Litter Interception Research Articles

Rainfall partitioning within semiarid juniper communities: effects of event size and canopy cover

AbstractPartitioning bulk rainfall into canopy interception, litter interception, stemflow and throughfall allows an estimate of the physical impact of trees on the local hydrologic budget. Despite recognition of the potentially large effect of interception and associated processes on the hydrologic budget, few, if any, studies have quantitatively evaluated the multiple components simultaneously in semiarid savannas, nor have the effects of rainfall intensity within storms been rigorously evaluated. We monitored interception and rainfall partitioning in individual Ashe juniper (Juniperus ashei Buchholz) canopies at ten sites over a 3‐year period. Averaged over all ten sites for 2700 total rain events, about 35% of the bulk rainfall falling on juniper trees was intercepted by the tree canopy, 5% was intercepted by the coarse litter and duff beneath the tree, 55% reached the ground surface as direct and released throughfall, and 5% was redirected to the base of the tree as stemflow. Small amounts of rainfall (<2·5 mm) were entirely captured by the canopy and evaporated to the atmosphere, contributing nothing to soil water under juniper trees. Low intensity rainfall (e.g. 13 mm over a 19‐h period) that could conceivably benefit the local plant community was largely intercepted by the tree canopy (>60% interception). High intensity rainfall was less influenced by juniper canopies. At high intensities (e.g. > 70 mm over a 15‐h period) only 20% of the bulk precipitation was intercepted by the canopy and litter. The hourly pattern of rainfall within extended storms demonstrated periods with low intensity and periods with high intensity. The interception rates during these periods closely mimic the rates seen in similar intensity short duration storms. Canopy and litter interception effectively reduced the beneath‐canopy precipitation from 600 to 360 mm in the western region and from 900 to 540 mm in the eastern region. Copyright © 2006 John Wiley & Sons, Ltd.

Experimental analysis of moisture dynamics of litter layers—the effects of rainfall conditions and leaf shapes

AbstractThe effects of rainfall conditions and the morphological characteristics of leaves on the moisture dynamics of litter layers were investigated. Maximum water storage capacity and interception storage capacity under various rainfall conditions were evaluated for two contrasting litter types: a needle‐leaf type, represented by Cryptomeria japonica leaves; and a broad‐leaf type, represented by Lithocarpus edulis leaves. An artificial rainfall simulator was applied to measure each litter type's interception storage capacity under various rainfall intensities. Our results indicated that (1) the maximum water storage capacity of each litter layer was proportional to the litter mass (kg/m2) regardless of layer thickness; (2) the litter interception storage capacity increased with rainfall intensity in the range of realistic rainfall conditions (under 50 mm/h); (3) the broad‐leaf litter of L. edulis intercepted more rainwater than the needle‐leaf litter of C. japonica; and (4) the rainwater moved laterally in the litter layer of L. edulis whereas it moved directly down in the litter layer of C. japonica. These results show that not only the litter mass but also the rainfall conditions and leaf shapes are important in evaluating the moisture dynamics of litter layers. Copyright © 2004 John Wiley & Sons, Ltd.

Litter Interception on Astrocaryum mexicanum Liebm. (Palmae) in a Tropical Rain Forest1

ABSTRACTThe goal of this study was to quantify litter interception onAstrocaryum mexicanumLiebm., an abundant and efficient litter–capturing palm. The study was done in a forest at Los Tuxtlas, Veracruz, on the Gulf of Mexico coast. Palms were randomly selected and total litter retention was quantified by determining dry weight over two years. Litter interception by palms was 4.4 and 27.1 Mg/ha/yr for the first and second years, respectively, and accounted for 47.9 and 239.4 percent of the reported annual litterfall in the same area. Results showed that litter interception by plants is related to litterfall and should therefore be added to total litterfall in order to calculate the net primary productivity.

Partitioning of rainfall by three Central Himalayan forests

Throughfall, interception losses and surface run-off studies during the monsoon season (June through September) in three different forests of Central Himalaya are described. The tree canopy covers of the stands were 80.0–91.5%. Canopy throughfall (throughfall directly beneath the canopy) made up 76.5% and canopy interception loss was 23.5% of the total rainfall (1965.8 mm) during the 1985 and 1986 monsoons. Values of throughfall and interception losses computed for entire forested stands (stand throughfall and stand interception) accounted for 79.6% and 20.2% of the total rainfall. The minimum canopy throughfall (74.9%) was recorded in chir pine and maximum (78.6%) in mixed banj oak-tilonj oak forest. Stand throughfall was maximum (80.7%) in mixed banj oak-chir pine forest and minimum (77.5%) in chir pine forest. Stand interception was higher in chir pine compared with mixed banj oak-chir pine and banj oak-tilonj oak forests. The highest value of surface run-off was recorded in chir pine forest which had the lowest litter interception (8.3%). Canopy throughfall and surface run-off were positively related ( P < 0.01) to bulk precipitation. The low proportion of surface run-off (0.46–0.53%) is a characteristic and a special feature of the forest ecosystems of the Central Himalaya.

