| Daxing'anling mountains is an important region with wide distribution of natural forests in China.Their potential to absorb and store carbon dioxide has been recognized to play a critical role for their contribution to the national carbon sink and carbon storage.In this study,Larix gmelinii,Betula platyphylla,and Populus davidiana,widely distributed in Daxing'anling mountains of Inner Mongolia,were selected to estimate their biomass in multiscale.1.We established additive biomass models for the three species.2.Stand biomass and production were calculated based on plot data and ring width,whilst the influence of stand factors on biomass and production allocation was studied.3.A regrevssion model between stand biomass and volume was developed for predicting forest biomass of the three species in Daxing' anling mountains of Inner Mongolia.(1)Log-transformed models are favorable and all models yield well fitting effects and predicting performance.Adding h(height)into the additive models did not significantly improve the model fitting or performance,with branches and foliage yielding worse-fitting effects.Given the uncertainty in height measurement,the additive system of biomass equa-tions using d(diameter)as the single predictor could be easily and readily applied to further applications.Correction factors can be ignored in practice due to their small values.(2)For the studied species,the stem wood alone accounted for about 60%of the indi-vidual aboveground biomass on average,whereas foliage accounted for only less than 10%In addition,the proportional distribution of biomass changed with diameter.Stem wood and branch showed an increasing percentage for all species,opposite to stem bark and foliage.(3)There was a significant linear relationship between leaf area and basal area at breast height for all species.At an individual scale,leaf area was nearly 5220 times as large as basal area for L.gmelinii,and the values were 4162 and 2834 for B.platyphylla and P.davidiana,respectively.Leaf area index of the three species were 6.2 m2/m2,4.0 m2/m2,and 2.5m2/m2,respectively.(4)The pattern of stand aboveground biomass allocating to stem wood,bark,branch,and foliage showed significant difference among various forest types.The influence of average diameter at breast height,stand density,and stand ageon biomass allocation also showed obvious regularity.Stem wood accounted for about 60%of the stand aboveground biomass for L.gmelinii and B.platyphylla forests,and it was 63%for P.davidiana forests.However,stand production allocated more to foliage,with 81%,68%,75%for L.gmelinii,B.platy-phylla,and P.davidiana forests,respectively.Stand production of the three species were 7.2 t/(hm2·yr),3.4 t/(hm2·yr),and 6.48 t/(hm2·yr),respectively.In addition,power function could adequately depict the relationship between stand production and biomass.(5)There was highly significant positive linear correlations between stand biomass and volume.Hereby,the biomass density for L.gmelinii,B.platyphylla,and P.davidiana were estimated at 60.4 t/hm2,61.0 t/hm2,and 46.7 t/hm2,respectively,and the aboveground biomass were 2.76×108 t?1.48×108 t and 0.14 × 108 t,respectively.The mid-age forests had the highest biomass storage,indicating a robust potential for carbon sequestration.Over the period of 1995 to 2010,the biomass density and aboveground biomass were increased in certain extent.Assuming the biomass density of intact area as the maximum value that forest region can reach,the growth potential of carbon storage estimated according to shoot-root ratio and carbon content would be 0.9 ×108 t for the three species in the study area.(6)This study explored the method for measuring ring widths of stem disk.Stem disk rings could be rapidly and accurately measured using GIS tools. |
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