A Flexible Hybrid Model of Life Cycle Carbon Balance for Loblolly Pine (Pinus taeda L.) Management Systems

Abstract

Abstract:In this study we analyzed the effects of silvicultural treatments on carbon (C) budgets in Pinus taeda L. (loblolly pine) plantations in the southeastern United States. We developed a hybrid model that integrated a widely used growth and yield model for loblolly pine with published allometric and biometric equations to simulate in situ C pools. The model used current values of forest product conversion efficiencies and forest product decay rates to calculate ex situ C pools. Using the model to evaluate the effects of silvicultural management systems on C sequestration over a 200 year simulation period, we concluded that site productivity (site quality), which can be altered by silviculture and genetic improvement, was the major factor controlling stand C density. On low productivity sites, average net C stocks were about 35% lower than in stands with the default average site quality; in contrast, on high quality sites, C stocks were about 38% greater than average productivity stands. If woody products were incorporated into the accounting, thinning was C positive because of the larger positive effects on ex situ C storage, rather than smaller reductions on in situ C storage. The use of biological rotation age (18 years) was not suitable for C sequestration, and extended rotation ages were found to increase stand C stock density. Stands with an 18-year-rotation length had 7% lower net C density than stands with a 22-year-rotation length; stands with a 35-year-rotation length had only 4% more C than stands harvested at age 22 years. The C sequestered in woody products was an important pool of C storage, accounting for ~34% of the average net C stock. Changes in decomposition rate, associated with possible environmental changes OPEN ACCESSForests 2011, 2 750 resulting from global climate change, affected C storage capacity of the forest. When decay rate was reduced to 10% or increased to 20%, the C stock in the dead pool (forest floor and coarse woody debris) was reduced about 11.8 MgC·ha −1 or increased about 13.3 MgC·ha −1 , respectively, compared to the average decay rate of 15%. The C emissions due to silvicultural and harvest activities were small (~1.6% of the gross C stock) compared to the magnitude of total stand C stock. The C model, based on empirical and biological relationships, appears appropriate for use in regional C stock assessments for loblolly pine plantation ecosystems in the southern U.S.

Life Cycle Analysis of Carbon Flow and Carbon Footprint of Harvested Wood Products of Larix principis-rupprechtii in China

“…Besides, forest rotation period could also have an influence on the carbon emissions in the forestry process, and thus it can have an impact on the carbon footprint in the forestry process. Gonzalez-Benecke et al [33] estimated a total carbon cost of 0.8536 tC/ha in the forestry process with the rotation period of 22 years, lower than our estimate of 1.59 tC/ha during one rotation period of 41 years. Therefore, it could be very important for comparing different research results in the future to have the same system boundary and methods used in life cycle inventory and carbon footprints.…”

Regional validation and improved parameterization of the 3-PG model for Pinus taeda stands

“…Using the raw data from 764 measured trees, we adapted the models reported by Gonzalez-Benecke et al (2014b) and produced alternative functions to estimate initial biomass pools. The parameter estimates and relationships presented in this study have a wide range of applicability, and not only for 3-PG 29 initialization, but also life-cycle analysis (Puettmann et al, 2010), and estimation of stand biomass and carbon sequestration dynamics (Gonzalez-Benecke et al, 2011). Landsberg and Sands (2011) remarked that relationships used for biomass allocation deserved further research.…”

“…As it has been documented that SG differs between trees growing in the United States and South America (Higa et al, 1973;Barrichelo et al, 1977), we developed separate models for each geographic location. For trees growing in the southeastern U.S. we used the data reported by Gonzalez-Benecke et al (2011) and fitted a new model that maintained parsimony with the 3-PG model structure. For trees growing in South America (Argentina, Brazil and Uruguay), we used data reported by Higa et al (1973), Barrichelo et al (1977), Pereyra andGelid (2002), Weber (2005), Von Wallis et al (2007), Pezzutti (2011) and Barth et al (2013).…”

Wood pellets, what else? Greenhouse gas parity times of European electricity from wood pellets produced in the south‐eastern United States using different softwood feedstocks

“…This estimate is conservative, as some studies indicate near 100% compensation (e.g. Gonzalez‐Benecke et al ., , ; Jonker et al ., ). Mass fractions of the different products orginating from softwood plantations (saw wood, small roundwood, etc.…”