Comparison of four methods for estimating relative solar radiation in managed and old-growth silver fir-beech forest

Dušan Roženbergar (Author), Uroš Kolar (Author), Matjaž Čater (Author), Jurij Diaci (Author)

Abstract

Methods based on the principle of hemispherical canopy projection, including hemispherical photography (digital andfilm), sensors like LAI 2000 (zenith cutoff anle 74,1°) andstable horizontoscope, represent less accurate, yet significantly less expensive andtime-consuming techniques for radiation measurements comparedto long-term measurement with a network of photosynthetically active radiation (PAR) sensors. With measurements taken at a single point in time they can provide reliable estimates of relative diffuse anddirect solar radiation andcan also be usedto estimate the light climate in different times of the year. The four above mentioned methods for solar radiation estimation were applied at the same points in gaps and under adjacent canopies in unevenaged, mixed Dinaric fir-beech and pure beech montane forests. Locations covereda range of radiation andstandstructure conditions. Data analyses showedgoodreliability of all four methods over the whole range (2–80%) of radiation conditions. The most comparable results come from LAI 2000 andfilm hemispherical photography (all R > 0.90). Digital hemispherical photography is an accurate andreliable (R = 0.89) replacement for film hemispherical photography, but the higher values estimatedfor direct radiation should be taken into account. Compared to the other three methods, the stable horizontoscope gives less accurate results, especially under canopies with poorly defined gaps. Our study showed that all four methods tested are suitable for estimating the solar radiation climate in gaps and stands with heterogeneous vertical structures, andhave potential value as a tool in decision making when practicing silviculture.

Keywords

male gozdne posesti;svetlobne razmere;gojenje gozdov;

Data

Language:	English
Year of publishing:	2011
Typology:	1.01 - Original Scientific Article
Organization:	UL BF - Biotechnical Faculty
Publisher:	Bogucki Wydawnictwo Naukowe
UDC:	630*22
COBISS:	3175846
ISSN:	1641-1307
Views:	1009
Downloads:	23
Average score:	0 (0 votes)
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Other data

Secondary language:	Unknown
File type:	application/pdf
Type (COBISS):	Scientific work
Pages:	str. 73-82
Volume:	ǂVol. ǂ65
Issue:	ǂno. ǂ1
Chronology:	2011
ID:	8752116