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Leaf Litter Fall (leaf + litter_fall)
Selected AbstractsEstimating net primary production of boreal forests in Finland and Sweden from field data and remote sensingJOURNAL OF VEGETATION SCIENCE, Issue 2 2004Daolan Zheng We calculated annual mean stem volume increment (AMSVI) and total litter fall to produce forest net primary production (NPP) maps at 1-km2 and half-degree resolutions in Finland and Sweden. We used a multi-scale methodology to link field inventory data reported at plot and forestry district levels through a remotely sensed total plant biomass map derived from 1-km2 AVHRR image. Total litter fall was estimated as function of elevation and latitude. Leaf litter fall, a surrogate for fine root production, was estimated from total litter fall by forest type. The gridded NPP estimates agreed well with previously reported NPP values, based on point measurements. Regional NPP increases from northeast to southwest. It is positively related to annual mean temperature and annual mean total precipitation (strongly correlated with temperature) and is negatively related to elevation at broad scale. Total NPP (TNPP) values for representative cells selected based on three criteria were highly correlated with simulated values from a process-based model (CEVSA) at 0.5° × 0.5° resolution. At 1-km2 resolution, mean above-ground NPP in the region was 408 g/m2/yr ranging from 172 to 1091 (standard deviation (SD) = 134). Mean TNPP was 563 (252 to 1426, SD = 176). Ranges and SD were reduced while the mean values of the estimated NPP stayed almost constant as cell size increased from 1-km2 to 0.5° × 0.5°, as expected. Nordic boreal forests seem to have lower productivity among the world boreal forests. [source] Respiration and annual fungal production associated with decomposing leaf litter in two streamsFRESHWATER BIOLOGY, Issue 9 2004M. D. Carter Summary 1. We compared fungal biomass, production and microbial respiration associated with decomposing leaves in one softwater stream (Payne Creek) and one hardwater stream (Lindsey Spring Branch). 2. Both streams received similar annual leaf litter fall (478,492 g m,2), but Lindsey Spring Branch had higher average monthly standing crop of leaf litter (69 ± 24 g m,2; mean ± SE) than Payne Creek (39 ± 9 g m,2). 3. Leaves sampled from Lindsey Spring Branch contained a higher mean concentration of fungal biomass (71 ± 11 mg g,1) than those from Payne Creek (54 ± 8 mg g,1). Maximum spore concentrations in the water of Lindsay Spring Branch were also higher than those in Payne Creek. These results agreed with litterbag studies of red maple (Acer rubrum) leaves, which decomposed faster (decay rate of 0.014 versus 0.004 day,1), exhibited higher maximum fungal biomass and had higher rates of fungal sporulation in Lindsey Spring Branch than in Payne Creek. 4. Rates of fungal production and respiration per g leaf were similar in the two streams, although rates of fungal production and respiration per square metre were higher in Lindsey Spring Branch than in Payne Creek because of the differences in leaf litter standing crop. 5. Annual fungal production was 16 ± 6 g m,2 (mean ± 95% CI) in Payne Creek and 46 ± 25 g m,2 in Lindsey Spring Branch. Measurements were taken through the autumn of 2 years to obtain an indication of inter-year variability. Fungal production during October to January of the 2 years varied between 3 and 6 g m,2 in Payne Creek and 7,27 g m,2 in Lindsey Spring Branch. 6. Partial organic matter budgets constructed for both streams indicated that 3 ± 1% of leaf litter fall went into fungal production and 7 ± 2% was lost as respiration in Payne Creek. In Lindsey Spring Branch, fungal production accounted for 10 ± 5% of leaf litter fall and microbial respiration for 13 ± 9%. [source] Soil nutrient supply and biomass production in a mixed forest on a skeleton-rich soil and an adjacent beech forestJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2002Dirk Hölscher Abstract In the natural forest communities of Central Europe, beech (Fagus sylvatica L.) predominates in the tree layer over a wide range of soil conditions. An exception with respect to the dominance of beech are skeleton-rich soils such as screes where up to 10 broad-leaved trees co-exist. In such a Tilia-Fagus-Fraxinus-Acer-Ulmus forest and an adjacent mono-specific beech forest we compared (1) soil nutrient pools and net nitrogen mineralization rates, (2) leaf nutrient levels, and (3) leaf litter production and stem increment rates in order to evaluate the relationship between soil conditions and tree species composition. In the mixed forest only a small quantity of fine earth was present (35 g l,1) which was distributed in patches between basalt stones; whereas a significantly higher (P < 0.05) soil quantity (182 g l,1) was found in the beech forest. In the soil patches of the mixed forest C and N concentrations and also concentrations of exchangeable nutrients (K, Ca, Mg) were significantly higher than in the beech forest. Net N mineralization rates on soil dry weight basis in the mixed forest exceeded those in the beech forest by a factor of 2.6. Due to differences in fine earth and stone contents, the volume related soil K pool and the N mineralization rate were lower in the mixed forest (52 kg N ha,1 yr,1, 0,10 cm depth) than in the beech forest (105 kg N ha,1 