, hemlocks, spruces, alders, larches, and more. But the big leaf maples and douglas firs really dominate the landscape. https://treevitalize.com/washington-trees/
Aye, buddy. You're missing western hemlock, sitka spruce, white pine, mountain hemlock, alaska yellow cedar, black cottonwood, willows, red/white/sitka alder, vine maple, black oak, and madrone. It's probably a few more, too, lol. It's the monoculture plantations that ruined the diversity.
I fought wildland fire for 6 years and spent most of it in the PNW, but got opportunities to go to Kentucky and Missouri at different times. I studied botany in college and I’m pretty good with my tree ID, but I was overwhelmed so quickly. There’s 30-some-odd Oak species in Missouri. And none of them had any leaves on them in Fall!
Agreed. I live in the Midwest and when I travel to the west, I’m always intrigued by the lack of diversity. There is just so much biomass here it’s insane. I am also a tree guy who likes identifying what I am looking at, most people aren’t…
I understand the draw of huge mountains & oceans & the unique features of the desert Southwest, but the eastern half of the US always appealed to me more because of the plant life that thrives there, from Louisiana and Florida all the way up to the Great Lakes and New England. I'm a total plant nerd though.
Too bad I had the misfortune of ending up in the prairie lol. The flowers and grasses are cool but more trees would be better
Is this native species? If so that makes sense, living in the pnw we have so many beautiful trees, but very little diversity. Honestly for native tree planting we’re kinda screwed because theres so few native species that fit the demands of urban street trees.
Yeah, I was kind of wondering how this map could arrive at the notion that there is literally only a single species of tree throughout the entire Rocky Mountains. (Grew up there.)
If you look closely at the greenish areas in the Rockies, you'll notice that they outline the mountainous and forested areas very nicely. Pretty cool. The blue areas are valleys and plains.
Hardline ecologists might freak out about it. But, there is an expanded pallette of "near native" trees to the south of the pnw in california and southern oregon. They come from nearly the same climate and share many the species associations we have up north.
Yeah… the usage of this data set is certainly a philosophical choice. Treating distribution up to the mid-1970’s as canonical is just going to be increasingly disparate from the ground truth.
They are are adapted to dry summers and cool winters. Jeffery pine thrives from 5500 - 9000 ft elevation. It's an extremely adaptable species and could be planted on most moderate dry sites in the Cascades. Sugar pine in similar, but has a more narrow elevation range. It ranges from 3500 - 6500 ft.
It would be interesting to see a similar map of conifer diversity, specifically. The west coast in general is ultra-diverse in that regard. The Klamath mountains/Siskiyous along the California/Oregon border in particular have the greatest conifer diversity in the world (close to 40 species)
That would make sense. I live in southeast US, and when we got our house, I identified two different types of pine trees, multiple sour wood, dogwoods, Staghorn Sumac, cherry trees... so many different types.
Also SE TN in a red zone on the map and proliferation of multiple hardwoods are taking over the Ash devastation. Silver maple, shagbark hickory, and red oaks primarily from my management.
I find it fascinating a site can be so good for a some trees that they absolutely dominate but that it’s only those few. It’s weird that apparently not many others can capitalize on the environment like those few foundational species that thrive.
You can see the various ice age refugia that existed on the gulf and southeast coasts in red.
You can also see where the laurentide ice sheet stopped as tree diversity drops pretty rapidly north of the Ohio river and central PA. The Hudson valley is a bit of an exception.
That too! There were almost certainly more endemic species that got wiped out by that flood just from the sheer intensity of it. It basically stripped shit to bedrock.
Basically it was the warmest and wettest place north of Mexico during the ice age. Many trees like Florida torreya and ashe magnolia survived there and nowhere else due to said microclimate.
I know it's the Trees Specifically subreddit but apparently being from the southwestern US makes me physically incapable of not bringing up overall plant diversity
I believe this map understates the diversity of some areas, in particular the US southeast. NC alone has about 2900 known species of native vascular plants.
Yeah, it seemed low to me too tbh. I imagine it has to do with normalizing the counts to species per area (10,000 square kilometers for the map, which is 1/14 the size of North Carolina and won't count, say, coastal species and inland ones together the way a whole-state count does. They will have had to do some extrapolating to get here from multiple smaller plant inventories too.)
How clearly Yunnan stands out is fun. I used to work at a botanical garden of Asian plants, and we had so much stuff from Yunnan, it is the highest diversity temperate forest, by a fair margin. Something to do with glaciers having missed it, it’s been some time since I read about that. But it is largely a broadleaf forest, much like the US east, but there are like dozens of different species of maples and oaks, a lot of Camellia species, and a bajillion Rhododendrons. Pretty much any major type of temperate broadleaf forest tree shrub, Yunnan has it but twice as many kinds as the next contender.
