The effects of thinning on carbon stocks and fluxes in a Chinese arborvitae plantation

Abstract

China has extensive areas of forest plantations that sequester and store large quantities of carbon. However, the rate of carbon sequestration by Chinese arborvitae (Platycladus orientalis Linn. Franco) is unknown. This research looks at carbon stocks and fluxes in forest vegetation, soil and litter seven years after thinning Chinese arborvitae in order to evaluate the effect of thinning levels on carbon sequestration. At 22 years, the plots were reduced from 5900 to 4100 and 3000 trees per hectare in three replicates. Carbon stocks of above-ground tree materials were lowest in the heaviest thinned plots and highest in the control plots. Above-ground shrub carbon pools were the opposite, i.e., largest in the heaviest thinned plots and lowest in the controls. Soil and litter carbon stocks were not affected by thinning treatment. Results suggest that thinning may positively affect vegetation carbon sequestration in the short term, an important observation for forest managers using thinning to optimize carbon sequestration capacity.Key words: forest management, carbon sequestration, warm-temperate forest, soil respiration Résumé La Chine comporte de vastes étendues de plantation forestière qui captent et emmagasinent de grandes quantités de carbone. Cependant, le taux de séquestration du thuya de Chine (Platycladus orientalis Linn. Franco) n' est pas connu. Cette étude porte sur les stocks et les flux de carbone dans la végétation forestière, le sol et la litière sept ans après une éclaircie réalisée dans un peuplement de thuya de Chine afin d' évaluer les effets de l' éclaircie sur la séquestration du carbone. Les parcelles localisées dans des peuplements de 22 ans ont été éclaircies pour réduire le nombre d'arbres par hectare de 5 900 à 4 100 et 3 000, dans un dispositif à trois répétitions. Les stocks de carbone de la partie épigée des arbres étaient les plus faibles dans les parcelles les plus éclaircies et les plus élevés dans les parcelles témoins. Les stocks de carbone de la partie épigée des arbustes se sont comportés à l'inverse, c' est-à-dire, les plus élevés dans les parcelles les plus éclaircies et les plus faibles dans les parcelles témoins. Les stocks de carbone dans le sol et la litière n' ont pas été influencés par l' éclaircie. Les résultats suggèrent que l' éclaircie pourrait affecter de façon positive le stockage du carbone dans la végétation à court terme, une constatation importante pour les aménagistes forestiers qui utilisent l' éclaircie pour optimiser la capacité de séquestration du carbone.

Effects of Different Thinning Intensities on Carbon Storage in Pinus koraiensis Middle-Aged Plantations in Northeast China

“…In this investigation, as soil depth increased, soil carbon storage under various thinning intensities declined. Additionally, surface layer soil bulk density is higher than bottom layer soil bulk density, which is consistent with earlier research and is linked to the action of plant roots and soil organisms that reduce soil depth-related carbon storage [52,53]. When the thinning intensity is 22%, soil carbon storage is improved, and ecosystem carbon storage can be significantly increased.…”

Carbon stock density in planted versus natural Pinus massoniana forests in sub-tropical China

“…In addition, management practices, such tree thinning and slash-burning, which are implemented in planted pine forests exert different effects on soil carbon. Studies have reported that management practices such as prescribed fire, mechanical treatment, and thinning do not affect soil carbon stock density (Boerner et al 2008;Liang et al 2013;Nilsen and Strand 2008). However, other studies have reported that management practices do affect soil carbon stock density of planted forests (Tian et al 2010;Wu et al 2013).…”

Ecological Rehabilitation Measures and their Carbon Fixation Effect on Degraded Red Soil Ecosystem in South China

“…The density of dry wood of Pinus massoniana in the same area and of the same age is 346.6 kg•m -3 , the dry wood density of Pinus elliotti is 298.9 kg•m -3 [4]; Pinus massoniana's trunk, leaf, branch and root accounted for 65.1%, 11.8%, 10.5%, and 12.6% of dry weight of biomass [5], respectively. The level of carbon was 51.614%, 44.617%, 47.563%, and 50.737% [6], respectively. And Pinus elliotti's trunk, leaf, branch and root accounted for 63.8 %, 11.2%, 12.9%, and 12.1% of dry weight of biomass [5], respectively, The level of carbon was 54.786%, 59.33%, 55.59%, and 56.311% respectively [7].…”

“…The level of carbon was 51.614%, 44.617%, 47.563%, and 50.737% [6], respectively. And Pinus elliotti's trunk, leaf, branch and root accounted for 63.8 %, 11.2%, 12.9%, and 12.1% of dry weight of biomass [5], respectively, The level of carbon was 54.786%, 59.33%, 55.59%, and 56.311% respectively [7].…”