木質(zhì)物殘?bào)w（Woody Debris,，WD）是森林生態(tài)系統(tǒng)中重要的結(jié)構(gòu)性和功能性組分。但是，極少學(xué)者認(rèn)識(shí)到全球木質(zhì)物殘?bào)w分解釋放的CO2總量（約7.7—9.5 Pg C year-1）與化石燃料燃燒釋放的CO2總量（約9.6 Pg C year-1）大體相當(dāng),。
為了探討木質(zhì)物殘?bào)w分解作用的變化規(guī)律及其影響因子，版納植物園土壤生態(tài)研究組碩士研究生劉偉杰在導(dǎo)師Douglas Schaefer博士的指導(dǎo)下,，針對(duì)哀牢山地區(qū)的三個(gè)原生優(yōu)勢(shì)樹(shù)種的木質(zhì)物殘?bào)w開(kāi)展了相關(guān)實(shí)驗(yàn),。
研究結(jié)果顯示：同組（相同樹(shù)種、相同分解等級(jí)）的不同木質(zhì)物殘?bào)w個(gè)體之間的呼吸速率差異很大,，而木質(zhì)物殘?bào)w的溫度和含水量的二元呼吸模型的R2值僅為0.25—0.57,。這說(shuō)明溫度和含水量是影響木質(zhì)物殘?bào)w分解的重要因子,，但是仍存在其他不確定因素導(dǎo)致木質(zhì)物殘?bào)w分解速率的差異。木質(zhì)物殘?bào)w分解者之間普遍是相互抑制的,，而且對(duì)人工接種的真菌群落而言,，具有較高物種多樣性的木質(zhì)物殘?bào)w分解反而較慢，但是仍需深入探討天然微生物群落與木質(zhì)物殘?bào)w分解作用之間關(guān)系,，這將對(duì)評(píng)估木質(zhì)物殘?bào)w在全球碳循環(huán)過(guò)程中的作用有重要意義,。
相關(guān)研究結(jié)果以What controls the variability of wood-decay rates？為題發(fā)表在Forest Ecology and Management上,。本研究得到了國(guó)際APN基金和國(guó)家自然科學(xué)基金項(xiàng)目的支持,。（生物谷Bioon.com）
生物谷推薦的英文摘要
Forest Ecology and Management doi.org/10.1016/j.foreco.2013.09.013
What controls the variability of wood-decay rates？
Weijie Liua,， Douglas Schaefera,， Lu Qiaoa， Xianbin Liua
Decaying wood provides essential habitats for forest biota,， and its CO2 return to the atmosphere is comparable to that from fossil-fuel combustion. Decomposition rates for wood debris (WD) from three tree species were measured by CO2 release in a subtropical forest over two years. Wood temperature and moisture were measured along with CO2,， and each WD piece (n = 320) was characterized by its initial weight， density,， volume,， surface area， and decay class. For individual pieces of WD in each wood-species and decay-class group,， predictions of release rates based on temperature and moisture together had R2 values ranging from 0.25 to 0.57,， predictions based on moisture alone had R2 values ranging from 0.16 to 0.35， and R2 values from 0.07 to 0.35 were seen in temperature-only predictions. Wood density and surface area were negatively related to CO2 release rates (R2 = 0.10 and 0.04 respectively,， over all groups). We also used daily meteorological measurements to predict WD temperature and moisture. Average air temperatures predicted WD temperatures with R2 values above 0.7 over 35 days,， but total rainfall was a very weak predictor of WD moisture over any interval. We used temperature – decay relationships to estimate annual total CO2 release from WD groups， and found that their average exponential decomposition rate (K) was 0.09 year,？1. Based on density loss,， most WD in the studied forest would be in the late stage of decay， in contrast to some previous studies. Our results support previous studies on the importance of environmental factors in determining WD decomposition,， but with only half of the variation explained,， we are challenged to explain the rest. Aggressive interactions are common among WD decomposers， and previous work with simplified microbial communities suggests that high diversity leads to slower decomposition. Uncertain predictions for WD decomposition rates,， and their global C- cycle implications,， will persist until interactions of WD microbial communities are better understood.
