How do we measure provisioning services?


Provisioning services include the production of material resources that improve human wellbeing. In FEST, we have focused on our efforts on two broad groups of provisioning services - provisioning of wood products (biomass) and maple syrup. Biomass provision represents the total resource that is produced through management and is made available for the production of wood products, use as an energy feedstock, etc. It is calculated by converting diameters of harvested stems to estimates of standing biomass using Jenkins et al.’s (2003) allometric equation for mixed hardwoods. In general, it is assumed that 30% of harvested biomass remained on site as residues (Lippke et al. 2011) except where different values have been directly measured or where silvicultural practices dictate otherwise (e.g., 100% of harvested biomass was removed in the whole-tree harvest in WS5 at Hubbard Brook - Figure 1). Estimates of sawtimber provision are taken directly from raw data or model outputs; harvested trees suitable for sawtimber were identified as such and board-foot volumes were tallied.

Potential maple syrup production is estimated from a tree inventory using the sustainable tapping guidelines of Heiligmann et al. (2006), in which all sugar maple trees over 25.4 cm (10 inches) are given a single tap and all maple trees over 45.7 cm (18 inches) are given a second tap. The number of taps in each stand is then multiplied by the average annual yield per tap to estimate the total potential annual syrup yield per hectare. For sites in the United States, we use measures of annual yield as reported through the USDA National Agricultural Statistical Service (2014).

FEST case studies involving provisioning services include quantification of energy feedstocks at Hubbard Brook and Turkey Lakes, and the inclusion of biomass harvest in a tradeoff analysis at Hubbard Brook. Additionally, we quantified the capacity for provisioning of energy feedstocks, sawtimber, and maple syrup in managed northern hardwoods stands in the Adirondacks.

Figure 1 (image from www.hubbardbrook.org)