Original scientific paper

Provenance studies of Douglas fir in the locality of »Kontija« (Istria)

SANJA PERIĆ ; Croatian Forest Research Institute, Cvjetno naselje 41, 10450 Jastrebarsko, Croatia
ANA MARIJA JAZBEC ; Faculty of Forestry, University of Zagreb, Svetošimunska 25, 10 000 Zagreb, Croatia
MARTINA TIJARDOVIĆ ; Croatian Forest Research Institute, Cvjetno naselje 41, 10450 Jastrebarsko, Croatia
JOSIP MARGALETIĆ ; Faculty of Forestry, University of Zagreb, Svetošimunska 25, 10 000 Zagreb, Croatia
MLADEN IVANKOVIĆ ; Croatian Forest Research Institute, Cvjetno naselje 41, 10450 Jastrebarsko, Croatia
IVAN PILAŠ ; Croatian Forest Research Institute, Cvjetno naselje 41, 10450 Jastrebarsko, Croatia
JASNICA MEDAK ; Croatian Forest Research Institute, Cvjetno naselje 41, 10450 Jastrebarsko, Croatia

Abstract

Background and Purpose: One of the most productive and economically important tree species in the USA is Douglas fir (Pseudotsuga menziesii (Mirb.)). Because of its broad natural range, in the horizontal as well as in the vertical sense (from California to British Columbia and from sea level up to an altitude of 1500 m), a variety of its provenances has been differentiated. European foresters, thanks to their insight into Douglas fir productivity
and usage in its native country, initiated at the beginning of the
19th century the establishment of provenance tests and research on the success of individual provenances outside their natural distribution. In the framework of the IUFRO programme, numerous European countries, among them Croatia, started provenance tests with the aim of researching the adaptability of this valuable species. In several bioclimatic localities in Croatia (Istria, North-West, Central and Eastern Croatia) different provenances have shown good success. The importance of Douglas fir is becoming
increasingly evident in conditions of a changing climate and when the possible application of Douglas fir in the establishment of forest cultures is taken into consideration. Douglas fir can be established on uncovered forest and non-forest areas for wood supply or as a potential renewable energy source. The exploitation of wood and biomass from forest cultures enables the conservation
of biodiversity and the survival of our natural forest ecosystems.

Material and Methods: This paper is based on research conducted on a Douglas fir provenance trial in the locality of »Kontija« in Istria. The trial, in which ten Douglas fir provenances were included, started in 1969. On the trial plots, dendrometric parameters such as DBH and tree heights were measured on the basis of which wood volume was calculated. Descriptive statistics were made for all analysed variables (DBH, h, V). The differences between the provenances for the investigated variables were tested with an analysis of variance (ANOVA). Provenances which differ between themselves
were determined using the Tukey post hoc test. According to data on
the survival rate for all provenances, the average survival rate inside the trial was estimated and tested with a test of proportion to determine which provenances differ statistically from the average survival rate. Using a non-hierarchical (κ-means) cluster analysis, provenances were grouped according to standardised variables (N, DBH, h, V). In the same way, the species’ health condition was determined, as was the resistance of provenances to forest pests.

Results and Conclusion: The average survival rate of all provenances in the trial amounts to 64.8% (ranging from 52% for the provenance PE ALL to 77% for the provenance ELMA). The best height growth was identified in the provenance SHELTON which originates from lower altitudes in Washington while the provenance SHADE COVE from higher areas of Oregon shows lowest growth. High volume is
evidenced in the provenance PE ALL. The results of the analysis of variance (ANOVA) show that there is a statistically significant difference for all analysed variables for the investigated provenances. A κ-means cluster analysis grouped ten Douglas fir provenances in four clusters. In cluster 1, only the provenance SHADY COVE is included with a high number of trees with lower heights and smaller DBH and volume. Provenances from cluster 3 (PE ALL and YELM) have, in a small number of trees, higher DBH and volume. The rest of the provenances are grouped in two clusters (cluster 2 and cluster 4) with similar values but with the difference
that the provenances SHELTON, CORVALIS, ELMA and HVIDILDE (cluster 2) have higher values than average for the analysed parameters, while the provenances [IPKA, BUZET and CASTLE ROCK (cluster 4) have lower than average values. In general, all the provenances in the trial are vital and show a good health condition without any determined pests.

Keywords

Douglas fir; provenances; survival; DBH; height; volume

Hrčak ID:

47944

URI

https://hrcak.srce.hr/47944

Publication date:

31.12.2009.

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