Climate change implications of shifting forest management strategy in a boreal forest ecosystem of Norway

Abstract

Empirical models alongside remotely sensed and station measured meteorological observations are employed to investigate both the local and global direct climate change impacts of alternative forest management strategies within a boreal ecosystem of eastern Norway. Stand-level analysis is firstly executed to attribute differences in daily, seasonal, and annual mean surface temperatures to differences in surface intrinsic biophysical properties across conifer, deciduous, and clear-cut sites. Relative to a conifer site, a slight local cooling of −0.13 °C at a deciduous site and −0.25 °C at a clear-cut site were observed over a 6-year period, which were mostly attributed to a higher albedo throughout the year. When monthly mean albedo trajectories over the entire managed forest landscape were taken into consideration, we found that strategies promoting natural regeneration of coniferous sites with native deciduous species led to substantial global direct climate cooling benefits relative to those maintaining current silviculture regimes – despite predicted long-term regional warming feedbacks and a reduced albedo in spring and autumn months. The magnitude and duration of the cooling benefit depended largely on whether management strategies jointly promoted an enhanced material supply over business-as-usual levels. Expressed in terms of an equivalent CO2 emission pulse at the start of the simulation, the net climate response at the end of the 21st century spanned −8 to −159 Tg-CO2-eq., depending on whether near-term harvest levels increased or followed current trends, respectively. This magnitude equates to approximately −20 to −300% of Norway's annual domestic (production) emission impact. Our analysis supports the assertion that a carbon-only focus in the design and implementation of forest management policy in boreal and other climatically similar regions can be counterproductive – and at best – suboptimal if boreal forests are to be used as a tool to mitigate global warming.

Quantifying the contribution of land use change to surface temperature in the lower reaches of the Yangtze River

“…They indicate that the effects of evaporation and convection usually dominate the land-atmosphere feedback of deforestation and urbanization in the mid to lower latitudes (Chen and Dirmeyer, 2016;Zhao et al, 2014). But at higher latitudes, the radiative forcing contributes more to the surface temperature change associated with the deforestation of boreal regions in North America (Lee et al, 2011) and Norway (Bright et al, 2014). Although the evaporative cooling and surface roughness are both important in landatmosphere interaction -even more than albedo changes in some regions at lower latitudes -their effects usually cannot be revealed accurately by models (IPCC, 2013) and the studies of these surface factor effects are still insufficient, especially in some regions with scarce in situ observations such as in the lower reaches of the Yangtze River.…”

“…Chen and Dirmeyer (2016) added the atmospheric background effect to the metric proposed by Lee et al (2011). This method can be used to calculate each factor's contribution to T s in areas with different vegetation cover (Bright et al, 2014;Li et al, 2015) as well as urban area (Zhao et al, 2014).…”

An enhanced forest classification scheme for modeling vegetation–climate interactions based on national forest inventory data

“…Most countries are currently conducting National Forest Inventories (NFIs) to quantify the extent and amount of forest resources with standardized reporting for compiling global Forest Resources Assessments (FRAs; e.g., FAO, 2015). NFI data have previously been used in research aiming to attribute climate effects to management activities because they reflect the human influence on forest structure (Bright et al, 2014;Naudts et al, 2015Naudts et al, , 2016. However, as NFI data characterize only forested areas, other LC data are needed to form the complete surface representation required by land models.…”

Biogenic CO2 fluxes, changes in surface albedo and biodiversity impacts from establishment of a miscanthus plantation

“…Under the conditions of an atmosphere with higher CO 2 concentration, emissions of CO 2 will gradually become less effective in warming the climate (Caldeira and Kasting, 1993). A recent study has simultaneously taken these two effects in to account showing that they approximately cancel out each other (Bright et al, 2013).…”