Forest Influences on Climate and Water Resources at the Landscape to Regional Scale - Landscape Ecology for Sustainable Environment and Culture - page 314

largest relative change in NW in all seasons except winter, and the lowest relative
change in NE. Precipitation disturbance is also consistently positive in SE. The
disturbance in KO is positive with a large value in winter but very small in other
seasons. The disturbance is small in all seasons in MO.
The spatial patterns of precipitation changes in spring and summer are char-
acterized by overall positive in the afforestation areas and in south of the affor-
estation areas over the southern North China region, which is surrounded by a
negative disturbance, mainly east of the afforestation areas along the China border.
The disturbance turns positive again with the most significant increase over the
oceanic region south to the Korea peninsula. The spatial pattern in the fall is closer
to that in the spring. In winter, a positive disturbance is dominant and occurs
mostly southeast of the afforestation areas.
In comparison with the precipitation disturbance, evapotranspiration distur-
bance is larger in NW and N, but smaller in NE, SE and MO in spring. The same
magnitude is found in NW and N, but it turns negative in NE. The disturbance is
slightly positive in autumn and small in winter in the three afforested areas.
Disturbance in air relative humidity is positive in all areas and all seasons except
summer in NE. Air temperature is increased in winter for all areas, but varies
among areas in other seasons. It is reduced by nearly 0.5 C in NW, and slightly
reduced in the other afforested areas with the exception of a large positive dis-
turbance that occurs during summer in NE.
Effects of reforestation differ from precipitation and evapotranspiration in the
afforested areas in that it is negative in all seasons except autumn in N. Distur-
bance outside of the afforestation areas can be either positive or negative, but
mostly the former for the disturbance with large magnitude. These results indicate
that runoff is mostly decreased in and outside the afforested areas. Disturbance in
soil moisture of the surface layer varies across the regions. It is positive during all
seasons for NW and SE, and positive in spring but negative during the three other
seasons for N and NE. The depth of the rooting layers increases after afforestation.
As a result, soil moisture increases in the afforested areas.
15.5 Knowledge Gaps and Future Research Needs
Fossil fuel burning and land use change (e.g., deforestation) are two of the top factors
that have directly contributed the ongoing climate change (IPCC 2007 ). Climate
change is the most serious environmental problem that humans will face for a long
time. Mitigating and adapting to climate change requires a comprehensive inte-
grated approach that must consider the interactions and tradeoffs of the options.