Aims The redistribution of forest gaps based on solar radiation and precipitation(mainly rainfall and snowfall)can create heterogenous microenvironments inside and outside the gaps.Here,we investigated the effects of ...Aims The redistribution of forest gaps based on solar radiation and precipitation(mainly rainfall and snowfall)can create heterogenous microenvironments inside and outside the gaps.Here,we investigated the effects of forest gaps on carbon(C),nitrogen(N)and phosphorus(P)stoichiometry in decaying logs by altering the microenvironments.Methods Minjiang fir(Abies faxoniana)logs of decay classes I–V were incubated in situ on the floor under the gap center(GC),gap edge(GE)and closed canopy(CC)in a subalpine forest in the eastern Qinghai-Tibet Plateau.The C,N and P concentrations in decaying bark,sapwood and heartwood were measured in August from 2013 to 2016.Important Findings Our results showed that the N concentration in bark decreased from the CC to the GC,while the opposite trend was found in sapwood and heartwood.Additionally,the C/N ratio in sapwood and heartwood of decay classes IV and V decreased from the CC to the GC,and the N/P ratio in heartwood of decay class V increased from the CC to the GC,implying that forest gaps have strong effects on C/N/P stoichiometry in highly decayed logs.Briefly,highly decayed logs are more susceptible to the microenvironment,and the proportion of highly decayed logs under the CC or the GC should be appropriately adjusted if necessary.展开更多
Aims Alpine forest gaps can control understory ecosystem processes by manipulating hydrothermal dynamics.Here,we aimed to test the role of alpine forest gap disturbance on total phenol loss(TPL)from the decomposing li...Aims Alpine forest gaps can control understory ecosystem processes by manipulating hydrothermal dynamics.Here,we aimed to test the role of alpine forest gap disturbance on total phenol loss(TPL)from the decomposing litter of two typical shrub species(willow,Salix paraplesia Schneid.,and bamboo,Fargesia nitida(Mitford)Keng f.).Methods We conducted a field litterbag experiment within a representative fir(Abies faxoniana Rehd.)forest based on‘gap openness treatments’(plot positions in the gap included the gap center south,gap center north,canopy edge,expanded edge and closed canopy).The TPL rate and litter surface microbial abundance(fungi and bacteria)of the two shrub species were measured during the following periods over 2 years:snow formation(SF),snow cover(SC),snow melting(ST),the early growing season(EG)and the late growing season(LG).Important Findings At the end of the study,we found that snow cover depth,freeze–thaw cycle frequency and the fungal copies g−1 to bacterial copies g−1 ratio had significant effects on litter TPL.The abundances of fungi and bacteria decreased from the gap center to the closed canopy during the SF,SC,ST and LG periods and showed the opposite trend during the EG periods.The rate of TPL among plot positions closely followed the same trend as microbial abundance during the first year of incubation.In addition,both species had higher rates of TPL in the gap center than at other positions during the first winter,first year and entire 2-year period.These findings suggest that alpine forest gap formation accelerates litter TPL,although litter TPL exhibits dual responses to gap disturbance during specific critical periods.In conclusion,reduced snow cover depth and duration during winter warming under projected climate change scenarios or as gaps vanish may slow litter TPL in alpine biomes.展开更多
基金This work was supported by the National Natural Science Foundation of China(31870602,31901295 and 32071745)the National Key R&D Program of China(2017YFC0503906)the Program of Sichuan Excellent Youth Sci-Tech Foundation(2020JDJQ0052).
文摘Aims The redistribution of forest gaps based on solar radiation and precipitation(mainly rainfall and snowfall)can create heterogenous microenvironments inside and outside the gaps.Here,we investigated the effects of forest gaps on carbon(C),nitrogen(N)and phosphorus(P)stoichiometry in decaying logs by altering the microenvironments.Methods Minjiang fir(Abies faxoniana)logs of decay classes I–V were incubated in situ on the floor under the gap center(GC),gap edge(GE)and closed canopy(CC)in a subalpine forest in the eastern Qinghai-Tibet Plateau.The C,N and P concentrations in decaying bark,sapwood and heartwood were measured in August from 2013 to 2016.Important Findings Our results showed that the N concentration in bark decreased from the CC to the GC,while the opposite trend was found in sapwood and heartwood.Additionally,the C/N ratio in sapwood and heartwood of decay classes IV and V decreased from the CC to the GC,and the N/P ratio in heartwood of decay class V increased from the CC to the GC,implying that forest gaps have strong effects on C/N/P stoichiometry in highly decayed logs.Briefly,highly decayed logs are more susceptible to the microenvironment,and the proportion of highly decayed logs under the CC or the GC should be appropriately adjusted if necessary.
基金supported by the National Natural Science Foundation of China(no.31570445 and 31800518).
文摘Aims Alpine forest gaps can control understory ecosystem processes by manipulating hydrothermal dynamics.Here,we aimed to test the role of alpine forest gap disturbance on total phenol loss(TPL)from the decomposing litter of two typical shrub species(willow,Salix paraplesia Schneid.,and bamboo,Fargesia nitida(Mitford)Keng f.).Methods We conducted a field litterbag experiment within a representative fir(Abies faxoniana Rehd.)forest based on‘gap openness treatments’(plot positions in the gap included the gap center south,gap center north,canopy edge,expanded edge and closed canopy).The TPL rate and litter surface microbial abundance(fungi and bacteria)of the two shrub species were measured during the following periods over 2 years:snow formation(SF),snow cover(SC),snow melting(ST),the early growing season(EG)and the late growing season(LG).Important Findings At the end of the study,we found that snow cover depth,freeze–thaw cycle frequency and the fungal copies g−1 to bacterial copies g−1 ratio had significant effects on litter TPL.The abundances of fungi and bacteria decreased from the gap center to the closed canopy during the SF,SC,ST and LG periods and showed the opposite trend during the EG periods.The rate of TPL among plot positions closely followed the same trend as microbial abundance during the first year of incubation.In addition,both species had higher rates of TPL in the gap center than at other positions during the first winter,first year and entire 2-year period.These findings suggest that alpine forest gap formation accelerates litter TPL,although litter TPL exhibits dual responses to gap disturbance during specific critical periods.In conclusion,reduced snow cover depth and duration during winter warming under projected climate change scenarios or as gaps vanish may slow litter TPL in alpine biomes.
