Browsing by Subject "euroopanpähkinäpensas"

European hazelnut (Corylus avellana L.) is native to Europe also in Southern Finland. Commercial varieties of it are used in hazelnut production. There are many pests like squirrels which are also interested of hazelnuts, and they are usually collecting and hoarding the hazelnuts in the early stage of ripening before nuts are fully mature. In this study the aim was to find out when is the earliest moment to harvest the yield from the trees and ripe them successfully postharvest. The study was done in Helsinki, Finland where there were three different sampling sites. Sampling started when the hazelnuts were still fully green and raw. Sampling continued until there was none of hazelnuts left in the trees or they were fully mature. One sample contained about ten nuts and three samples were taken from each sampling site at each sampling date. After hazelnuts were collected, they were placed for post-harvest ripening to the growth chambre. The quality, stage of development and convenient harvest of time of hazelnuts were evaluated based on physical properties measurements of hazelnuts before and after post-harvest ripening. In addition, control samples were taken of the nuts that ripened natural way in the trees. There was done comparison of samples to the control sample for success of post-harvest ripening. The successful post-harvest ripening was founded earliest in the hazelnuts which would have started ripening process in the tree naturally in the moment of harvest. Earliest moment to harvest hazelnuts is when the kernels have reached their final size and the color of the nutshell begins to change from green to brown. But it is challenging to determine one harvest time for premature harvest because hazelnuts grow and ripe various times in the same tree in a long period. The further it is possible to postpone the harvest, the more certain it is to succeed in post-harvest ripening most of the nuts.