reforestation

Jul

2022

Local temperature response to land cover and management change driven by non-radiative processes

Cooling forests: Here, we combine extensive records of remote sensing and in situ observation to show that non-radiative mechanisms dominate the local response in most regions for eight of nine common LCMC perturbations. We find that forest cover gains lead to an annual cooling in all regions south of the upper conterminous United States, northern Europe, and Siberia—reinforcing the attractiveness of re-/afforestation as a local mitigation and adaptation measure in these regions. Our results affirm the importance of accounting for non-radiative mechanisms when evaluating local land-based mitigation or adaptation policies.

Jul

2022

Large-scale semi-arid afforestation can enhance precipitation and carbon sequestration potential

More forests, more rain: …that implementing measured characteristics of a successful semi-arid afforestation system (2000 ha, ~300 mm mean annual precipitation) over large areas (~200 million ha) of similar precipitation levels in the Sahel and North Australia leads to the weakening and shifting of regional low-level jets, enhancing moisture penetration and precipitation (+0.8 ± 0.1 mm d−1 over the Sahel and +0.4 ± 0.1 mm d−1 over North Australia), influencing areas larger than the original afforestation. These effects are associated with increasing root depth and surface roughness and with decreasing albedo. This results in enhanced evapotranspiration, surface cooling and the modification of the latitudinal temperature gradient. It is estimated that the carbon sequestration potential of such large-scale semi-arid afforestation can be on the order of ~10% of the global carbon sink of the land biosphere and would overwhelm any biogeophysical warming effects within ~6 years.

Jun

2022

Cloud cooling effects of afforestation and reforestation at midlatitudes

Interesting analysis:

Here, we carefully analyze the situation for reforestation and afforestation (R&A) at midlatitudes, where the warming effects due to vegetation albedo are regarded to be almost balanced by the cooling effects from an increased carbon storage. Using both satellite data and atmospheric boundary-layer models, we show that by including cloudalbedo effects due to land–atmosphere interactions, the R&A cooling at midlatitudes becomes prevalent. This points to a much greater potential of R&A for wet temperate regions than previously considered.

Jun

2022

Shifts in regional water availability due to global tree restoration

Nature is incredibly complex. My feeling in general is that we should imitate the natural systems as much as possible. In one study on the shifts of regional water availability due to global tree restoration the authors come to the conclusion:

Large-scale tree-cover expansion can increase water availability by up to 6% in some regions, while decreasing it by up to 38% in others. There is a divergent impact on large river basins: some rivers could lose 6% of their streamflow due to enhanced evaporation, while for other rivers, the greater evaporation is counterbalanced by more moisture recycling.

Difficult thing: Should we consider planting forests where forests have been before, even if water availability is decreasing (after the models)? What are other impacts of planted forests? More humidity in the air, more water circulation, more precipitation somewhere else?

Jun

2022

Forest restoration must navigate trade-offs between environmental and wood production goals

New research shows forest restoration schemes should prioritise restoring native forests for greatest climate and environmental benefits. However these benefits have a trade-off with wood production in comparison with tree plantations.

The faster growth of trees in plantations managed for timber or pulp production implies greater uptake of water from the soil, which leaves less water for replenishing the groundwater reserves that sustain streams, especially in drier areas. To make matters worse, trees in such plantations are typically harvested more frequently than those in native forests, leading to greater soil disturbance and poorer streamflow regulation.”