Evaluation of forest management effects on the mineral soil carbon pool of a lowland, mixed-species forest in Maine, USA

Abstract

Concerns about climate change have increased interest in ways to maximize carbon (C) storage in forests through the use of alternative forest management strategies. However, the influence of these strategies on soil C pools is unclear. The primary objective of this study was to test for differences in mineral soil C stocks among various silvicultural and harvesting treatments that were initiated in the 1950s and have been maintained since on the Penobscot Experimental Forest in central Maine, USA. Five mineral soil cores below the surface organic horizon to a depth of 1 m were collected from each replicate (n = 2) of selection, shelterwood, and commercial clearcut treatments. For these treatments, the mean mineral soil C stock was 47.7 ± 16.4 Mg ha −1 (mean ± SD). We found no significant differences in average mineral soil C stocks among treatments. However, a post hoc power analysis indicated that the probability of detecting a significant treatment effect was only 6%. We determined that 98 stands per treatment would be required to be 80% certain that the F test would detect a difference in average mineral soil C stocks whenever any pair of treatments had C stocks differing by more than 5 Mg ha −1 .Key words: soil carbon variability, silviculture, coarse fragments.Résumé : Les préoccupations associées au changement climatique ont accru l'intérêt pour les façons dont on pourrait stocker un maximum de carbone (C) dans les forêts en recourant à de nouvelles stratégies de gestion. Malheureusement, on connaît mal l'influence de telles stratégies sur les réserves de C du sol. La présente étude devait essentiellement vérifier la fluctuation de ces réserves en fonction des méthodes de sylviculture et de récolte lancées dans les années 1950 et maintenues depuis, dans la forêt expérimentale de Penobscot, dans le centre du Maine, aux États-Unis. Les chercheurs ont prélevé cinq carottes de sol minéral sous l'horizon organique de surface à un mètre de profondeur sur chaque parcelle forestière (n = 2) de coupe jardinatoire, de coupe progressive et de coupe à blanc commerciale. Les réserves de C minéral dans le sol des parcelles correspondant à ces différents traitements s'élevaient en moyenne à 47,7 ± 16,4 Mg ha −1 (moyenne É.-T.). Les réserves moyennes de C minéral dans le sol ne varient pas de manière significative d'un traitement à l'autre. Cependant, une analyse de puissance ultérieure a révélé que la probabilité de déceler un effet significatif attribuable au traitement n'était que de 6 %. Les auteurs estiment qu'il faudrait examiner 98 peuplements par traitement pour être sûr à 80 % que le test F détecterait un écart dans les réserves moyennes de C minéral, chaque fois que ces dernières varient de plus de 5 Mg ha −1 entre deux traitements. [Traduit par la Rédaction]Mots-clés : variabilité du carbone dans le sol, sylviculture, fragments grossiers.

Improved forest management as a natural climate solution: A review

“…In the Northeastern United States, partial and complete harvesting treatments (light thinning, heavy thinning and clearcutting) were reported to have no effect on forest floor and mineral soil C (Hoover, 2011). Similarly, a study in a lowland mixed species stand found no difference in mineral soil C stocks following selection, shelterwood and clearcutting treatments (Puhlick et al, 2016). All of these findings suggest that a less intense management action could be considered in stands where maintaining and/or increasing soil C stocks is of interest (Jandl et al, 2007;Powers et al, 2012).…”

Assessing the role of natural disturbance and forest management on dead wood dynamics in mixed-species stands of central Maine, USA

“…These PSPs were selected in a random, 187 stratified process, with stratification according to the proportion of major soil types on glacial till 188 within each replicate (Puhlick et al 2016a). Species and dbh were recorded for each tree and shrub, and biomass in woody portions shrub biomass as "live tree biomass" throughout the remainder of the manuscript.…”

Land use change and forest management effects on soil carbon stocks in the Northeast U.S.

“…The mutually consistent O horizon increase in our two observational datasets, one of which (the soil survey pedon dataset) samples by horizon and the other of which (the national forest inventory dataset) samples by a horizon / depth hybrid approach, may imply that there may be functional interactions between soil horizons. However, as discussed in the prior paragraph, we discount these results due to the potential for spatial design problems, which should be expected in a region where a large share of the harvesting is done in northern coniferous forest types with large O horizon C stocks [ 42 , 44 , 73 – 75 ].…”

“…First, we incorporated bulk density (Db) as a specific response parameter of interest. Second, in several cases, we directly contacted study authors to obtain data not reported in, but underpinning several forest harvest papers from the region [ 73 , 83 , 84 , 87 , 88 ]. These personal communications were necessary to bring summarized data from these important regional papers to the same level of site-specific detail found in the majority of other forest harvest papers (or their associated Additional file 2 : Datasets).…”