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ŠUMARSKI LIST 1-2/2022 str. 53     <-- 53 -->        PDF

Phytotoxicity of clopyralid at high rates on seed germination of mediterranean pines
Fitotoksiènost klopiralida vezano uz klijanje sjemena mediteranskih borova
Oguzhan Bakan, Derya Eºen, Bilal Çetin
Summary
Black pine (Pinus nigra J. F. Arnold), maritime pine (P. pinaster Aiton), Scots pine (P. sylvestris L.), and Turkish red pine (TRP, P. brutia Ten.) are ecologically and economically important conifers of the Mediterranean Basin, and in particular for Turkish forestry. They are commonly used for the regeneration and restoration of degraded ecosystems in Turkey. Weeds compete with tree seedlings for vital site elements such as soil moisture and nutrients and solar radiation, substantially reducing tree establishment and growth. Herbicides can offer the practitioner efficient and cost-effective weed control compared to other methods. Rapid herbicide seed screening allows testing of crop-safe herbicides and application rates at much lower costs in a very short time-frame when compared to lengthy field trials. Clopyralid is a systemic herbicide used to rid pine seedlings of competing vegetation. The present study examined the effect of clopyralid phytotoxicity on these pine species using a rapid herbicide seed screening test in order to compare different application rates on seed germination and to identify crop-safe rates. Clopyralid was not phytotoxic to any of the pine species at low rates (i.e., <2%, v:v); however, pine sensitivity to the herbicide increased with increasing rates, especially for rates higher than 3%. Moreover, at high rates, clopyralid reduced the germination speed. This herbicide can be used at low rates for degraded areas and nursery sites in which sowing is used as the main regeneration or restoration method. Field confirmation of the obtained results is also recommended.
Key words: Forestry, forest nursery, herbicide sensitivity, Pinus, seed screening, weed control
INTRODUCTION
UVOD
Pines make up a significant share (47%) of Turkish forests (22.7 million ha) (OGM 2019). Turkish red pine (Pinus brutia Ten.), black pine (P. nigra Arnold), and Scots pine (P. sylvestris L.) are important natural Turkish forest pine species, with distributions of 5.7, 4.4, and 1.5 million ha, respectively (OGM, 2019). Maritime pine (P. pinaster Aiton) in Turkey is distributed over almost 58,000 ha, mostly in plantations (Güner et al. 2019). These pines benefit the society greatly with their significant economic (i.e., wood and, specifically for Turkish red pine, honey production) and ecological (i.e., biodiversity, erosion control, and land restoration) contributions and are widely used for natural regeneration and afforestation by the Turkish General Directorate of Forestry (Genç 2012; Boydak and Çalıºkan 2014; Dağlar et. al. 2016; Bakan et al. 2018; Bakan and Eºen 2018; Cap and Eºen 2018; Türedi et al. 2018; Bakan 2019; Güner et al. 2019). Most of these pines are distributed on degraded land that is under a high level of environmental