Pine root exploration of standing dead tree trunks: a short-cut biocycling process

Authors: CONSALTER, R - Universidade Federal Do Parana; MOTTA, A.C.V. - Universidade Federal Do Parana; BARBOSA, J - Uninga University Center; VEZZANI, F - Universidade Federal Do Parana; RUBILAR, R - University Of Concepcion; Prior, Stephen - Steve; BASSACO, V - Universidade Federal Do Parana

Submitted to: Forest Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2023
Publication Date: 7/20/2023
Citation: Consalter, R., Motta, A., Barbosa, J.C., Vezzani, F.M., Rubilar, R.A., Prior, S.A., Bassaco, V.M. 2023. Pine root exploration of standing dead tree trunks: a short cut biocycling process. Forest Systems. 32(2):eSC01. https://doi.org/10.5424/fs/2023322-19715.
DOI: https://doi.org/10.5424/fs/2023322-19715

Interpretive Summary: Besides growing in soil, Pinus roots colonize litter debris and dead roots, especially under low soil fertility conditions. In a Pinus herrerae M. plantation, root growth within standing trunks of dead adult trees was observed. Our study investigated the extent of this phenomenon by evaluating dead trees colonized by roots, dead trees without roots, and live trees. This study showed that Pinus herrerae roots of live trees can colonize the wood/bark interface of dead neighboring trees. Roots at the wood/bark interface of dead trees reached up to 3.3 m above the ground and showed different morphological characteristics, ectomycorrhizal colonization levels, and P levels compared to roots found in litter and soil layers. This could be considered a shortcut in biogeochemical cycling where colonizing roots decreased levels of P, K, and Fe in wood and Zn in bark of dead trees. This study increases our knowledge base on different ways that nutrients are cycled in forest ecosystems.

Technical Abstract: Besides growing in soil, Pinus roots colonize litter debris and dead roots, especially under low soil fertility conditions. In a Pinus herrerae M. plantation, root growth within standing trunks of dead adult trees was observed. Our study investigated the extent of this phenomenon by evaluating dead trees colonized by roots, dead trees without roots, and live trees. Our results showed that an initial phase occurs after tree death where the action of saprophytic fungi is important for creating a suitable growth media. Approximately 2 to 3.5 years after tree death, roots of adjacent trees grow into the wood/bark interface, beginning in litter of the F and H horizons. Eight and a half years after tree death, roots of adjacent trees reached up to 3.3 m above the litter surface. At the wood/bark interface, a root mantle formed (length greater than 1 km m-2) with ~5 % ectomycorrhizal colonization. Root presence in the wood/bark interface reduced P, K, and Fe content of dead wood and Zn content in bark. Our results indicate that roots of P. herrerae are capable of colonizing dead tree trunks as a nutrient resource pool. This nutrient acquisition mechanism may my function as a shortcut in the biogeochemical cycling of nutrients in forest systems.