Biomass Stock and Carbon Sequestration in a Chronosequence of Pinus massoniana Plantations in the Upper Reaches of the Yangtze River

Abstract

Planted forest plays a significant role in carbon sequestration and climate change mitigation; however, little information has been available on the distribution patterns of carbon pools with stand ages in Pinus massoniana Plantations. We investigated the biomass stock and carbon sequestration across a chronosequence (3-, 5-, 7-, 9-, 12-, 15-, 19-, 29-, 35-and 42-year) of stands with the main objectives: (1) to determine the biomass and carbon stock of the forest ecosystem; and (2) to identify factors influencing their distribution across the age series. Simple random sampling was used for collecting field data in the ten (10) stand ages. Three 20 × 20 m standard plots were laid out in February 2015 across the chronosequence. The diameter at breast height (DBH) and tree height (H) of each tree within each plot were measured using calipers and height indicator. Sub-plots of 2 × 2 m were established in each main plot for collecting soil samples at a 0-30-and 30-60-cm depth. Plantation biomass increased with increasing stand ages, ranging from 0.84 tonnes per hectare (t· ha −1 ) in the three-year stand to 252.35 t· ha −1 in the 42-year stand.The aboveground biomass (AGB) contributed 86.51%; the maximum value is 300-times the minimum value. Carbon concentrations and storage in mineral soil decreased with

Dynamics of biomass and carbon sequestration across a chronosequence of masson pine plantations

“…We established three 400 m 2 plots (20 m × 20 m) at each stand age during the month of November 2015; a total of 12 sampling plots were established along the chronosequence. Destructive and nondestructive sampling methods were used to estimate the aboveground biomass carbon in the tree layer components that involve measurement of diameter at breast height (DBH) and height ( H ) of the standing trees using calipers, diameter tapes, and a height indicator (NIKON 550A S, Tokyo, Japan) [ Justine et al ., ] and felling down a representative tree in each sampling plot to determine its actual height and obtain the aboveground tree components for determination of tree layer components C tissue content. The collected tree layer components (wood, bark, branch, litter, and roots) were then oven dried at 65°C to a constant weight for determination of plant tissue C content.…”

“…The differences in the tree layer biomass stocks were mainly caused by inherent variations in growth rates [ Houghton , ]. The 27 year stand displayed greater biomass stock followed by the 39 year stand which demonstrates that the 39 year stand is approaching maturity since these plantations are managed on a fixed rotational age of 40 years [ Justine et al ., ].…”

“…Similarly, the herb layer C is considerably lower than 7.4 and 16.5 Mg ha −1 stored within the forest floor of a 16 and 27 year old Ponderosa pine and Pinus elliottii plantations [ Kinerson et al ., ] and [ Gholz and Fisher , ]. The above larger differences are associated with the racking or litter collection from the forest floor for biogas production in our study plantations [ Justine et al ., ], that may create disturbances on the biological processes of the herb layer and exposes the aboveground shrub layer components to trampling as manifested by the higher shrub layer R/S ratio.…”

“…The area was characterized by a subtropical subhumid monsoon climate with an annual total mean rainfall distribution of 1,021 mm. The minimum and maximum temperatures of 7.8°C and 36.8°C were recorded for the months of January and July, with an annual mean value of 18.1°C [ Justine et al ., ]. The vegetation Canopy of the forest is dominated by Pinus massoniana with some understory shrubs such as Rubus pirifolius , Viburnum setigerum , Myrsine africana , and grasses such as Pteridium aquilinum , Dicranopteris dichotoma , and Setaria plicata [ Justine et al ., ].…”

“…Previous investigations conducted on biomass carbon stock and carbon sequestration using a chronosequence approach have reported significant increase in biomass C with forest age except the SOC that either increases or decreases [ Yen and Joou , ; Justine et al ., ] which proves the positive impacts of stand age and its influence on forest ecosystems elements and nutrients cycling, but studies were lacking on biomass carbon stock and carbon sequestration at fixed intervals in even‐aged plantation forests. Therefore, it is justifiable to consider stand age at fixed intervals for (1) assessing and reporting changes in C stock accumulation during the various growth and developmental stages in even‐aged plantations and (2) projecting and predicting the future ecological, social, environmental, and productive values of forest ecosystems.…”