Porównanie wzrostu i produkcyjności jodły olbrzymiej, świerka pospolitego i modrzewia europejskiego w Nadleśnictwie Milicz

Autorzy

• Daniel J. Chmura Instytut Dendrologii Polskiej Akademii Nauk
  ul. Parkowa 5, 62-035 Kórnik,
  e-mail: djchmura@man.poznan.pl

Abstrakt

Anthropogenic climate change – both ongoing and projected – is likely to lead to global warming and increased disturbance in forest ecosystems, resulting in changes in species distributions and the composition and structure of forest stands. Sustainable forest management aims to maintain and support the full range of ecosystem services. Under changing environmental conditions, ensuring that forests retain the capacity to provide most ecosystem services at current or similar levels will require not only active measures by foresters, but also changes to existing approaches to managing forest ecosystems. Such changes may include the use of introduced non-native species with proven silvicultural suitability in forestry practice.
Grand fir (Abies grandis (Douglas ex D.Don) Lindl.), a North American conifer, has a long history of introduction into western Europe, dating back to the 19th and early 20th centuries. However, research sites with this species in Poland are much scarcer, and organized series of provenance trials were established only after the IUFRO-coordinated seed collections of the 1970s. In addition to determining the extent of inter-population trait variation, it is crucial to understand the silvicultural characteristics of the introduced species. The experiment described in this study aimed to compare, under uniform environmental conditions, the growth traits and productivity of two provenances of grand fir (12046 from Vancouver Island, and 12050 from the Washington Cascades) with those of native, highly productive coniferous species: Norway spruce (Picea abies (L.) H. Karst) and European larch (Larix decidua Mill.).
The research site was established in spring 1981 in the Milicz Forest District in southwestern Poland. The experiment was designed as 10 randomized complete blocks, with 120-tree-plots planted at a density of 2,500 trees ha-1. Measurements were taken after the end of the 2019 growing season, when the trees were 45 years old (grand fir), 41 years old (spruce), and 40 years old (larch). Measurements included diameter at breast height (DBH) of all living trees and tree heights (30% measured directly, with the remaining heights estimated using Näslund’s formula). Individual tree volumes (m3) were calculated and summed to obtain area-based productivity (m3 ha-1).
Statistically significant differences were found between the tested objects for all traits (Table 1, Figure 1). The two compared provenances of grand fir formed a statistically homogeneous group, exhibiting the highest values for the traits studied. The spruce in the experiment showed the lowest values for all traits, except for stand density (Figure 1). Average stand productivity was 784 ± 165 m3 ha-1 (mean ± SD) for grand fir and was 47% higher than for larch, and 84% higher than for spruce. Larch exhibited average tree heights comparable to grand fir (Figure 1) and a DBH that, although slightly lower, did not differ significantly from that of provenance 12046; however, it showed significantly lower stand volume and density (Figure 1).
The results confirm that grand fir can be a valuable species for cultivation in Poland. When introduced to suitable sites, it can successfully replace Norway spruce and enhance productivity and stability in mixed forest stands. With due caution, the promising results of this study also indicate that appropriate seed source selection is crucial for the adaptive potential of grand fir in novel conditions; however, they do not yet allow specific practical recommendations to be formulated. The limitations of the current study and the limited experimental data available in our country necessitate testing the potential of grand fir in silvicultural practice across a wider range of site conditions. Seed for this purpose should be sampled from populations that have performed well on existing sites, not only experimental ones, but also those located outside Poland.

Słowa kluczowe

• Abies grandis
• zmienność
• gatunki obce
• introdukcja
• alien species
• introduction
• Larix decidua
• variability
• Picea abies
• adaptation
• adaptacja