(outdoor ambience) - [intviewer] my firs estion iwhat is tree? - , what ithe tree aughing) - damn it! - at's tou one, acally. at is thtree? (pianopbeat muc)

human beings have been living at the edge of forests for a very, very long time. (upbeat music) (wind whirling) the edge of the forest is where we belong. (upbeat music) (wind whirling) trees are both familiar and alien. (upbeat music) (wind whirling) th don't gany plac ry fast,ut they dure.

(upbeat music) (wind whirling) compared to humans, they're old creatures that we scarcely understand. (upbeat music) (wind whirling)

the rld of pes preced the wor in whi humans uld live itakes a setch of imagation tosk, ll, whatoes that wod look le?

(beeping) utdo ambienc [dr. milr] we don't ually sethem until ey're a w years d. you could imagin w vulnerle it is in tse arid ils gettinenough wer thugh thoslong hotummers buif mom w living therfor 4,00years, then that was a pretty good place. the estimates are less than 1% of survival, but if they survive those first few years, they're pretty good to go. and really there isn't much that kills the bristlecone. (upbeat music) (wind whirling)

as an historical ecologist, i think a lot about times when there were trees, but no humans.

and so sometimes i'll go to places where there was before humans in my mind, because i know those places well from studying them where pines evolved and the bristlecones and the mber pin forests e those aces. i am intested in tryi to undetand how thestrees in untain eironment toleratehistoric naturaclimatchange, becae i thin that c be usef founderstaing what will ce in theutur thugh the owth ringof the wd. i can construc the pastlimate and i n know h they resnded. soo see a 000 yearld tree and tohink of w much it'endured anwhat is le to perst under

5,000 yrs, at's beean enormous ount of imate chge. they c't move get awaythey havto stay and ce what mes. theibest, peectl apted toe in onelace. (beeping) ind whirng) (speaking in foreign language)

(cutng) (upbeat sic) (saking inoreign lguage)

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(speaking in foreign language) (tin enginroaring) pbeat muc) (saking inoreign lguage) (upbeamusic) (speakinin forei languag

(heartounding) (speakinforeign nguage) (ueat musi

(speakinin forei languag (water splashing)

(speaking in foreign language) ater splhing) (ueat musi

(speakg in forgn langue) (upbeamusic) (heart pnding)

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(ueat musi (speakg in forgn langue)

(upbeat sic) peaking foreignanguage)

pbeat muc) (beepi)

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- [leah] was sev and was withy ski grp and could rember the weavinthrough e trees. and i n't know wh happeneto me, t i justemember one point beg lost in the ees. and just sathere wooing f a little ile anrealizing that i w alone. (outdoormbience) growg up treskiing, you had have a ll. i, a l of timese the pers that i'skiing wh d then a of a suen, my frienwill be ke, (wing)

as like a signaling beacon. u'll get t reverbetion from seone els and thene know we' rely closeogether. it's kinof a cooway of communicing throh the trs witht being le to seeomeo. utdoor aience) (upbeat music) - [dr. suzanne] the forest is a holistic place. it's a place that's connected. since i was a little kid, i played in forest like this. they're like treasure chest full of biodiversity, of genes, of species that are really, really old.

kn that th is a special ttle heabeat inhe landspe where thesthings ride. 0 years a long timyou know th's 12 tis as olds i am. and you gethe sense history many spits have be here bere, t just han spiri, bumany creures havlived here a they stl live he d i get at sensehat i'm t here ane ever. feel by co, i've enred intohis cathal and thpews areull. walk in d i feelt home because i feel like i'm in this community of a these catures. (upbeat sic) (waterripping)

prty much ery day the yea the winr i ski some wa i'm alys in thforest. don't thk that iould ve been scientis unss i hadhese conntions mylf being ouhere is sourcef that scien. let's ave scrah th a raiactive g d the tr will ta up thatas-- thesare my pple, anthey're lling we'rtalking d they'rshowing thgs and i saying, "oy, let'study tt." so, ah, it's constan ck and fth conveation betweeme and tse guys. oh, th is real hot. ohwow! it's rlly, reay, really leled. if youo into aold grth forestn is quite dark, itan be que shady d you can selittle pnts growg in the uerstory seedlin that a kind ofropping .

and there's noa lot of ligs, so theig old treeare comping with tho little selis for light, but they're able to live. well, why is that if they can't photosynthesize very well? how could they live? [dr. suzne] as soo as y walk in forest, most of look arnd and wgo, when we see th big oldree. d so ts one ught meye. myrttrees arthe biggt ones andhe oldesones the fort. we've en able trace thisree woulbe concted toll theserees arod it. as fars you casee these biold tree are likehe centeof the hs and at they' nurturi the ung seedngs arou them. as the seed is germinating, the mother tree is communicating with the seed.

sometimes in a really dense shaded forest, those seedlings can sit there for a hundred years and just be feeding off the mother tree, waiting for a little gap to open up for a tree to fall over a branch to fall, just waiting patiently, just waiting my time will come. (lauing) ind whirng) this fungal highway is kind of like a direct way to communicate. so you can think of the network is kind of like an internet or a bunch of telephone lines

and the trees will call each other up and say, "hey, did you know that there's an insect over here?" or, "hey, i got some extra nitrogen do you want some." (upbeat music) they cmunicate alkinds ofhings. they cmunica about psons. they comnicate aut sects andiseases theyommunica about resour availility. they c communite about their resses, eir happess, or wheth they're plete orot. (ueat musi when yore skiin rough the forest you knowthere's ill, this comnications going between ese tree the winr, it's vy much ave. (upbeat sic)

when wlook at e patter of theycorrhiz network en we acally disct it anlook at l the mathematicalelationsps, it the sampattern as a nral netwk, and it'svolved f ficiencyf communation. anthat lea you tthink while it kind ofike a brn, it's highly coerved stcture thatvolves bause it rks. (brit upat music you're look fothat, then tharesides thcommunitlevel. it not in e didual trelevel,

it's aually at the forest level. and then i started thinking about the materials that are moving through that network. when we look at the actual compounds, it turns out that some of them are exactly the same as neurotransmitters that are in our brains. intellence is wo that wescribed toumans ananimals, d we tento assocte it with nerus syste and bras. plts don'tave nervs system d they d't have ains like wdo with urons anaxons. in the aditionasense of if wrestrictur thghts of telligen the phycal braiand the phical nerus syste will theyeah, no plan don't he that, trees dot have tt, but theyo have ielligenc in a broer sense in that ey are pceptive and ey recei informaon,