Nils Henriksson

I am a researcher at the department of Forest Ecology and Management (SLU, Umeå). As a  forest ecophysiologist, I use element fluxes to study biological processes related to forest growth and ecosystem functioning. This basis on physiological processes (like photosynthetic carbon assimilation, cellular respiration, or root and mycorrhizal nitrogen acquisition and water uptake) lets me study the functions of forest ecosystems. That means asking questions about what various plant or fungal species are doing in different environbments, how is carbon being allocated, or how is nitrogen moving between organisms. This sort of muchanistic approach is very useful in understanding a dynamic ecosystem, and it is the kind of understanding that is needed in order to adjust our forest management practices to changing environmental conditions or new management goals.

For this purpose, stable isotope techniques are very useful.  I have used stable isotope tracers (13C, 15N, 2H) to study tree carbon partitioning, competition for nitrogen within common mycorrhizal networks (CMNs), as well as tree water/nitrogen uptake strategies. I combine field experiments in various boreal forest systems (such as long-term nitrogen addition experiments and root exclusions) with laboratory or greenhouse experiments where specific processes can be targeted with a greater degree of experimental control. 

Course leader

Bachelor thesis course in biology and forest science (BSc)

Ecophysiological concepts and tools in managed forests (PhD)

I teach on the following courses:

Praktiskt skogsbruk (BSc)

Skogsskötsel och naturvårdsbiologi (BSc)

Bachelor thesis course in biology and forest science (BSc)

Forest ecology (BSc)

Forest ecosystem ecology (MSc)

Ecophysiological concepts and applications in managed forests (PhD)

Currently, I am working in projects studying

- how gap harvesting affects forest regeneration and mycorrhizal diversity

- interactions between pine seedlings, ericaceous dwarf shrubs, and mycorrhizal fungi 

- effects of altered soil nitrogen forms (such as after fertilization) on plant root physiology

2018-2021 - Post-doctoral researcher at the department of forest ecology and management, SLU, Umeå.

2013-2017 - Ph.D. student at the department of forest ecology and managment, SLU, Umeå. My supervisors were professors Torgny Näsholm, John Marshall, and Lasse Tarvainen. Thesis title: "Tree carbon partitioning, respiratory efficiency, and nitrogen acquisition"

MSc students
2023-2024. Marcus Björs: Masters thesis, 60 credits.
Thesis title: Mycorrhizal species composition as a function of distance from clearcut edges
Supervisors:
Nils Henriksson (Main)
Andreas Schneider (Assistant)
 
2022. Tyra Tornberg: Masters thesis, 30 credits.
Thesis title: Physiological evaluation of tree regeneration in forest gaps, with a focus on nitrogen nutrition and belowground competition
Supervisors:
Nils Henriksson (Main)
 
2021. Louise Nordström: Masters thesis, 30 credits.
Thesis title: Growth and development of Eucalyptus grandis seedlings in response to Arginine phosphate application
Supervisors:
Jonathan Love (Main)
Nils Henriksson (Assistant)
 
2019. Hilda Mikaelsson: Masters thesis, 30 credits.
Thesis title: Alternative oxidase respiration in the mycorrhizal fungus Laccaria bicolor
Supervisors:
Nils Henriksson (Main)
 
BSc students
2022. Marcus Björs: Bachelor thesis, 15 credits.
Thesis title: The role of common mycorrhizal networks for forest regeneration near clear-cut edges – Implications for management 
Supervisors:
Nils Henriksson (Main)
 
2018. Aria Tahmasebi: Bachelor thesis, 15 credits.
Thesis title: Teknikutveckling för att strypa träd. (development of method for terminating tree belowground carbon transport)
Supervisors:
Nils Henriksson (Main)
 
Ongoing doctoral projects
2023-2027 Alexina Brännlund
Project topic: Belowground constraints on forest regeneration – competition for nitrogen with nearby trees and field vegetation and the role of mycorrhizal networks
Supervisors:
Torgny Näsholm (main)
Nils Henriksson (Assistant, project leader)
Hyungwo Lim (Assistant)
Sandra Jämtgård (Assistant)
 
2024-2028 Ellen Svensson
Project topic: Root morphological and functional responses to local occurrence of inorganic and organic nitrogen
Supervisors:
Torgny Näsholm (main)
Nils Henriksson (Assistant)

Sandra Jämtgård (Assistant)

Henriksson, N., Marshall, J., Högberg, M.N., Högberg, P., Polle, A., Franklin, O., Näsholm, T., 2023. Re-examining the evidence for resource sharing among trees via ectomycorrhizal networks and the mother tree hypothesis, New Phytologist.

Lutter, R., Henriksson, N., Lim, H., Blaško, R., Magh, R., Näsholm, T., Nordin, A.,
Lundmark, T., Marshall, J. (2021). Belowground resource utilization in monocultures and mixtures of Scots pine and Norway spruce. For Ecol Man 2021.

Henriksson, N., Franklin, O., Tarvainen, L., Marshall, J., Lundberg‐Felten, J., Eilertsen, L., Näsholm, T., 2021a. The mycorrhizal tragedy of the commons. Ecology Letters 24, 1215–1224. 
Henriksson, N., Lim, H., Marshall, J., Franklin, O., McMurtrie, R.E., Lutter, R., Magh, R., Lundmark, T., Näsholm, T., 2021b. Tree water uptake enhances nitrogen acquisition in a fertilized boreal forest – but not under nitrogen‐poor conditions. New Phytologist 
Henriksson, N., Marshall, J., Lundholm, J., Boily, Å., Boily, J., Näsholm, T., 2019. Improved in vivo measurement of alternative oxidase respiration in field‐collected pine roots. Physiol Plantarum 167, ppl.12910.
Henriksson, N., Tarvainen, L., Lim, H., Tor-Ngern, P., Palmroth, S., Oren, R., Marshall, J., Näsholm, T., 2015. Stem compression reversibly reduces phloem transport in Pinus sylvestris trees. Tree Physiol 35, 1075–1085.