Tag Archives: kauri

Canopy fieldwork = tree climbing fun in the kauri forest

So many things can go wrong in ecoshysiology fieldwork. The main concern is the weather, then there are equipment failures, battery issues, helpers becoming unwell, forgetting gear, the list goes on but we had a close to perfect field trip last week. Here are some photos of our adventures in the field. We were measuring leaf gas exchange (photosynthesis and stomatal conductance) and leaf water potentials of several species in the kauri forest at Huapai Scientific Reserve. We also installed some sap flow sensors at the base of the canopy in our two largest sample trees to complement the sensors at breast height.

Thanks to Dan, Sarah, Jo and Julia for their efforts throughout several long days and a big thank you to Freddie Hjelm from The Living Tree Company and his team, Scotty and Chrissy for their assistance in getting everything happening up above. Some of these photos were taken by Freddie too. Stay posted for some of the results and more photos soon.

There are climbers in each of these trees. Can you spot them?

There are climbers in each of these trees. Can you spot them?

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Let the litter fall! Leaf loss to safe water. Kauri and drought part 2.

During the 2013 drought, the most noticable impact on the kauri forest was the increase in litterfall. It’s well established that many tree species lose their leaves in response to drought, leading to decreased plant water loss. Deciduous trees may lose their leaves early while semi deciduous trees may lose more leaves in a dry year. By reducing leaf area, trees reduce the aarea of water-losing surfaces, thereby reducing overall water loss.

In a recently accepted paper in Plant Ecology, we report that litterfall increased 72% in 2013 compared to 2012 because of dry soil conditions (see figure). Most of the extra litter was kauri leaf and twig material.

Kauri are known to self-prune branches but the reason for branch abscission has been unclear.  It may be that this costly process occurs to protect the highly vulnerable hydraulic system of these forest giants. During dry periods, trees through off twigs to prevent failure of the water conducting system of the plant.

We are doing ongoing monitoring to determine the lag impact of this massive biomass loss to the forest floor.