A Comparison of Aboveground Biomass Estimates from Different Allometric Formulas using Vegetation Sampling Protocol in Rouge National Urban Park

Abstract

Forests are an important part of the global carbon cycle and their ability to mitigate atmospheric carbon dioxide levels is increasingly being recognized. The sale of carbon credits represents a significant emerging opportunity for realizing additional revenue from forested land while promoting carbon storage and sequestration, biodiversity conservation, sustainable forest management, and strategic landscape planning (IPCC 2007). When considering the potential application for a forest carbon offset project within a multifunctional landscape such as southern Ontario it is critical to build upon available and proven tools that accurately estimate biomass and carbon stocks (Puric-Mladenovic et al. 2016). The Vegetation Sampling Protocol (VSP) (Puric-Mladenovic et al. 2009), an inventory and monitoring protocol, can be used to quantify baselines and support subsequent monitoring for forest carbon offset projects. However, to estimate carbon offsets from the forest agreeing on a set of tree allometric equations that accurately and consistently predict biomass is a priority. This study contributes to the understanding of forest carbon quantification in southern Ontario by comparing live aboveground biomass estimates (AGB) derived from three commonly used allometric formulas (Lambert et al. 2005, Jenkins et al. 2003 and Ter-Mikaelian and Korzukhin 1997) using VSP DBH data from plots situated within Rouge National Urban Park (RNUP). In order to determine whether there are any statistical differences between the three allometric formulas, sets of test-statistics were used on all species considering all sampled plots, all species and the most common tree species by DBH class and component biomass where applicable. Results from this study show that the formulas generate significantly different estimates of biomass, more noticeably for the smaller sized DBH classes. The set of formuals by Jenkins et al. (2003) consistently overestimated AGB more than the other two formulas especially for the softwood species. Component biomass was significantly different for foliage but not for stem biomass. Until a set of standardized formulas specific for southern Ontario are created, the results of this study suggest that RNUP uses the average of the three formulas for total AGB estimation since the value was not significantly different from two of the three sets of generalized formulas. Accurate local (RNUP) and regional (southern Ontario) carbon storage estimates could be used to improve long-term landscape and land-use planning, enhance forest management and forest conservation measures and support the province’s plans for creating carbon offset projects from the forest sector.