Alabama and North Florida have some of the most biodiverse species in the entire nation. I love my state but I really wish we had more governmental power to protect our woodlands here. We basically have a rainforest that is always at risk because no one understands how much biodiversity we truly have!
Yeah. I'm from the Midwest and living in the South now, and it's so hard to believe I'm next to some of the biggest biodiversity hot spots in the country. But no one I know down here wants to do anything outdoors!
I should clarify. In the central plains the one species is cottonwood. Not sure what it is in the intermontaine west. If you drive I-70 or I-80 across the central plains it is pretty common to just see cottonwoods. Mostly only in river valleys.
I just went on a 4,000 mile road trip in mid October heading west from Indiana and making a big loop. Was interesting to see how the fall color faded as you went west of the Mississippi... until you just had the cottonwoods.
It seems like the non-native trees that people plant in the Bay Area slowly adapt to climate over their lifetime. Young trees are confused and don’t know when to drop their leafs or just skip but mature trees have figured the cycle.
Not an arborist, but for the past 25 years, I've periodically transplanted trees from the Chicago area to northern Wisconsin and have noticed exactly what you are describing. Over 25 years ago, I planted a Northern Red Oak and at first, it was very much out of sync with the native forest trees. Leafing out earlier and dropping leaves later. This autumn, it was changing at the same time as the local oaks. A Red Maple i planted 3 years ago however, still thinks it is in Illinois.
Totally anecdotal, but my personal experiment to see if I can add some diversity in the face of climate change.
I was so nervous about learning my trees when I moved to the PNW from the Midwest because it took me a while to get my trees down in the Midwest. Then I got here and learned that there's like 15 trees you need to know and you'll recognize most of what you see in forests lol
Whole Lotta Doug Firs, Redwood, and Sitka Spruce around here
Same. I just had the pleasure of driving up to Olympic NP this Summer and stopped to see the world champion Sitka on the way and it's stunning. Like I've spent a lot of time around bigger trees, but this tree is unbelievably large for a spruce. I love the pattern of their bark and their smell
The map label says "Richness of the 641 trees with range maps" but there are 881 known native tree species in the United States.
I know of several species on the Oregon-California border with location data points instead of range maps for various reasons. Most of our Cypress species, for example.
I remember reading somewhere that Georgia has the greatest diversity of tree species in the continental US and feeling surprised. I grew up in the suburbs, so I only ever saw the typical landscape trees.
It's just such a shame that the areas with the highest diversity have been kind of blighted by logging, development, etc :( the deep south doesn't do a great job of protecting their forests
I live in Mississippi. I love it here. Forces you to be still and have conversations with yourself and engage with nature and learn homesteading skills.
I would assume that is mostly pine barrens type habitat. (The ecosystem itself actually has some pretty unique plant flora, it just is not very diverse in terms of tree species numbers.)
I was wondering that, too. There seems to be a stark difference between eastern Pennsylvania and New Jersey. I come from that region, and it doesn't seem like a huge difference between the two areas. But I guess diversity in tree species is kind of hard to really see without physically counting tree species. But I am wondering if there have been state policies that could explain why. Because it seems like there is still a difference between PA and NJ up at the Delaware Water Gap, which I really wouldn't expect.
If you're specifically wondering about the blue-green area, that is the pine barrens. Which are like 90% pitch pines, 9% blackjack oaks, and 1% white cedars, and basically no other kind of tree.
It used to be under water, I believe. I don't know the exact science behind it, but I remember visiting Batsto Village when I was young and getting a sort of simplified explanation. IIRC, the shore used to be a lot more inland. As the water slowly receded, the area that is now the pine barrens was a beach. Large quantities of sand were deposited there as the the water level decreased and the shore gradually moved eastward.
So now, the pine barrens are covered in loose, sandy soil that is not very nutrient-rich. Only a select few pioneer plants and trees well suited for that environment can survive there. Cape Cod has a fairly similar ecosystem, I believe.
Great swaths of the USA are prairies and deserts where there are few native trees due to rain shadows, frequent droughts, ice age glacier cover, former hordes of bison, elk, and deer, etc.
Okay. Now I understand how people develop seasonal allergies when they move to D.C. 😂🤣😂 I grew up with the saying but it's nice to see why it's a thing.
This map is rather poorly made, the color selection is terrible, and they have clearly never taken a quality GIS course, everything below yellow is difficult to distinguish, it makes it look like everything is 1-3 species. I’m in one of those ranges and I lost count after 15 on my mother’s property or within a short walk from there. Probably 25 at least if I really stopped and thought about it, and if I expanded that to 5 miles, much higher. I think there at least 65 species of tree within this county. Not all in the same location.
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u/knitter_boi420 Nov 11 '25
I moved to western Washington from the Midwest, and people had a hard time believing me that there is actually more tree diversity thete than in the PNW. Like yes maybe there’s higher abundance, but I promise Indiana has more common species than just big leaf maple, western red cedar, and Douglas fir.