Kali Middleby

In full sun, tropical leaves can become much hotter than the surrounding air. Their ability to cope can be a matter of life or death.

👉 Read the full story: theconversation.com/some-tr...

Some Rainforest Trees Can Beat the Heat New research reveals some rainforest tree species use self-cooling strategies to withstand rising temperatures, but others are more at risk.

New research reveals some rainforest tree species use self-cooling strategies to withstand rising temperatures, but others are more at risk.
Full story: shorturl.at/piQ5B

Featured on the cover of @globalchangebio.bsky.social is a thermal image of Elaeocarpus Grandis taken at @jcuofficial.bsky.social Daintree Rainforest Observatory. In this species we find that populations originating from warmer climates have narrower leaves with higher rates of water loss.

Some tropical trees cool their leaves to survive the heat — but not all species have ways to cope In full sun, tropical leaves can become much hotter than the surrounding air. Their ability to cope can be a matter of life or death.

Check out our piece in @theconversation.com explaining how intraspecific trait coordination across climatic gradients helps to avoid heat stress in some (but not all) tropical tree species

theconversation.com/some-tropica...

Big thanks to all the support from coauthors @drrebeccajordan.bsky.social @awcheesman.bsky.social @martinbreed.bsky.social @mrossettorecer.bsky.social @dcrayn.bsky.social @lucascernusak.bsky.social

Local Adaptation Drives Leaf Thermoregulation in Tropical Rainforest Trees We tested whether tropical rainforest trees adjust their leaf traits and resulting leaf temperatures across their distributions within the Australian Wet Tropics. Using field measurements from across...

Can tropical rainforest trees keep their cool? Now out in @globalchangebio.bsky.social we explored whether intraspecific variation in leaf energy balance was a result of adaptation to local climate.
doi.org/10.1111/gcb....

What a wonderful time sharing ideas with fellow plant nerds 💚

Link to our session and more information on our speakers here:

www.xcdsystem.com/atbc/program...

Heading to Oaxaca for #ATBC2025 ? Make sure you stop by our symposium for all things leaf temperature, heat tolerance, and tradeoffs across climate gradients 🌿💧🌡️

Responses of tropical forest trees to rising carbon dioxide - conifers versus angiosperms at James Cook University on FindAPhD.com PhD Project - Responses of tropical forest trees to rising carbon dioxide - conifers versus angiosperms at James Cook University, listed on FindAPhD.com

I have an opportunity for a new PhD student in tropical tree ecophysiology in my lab. Some more details at the link below. Please pass along!

www.findaphd.com/phds/project...

Proud to have my thermal image on the cover of this fantastic issue - now time to check out the research inside!

We didn't record it unfortunately - but I would be happy to share the slides with you

#AMAPwebinar april 29th, 11:00 (CET)
Kali Middeby, post-doc, AMAPlab, Montpellier
"Patterns and drivers of leaf thermoregulation in rainforest trees of the Australian Wet Tropics"
amap.cirad.fr/fr/edit-even...

Leaf minimum conductance dynamics during and after heat stress: Implications for plant survival under hotter droughts Temperatures above a critical threshold can increase leaf minimum conductance after cooling, evidencing a “thermal leaky legacy effect” that can reduce pla

🔥Can heatwaves leave a thermal leaky legacy?🔥

Check out our latest paper on gmin dynamics during and after thermal stress🍃📄

Extremely proud of my student Viviane!

Special thanks to @hcochard.bsky.social @torresruizjm.bsky.social @martijnslot.bsky.social

doi.org/10.1093/plph...

Happy to share a new paper, "Effects of Hot Versus Dry Vapor Pressure Deficit on Ecosystem Carbon and Water Fluxes," led by the amazing Miriam Johnston w/ @mallorybarnes.bsky.social and others agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Study shows hot leaves can’t catch carbon from the air. It’s bad news for rainforests – and Earth An experiment in the Daintree rainforest found the rate of photosynthesis in leaves warmed by 4°C dropped by an average of 35% compared to non-warmed controls.

Check out our new article just out in The Conversation highlighting the effects of warming leaves +4°C in tropical trees. 🌿🌡️ theconversation.com/study-shows-...

Just updated it!

Could I please be added?

Surrounded by lush vegetation in a tropical forest canopy, three take-away containers have been customised to warm leaves continuously

A density plot shows the distribution of observed leaf temperatures for one example species - Myristica globosa. The graph shows that warmed leaves surpass their optimum temperature far more frequently than control leaves, and are close to their critical temperature threshold

How do tropical rainforest trees respond to warming? 🌡️🌿We experimentally warmed canopy leaves by 4°C for 8 months and found significant declines in photosynthesis and stomatal conductance, with no shift in Topt. Read the new paper, led by Kristine Crous here: shorturl.at/AVTOk

I remember that paper - I was actually speaking with Lucas about it recently, definitely have some ideas that could be fun to explore!

Key finding? Intraspecific variation in leaf traits plays a crucial role in preventing exposure to damaging temperatures. However, broader assessments across more species are needed to determine whether patterns emerge across phylogeny, functional types, or biomes.

Reach out if you’d like to chat!

To see how physiological and morphological acclimation to treatments affected thermoregulation, I then monitored leaf temperature & water use. Air temperature was ramped up from 18 to 38°C, and VPD was lowered from 4 to 1.5 kPa. This revealed some very complex responses - watch this space!

Temperature and vapour pressure deficit are highly correlated, complicating efforts to assess their impact on trait variation. I disentangled the effects of these variables on sapling growth, physiology, and leaf traits in a glasshouse experiment shorturl.at/kb87b @newphyt.bsky.social

Although intraspecific variation led to enhanced leaf cooling at warmer sites for some species - this was not always the case. Diverse species thermoregulation strategies were also observed when comparing lowland vs upland origin trees grown in a provenance trial for 2 years shorturl.at/sjdtV

Local adaptation drives thermoregulation in tropical rainforest trees AbstractGlobally, the increasing frequency of heatwaves and droughts are impacting tropical forests, which are vital for maintaining biodiversity, carbon sequestration and climate regulation. But vuln...

After this, most of my time/life was spent in the forest measuring heat tolerance & leaf traits across elevation gradients. This was used to paramaterise a leaf energy balance model to predict leaf-air temperature variation, & combined with genomic data to assess local adaptation shorturl.at/lDr2U

Early in my PhD, I had the opportunity to collaborate with Kristine Crous and others on an insitu leaf warming experiment assessing thermal acclimation of mature trees shorturl.at/eJA9Q. This project, among others, revealed that tropical leaves can reach high temperatures shorturl.at/W2wIs.

Time to introduce myself! Recently, I defended my thesis titled "Patterns and Drivers of Leaf Thermoregulation in Rainforest Trees of the Australian Wet Tropics" where I focused on the role of within-species acclimation and adaptation on leaf temperature. Here’s a little summary of what went on…

Congrats!

Emailed it to you!

yes please!