How Time since Forest Fire Affects Stand Structure, Soil Physical-Chemical Properties and Soil CO2 Efflux in Hemiboreal Scots Pine Forest Fire Chronosequence?

Kajar Köster,Egle Köster,Argo Orumaa,Frank Berninger,Jukka Pumpanen,Kalev Jõgiste,Marek Metslaid,Kristi Parro

doi:10.3390/f7090201

Kajar Köster, Egle Köster + Show 6 more

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https://doi.org/10.3390/f7090201

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Abstract

We compared the changes in aboveground biomass and initial recovery of C pools and CO2 efflux following fire disturbances in Scots pine (Pinus sylvesteris L.) stands with different time since stand-replacing fire. The study areas are located in hemiboreal vegetation zone, in north-western Estonia, in Vihterpalu. Six areas where the last fire occurred in the year 1837, 1940, 1951, 1982, 1997, and 2008 were chosen for the study. Our results show that forest fire has a substantial effect on the C content in the top soil layer, but not in the mineral soil layers. Soil respiration showed a chronological response to the time since the forest fire and the values were lowest in the area where the fire was in the year 2008. The respiration values also followed seasonal pattern being highest in August and lowest in May and November. The CO2 effluxes were lowest on the newly burned area through the entire growing season. There was also a positive correlation between soil temperature and soil respiration values in our study areas.

Highlights

Disturbances are an important factor influencing forest structure formation, composition and forest functioning [1,2]
Our results show a clear reduction of soil C stocks after the fire in the organic layer (O-horizon) the above- and belowground biomass recovery, community dynamics and soil processes [23]
Our results showed that forest fire has a substantial effect on the soil C content in the top soil layer, but not in the mineral soil layers

Summary

Introduction

Disturbances are an important factor influencing forest structure formation, composition and forest functioning [1,2]. Boreal forests are a crucial part of the climate system since they contain about 60% of the C (703 billion tons) bound in global forest biomes [4]. 15%–35% of the above-ground biomass and 37%–70% of the ground layer due to combustion [6,7] Since both high severity (stand replacing) and intermediate severity fires are common in Eurasia [4,8], it is important to understand how these ecosystems respond to the different disturbances. Increases in disturbance will lead to a net release of C and contribute to global warming, Forests 2016, 7, 201; doi:10.3390/f7090201 www.mdpi.com/journal/forests

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