(A) Distribution of forest AGBD in a two-dimensional space with (MAT) and (MAP) binned into intervals of 1°C MAT and 100 mm MAP.

<p><b>(B) The sensitivity of AGBD on temperature (S</b>_<b>T</b><b>) along precipitation gradient. (C) The sensitivity of AGBD on precipitation (S</b>_<b>p</b><b>) along temperature gradient.</b> The shaded area in (B) and (C) indicates 95% significance intervals of S_T and Sp. Sensitivities were only calculated in bins having more than 100 grid pixels.</p

Explanatory variables used in MTE.

<p>¹ The 2001–2013 summer values of MODIS reflectance and Vegetation Indices are calculated by averaging values from June to August during 2001–2013.</p><p>Explanatory variables used in MTE.</p

Comparison of observed AGBD (Mg C ha^-1) against predicted AGBD using MTE algorithm.

<p>The blue dots indicate the training samples (R² = 0.57, RMSE = 22.4 Mg C ha^-1), and the red ones refer to the validation samples (R² = 0.46, RMSE = 22.7 Mg C ha^-1).</p

Forest types and the distribution of AGBD data in China.

<p>The forest types are according to the 1:4000000 vegetation map of China. DNF = deciduous needle leaf forests, ENF = evergreen needle leaf forests, MF = needle leaf and broadleaf mixed forests, DBF = deciduous broadleaf forests, EBF = evergreen broadleaf forests. The AGBD data is from Luo <i>et al</i>. [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130143#pone.0130143.ref018" target="_blank">18</a>].</p

Spatial distribution of mean forest AGBD during 2001–2013.

<p>Spatial distribution of mean forest AGBD during 2001–2013.</p

Area and aboveground biomass characteristics for five forest types in China during 2001–2013.

<p>DNF = deciduous needle leaf forests, ENF = evergreen needle leaf forests, MF = needle leaf and broadleaf mixed forests, DBF = deciduous broadleaf forests, EBF = evergreen broadleaf forests.</p><p>Area and aboveground biomass characteristics for five forest types in China during 2001–2013.</p

The Effect of Afforestation on Soil Moisture Content in Northeastern China

<div><p>Widespread afforestation programs sequester carbon from the atmosphere and mitigate the rising of atmospheric carbon dioxide (CO₂). Meanwhile, afforestation carbon sequestration may cost soil water. However, changes in soil moisture content (SMC) after large-scale afforestation or reforestation have rarely been quantified. In this study, we measured changes in SMC following afforestation using a paired plots method with data from 757 plots in Northeastern China. We found a marginally significant decline in soil moisture content of the top 1-m soil (SMC_0-1m) after afforestation (P = 0.08) at the regional scale. The SMC responses to afforestation also vary across species. For example, significant SMC decrease are found for <i>Populus</i> spp. plantations (P < 0.05) and plantations of <i>Pinus sylvestris</i> var. <i>mongolica</i> (P < 0.05). Splitting the first meter of the soil profile into different depth intervals revealed that SMC declined significantly in shallow layers (0–30 cm) for <i>Populus</i> spp. and <i>Pinus sylvestris</i> var. <i>mongolica</i>. We also found that when SMC in the control exceeded a specific threshold, SMC for all five tree species considered tended to decrease, suggesting that the effects of afforestation on soil hydrology vary across different regions.</p></div

Map of the study area.

<p>The locations of sampling sites surveyed during 2012–2013 are marked with “+” symbols. The texts displayed refer to the name of provincial administrative unit, which are Inner Mongolia Autonomous Region, Shaanxi Province, Shanxi Province, Hebei Province, Liaoning Province, Jilin Province and Heilongjiang Province, respectively. Land cover map was adapted from the vegetation distribution map of China [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0160776#pone.0160776.ref028" target="_blank">28</a>].</p

Changes of top 1-m soil moisture content (ΔSMC_0-1m) in afforested plots (N = 586).

<p>(a) Frequency distribution of ΔSMC_0-1m; (b) Spatial distribution of ΔSMC_0-1m. In panel (a), the median, 25^th and 75^th percentile of ΔSMC_0-1m are displayed in texts. Negative ΔSMC_0-1m is found in 52% of the plots.</p

Relationships between the change of top 1-m soil moisture content (ΔSMC_0-1m) and the top 1-m soil moisture content in control plots (SMC_c,0-1m).

<p>SMC_c,0-1m was divided into bins by every 2% SMC_c,0-1m. The numbers on top of the bars refer to the number of plots falling into each group. The asterisks (*) indicate significantly (P < 0.05) positive or negative non-zero ΔSMC_0-1m depended on the median of ΔSMC_0-1m.</p