沙地樟子松人工林碳库动态及其分配特征

Carbon storage dynamics and its distribution pattern in Pinus sylvestris var. mongolica plantation in sandy land

沙地樟子松人工林作为三北防护林的重要组成部分,在防风固沙和固碳增汇过程中起着重要作用。本研究在辽西北付家林场选择不同林龄的樟子松人工林,包括10~20、20~30、30~40及40~50年生等4个林龄,并结合已建立的辽西北地区樟子松的异速生长方程,分别对其乔木和土壤碳储量进行研究。结果表明：樟子松人工林乔木碳储量随林龄的增加逐渐增大,10~20、20~30、30~40和40~50年生乔木碳储量分别为20.98、25.89、33.83、34.94 Mg C·hm-2,这主要与树干碳储量随林龄的增加逐渐增大有关,且树干碳储量占乔木总碳储量的比例最大,为47.25%~56.17%;樟子松人工林土壤碳储量随林龄增加呈逐渐增大的趋势（30~40年生林略有下降）,其中10~20年生林最小,40~50年生林最大,分别为32.80和51.46 Mg C·hm-2;此外,在土壤垂直剖面上,有机碳储量和碳含量均随土层深度的增加逐渐减小,其中土壤碳储量变化范围为19.20~4.57 Mg C·hm-2,碳含量为2.04%~0.35%;樟子松人工林生态系统总碳储量随林龄增加逐渐增大,10~20年生到40~50年生樟子松林分别为53.78、61.88、67.48和86.40 Mg C·hm-2,整体固碳作用明显;此外,土壤碳库作为该地区樟子松林生态系统碳库的主要组成部分,其占总碳储量的比例为49.87%~60.99%,乔木碳储量占总碳储量的比例为38.91%~50.13%。该研究结果为综合评价三北防护林的生态效益提供了可靠的基础数据。

Pinus sylvestris var. mongolica plantations are an important part of the Three-North Shelterbelt, playing a key role in wind prevention and sand fixation, and carbon sequestration. To quantify carbon storage dynamics and distribution patterns of these forests with forest age, this study selected different age classes of P. sylvestris vat. mongolica plantation in Fujia Forest Farm in northwestern Liaoning Province, including 10-20, 20-30, 30-40 and 40-50 years old to as- sess tree and soil carbon pools. Tree carbon was estimated through allometric equations that were established for P. sylvestris var. mongolica in northwestern Liaoning, and soil carbon storage was obtained via soil organic carbon content multiplied by bulk density from soil profile. The results showed that： Tree carbon storage increased with forest age, and carbon storage levels were 20.98, 25.89, 33.83 and 34.94 Mg C · hm-2 in 10-20, 20-30, 30-40 and 40-50 years old P. sylvestris var. mongolica plantations, respectively; this was mainly attributed to increased trunk carbon storage that accounted for the largest proportion of tree carbon storage, being 47.25%- 56.17%. Soil carbon storage also showed an increased pattern with forest age, with the smallest level of 32.80 Mg C · hm-2 and largest level of 51.46 Mg C · hm-2 in 10-20 and 40-50 years old P. sylvestris var. mongolica plantations, respectively. In addition, both soil carbon storage and or- ganic carbon content decreased with the increase of soil depth, with the carbon storage range of 4.57-19.20 Mg C · hm-2 and organic carbon content range of 0.35%-2.04%, respectively. Total carbon storage of P. sylvestris var. mongolica plantation also increased with forest age, and carbon storage levels were 53.78, 61.88, 67.48 and 86.40 Mg C ~ hm-2 in 10-20, 20-30, 30-40 and 40-50 years old plantations, respectively. It implied that P. sylvestris var. mongolica plantation ecosystem acted as a carbon sink during its growth process. In addition, the contribution of soil carbon storage to total carbon storage ranged from 49.87% to 60.99%, while the contribution of tree carbon storage to total carbon storage ranged from 38.91% to 50.13%. These data were of scientific importance to comprehensively predicting ecological values for Three-North Shelterbelt.