(thebrainscoop Intro Music)

(Sweeping violin and piano music playing sweetly)

Emily Graslie: Tree number 83.

Mmmm.

(Hacking noises)

E: This one?

Nigel Pitman: The other one.
E: Cut.
(Hacking noises)

N: Try to smell?
E: (sniffing noises)
Oh, it smells spicy!

N: Yes.
E: Yeah...
N: Nutmeg family, mace.
E: It smells really good.
N: Yeah, that's a good one. And it's also in a group that, um, people commonly call chicken blood because the latex is red, and so... so this is a group that's super diverse. It's sort of their version of oaks.

E: Oh, OK. So it's -- it's one of the more common things to see around here.
N: Yes. The family and this genus you run into a lot.
E: The chicken blood tree.
Man: Yeah, you can see a little bit of the...
E: Yeah!
N:... of the texture in there.

E: When you're locating these trees and they have all of these different odors, and, and things like that -- is that just a ... a indicative way to identify different species, or does that tell you anything about the quality of the forest itself?
N: It's just one of the characteristics you use to identify species... most of the trees on this transect don't smell like anything.
E: Mhhhm.
N: You could cut it and cut it and try... and they would just smell sort of like wood.
E: Yeah.
N: But there are a few... the ones that we're showing you... ones that do give you a clue through your nose...and those are a small proportion of the whole tree floor.
E: Yeah.
N: And the other ones you have to use bark or roots or latex: the other things that we always look at.
E: So we were just using our smell skills to identify those.
N: Right, right.
E: Cool.

(Energetic piano scales)

E: Smells like a new car. If you had a key lime pie in a leather Porsche. That's what this one smells like. Nigel, what do you think it smells like?

(Sniffing noises)

N: I'm going to go with turpentine.
E: Corine, what's the verdict?
Corine Vriesendorp: I gotta make sure.
E: You gotta make sure?
C: Like carrots...dipped in turpentine.
E: Carrots dipped in turpentine.
C: That's how you're going to get this family, the Burseraceae.
E: How would I have ever come to that conclusion?
C: You gotta work.
E: Oh, wow.
C: You gotta train.
E: I don't get the carrots, though.
C: Oh, yeah. Totally.
E: Really? Let me see.
C: Think about it.
E: So, key lime pie in a Porsche wasn't really close?
C: No, but it's perfect. That's how you're going to remember it. You're going to come up to one of these and you're going to cut it, and you're going to be like "Key lime pie. Porsche. Burseraceae."
E: Key to becoming a great botanist.
C: Totally. You have to make up your own smell associations because that- it's totally gonna work.
E: That's awesome.
C: Yeah.
E: Cool.

(Softer piano music)

C: What's incredible here is that we're actually finding rocks. In the place just north of here, where the Matsés live? It turns out the Matsés don't even have a word for rock in their language. So, to be finding these little pebbles, these are probably sandstone or quartzite. And these are creating these really sandy, rocky, pebbly substrates. And this tells us something about what these trees are growing on. These very nutrient poor soils. Even though it's extremely nutrient poor, there's still thousands of species that are making a living on this.

(Water splashes)

(Softer piano music)

N: One of the interesting things in tropical forests on really poor soils is that it's expensive for the trees to make leaves and fruits and flowers. So unlike the temperate zone, where you make a leaf for the season and then it does its job and it's done, in the tropics, trees build leaves to last. So some leaves have been monitored: same leaf, on the same tree, doing its job for decades.
E: Really?
N: Yeah. One thing that leaves need to have in order to last a long time is defense against insects. So, that one. It's one strategy, right?
E: Yeah, it's really thick. It's like leather.
N: Yeah, it's like a credit card. Imagine trying to take a bite out of that. Here's another strategy that's really neat.
E: Ooh!
N: So these are young leaves. They're gonna get this big, but they're just emerging now. And right when they emerge, there's this blob of resin right there. So as they emerge, they get coated with this resin. And feel that.
E: That's strange, yeah. It's like it's been crystalized in honey or something.
N: Yeah, it's like it's covered with bug spray. So, they're really young but if they didn't have that, they'd be super delicate and soft and perfect for...
E: And tasty?
N: Uh huh.
E: That's...insane. Wow, it looks plastic. Like, it doesn't even look like a real leaf.

(Dreamy light piano music)

Tom McNamara: (Offscreen, cameraman) Okie dokie.
E: Ready?
T: (Offscreen, cameraman) Mhm!
E: Alright, Nigel. What are we doing with these poles?
N: When things are too tall to cut with the clippers or to climb a bit and grab a branch, we put these extendable tubes together and they get us to maybe eight meters.
E: Wow.
N: So we have this cutting mechanism up here. Same thing as pruners...
E: Yeah!
N: Tree pruners you use in the States.

E: Wow. Are you going for that branch?
N: Yeah.
E: Whoa. Whoa! Hey, I saved you, Tom! Well, that's your branch. So, what is this tree?
N: So, hmm...
E: He's the plant whisperer.
N: So, they're alternate.
E: Oh!
N: The leaflets are opposite, but the leaves are alternate.
E: Mmm.
N: So that narrows us down to maybe ten families? This one...I don't know.
E: You don't know what it is?
N: I'm not sure what it is. I think it's a Sapindaceae. We've been getting a lot of weird stuff. And we're wondering how to sat that in a report. "We're finding a lot of weird stuff!"
E: Yeah! That's the scientific conclusion that you came to.
N: I guess that any forest you come to that's incredibly diverse you find lots of these unusual species that are really rare.
E: It's so incredible to me how you can have so many different species, like such an incredible wide variety that are all existing in the same area. It just seems like there would be too much competition.
N: Right! So that's one of the big mysteries that gets a lot of people interested in tropical ecology in the first place. Why...?
E: Yeah.
N: Why isn't there a winner? These guys who are better at being Amazonian trees...how come they don't take up 50% of the forest and knock off the species that aren't so good at being trees?
E: Huh.
N: So there are lots and lots of ideas about that, but we're not really sure what the answer is.
E: Wow.

(Gentle piano music)

(thebrainscoop outro)

E: It still has brains on it.