Site water balance and tree water status in irrigated and fertilised stands of Pinus radiata

Soil water content and pre-dawn needle water potential were measured at 2-week intervals for 4 years in a field study of the interaction of water and nutrients in controlling growth of 10- to 14-year-old Pinus radiata near Canberra, Australia. Growth on the shallow low-fertility duplex soil was limited by both nutrient and water deficiencies. The 40 cm deep A horizon, which contained about 85% of the fine root system, had a plant-available water (PAW) holding capacity of about 60–70 mm or about 8 days supply at peak summer transpiration rates. About 33% of total annual precipitation was unavailable to the trees because of canopy and litter interception losses (28%) and run-off (5%) resulting from dissimilarity in seasonal distribution of precipitation and potential water use. Net canopy interception was 20% of annual rainfall and litter/ understorey interception was 8%. Net interception was strongly affected by size of rainfall event during individual storms, ranging from more than 55% of a 5 mm event to less than 10% of a 40 mm event. However, stand basal area (as it reflects mass of foliage) was the main source of variation in annual net canopy interception, varying from 15% of total precipitation at a basal area of 20 m 2 ha −1 to 25% at 34 m 2 ha −1. Trees appeared to extract soil water below the conventionally accepted wilting point (−1.5 MPa) and progressively dried out the profile to at least 2 m depth, resulting in growth being restricted by water deficiency. Water availability was a more important determinant of water use than was canopy size, but in non-water-limited stands annual transpiration varied directly with foliage mass and ranged from 0.88 to 1.19 times pan evaporation. Seventy percent of annual water use occurred in the 6 months from October to March inclusive. Differences in water use between stands were largest in summer because of maximum differences in water availability and maximum foliage mass at that time. At soil water contents above 40% PAW, pre-dawn needle water potential was independent of soil water content, but it increased with increasing soil temperature and foliar nitrogen concentration. Below 40% PAW, pre-dawn potential decreased linearly with declining soil water content.

Reactions of the Macrofauna of a Forest Mull to Experimental Perturbations of Litter Supply

Jean-Fransois David, Jean-Fransois Ponge, Pierre Arpin, and Guy Vannier David J.-F., Ponge, J.-F., Arpin, P. and Vannier, G. 1991. Reactions of the macro- fauna of a forest mull to experimental perturbations of litter supply. - Oikos 61: 316-326. The effects on forest soil macrofauna of two treatments, viz. litter interception and twofold litter supply, were studied for five yr in the field. Results concern five saprophagous groups (Lumbricidae, Diplopoda, Isopoda, Coleoptera larvae, Diptera larvae) and five zoophagous groups (Geophilomorpha, Lithobiomorpha, Pseudo- scorpionida, Coleoptera larvae, Diptera larvae). The litter interception had a nega- tive effect on the abundance of most taxa, but was rather slow; there was no significant decrease in abundance before at least 1 yr in Lumbricidae, 2 yr in Isopoda and zoophagous Diptera larvae, 2.5 yr in Diplopoda, saprophagous Diptera larvae, Geophilomorpha and Lithobiomorpha. The twofold litter supply had no significant effect on the abundance of most taxa; on the other hand, it initiated a process of dead leaf accumulation in relation to control, with an annual decomposition rate (k') higher on the control plot than on the plot with an increased litter supply. The results do not support the assumption that saprophagous soil macrofauna are food-limited in acid mull conditions.

Interception by eastern white pine

Measurements of gross rainfall, throughfall, stemflow, and litter interception in three eastern white pine stands, age 10, 35, and 60 years, in the Southern Appalachians of western North Carolina, were used to derive regression equations for estimating throughfall, stemflow, and the sum of throughfall and stemflow from measurements of gross rainfall. Equations for total interception loss were derived by algebraically combining losses from the canopy and litter. These equations were used to predict total seasonal interception loss (I) from measurements of total seasonal rainfall (ΣP) and number of storms (N). Equations for the 10‐, 35‐, and 60‐year‐old stands are I = 0.05(N) + 0.08 (ΣP), I = 0.05(N) + 0.12(ΣP), and I = 0.06(N) + 0.18(ΣP), respectively. Total interception loss in white pine increased with stand age, and total loss from all pine stands studied exceeded losses calculated for mature hardwoods. During the dormant season, calculated monthly interception loss from mature hardwoods and white pine exceeded potential evapotranspiration calculated by the Thornthwaite method.

Canopy and litter interception of rainfall by hardwoods of eastern United States

All available reports of rainfall interception by hardwoods of the eastern United States were reviewed and, where possible, combined. Results from these independently designed and analyzed experiments showed that hardwood throughfall and stemflow vary over a surprisingly narrow range. Combined regression analysis describes the relation between inches of gross rainfall (P), throughfall (T), and stemflow (S) for summer as T = 0.901P ‐ 0.031, S = 0.041P ‐ 0.005; for winter as T = 0.914P − 0.015, S = 0.062P ‐ 0.005. These equations can be modified for specified forest conditions or for use with seasonal rainfall. Fifteen standard gages were found necessary to sample the growing season throughfall within 5% error limits, and 6 were necessary for the dormant season. Hardwood litter interception, studied inadequately in most parts of the east, amounted to 2 to 5% of the annual rainfall in the southern Appalachians. Applicability of equations to research and to practical problems is discussed as well as need for further research.