Evaluating a proposed quantitative method to record plants phenological stages in comparison with other approaches for Olive species (Olea europaea L.)

1. A. Shahbazi

2. S.H. Matinkhah

2. H. Bashari

1*- Corresponding author, M.Sc. student of range management, Faculty of Natural Resources, Isfahan University of technology, Iran.

2- Assistant Prof., Faculty of Natural Resources, Isfahan University of technology, Iran.

Received: 22.02.2011 Accepted: 27.05.2011

Abstract

Phenology describes the phenomena that happen periodically in the life of living creatures. The

differences between the appearance of this phenomena result in phenology behavioral patterns. The

phonological studies are important for many applications such as typology in silviculture, afforestation,

natural regeneration, livestock grazing planning, and species selection for park designing and decorating.

Detecting changes in phenology of plant species receives more attention due to undergoing current

climate changes studies. According to the literature, there are two main methods for registering

phonological events including descriptive and remote sensing approaches. In this paper the advantages

and disadvantages of these methods are discussed, and a new quantitative method based on the leaves and

fruits colours changes is proposed. A case study on Olea europaea L. was used to describe the

quantitative methods. In the proposed quantitative method, imaging of the plant parts (Leaf and fruit) was

done in every other week intervals. Using smudge tools in Photoshop software, the colour of each part of

the plant were uniformed and their RGB digits were assessed. Then the percentage of each colour

channels was determined and their diagrams of changes during the time were analyzed. This method

results in an exact determination of the plant transformation. The studied method analyzes image series of

plant parts to detect color changes; hence, it provides a base to study of phenological changes in a

quantitative manner. By detecting the RGB digital number, it is easy to report the exact color and it

provides a comparable bases. Descriptive method is the most common way for phenology studies. In this

method, viewpoints of the observer extremely affect the result and may cause misreporting during an

observation or recording. The remote sensing method is more appropriate to be used in large scales

environmental condition monitoring programs and also for vegetation responses to universal continental

changes. This method is not suitable for small scales studies. The RGB based reporting system can be

useful in other field of studies such as pedology, geology, horticulture and so on.

Key words: phenology, descriptive recording, quantitative recording, RGB.

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Winter

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2012

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