کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4577793 1630030 2011 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Latent heat fluxes during two contrasting years from a juvenile plantation established over a waste disposal landscape
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Latent heat fluxes during two contrasting years from a juvenile plantation established over a waste disposal landscape
چکیده انگلیسی

SummaryRevegetation to restore hydrological function to highly disturbed landscapes used for waste disposal or mining is often constrained by the initial low rates of water-use during the early phases of the developing vegetation. This problem is especially pronounced for revegetation that relies on trees due to their prolonged lead-time to achieve canopy closure. Initial low rates of water-use can however be overcome if a groundcover of quick-growing herbaceous species is planted first. To demonstrate the significance of groundcover in the early phase of revegetation, we undertook an energy balance analysis using the Bowen ratio technique for a juvenile plantation growing over a heavy groundcover of herbaceous species on a waste disposal site in 2006/2007 and 2007/2008. Latent heat flux (λE) from the landscape (trees plus groundcover and soil) fluctuated widely between 0.5 and 22 MJ m−2 d−1 and accounted for between 60% and 90% of available energy at the site; this percentage exceeded 100% during periods with significant advection. The latent heat emanating from the tree canopy (λEc), derived from sapflow measurements in the trees, accounted for only between 4% and 18% of daily λE with the balance arising from the groundcover that intercepted more than 90% of incident solar radiation. The λEc was mostly smaller than the net radiation intercepted by the tree canopy (Rnc) with the excess energy expended by the canopy as sensible heat (Hc), which accounted for up to 18% of bulk sensible heat from the landscape. The λE expressed as ET was in excess (114%) of rainfall in the relatively dry first growing (September–May) season, when rainfall was only 87% of the long-term average. It was, however, smaller (80%) than rainfall during the second season, when the annual rainfall was close to the long-term average. We used these data to develop an empirical model for predicting λE from soil–water content and the prevailing evaporative demand.

Research highlights
► We used energy balance to assess restoration of evaparotranspiration (ET) to a waste disposal site.
► Latent heat flux (λE) was 60–90% of solar energy incident on the juvenile plantation.
► The λE arose mostly (>80%) from the groundcover and the rest from the sparse tree canopy.
► There was no evidence of deep drainage since annual λE was close to rainfall in the 2 years.
► Good groundcover is critical to restoring ET during the early phases of tree growth.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hydrology - Volume 399, Issues 1–2, 8 March 2011, Pages 48–56
نویسندگان
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