yr,1). The leaf N and K concentrations of the beech trees did not differ significantly between the stands, which suggests that plant nutrition was not impaired. In the mixed forest leaf litter fall (11,%) and the increment rate of stem basal area (52,%) were lower than in the beech forest. Thus, compared with the adjacent beech forest, the mixed forest stand was characterized by a low volume of patchy distributed nutrient-rich soil, a lower volume related K pool and N mineralization rate, and low rates of stem increment. Together with other factors such as water availability these patterns may contribute to an explanation of the diverse tree species composition on Central European screes. Bodennährstoffangebot und Biomasseproduktion in einem Mischwald auf einem stark skeletthaltigen Standort und in einem benachbarten Buchenwald In den natürlichen Waldgesellschaften Mitteleuropas dominiert die Buche (Fagus sylvatica L.) über ein weites Spektrum an bodenchemischen Standortsbedingungen. Eine Ausnahme in Bezug auf die Buchendominaz bilden stark skeletthaltige Standorte, wie etwa Blockhalden, wo bis zu 10 Laubbaumarten gemeinsam vorkommen. In solch einem Tilia-Fagus-Fraxinus-Acer-Ulmus -Wald und einem benachbarten Buchenreinbestand haben wir (1) die Bodennährstoffvorräte und Stickstoffmineralisationsraten, (2) den Blattnährstoffstatus und (3) die Blattproduktion und die Stammzuwachsraten vergleichend untersucht, um die Beziehung zwischen den Bodenbedingungen und der Baumartenzusammensetzung zu charakterisieren. In dem Mischwald fanden wir nur eine geringe Menge an Feinboden (35 g l,1), die sich in Taschen zwischen den Basaltsteinen befand, wohingegen ein signifikant (P < 0.05) höherer Gehalt an Feinboden (182 g l,1) in dem Buchenwald vorhanden war. In den Bodentaschen des Mischwaldes waren die C- und N-Konzentrationen und auch die Konzentrationen an austauschbar gebundenem K, Ca und Mg signifikant höher als im Buchenwald. Die Netto-N-Mineralisation pro Gewichtseinheit im Mischwald überstieg diejenige im Buchenwald um den Faktor 2,6. Wegen der unterschiedlichen Anteile an Feinboden und Skelett waren der volumenbezogene K-Vorrat und die volumenbezogene N-Mineralisationsrate im Mischwald (52 kg N ha,1 yr,1, 0,10 cm Tiefe) geringer als im Buchenwald (105 kg N ha,1 yr,1). Die Blattnährstoffgehalte von Buchen unterschieden sich zwischen den beiden Beständen nicht signifikant, was darauf hinweist, dass die Pflanzenernährung nicht beeinträchtigt war. Der herbstliche Blattstreufall (11,%) und die Zuwachsraten der Stammquerflächen (52,%) waren im Mischwald geringer als im Buchenwald. Im Vergleich mit dem benachbarten Buchenwald wies der Mischwald somit einen geringen Gehalt an sehr ungleichmäßig verteiltem, nährstoffreichen Boden, geringere volumenbezogene K-Vorräte und N-Mineralisationsraten und geringe Stammzuwächse auf. Gemeinsam mit anderen Faktoren, wie etwa der Wasserverfügbarkeit, können diese Muster zu einer Erklärung der Baumartenvielfalt auf mitteleuropäischen Blockstandorten beitragen. [source] Uptake of perchlorate by vegetation growing at field sites in arid and subhumid climatesREMEDIATION, Issue 4 2007Dawit D. Yifru Previous greenhouse and field studies show that terrestrial and aquatic vegetation, including trees, grasses, and agricultural produce grown on perchlorate-contaminated soil or with perchlorate-contaminated irrigation water, accumulate perchlorate mainly in their leaf tissue. The phytoaccumulated perchlorate poses potential ecological risk by either contaminating the food chain of humans and animals or recycling in the ecosystem as leaf litter fall that accumulates on topsoil. In this study, the uptake and phytoaccumulation of perchlorate in terrestrial and aquatic vegetation growing at two perchlorate-contaminated sites (the Longhorn Army Ammunition Plant [LHAAP] in Karnack, Texas, and the Las Vegas Wash [LVW], Nevada) was monitored during multiple growing seasons. The LHAAP site is located in a subhumid climate, while the LVW site is located in an arid climate. All vegetation species collected from both sites contained quantifiable levels of perchlorate. The detected concentrations varied with the type of plant species, amount of perchlorate concentration in soil, and season and stage of plant maturity. The highest perchlorate concentrations were measured in willows (Salix nigra), crabgrass (Digitaria spp.), and Bermuda grass (Cynodon dactylon) at the LHAAP, while salt cedar (Tamarix ramosissima) at the LVW phytoaccumulated the highest mass of perchlorate. The concentrations of perchlorate measured in plant leaves growing over contaminated soils at multiple LHAAP locations did not reveal the strong seasonal variability observed at the LVW site. The slow rate of phytodegradation of the perchlorate fraction taken up by plants during the growing season explained the detection of higher perchlorate concentrations in leaves collected later in the growing season (fall) and in senesced leaves compared to younger, live leaves. This proves that senesced plant leaves potentially recycle perchlorate back into the soil on which plant litter collects. To minimize the potential recycling of perchlorate during phytoremediation, it is recommended that senesced leaves be collected and composted or phytoremediation be designed to enhance rapid rhizodegradation (rhizoremediation). © 2007 Wiley Periodicals, Inc. [source] | ||||||||||