李勋　刘洋　张健　杨万勤　张艳　邓长春　张明锦　刘华

(四川农业大学,成都，611130)



林窗大小对马尾松人工林凋落叶可溶性有机碳损失的影响1)

李勋刘洋张健杨万勤张艳邓长春张明锦刘华

(四川农业大学,成都，611130)

基于人工林近自然改造，调控低山丘陵区马尾松低效林林分结构，探明马尾松人工林不同面积林窗下，凋落叶可溶性有机碳(DOC)释放规律。以长江上游低山丘陵区人为采伐形成的马尾松人工林7种林窗(100、225、400、625、900、1 225、1 600 m2)为研究对象，研究不同面积林窗的马尾松(Pinusmassoniana)、红椿(Toonaciliata)、樟(Cinnamomumcamphora)、桢楠(Phoebezhennan)等凋落叶可溶性有机碳(DOC)的损失率。结果表明：(1)林窗面积对凋落叶DOC损失率有显著影响。中小面积林窗(225～625 m2)内凋落物的DOC损失率高于其它面积林窗。(2)经过1 a的分解，4种凋落叶的DOC损失率为61.55%～90.06%，其中：DOC损失率红椿最高，马尾松最低。(3)凋落叶的DOC损失主要集中在分解前期(0～90 d)，此后凋落叶的DOC损失速率不断降低，且不同凋落物之间DOC损失速率的差异不断减小。因此，在马尾松低效林改造过程中，可利用中小面积林窗这一显著作用，引入乡土阔叶树种红椿、樟、桢楠，加速马尾松人工林的物质循环，维持林地肥力。

可溶性有机碳；林窗；马尾松人工林；马尾松凋落叶

We adjusted the structure of forest and explored the regularity of litter dissolved organic carbon (DOC) release in seven gap sizes of aPinusmassonianaplantation in a hilly area of the upper reaches of Yangtze River. The experiment was set up inPinusmassonianaplantation with seven different gap sizes (100, 225, 400, 625, 900, 1 225, and 1 600 m2) established by artificial thinning. The contents of DOC forPinusmassoniana(Pm),Toonaciliate(Tc),Cinnamomumcamphora(Cc) andPhoebezhennan(Pz) were evaluated in different sized forest gaps, with closed canopy as the control. Litterbags were collected from the gap center and the closed canopy in December of 2013, February, May, August and November of 2014. The forest gap size had significant effects on DOC loss rate small and medium sized gaps (225-900 m2) had greater effect on DOC loss rate forPm,Tc,Cc, andPzleaf litter. Over one-year decomposition, variation trend of DOC loss rate of descending order for four species wasTc(90.06%),Cc(85.17%),Pz(78.74%) andPm(61.55%). The DOC loss rate for four species mainly was concentrated in the early decomposition stages (first 90 days), and then was decreased quickly, and the difference of DOC loss rate (per 30 days) among four species diminished gradually. Therefore, when we reconstruct the low-function forest, we can take advantage of small and medium sized gaps, introduce native broad-leaf tree speciesTc,Cc,Pzto accelerate nutrient cycling, and maintain the soil fertility ofPinusmassonianaplantation.

凋落物分解过程中可溶性有机碳(DOC)的释放不仅是森林生态系统养分循环的重要环节,也对碳循环起着极其重要的作用[1-2]。DOC是森林生态系统中一类重要的、十分活跃的化学组分，也是微生物生长和生物分解过程中的重要能量来源。DOC对森林生态系统营养物质的有效性和流动性、污染物质的毒性及其迁移特性、pH有直接影响[3-4]。……