Range Of Rainfall Conditions Research Articles

Rainfall Interception in Two Contrasting Forest Types in the Mount Gongga Area of Eastern Tibet, China

An important component of the water cycle in ecological systems, rainfall interception by virgin forests was here calculated from gross precipitation minus through fall and stem flow. The through fall measurement system was designed on the basis of a 3 m long trough mounted beneath the canopy and able to operate successfully under a range of rainfall conditions. Stem flow was measured using spiral collars consisting of a split plastic hose attached to sampled trees, with gross precipitation measured in an open area via a tipping-bucket rain gauge. This study was carried out to evaluate rainfall interception and distribution patterns of gross precipitation in two contrasting rainforest types (coniferous and broadleaved/coniferous mixed) in the Mount Gongga area on the eastern fringe of Tibet, China, from 2008 to 2009. Net precipitation was found to be primarily composed of through fall, while stem flow contributed less than 0.5% (0.1% and 0.4% in conifer and mixed forest, respectively) to total gross precipitation (GP) and was thus negligible in both forest types. The difference in the interception loss fraction between conifer and mixed forest was greater than 30%, with the interception loss of the former apparently more than that of the latter mainly due to the increased presence of small droplets produced by coniferous leaves. Additionally, interception loss in conifer forest was more dependent on rainfall than that in mixed forest. In contrast, through fall and stem flow exhibited the opposite pattern, likely attributable to a through fall lag of 8 to 10 h after rainfall in mixed forest but not in conifer forest.

Precipitation interception in Australian tropical rainforests: I. Measurement of stemflow, throughfall and cloud interception

AbstractMethods for measuring throughfall, stemflow and, hence, interception in the tropical rainforests of the Wet Tropics region of North Queensland, Australia, were tested at three sites for between 581 and 787 days. The throughfall system design was based on long troughs mounted beneath the canopy and worked successfully under a range of rainfall conditions. Comparison of replicated systems demonstrated that the methodology is capable of capturing the variability in throughfall exhibited beneath our tropical rainforest canopies. Similarly, the stemflow system design which used spiral collars attached to sample trees worked well under a range of rainfall conditions and also produced similar estimates of stemflow in replicated systems.Higher altitude rainforests (>1000 m) in North Queensland can receive significant extra inputs of water as the canopy intercepts passing cloud droplets. This additional source of water is referred to as ‘cloud interception’ and an instrument for detecting this is described. The results obtained from this gauge are compared with cloud interception estimates made using a canopy water balance method. This method is based on stemflow and throughfall measurements and provides an alternative means to fog or cloud interception gauge calibration techniques used in the literature. Copyright © 2007 John Wiley & Sons, Ltd.

Quantitative Floristic Studies of the Ground Layer in Some Mulga (Acacia aneura F. Muell.) And Mitchell Grass (Astrebla Spp.) Communities in South-Western Queensland

A survey of 36 sites of known history in S.W. Queensland was made with a wheel-point apparatus to establish quantitative standards of botanical composition and basal cover for the ground layer vegetation of 4 main soil types in the mulga and Mitchell grass regions. It was shown that dominant species were similar on sites within a soil group, over a wide range of rainfall conditions. Basal cover over all sites averaged 3.0%, while an average of 23 species made up the ground layer of the vegetation. A total of 65 grasses and 95 non-grasses was recorded in the wheel-point surveys. The implications of the survey results are discussed.

Pattern in a Forest Communuity

All these ranges of microclimatic conditions in sugar maple stands were based on measurements made 5 ft above ground. This height was chosen to make comparisons with Weather Bureau data more meaningful. The ranges of recorded values would no doubt be somewhat different if the measurements were made at an appreciably different level. Rainfall was generally high in Oklahoma in 1958, 1959, and 1960, and the recorded microclimatic data would probably have been at least slightly different if severe drought conditions had prevailed during the study periods. Actually, a fair range of rainfall conditions was encountered. Total rainfall from May-Oct., 1958, was 12% below normal in the Devils Canyon area, and 25% below normal there in the summer of 1960. Most ranges of microclimatic data during these periods were similar to those measured in the summer of 1959, however, when precipitation was 77% above normal in the same area. Rainfall in the eastern stand was 37% above normal in the summer of 1959 and 20% above normal in the summer of 1960.