DIGITALNA ARHIVA UMARSKOG LISTA
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|UMARSKI LIST 1-2/2015 str. 57 <-- 57 --> PDF|
is possible based on altitudinal location of the planting site, without neglecting the effect of population. Very close values to the average of the four experiments (27.1%) and also of those resulted in the ONR trials (22.3%) were recorded already in an earlier study in Romania (Stănescu & Șofletea 1992). LP values between 18% and 29% were reported in Finland and Norway (Skrøppa et al. 1999; Miina 2000; Mäkinen et al. 2002; Steffenrem et al. 2007; Zubizarreta Gerendiain et al. 2007, 2008).
The average CWD value in the all four trials (0.350 g / cm3) is also similar to that previously obtained in Romania (Stănescu & Șofletea 1992) and also confirm the values recorded in trials carried out in other geographical regions regarding decreasing of wood density with increasing RI values (Blouin et al. 1994; Bouriaud et al. 2005; Jyske et al. 2008; Zubizarreta Gerendiain et al. 2009), which has implications for both the mechanical and physical properties of the wood. However, the literature data show and differences from our study. Thus, the studies performed in Northern Europe have produced a considerable variety of results, with 8% lower values recorded than those presented here (Hylen 1997; Skrøppa et al. 1999), as well as 17% greater in a full-sib test involving 30-year old trees (Steffenrem et al. 2007). In summer, the monthly aridity values were seen to have an inverse and highly intense influence (r = -0.91 − -0.94) concerning wood density. The same result was recorded in Germany (Van der Maaten-Theunissen et al. 2013).
The ranking of mean values in the four trials concerning the bioaccumulation (TH, AV/T and RI) reveals an asymmetry of response of the two tests installed outside the natural range. Differences between Avrig and Câmpina are the result of more restrictive climatic conditions in the last location. On the other hand, the populations that have high values for LP, have had, in general, high values of the radial growth in the second part of the growing season.
A basic idea of our research was to identify populations able to be adapted in various environmental conditions, to combine the two concepts relating to the transfer of seeds: maximizing growth and minimizing risks (Hamman et al. 2011). To this end, the first step was to identify the populations that have had very good results in each of the four test sites, to be recommended for installing of stands in environmental conditions similar to Avrig (1), Câmpina (2), Brețcu (3) and Gurghiu (4). As a result, according to this criterion the following populations were selected:
(1): 5-Moldovița, 32-Câmpeni, 15-Comandău and 28-Turda;
(2): 19-Azuga and 15-Comandău;
(3): 4-Marginea, 32-Câmpeni, 28-Turda and 15-Comandău;
(4): 28-Turda, 12-Gurghiu, 4-Marginea and 5-Moldovița.
At the same time, based on the previous selection, some populations have shown a relatively wide capacity to adapt to different environmental conditions, being among those identified as valuable in two or even three of the four test sites. The environmental conditions in the Câmpina test have restricted the populations recommended for installation of stands under similar conditions to only two.
No significant differences between the mean values of all the 33 tested populations resulted between the two INR trials. In contrast, the response of populations in the two ONR tests was asymmetric, especially for TH, RI and AV/T, due to different environmental conditions of the test sites. In our opinion, the TPFV-IX value registered in Avrig trial (25.3) does not interfere negatively in the growth, while the one registered in Campina trial (21.7) should be considered as a minimum for that area or in equivalent situations in the Romanian Carpathians.
The significant differences between seed stands for all studied traits suggest that, in breeding programs, artificial selection at the seed stand level could be possible. The significant seed stand Ś environment interaction demonstrates that the same seed stand reacts differently to different environmental conditions and the best adaptive populations may be used only in similar ecological conditions to those of the test site.
In all experiments, the populations originating from Eastern and Western Carpathians presented sustained growth, both in height and radial increment. Local provenances were mostly ranked in the first half and the IUFRO standard provenance (5-Moldovița) obtained better results in trials located ONR. For the ensemble of all experiments, giving equal importance to all of the analyzed growing traits, the highest scores were obtained by the populations: 5-Moldovița, 4-Marginea, 15-Comandău, 28-Turda, 32-Câmpeni and 12-Gurghiu. Using seeds from these populations, only in similar environmental conditions, will favor to obtain an important genetic gain, and therefore an economically benefit. Regarding the biomass with high proportion of latewood, the populations originating in the Eastern Carpathians were found to be most suitable, both for INR and ONR stands. A good example of this is that of the 5-Moldovița population. On the other hand, the traits analyzed showed low intensity correlations between their values in the four trials and geographical location (altitude, latitude, longitude and ecophysiological latitude) of the tested seed sources.
This study is dedicated to dr. doc. Valeriu Enescu, the author of this grandiose experiment, and also to dr. Gheorghe