Naslov
A contribution to the definiton of batch size -control units and minimum average sample for analysis of the seeds of some forest tree species in Croatia

Autori
Gradečki, Marija ; Poštenjak, Karmelo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
"Towards the future in seed production, evaluation and improvement" ISTA SeedSympsioum, 2004, Abstracts / - Basserdorf : The International Seed Testing Association, 2004, 97-97

Skup
27th ISTA Congress Seed Symposium

Mjesto i datum
Budimpešta, Mađarska, 17.05.2004. - 19.05.2004

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
seed unit; selected seed stand; seed production; seedlot

Sažetak
In Croatia forest seed husbandry has a long tradition which is interwoven in written documents and legislation and the conditions inherited – raised pine cultures several centuries old. The area of Croatia is extremely diverse, and although it only covers 0, 59 % of the area of Europe, 4 500 (36, 93 %) of the plant species in Europe (totalling 12 184) can be found here. However, today we are witnessing the drastic consequences of disruption of forest ecosystems, which can be seen in forest seed husbandry, by the increasing need for greater amounts of seeds which are necessary for supplementing natural regeneration. In order to satisfy as far as possible the demand for seeds and at the same time to protect the disrupted forest ecosystems rational management of seeds is necessary, during which it is particularly important to preserve the biodiversity of particular species. The law in Croatia differentiates selected seed from seed orchards and normal seed from selected seed stands. Selected seed stands are phenotypically the best parts of the forest for certain species which are separated within a certain seed unit in order to satisfy the need for seed of certain species in the area of particular seed unit. In Croatia there are three districts with 79 ecological-managerial forest types (EMFT), which are a good guideline for definition of seed units and consequently their area (the average area ranges from 250 to 69 250 ha). The size of the area of selected seed stands in particular seed units depends on several parameters, among which the following are important: mixture ratio (according to the number of trees) of seed species, relation of normal and actual number of trees in seed stand by ha, average age stands, average degree of crown defoliation, periodic full seed crop, and success of natural regeneration (average optimal area in a certain seed unit ranges from 0, 003% to 20, 05 of the area of the seed unit, i. e. 5 to 210 ha, and the average annual production of forest seed in a certain seed unit ranges from 13, 75 kg for Spruce to 10 086 kg for Peduncle Oak). The seedlot should be collected from the area of one seed unit, i. e. there may be more, but on the whole it should be a guarantee of protection of the biodiversity and preservation of the particular ecotype of individual tree species. Croatian legislation and standards in forest seed husbandry, with regard to seedlots and minimal working samples, differ significantly from ISTA standards. This difference is conditioned by several specific parameters which have determined these differences (differences are from 0 to 2 000%) and which function as protection of the biodiversity of a certain species and rational use of seed.

Izvorni jezik
Engleski

Znanstvena područja
Šumarstvo

POVEZANOST RADA