GSTDTAP  > 气候变化
DOI10.1016/j.foreco.2019.05.015
Characterizing light across a strip shelterwood in a mixed conifer forest
Hossain, Kazi Liaquat; Comeau, Philip G.
2019-08-01
发表期刊FOREST ECOLOGY AND MANAGEMENT
ISSN0378-1127
EISSN1872-7042
出版年2019
卷号445页码:134-145
文章类型Article
语种英语
国家Canada
英文摘要

A knowledge of how light varies within gaps is fundamental to understanding variation in survival and growth of regenerating trees. Simple indices based on a small number of instantaneous measurements by portable sensors or cameras are widely used for this purpose. But the effectiveness of these indices for estimating growing season transmittance is influenced by stand characteristics and local weather conditions. This study was conducted in two small (50 m x 150 m) clearings in a mixed stand of the interior cedar hemlock zone of southern British Columbia to evaluate several commonly used light estimation techniques, including: (1) hemispherical photography; (2) LAI-2000 plant canopy analyzer; and, (3) midday measurements of % photosynthetic photon flux density (hourly average PPFD) under sunny and overcast skies in a strip-shelterwood system. While diffuse indices from hemispherical methods (LAI-2000 and photograph) performed poorly, their direct and total indices (photograph) gave lower variability (lower rmse) and stronger correlations (higher r(2)) with growing season transmittance. Sky conditions under which light measurements were recorded by photosynthetically active radiation (PAR) sensors influenced the relationships between PAR sensor indices and growing season transmittance. For example, measuring light around midday on a sunny day provided stronger correlation with growing season transmittance than overcast day measurements. Moreover, rather than using one midday light measurement on a sunny or an overcast day, an average of two measurements increased r(2) and reduced bias while measuring light three times on a sunny day (morning, noon and afternoon) gave the highest r(2) and the lowest variability. Several indices also correlated strongly with monthly light levels, measured from May - September. Based on the finding that indices that accounted for direct beam contribution gave the best outcomes, we suggest that canopy conditions (degree of heterogeneity), stand orientation and gap sizes should be considered in selecting an instantaneous light index for studies in high latitude forests.


英文关键词Light transmittance LAI-2000 Plant Canopy Analyzer Hemispherical photography Strip shelterwood
领域气候变化
收录类别SCI-E
WOS记录号WOS:000472690100013
WOS关键词PHOTON FLUX-DENSITY ; SOLAR-RADIATION ; UNDERSTORY LIGHT ; EFFICIENT METHOD ; CANOPY ; AVAILABILITY ; ENVIRONMENT ; TEMPERATE ; SURVIVAL ; HEMLOCK
WOS类目Forestry
WOS研究方向Forestry
引用统计
文献类型期刊论文
条目标识符http://119.78.100.173/C666/handle/2XK7JSWQ/185646
专题气候变化
作者单位Univ Alberta, Renewable Resources, 751 Gen Serv Bldg, Edmonton, AB T6G 2H1, Canada
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Hossain, Kazi Liaquat,Comeau, Philip G.. Characterizing light across a strip shelterwood in a mixed conifer forest[J]. FOREST ECOLOGY AND MANAGEMENT,2019,445:134-145.
APA Hossain, Kazi Liaquat,&Comeau, Philip G..(2019).Characterizing light across a strip shelterwood in a mixed conifer forest.FOREST ECOLOGY AND MANAGEMENT,445,134-145.
MLA Hossain, Kazi Liaquat,et al."Characterizing light across a strip shelterwood in a mixed conifer forest".FOREST ECOLOGY AND MANAGEMENT 445(2019):134-145.
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