Carbon isotope discrimination as a ..

T1 - Photosynthesis and carbon isotope discrimination in boreal forest ecosystems

isotope carbon-12 compared with the heavier carbon-13.

Because wood fibers cannot be recycled indefinitely, a constant flow of fresh fiber into the fiber network is needed. Depending on the origin of the fresh fiber and the type of products, fiber is typically degraded and unusable after five to seven cycles . Thus, fresh fiber is constantly needed to compensate for the retirement of degraded fiber, archival storage of paper, and loss of fiber through normal use and disposal of certain non-recyclable paper products, such as personal care and tissue products.

Carbon isotope discrimination during photosynthesis …

Some argue that old-growth forests with stable carbon stocks should be replaced with stands of young, vigorously growing trees as a way to increase carbon uptake. However, this would reduce the amount of carbon stored on the land, and it would take decades, or even centuries, for the GHG benefits of the newer stands to overcome the loss of carbon from the original forest. Furthermore, old-growth forests, particularly in the tropics, are important to preserving the world’s biological diversity, and therefore should not be considered on the basis of carbon stocks and flows alone.

Compared with other materials (e.g., concrete, steel, plastic), products made from sustainably managed forests are generally advantageous from a GHG perspective because wood is produced by taking carbon from the atmosphere while producing other materials require use of fossil fuels.


Carbon Isotope Discrimination in Photosynthesis of …

Establishing new forests on suitable land and replanting on formerly forested areas can store additional carbon (Box 12 below). The Global Partnership on Forest and Landscape Restoration estimates that over 2 billion hectares of deforested and degraded landscapes worldwide can potentially be restored (WRI, 2011). Thanks to growing recognition of forest and landscape restoration’s role in reducing carbon dioxide emissions and increasing carbon sequestration, countries have pledged over 20 million hectares to the Bonn Challenge—a global commitment to restore 150 million hectares of lost and degraded forests by 2020. Countries committed to the challenge, including Brazil, Costa Rica, El Salvador, Rwanda, and the United States, are beginning to announce their restoration pledges (IUCN, 2012).

Carbon Isotope Discrimination And Photosynthesis | …

The amount of carbon stored in wood products is estimated to be increasing by 189 million tons per year (Pan et al., 2011). The amount of carbon stored in wood products varies significantly among product types and depends on the method of disposal. On average, solid wood products last longer than paper-based products (Larson et al., 2012) and carbon in both forests and products is released back to the atmosphere either slowly through decomposition or quickly by burning.

Photosynthesis and carbon isotope discrimination in …

There is no widely accepted definition of ‘carbon neutrality’. Generally, ‘carbon neutrality’ is achieved when the amount of carbon released from the production process is offset by an equivalent amount captured in new growth, thus resulting in net zero emissions. Wood harvested from forests with stable or increasing carbon stocks can be considered carbon neutral (WBCSD, 2013). In contrast, wood from forests that are being converted to non-forest land use would not be carbon neutral. Additionally, greenhouse gas emissions are released along the production process of wood products. Hence, wood products might not be carbon neutral if additional steps are not taken to offset the emissions from the production process (Lippke, Wilson, Meil, and Taylor, 2009).

Carbon Isotope Discrimination and Photosynthesis …

Climate and forests are intrinsically linked. As a result of climate change, forests are stressed by higher mean annual temperatures, altered precipitation patterns, and more frequent and extreme weather events. At the same time, forests mitigate climate change through uptake of carbon, and the loss of forests through land-use conversion and forest degradation causes carbon dioxide emissions that contribute to climate change (IPCC 2014).